Manufacturing Single-Use Products: 8 Things To Keep In Mind

A single-use product is meant to be used or applied once and then discarded. The term “single-use” is sometimes intended to mean “disposable,” though this isn’t always the case. A bullet and a booster rocket, for example, are both single-use products—but most people wouldn’t refer to them as a disposable. But many medical products, like tongue depressors and test vials, are perfect examples of single-use, disposable products. For the majority of single-use products, the primary goal of the manufacturing process is to keep the cost low and the volume high, all while maintaining quality standards. With that in mind, here are eight things you’ll need during the product design and manufacturing processes:

1. Inexpensive Materials
It’s important to find materials that are inexpensive yet still meet your industry-specific needs or standards. For example, if you’re manufacturing a mouth swab or a single-use dental pick, the material will need to meet FDA standards while staying beneath a certain price point. Your injection molding partner should be able to offer suggestions on types of material that fit the bill.

2. Fast Cycle Times
The quicker a machine goes through a cycle, the more parts you can create, which drives part cost down. If you’re evaluating partners to help create your single-use plastic product, be sure to find out the average length of their cycle times.

3. Automation
The more automated elements the injection molding process has—for example, robots that remove parts from the mold or put them into boxes for shipping—the more you can drive part costs down. The only exception to this is if you go overseas, where human handling of parts is significantly less expensive than it is in the U.S. This article will walk through the benefits and considerations of injection molding in China vs. the U.S.

4. Quality Assurance
If a problem in the production cycle goes unchecked, you may be recalling millions of parts—so you need a very robust quality assurance system around your manufacturing. For instance, Micron uses robots in approximately 70% of our machines and camera-based vision systems that check the quality of every single part. This helps ensure that only good parts go through the molding process.

5. Inexpensive Packaging
A common problem for many companies that manufacture single-use applications is the high cost of packaging—it could be more expensive than the product itself! This may be unavoidable for extremely inexpensive single-use products that require specific packaging (like a syringe), but you’ll want to explore your packaging options to keep costs as low as possible.

7. High Capacity Mold
If you’re able to run your parts using a 96-cavity tool, you’ll see more cost savings than if you run your part on a 16-cavity tool. This is primarily because a high-cavity tool allows you to get more pieces molded per hour, which means you’ll see lower charges passed along from the molder for things like electricity use, machine depreciation, maintenance, and overhead.

8. Economical Production Processes
To avoid slowing down cycle time, you’ll want to have an effective process design for gating and part ejection. Additionally, it’s important to ensure the hot manifold that delivers the plastic material to the mold cavity does so without any waste. These processes will help accommodate inexpensive single-use pricing.

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Edited by Leafly Mould Provides Injection Mold, Plastic Mold, Injection Molding, Die Casting Mold, Stamping Mold

11 Questions To Ask Before Picking A Plastic Mold Manufacturing Partner

When you’re getting ready to begin the injection molding process, the first choice you make—and one of the most crucial decisions—is which plastic mold manufacturing partner you’ll select. The partner you choose should, of course, deliver on all your mold requirements—but they should also prototype your part, help you with part design adjustments, warranty their work, and much more. And most importantly, the right partner will ensure you don’t end up with a useless mold that doesn’t produce quality parts—or, as we like to call a faulty mold—a boat anchor.

By asking potential plastic mold manufacturing partners these 11 questions, you’ll all but eliminate any doubt that they will be a great partner for you.


1. Can you build a tool that will match my annual volume requirement?

Molds are most often constructed in one of three classes: Class 101, 102, or 103. Each class varies in the material it uses, how (or whether) it’s hardened, the maintenance it requires, and the cycles it can tolerate before it requires adjustments. A class 101 mold, for example, is most often built from hardened stainless steel—but if you’re only going to run 50,000 parts a year, a class 102 tool built from a different, less expensive material may be more appropriate for your part. A good plastic mold manufacturing partner will walk you through the benefits and considerations of each class of mold, and guide you to the class that is ideal for your situation.

2. Can we get a warranty on the tool?

Be advised: Many plastic mold manufacturing companies do not offer warranties unless you specifically request one. Even if they do, study the ins and outs of the warranty and precisely what it covers before signing on the dotted line.

At Micron, we typically warranty a class 101 tool, for example, for up to one million cycles without any cost to the customer. This means we’d cover any and all maintenance and/or expense on the mold up to that point. So if you have a 64-cavity tool from Micron, this warranty would last you through 64 million parts.

3. Do you do mold-making in house or are they made overseas?

Some plastic mold manufacturers simply broker a mold deal between your company and an overseas mold maker. There can be major differences between a tool created in China vs.the U.S.—check out this article for a full rundown.

4. Do you have the ability to rapid prototype or 3D print parts to reveal potential flaws in the design?

The creation of your tool is one of the most expensive parts of the injection molding process, so doing it wrong is not an option. You can make adjustments in the prototyping stage until the mold is correct—but otherwise, changes are expensive.

Here at Micron, once we have a tool order, we print a prototype of the part for free. Giving customers a chance to see alternate ideas, or flaws in the design, helps us both in making a better part.

5. Can you build a mold for the size part I need?

Not every molding manufacturer is equipped to mold extremely large or extremely small plastic parts. If you’re building an injection molded car bumper, for example, some plastic mold manufacturers won’t have the capability to mold something of that magnitude. If the company asserts that they can build an unusual-size injection mold, ask for examples of similar parts they’ve previously created .

6. What materials will the finished mold be able to handle?

If your plastic part will be molded using highly abrasive plastic material—or a type of plastic material that is injected at very high temperatures—you’ll want to be certain the company you’re considering can build a mold that will handle these requirements.

7. How do you achieve the right mold tolerances?

Specific mold tolerances may be critical for your plastic part, and understanding how the molder achieves and validates those tolerances is useful information to have. Additionally, if any part of your mold needs specialized measurements—say, an one-dimensional automotive part that needs to be extremely precise so there’s no variation part-to-part—be sure to let them know ahead of time.

8. What is your process for high-cavitation molding?

If you need a high-cavity mold, find out how your potential mold manufacturing partner manages the mold building process. For example, to ensure that plastic evenly distributes in your high-cavitation mold, your partner should include a high-quality hot manifold (used to inject plastic into the mold) to assist with this distribution process.

9. Can you validate that the mold will work?

To validate what they build, your mold manufacturing partner will need to sample the tool to ensure it produces quality parts. If you’re getting your mold separate from your injection molding manufacturer, be sure that the tool is sampled at the same cycle and cooling time you’ll need when you move to production. For example, if your part requires a 30-second cycle time and the part needs to cool for 15 seconds, but the sample only includes a 2 second cooling stage, the sample parts won’t be an accurate reproduction of what you’ll get during production.

10. What specific molding capabilities can you accommodate?

If you need to fit a small metal bearing inside your plastic part, you likely need a vertical injection mold. If you’re molding a computer mouse or a toothbrush with a hard plastic material and soft plastic grip, you’ll need either two-shot or overmolding. Be certain your mold manufacturer can create a mold for the characteristics you require.

11. How quickly can you turn out a mold?

Everyone wants something fast, cheap, and high quality—but we typically tell our customers they can can have two out of three. For example, if you want a high-quality mold created fast, it’ll cost you. And some mold manufacturers specialize in rapid tooling, but these molds are typically fast and cheap, not high quality. At any rate, be sure the mold manufacturing company you select can turn out a mold in the timeline you require. Here at Micron, if you need a tool built more quickly than usual, we can often partner with outside resources to save time. Or, if you need a mold built for less than our mold shop can create it for, we can partner with outside tool builders that will work under our quality and engineering guidelines.

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Edited by Leafly Mould Provides Injection Mold, Plastic Mold, Injection Molding, Die Casting Mold, Stamping Mold

plastic injection molding vs. plastic machining: how to decide

Plastic molding, also known as “injection molding,” and machining plastic components are very different processes. But how are they different? And which process is right for your custom plastic fasteners?
First, let’s define what they are. During the injection molding process, plastic pellets—rigid when cool but viscous at higher temperatures—are heated to their melting point and then injected into a cavity. As they cool, they harden in that cavity’s shape.
Plastic machining, however, is the process of whittling plastic down from a larger shape—like shaving slivers from a branch with a knife.
So how do they stack up?
Plastic machining can cost as much as 25 times plastic molding. Yet, sometimes it is cheaper to machine plastic parts. How can this be?
The reason is the cost of creating the initial mold in which the parts are manufactured. Its price ranges anywhere from $5,000 to $200,000, depending on the complexity. Molding plastic may be a less expensive process, but if you only need a few parts—and you spend $10,000 to make the initial mold to create them—you spend more than if you had just machined those parts.
And keep this in mind: once you create a plastic mold, you cannot easily change it. Wholesale changes cannot be made.
Typically, when you need a few hundred or fewer parts, machining is the answer. At these levels, the cost of creating the mold almost always outweighs the expense of machining. When you’re dealing with larger orders, molding is likely the answer.
There are, however, a few exceptions.
As a process, plastic machining is more precise than plastic molding. When molding, you can expect results within .005 inches of specifications. When machining, you can bank on results within .001 inches of specifications. This level of precision is necessary for some industries and projects.
Another exception arises if your parts require uniform surface smoothness. The process of transferring plastic into a mold leaves behind surface imperfections on the finished product. During injection molding, plastic flows through runners and is introduced into a cavity through a gate which meters the flow as it fills the part.
As a result, when the finished parts are removed from the mold, the gates leave a slight cosmetic imperfection. In addition, most molds use knockout pins to push the part out of the cavity after it cools. These knockout pins leave a slight depression in the place where they contact the part.
If your plastic parts must be blemish free, strongly consider plastic machining.
Also, another benefit of plastic machining is its faster turnaround time, which may be important if your project is behind schedule.
So, if you or your company is choosing between plastic molding and machining, we hope you’ll keep the following in mind:
If you require a couple hundred or fewer parts, the best choice is very likely plastic machining.
If you are considering molding, make sure to weigh the cost of creating the initial mold against the higher expense of machining.
Give machining serious thought if (1) your project requires a high degree of precision and/or (2) your parts must have uniform surfaces smoothness.
NB: Keep in mind that not all plastic materials can be injection molded!

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Plastic mould is an important method

plastic mould is an important method, which is primarily applicable to thermoplastic plastic mould; Molding can be a complex shape of precision plastic parts.

The necessity to cool or chill plastics processing machinery is mainly related to thermoplastic materials. At room temperature thermoplastic materials (polypropylene, nylon and PET etc) are solid. In order to shape them they must first be heated to their molten temperature. When molten, they can then be manipulated (injection molded, extruded etc) to a new shape. When for med to their new shape they must then be cooled to solidify them. Considerable amounts of heat energy have to be extracted from the material, the tooling and the machinery that is doing the forming.

plastic mould produce components by using techniques such as thermoplastic or injection mould, blow molding, rotational molding, thermoforming, structural foam molding, compression molding, and resin transfer molding (RTM). They also provide services such as mold prototyping, low-volume production, high-volume production, insert molding, micro-molding, large-part molding, two-shot injection mould, reel-to-reel molding, machining, hot stamping, assembly, bonding, packaging and shipping.

There are many different types of plastic mould services. Examples include blow molding services, compression molding services, dip molding services, film injection mould services (FIM), and gas assist molding services. plastic mould services may also perform reaction injection mould (RIM), resin transfer molding (RTM), rotational molding, structural foam molding, thermoplastic injection mould, thermoset casting, thermoset injection mould, and thermoforming. Vacuum assist resin transfer molding (VARTM), vacuum bag molding, and vacuum forming services are also available. In terms of material capabilities, plastic mouldservices address considerations such as impact strength, high and low temperature characteristics, warpage, and resistance to ultraviolet (UV) light. Commodity grade resins are more widely used than other graded resins and include polyethylene, polypropylene, polystyrene and polyvinyl chloride (PVC). Engineering grade resins are more difficult to process than other graded resins, but have characteristics that make them desirable for specialized use. Widely used engineering grade thermoplastics include acetal, acrylonitrile butadiene styrene (ABS), nylon, noryl and polycarbonate.

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Plastic molding and the main processing methods

Plastic molding process is a construction technology, involving the contents of the plastic into the various processes of plastic products. Central Standing Committee in the process of change one or more of the following circumstances occur, such as polymer rheology and the physical and chemical properties change. Many methods of plastic molding

Plastic molding method

Pressing: Compression molded laminated low-pressure molding cold molding transfer molding casting centrifugal casting embedded static casting spin casting plastic rotational casting slush cast sculpture

Extrusion molding hand lay

Extrusion molding fiber pull-winding

Exhaust injection molding of mobile non-runner injection molding injection moldinginjection molding thermoset reaction injection molding injection molding calendering

Blow Molding Injection Blow Molding Extrusion Blow Molding Stretch Blow film coating melt stream of spray deposited by flame spraying, plasma spraying electrostatic spraying

Physical foaming foaming foaming molding machine foam molding Thermoforming second solid phase forming biaxial tensile

1. Compression molding. Also known as compression molding molding is molding with pressure in the closed mold cavity (generally yet to heating) of the molding method. Typically, compression molding applied to thermosetting plastics, such as phenolic, amino plastic, unsaturated polyester plastics.

Compression molded by the pre-press, preheating and molding the composition of three processes:

Preloading to improve product quality and increase efficiency, molding, molding the powder or fibrous pre-pressure to shape the operation.

Preheat molding processing to improve performance and shorten the molding cycle, the molding compound before the first heat in the molding operation.

Molded in the mold to add the required amount of plastic, closed mold, exhaust, temperature and pressure in the molding to maintain a period of time, then stripping clean mold operation.

Compression molding press with the main equipment, and modeling. Press with the most is self-contained hydraulic machine, tonnage from several tons to several hundred tonnes. Are under pressure type press and the pressure type press. The mold for compression molding as to suppress mold is divided into three categories; flash-type mold, semi-flash-type mold is not overflow-type mold.

The main advantages of compression molding can be molded products and a larger plane to mass production, the drawback is long production cycle and low efficiency.

2. Laminate molding. With or without adhesive, by heat, pressure to the same or a different combination of two or more layers of materials for the holistic approach.

Laminating machines commonly used laminate molding operation, the dynamic of this press fitted between the plate and fixed plate may be floating multi-layer hot plate.

Laminated reinforced material forming a common cotton cloth, glass cloth, paper, stone and cotton cloth, phenolic resin, epoxy, unsaturated polyester and certain thermoplastic resins.

3. Cold molding. Cold molding is also called cold sintering, and the general compression molding of the difference is in the room temperature compression molding of materials. After stripping the molded product can be re-heating or using chemical reaction to cure. The method is mainly used PTFE molding, also used in some high-temperature plastic (such as polyimide, etc.). General process for the system blank – sintering – the cooling of three steps.

4. Transfer molding. Thermoset transfer molding is a molding method, molding plastic mold when the first heat in the heating chamber to soften, and then pressed into the cavity had been heated Curing. Transfer molding equipment according to different types of forms are: (1) live plate; (2) tank; (3) plunger.

Transfer molding of plastic demand is: does not meet the pre-curing temperature, plastic should have greater mobility, to curing temperature, it should have a faster cure rate. Meet this requirement are phenolic, melamine formaldehyde and epoxy resins.

Transfer molding has the following advantages: (1) edge less waste products, can reduce the amount of post processing; (2)can with a fine or brittle molded insert and perforated products, and can maintain the insert and the correct hole location; (3) product performance uniform, accurate size, high quality; (4) wear a smaller mold. Drawback is: (5) mold manufacturing costs higher than the compression mold; (6) plastic deplete; (7) fiber reinforced plastics produced by fiber orientation and anisotropy; (8) around the plastic around the inserts, sometimes due to fusion products by not strong Er Shi the intensity decreases.

    5. Low pressure molding. Using the molding pressure equal to or less than 1.4 MPa pressure or laminated touch method.

Low pressure molding method for the manufacture of reinforced plastic products. Reinforced materials such as glass fiber, textiles, asbestos, paper, carbon fiber. Most commonly used are thermosetting resins, such as phenolic, epoxy, amino, unsaturated polyester, silicone and other resins.

Low pressure molding, including bags, spray method.

(1) bag molding. With flexible bag (or other flexible diaphragm) received fluid pressure and elastic modulus Er Shi bags between rigid reinforced plastic between the uniform compression and a workpiece, a method. Fluid pressure caused by different methods, generally can be divided into bags of molding pressure, vacuum bag molding and autoclave molding hot.

(2) injection molding. Reinforced plastic molded products, the use of spray gun to short fiber and resin spray while laminated mold and curing methods for the products.

6. Extrusion. Extrusion molding or extrusion, also known as extrusion, it is the extruder by heating, pressure Ershi material to flow through the port state continuous casting method.

Extrusion method is mainly used for molding thermoplastics, thermosetting plastics can also be used for some. Extrusion products are continuous profiles, such as tubes, rods, wire, sheet, film, wire and cable coating layer. In addition, the mixture can be used for plastics, plastics granulation, color, blending and so on.

Extruder from the extrusion device, transmission, and heating and cooling systems and other major components. Extruder with screw-type (single screw and multiple screw) and plunger types. The former is a continuous extrusion process, which is intermittent.

Single screw extruder, including the basic structure of the main transmission device, feeding device, cylinder, screw, die and die and some other.

Auxiliary equipment extruder before the material handling equipment (such as material handling and drying), extrusion material handling equipment (shape, cooling, traction, or roll material cut paper) and the production condition control equipment three categories.

7. Crowded drawing forming. Crowded drawing forming a thermoset fiber reinforced plastic molding methods. Fixed for the production cross section shape, length, unlimited profiles. Molding process is a continuous fiber impregnated with resin glue pulled out by the heating mode, and then through the heating chamber, further solidifying the resin prepared with a one-way continuous high strength reinforced plastic profiles.

Commonly used in extrusion molding of the resin pull unsaturated polyester, epoxy and silicone are three. Unsaturated polyester resin used most.

Squeeze pulling machine is usually arranged by the fiber device, resin tank, pre-forming device, die, and heating devices, traction devices and cutting equipment and other components.

8. Injection molding. Injection molding (injection) is to make the first thermoplastic or thermosetting molding plastics in uniformly heated barrel, then pushing the plunger or screw to move the die cavity in closed molding methods.

Injection molding is suitable for almost all thermoplastics. In recent years, injection molding is also successfully used in forming some of the thermosetting plastic. Injection molding cycle is short (seconds to minutes), the quality of molding products can be several tens of grams to kilograms, can form a complex shape, size precision, with a metal or non-metallic insert molded products. Therefore, the method has strong adaptability and high productivity.

Injection Molding injection machine into plunger injection machine and injection machine screw two major categories, from the injection system, clamping system and the mold has three major components; the molding methods can be divided into:

(1) exhaust injection molding. Exhaust vent type injection molding applications, injection machine, the barrel with the central exhaust port, connected with the vacuum system, when the plastics plastic, plastic vacuum pump can be combined and some water vapor, single, volatile material and air by the exhaust suck out; materials without pre-drying, thereby increasing productivity, improving product quality. Particularly suitable for polycarbonate, nylon, glass, cellulose materials such as molding moisture easily.

(2) injection molding. Injection molding can be used ordinary mobile screw injection machine. Plastics and plastic that is constantly squeeze through a certain temperature, the mold cavity, the cavity filled with plastic, the screw stops turning, through the thrust screw to mold material under pressure to maintain an appropriate time, then cooling setting. Flow injection molding have overcome restrictions on the production of large products, equipment, part quality can exceed the maximum injection volume of injection machine. It features an object is not stored in plasticizing the barrel, but continued to squeeze into the mold, so it is the combination of extrusion and injection method.

(3) of injection molding. Coinjection molding is used with two or more injection units of the injection machine, different species or different color of plastic, simultaneously or successively injected into the mold method. This method can produce a variety of colors and (or) a variety of plastic composite products, representative of a total of two-color injection molding is the injection and multi-color injection.

(4) No runner injection molding. Mold does not set the shunt, but by the injection machine nozzle extension points directly to the molten material to each mold cavity injection moldingmethod. In the injection process, the flow of plastic to maintain melt flow within the state, the ejection time and the products together emerge, so there is no flow workpiece residue. This molding method not only saves raw materials, lower costs, and reduce the process to achieve fully automatic production.

(5) reaction injection molding. Reaction injection molding materials will reflect the principle is measured by the measuring device after the pump into the mixing head, mixed in the mixing head in the collision, and then injected into the closed mold high speed, the fast curing, stripping, removal products. It is suitable for processing polyurethane, epoxy and unsaturated polyester resins, silicone resins, alkyd resins such as some of thermosetting plastics and elastomers. Now mainly used in polyurethane processing.

(6) thermosetting plastic injection molding. Granular or agglomerate thermosetting plastics, in the strict control of temperature of the barrel, the role of the screw, stick plastics into plastic state, in the high injection pressure, the materials into the mold within a certain temperature range, crosslinking. Thermosetting plastic injection molding except for changes in physical state, there are chemical changes. Therefore, compared with thermoplastic injection molding, molding equipment and processing technology in the existence of significant differences. The following table compares the thermoset and thermoplastic injection molding difference.

Thermosetting and thermoplastic injection molding conditions for comparison

Thermoset thermoplastic processing conditions

Barrel temperature, low temperature, plastics, barrel temperature below 95 ��, temperature control, demanding high temperature plastics, barrel temperature above 150 ��, temperature control is not strict

In the barrel in a short time longer

Barrel heating mode liquid medium (water, oil) heating

Mold temperature of 150 1 200 �� 100 �� the following

Injection pressure 100-200MPa 35-140MPa

Injection volume of injection was smaller, front barrel more than a small injection of large amount of material, front barrel more than expected

Thermosetting plastic injection molding is the most widely used Bakelite.

9. Blow molding. Closed by gas pressure in the heat in the mold of parison inflation become hollow products, or possession of non-parison into a tubular film die Inflation a way. The method is mainly used for a variety of packaging containers and the manufacture of tubular membrane. Where melt index of 0.04 to 1.12 is rather good Blow Molding materials such as polyethylene, polyvinyl chloride, polypropylene, polystyrene, thermoplastic polyesters, polycarbonates, polyamides, cellulose acetate and poly acetal resin, of which polyethylene applications most.

(1) injection blow molding. Department of Law with the first plastic injection moldingparison with bottom, then move the parison then blow blow mold made of hollow products.

(2) extrusion blow molding. Line with the extrusion parison with bottom plastic first, then move the parison then blow blow mold made of hollow products.

Injection blow molding and extrusion blow molding of the difference is that different methods of manufacturing blanks, blow molding process is basically the same.

In addition to injection blow molding machines and extrusion equipment, machines, the main blow molding mold. Blow mold usually 2 synthesis, which has coolant channels, a small hole into the surface type of pressurized gas blowpipe.

(3) stretch blow molding. Biaxial oriented stretch blow molding is a stretch blow molding, which is also first-type longitudinal stretching, and then blown with compressed air to transverse tensile expansion. Stretch blow molding products can transparency, impact strength, surface hardness and rigidity is greatly improved for polypropylene, polyethylene terephthalate (PETP) of the blow molding.

Stretch blow molding include: injection stretch blow molding parison orientation, extrusion stretch blow molding parison directional, multi-directional stretch blow molding, compression molding and other directional stretch blow molding.

(4) blown film method. A method of forming thermoplastic films. Line with the extrusion of plastic extruded tube first, and then blown through the air to the tube so that a continuous expansion to a certain size tubular membrane, cool, double layer winding folded flat film.

Manufacture of plastic film can be used many ways, such as blow molding, extrusion, casting, rolling, casting and so on, but blowing the most widely used method.

This method is suitable for polyethylene, polyvinyl chloride, polyamide films such as manufacturing.

10. Casting. Without pressure or under slight pressure, the liquid monomer, resin or their mixture into the mold and make it a method of solid-state products. Casting method into a static casting, inlay casting, centrifugal casting, slush, rotational molded plastic, rotational molding and casting plastic and so on tape.

(1) static casting. Static casting is the casting forming the more simple and more extensive use of two methods. This method commonly used in liquid monomer, part of the polymerization or condensation of the slurry material, polymer and monomer solution, blended with additives (such as initiator, curing agent, promoting etc), or thermoplastic resin melt into the mold cast cavity shape.

(2) embedded cast. Insert molding casting, also known as enclosure is to the samples, spare parts and other entrapment to the middle of a plastic molding technology. Embedded object will be placed in the mold, into the monomer, prepolymer or polymer such as liquid, and then to polymerization or curing (or hardening), ejection. This technique has been widely used in electronic industry. Plastic molding process for these species have gills formaldehyde, unsaturated polyester, acrylic and epoxy resins.

(3) centrifugal casting. Centrifugal casting is the use of centrifugal force, forming tubular or hollow tubular products approach. Through the extruder hopper or dedicated to quantitative liquid resin or resin dispersion into the rotation and heating of the container (ie, mold), by its rapid rotation around the axis (tens of per minute to 2000 rpm), then put Jibei centrifugal force into the material distributed in the mold area near the wall. In the rotation, while the material into the curing occurs, and then as needed through the cooling or post-processing that is able to obtain products. When the molding reinforced plastic products can also added to enhance the filling of.

Centrifugal casting melt viscosity are usually smaller, better thermal stability of thermoplastics such as polyamide, polyethylene, etc..

(4) slush. Slush is a method of molding hollow articles. When the plastic molding paste down and start the hollow mold until the required capacity. Mold in the loading should be carried out before or after the heat loading in order to make the material into a gel in the mold wall. When the gel when the intended thickness, pour excess liquid materials, and re-heated to make it melt, after cooling can be stripped out of products from the mold. Slush is mainly used in PVC plastic.

(5) spin-cast plastic. The law is the liquid material into a closed mold in which it at a lower speed (several to tens of change per minute) around a single or multi-axis spin, so that materials that can be distributed by gravity and the inner wall of the mold on, and then cured by heating or cooling or hardening up, you can get products from the mold. Around the axis of rotation for the production of cylinder-shaped product, or by vibration around the axis movement is used to produce closed products.

(6) rotational (rotational molding). A similar spin casting plastic molding methods, and different is its use of the materials are not liquid, but sintering of powder materials. The process is the powder into the mold and make it around the two vertical axis rotation, heat and even melt in the mold wall on bedrock, and then after cooling can be obtained from the mold hollow articles.

Rotational use of a polyethylene, modified polystyrene, polyamide, polycarbonate and cellulose plastics.

(7) cast sculpture. Preparation of thin film methods. Manufacturing, the first dispersion liquid resin or resin is dispersed in the running of the carrier (usually metal band), the subsequent use of appropriate methods to cure (or harden), and finally stripping can be obtained from the carrier film.

Casting for the production of plastic film are: the three cellulose acetate, polyvinyl alcohol, vinyl chloride and vinyl acetate copolymers, etc., in addition to some of the engineering plastics such as polycarbonate, etc. can also be used to produce cast film.

11. Hand lay-up. Hand lay-hand wall paper, also known as forming, molding, manufacturing reinforced plastic products is one way. In this method, the mold release agent coating on the reinforcing material laid by hand while brushing aside until the resin until the desired thickness, and then obtained by curing and stripping products. Hand lay in the synthetic resin is mainly used in epoxy resins and unsaturated polyester resin. Reinforcement with glass cloth, rovings Plaid, glass blankets.

12. Filament Winding. Scheduled in control of tension and linear conditions in order to dip a resin glue to the core of continuous filament winding up mold or mold forming reinforced plastic products. This method is only suitable for manufacturing such a cylindrical and spherical rotating body. Commonly used resin is phenolic resin, epoxy resin, unsaturated polyester resin. Glass fiber reinforced materials commonly used winding, it has two: a twist fiber and untwisted fiber.

13. Rolling. Will be through a series of heated thermoplastic roller, but its role in the compression and extension under the link to become a film or sheet molding method. Ting-pressure product film, sheet, leather and other coated products. Calendering the main raw material used is PVC, cellulose, modified polystyrene.

Rolling equipment, including rolling machine and other auxiliary equipment. Calendar roll is usually the number and arrangement of classification. According to the number of different roller, rolling machine with double rollers, three rollers, four rollers, five rolls, and even six-roll, with three or four roll calendar roll used most.

14. Coating. For anti-corrosion, insulation, decoration and other purposes, in liquid or powder form in the fabric, paper, metal foil or board surface on the coated plastic thin (for example .0.3 mm or less) of the method.

The most common plastic coating method is generally thermoplastic, such as polyethylene, polyvinyl chloride, polyamide, polyvinyl alcohol, PCTFE, etc..

Hot melt coating process has deposited, fluid spraying, flame spraying, electrostatic spraying and plasma spraying.

(1) hot melt deposition. After the plastic powder with compressed air spray gun, spray off the surface to warm, plastic melting, cooling form a covering layer.

(2) fluid spray. Preheat the workpiece immersed in a container suspended in a resin powder resin powder melt and adhere to the surface.

(3) flame spraying. The fluidized resin through the mouth of the cone-shaped flame spray gun to make it melt and to achieve a method of spraying.

(4) electrostatic spraying. Electrostatic field caused by high voltage static electricity, that is a positive level ground parts, plastic powder emitted when a negative charge, the electrostatic spray plastic to the workpiece.

(5) plasma spraying. Plasma spray gun used to flow through areas such as ions of inert gas (such as argon, nitrogen, helium gas mixture) into a high-speed 5500 ~ 6300 �� high energy plasma flow, volume, high-speed spray resin powder lead to surface melting Results into the coating.

15. Foam molding. Plastic foam molding is to produce porous structure of the process. Almost all of thermosetting and thermoplastic plastics can be made of foam, commonly used resin is polystyrene, polyurethane, polyvinyl chloride, polyethylene, urea formaldehyde, phenol and so on.

In accordance with the foam cell structure can be divided into two categories, if the majority of pores connected to each other, then known as the hole foam; if the majority of stomata are separated from each other, then known as closed-cell foam. Opening or closed cell foam structure is determined by the manufacturing method.

(1) chemical foam. Specifically added by the chemical foaming agent, thermal decomposition or chemical reaction between components of raw materials caused by the gas, so full of foam plastic melt. Chemical blowing agent released in the heating gas are carbon dioxide, nitrogen, ammonia and so on. Chemical foam used in the production of polyurethane foam.

(2) physical foaming. Physical foaming plastics dissolve in the gas or liquid, and then to expand or gasification foaming method. Physical foaming plastic varieties more suitable.

(3) Mechanical foam. By mechanical stirring method to gas mixed with the liquid mixture, then shape the process through the formation of foam in the foam. This method is commonly used in the urea-formaldehyde resin sleep, others such as polyvinyl formal, poly vinyl acetate, polyvinyl chloride sol, also apply.

16. Secondary molding. Secondary molding is one of the methods of plastic molding. Parison of plastic material or as raw materials to make it through the heating and the external force into the shape of the products required for a method.

(1) hot molding. Thermoforming thermoplastic sheet is heated to soften, the gas pressure, liquid pressure or mechanical pressure, the use of appropriate molds or fixtures and products to become a molding method. Plastic thermoforming many ways, and can be divided into:

Molding using single-mode (mode or yin yang mode) or mode, using external mechanical pressure or weight, will be a variety of products made from sheet molding method, which is different from a process of compression molding. This law applies to all thermoplastics.

Differential pressure molding using single-mode (mode or yin yang mode) or to die, you can not die, under the effect of differential pressure in the gas, so that heat to the soft plastic sheet close to mold surface, made of a variety of products, after cooling The molding method. Pressure forming can be divided into vacuum forming and pressure forming.

Especially suitable for hot forming thin wall, the manufacture of large surface area. Varieties of common types of polystyrene plastics, glass, PVC, ABS, polyethylene, polypropylene, polyamide, polycarbonate and polyethylene terephthalate, etc..

Thermoforming equipment, including clamping system, heating system, vacuum and compressed air systems and forming tooling.

(2) biaxial tension. To thermoplastic film or sheet such as molecular reorientation, especially above the glass transition temperature of the process of two-way stretch. Tensile direction in the polymer glass transition temperature and melting point between, after orientation stretch and quickly cooled to room temperature after the film or the single wire, the tensile direction on the mechanical performance has greatly improved.

For the polymer stretching direction are: PVC, polyethylene terephthalate, polyvinylidene chloride, polymethylmethacrylate, polyethylene, polypropylene, polystyrene, and some styrene.

(3) solid phase forming. Solid phase formation is a thermoplastic material or blank in the mold under pressure to use the method of forming the products. Melting in the plastic molding process (as softening) temperature of the following (at least below the melting point of 10-20 ��). Are solid phase forming. One class of non-crystalline plastic in the glass transition temperature above the melting point below the processing of high-elastic region often referred to as hot forming, the glass transition temperature in the following processing is known as cold forming or molding at room temperature, often referred to as plastic cold plastic processing method or at room temperature.

The method has the following advantages: short production cycle; improve the toughness and strength of products; equipment is simple, can produce large and very large products; cost reduction. Disadvantage: difficult to produce complex shapes, precision products; production process difficult to control, products, deformation, cracking.

Solid phase forming, including: sheet rolling, deep drawing or sheet punching, hydraulic molding, extrusion, cold stamping, roll forming and so on.

17. Secondary processing. After molding of plastic products, or profiles, according to the need for re-processing, such as mechanical processing, connection, modification, etc.. The following table lists the methods of secondary processing of plastics.

Plastics secondary processing methods

Classification processing method

Machining sawing, shearing, punching, car, plane, scraping, milling, drilling, grinding, polishing, sand blasting, kneading dough, thread processing

Laser processing finding, drilling, carving, etc.

Connect hot air welding, heating tools, lasers, rotating friction, vibration, friction, high-frequency, ultrasonic, induction, etc.

Bonding solvent, solution, melt, etc.

Machine screw, spring, spring bolt, rivet, hinges, etc.

Decorative paint surface coating, solvent brightening, coating, printing, painting, hot stamping, vacuum coating, plating, electroplating, etc.

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Edited by Leafly Mould Provides Injection Mold, Plastic Mold, Injection Molding, Die Casting Mold, Stamping Mold

Cost of an Injection Mold

Custom Injection Molds can be very expensive to manufacture.  One of the key factors driving up cost is the tool material selection.  Typically molds constructed out of steel would cost more than double than that of aluminum.  This is due to the much slower machining process of steel, as cutter wear vs speed becomes a major factor.  High volume projects typically require steel because of its wear resistance.  However, with the advance made in alloy blends, higher grade aluminum such as QC-7 and QC-10 or Aircraft Aluminum have closed the gap on the durability between steel and aluminum.  Today, aluminum molds can produce hundreds of thousands of parts in a life cycle, with no wear.

Aluminum tools also offer quick turnaround and faster cycles because of better heat dissipation for cooling.  Faster heat dissipation will result in cost savings on the production parts as well.  This is because most of the shot cycle (time), consists of cooling time.  In addition, when parts require high abrasive materials, the aluminum tool can be coated for better wear resistance.  Furthermore, Aluminum molds can be engineered  with steel components for high wear areas of the tool.

Other Driving Factors

The cost of plastic injection molds depends on a wide range of factors ranging from the number of cavities, size of the parts, complexity, life of the project, surface finishes and many others. The initial tooling cost can be high, however the piece part cost is low, as with greater quantities the overall price decreases.  With the expanding  global market, many injection molding service companies have found ways through technology and processes and quality systems such as ISO-9000, to drastically reduce the cost of tooling and parts..

Consider the following when designing your part for injection molding as these will have an impact on pricing;

  • Annual Volume – Volumes over 100,000 annually will require multi-cavity tooling.  This will increase tooling price significantly but will reduce the piece price by as much as 60% per additional cavity.  Be sure to specify your annual volume accurately so you do not incur unneeded extra tooling costs.
  • Undercuts– Although Xcentric can handle unlimited undercuts in the part geometry, these do not come without a price.  So try and reduce the number of undercuts if possible.
  • Surface Finish – Surface finishes can add awesome aesthetics to your part.  However, if the part is hidden in an assembly, you can save money by choosing a 320 sand paper finish.
  • Part Complexity – Part complexity can drastically increase the cost of your tool.  The more faces or surfaces you cad model has the higher the cost.  Consider this when adding blends or unneeded features.
  • Mold Construction Materials – At Xcentric we will determine the best materials to build your Plastic injection mold.  This is why we offer a lifetime mold warranty, Because we stand behind our work and engineering
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Injection Molding Definitions and Terminology


Refers to the injection mold that is created to make plastic parts in the molding process

Shrink Rate

Refers to how much the plastic material will shrink after cooled.  The shrink rate of the plastic is added to the part before the mold is designed.  Every plastic material has its own shrink rate ranging from .001 per inch to as much as .060 per inch.  Although most fall in between .004 and .021.


This is the location where the plastic enters into the cavity of the mold. Types of gates include; sub, edge, fan, cashew and XME exclusive vestige free edge for perfect shear


Material or witness of material protruding from gate area after gate runner has been removed from the injection molded part.


Friction produced by speed and pressure.   Too much shear during injection molding can cause the plastic material to burn, likewise, too little can cause the material to freeze off which can cause a short shot.


A channel cut into custom injection molds, in which plastic travels from the injection molding machine, through the sprue, through the runner and then through the
gate ultimately filling the part.

Short Shot

Is the result of a plastic part not filling completely during the injection molding process, including some or all of the details.


The Sprue is perpendicular to the runner and is the channel that links the injection molding machine nozzle to the runner.

Hand Pull

Portion of the custom injection mold that is used for creating undercuts in plastic parts. See (Fig.1)


Portion of custom plastic injection molds that is used for creating undercuts.  Required for automatic injection molds. See (Fig.2)


Portion of the custom injection mold that holds the slide down so the cam can actuate it. See (Fig.2)


The cam commonly referred to as Horn pin is used to actuate the slide on an automatic injection mold. See (Fig.2)

Ejector Pins

Ejector Pins are used to push the part off the core half of the injection molds. See (Fig.1) and (Fig.2)


Referring to the portion of the designed component where a slide or hand pull is required to create holes, windows or clips that are not in the line of draw.


Refers to side of the tool where the plastic part will stick to and is ejected from, also known as bottom half of the tool.  See (Fig.2)


Refers to the upper half of the injection mold, usually the show surface of the finished product but is mainly concave. There is not as much standing core outs on this side of the tool.
Therefore, the part will generally not stick to it when the injection molding machine opens the mold. See (Fig.2)

Core Outs

Refers to the portion of a part that is gutted out in order to achieve uniform wall thickness.  Core outs have no end use or function other than lightening the part and thus reducing warp.

Line of draw

Line of draw is the direction in which the two custom injection mold halves will separate from the plastic part allowing it to be ejected without any obstructions from metal creating the undercuts.

Side Action

Is the term used for slides and/or hand pulls used in the injection mold build process where undercuts in the part are present See (Fig.1) and (Fig.2)

Piece Price

Refers to the cost of each plastic part as produced in the injection molding process.


Stereo Lithography Apparatus uses 3D printing technologies such as laser sintering and electron beam melting.


Fused Deposition Modeling uses three dimensional printing technology.  The Prototypes parts are made by fusing layers of actual ABS plastic together.  Much like an inkjet printer except it lays Plastic instead of ink.


A person used to run a plastic injection molding machine.

Wall Thickness

Refers to how thick the cross section of the plastic part is. See (Fig.9)

Thin Wall Molding

Thin wall molding is the molding of plastic parts with wall thicknesses .005 to .060 thick.


Refers to round protrusions on plastic parts and molds. See (Fig.7)


Refers to thin bladed features on a part that are used for strengthening wall sections and bosses.  Also, used to minimize warp. See (Fig.6)

Sink Marks

Refers to areas of the molded part where the plastic sinks below the surface, due to un-uniformed wall sections, thick wall sections and rib/boss to thickness ratios being off. See (Fig.3)


Refers to area of a injection molded part that distorts during cooling or molding, causing undesired results in the finished product. Usually caused by un-uniform wall sections. See(Fig.5) for prevention.


Refers to portion of injection molded part that has a taper or angle on the side wall.  Designers should incorporate draft to all plastic parts. See here for tips.

Heel  Block

Heel blocks are used to keep the slide in the forward position when the molding machine is closed on the mold.  See (Fig.2) for Visual.

Stock Safe

Refers to the amount of metal left on the mold in order to tweak in a dimension.  For example, leaving stock on a diameter of boss that requires a tight tolerance.  As a rule of thumb, it is cheaper to remove metal than it is to add it.

Bulk Pack

Refers to shipping plastic parts in a box without any form of stacking.

Reverse Engineering

Refers to the process of taking an existing plastic part and creating a 3D solid model for duplicating in the injection molding process. Sometimes the design may include some custom changes from the OEM.


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Edited by Leafly Mould Provides Injection Mold, Plastic Mold, Injection Molding, Die Casting Mold, Stamping Mold

Injection Molding Plastic Material Guide

ABS (Acrylonitrile Butadiene Styrene)

ABS Injection Molding plastics provide a balanced combination of mechanical toughness, wide temperature range, good dimensional stability, chemical resistance, electrical insulating properties, and ease of fabrication. ABS plastic is available in a wide range of grades including medium and high-impact, heat-resistant, plateable fire-retardant, and both low and high gloss varieties.

Applications: Computer housings, small appliances, automotive interior trim and medical components

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
5000-7500 psi 270,000-380,000 psi 3.0-7.5 ft-lb/in notched izod 140°-200° F Poor to Fair


ABS + PC (ABS + Polycarbonate Alloy)

PC + ABS Injection Molding plastics offer improved strengths over ABS at a lower cost than Polycarbonate. Exceptional low temperature Impact Strength. The Injection Molding Plastic material can be modified by the addition of glass fiber, mineral fillers and flame retardant.

Applications: Automotive exterior and interior components, medical hardware, electrical housings, computers, monitors, business equipment housings and enclosures

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
6400-9150 psi 300,000-400,000 psi 8-12 ft-lb/in notched izod 140°-210° F Poor to Fair


Acetal (POM) (Polyoxymethylene)

Acetal Injection Molding Plastic are semi-crystalline. They offer excellent inherent lubricity, fatigue resistance, and chemical resistance. Acetals suffer from outgassing problems at elevated temperatures, and are brittle at low temperatures. Glass filled, and added lubrication grades are available, flame retardant grades are not.

Applications: Mechanical Automotive, Business Machine and Household Appliance, Components i.e. Slides, Gears, Cams, Bushings, Door Handles and Seat Belt Parts.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
6000-22,000 psi 120,000-170,000 psi .8-2 ft-lb/in notched izod 180°-300° F Excellent


Acrylic (PMMA) (Polymethyl methacrylate)

Acrylic PMMA is a tough, highly transparent Injection Molding Plastic material with excellent resistance to ultraviolet radiation and weathering. It can be colored, molded, cut, drilled, and formed. Acrylic is an economical alternative to polycarbonate (PC) when extreme strength is not necessary. It is often preferred because of its moderate properties, easy handling and processing, and low cost, but behaves in a brittle manner when loaded, especially under an impact force.

Applications: Automotive Transparent Items such as Head/Tail Lenses and Trim, Household Light Fixtures and Decorative Items, Safety Equipment and Shields.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
2800-10,9000 psi 221,000-534,000 psi .22-1.1 ft-lb/in notched izod 183°-217° F Excellent


LCP (Liquid Crystal Polymer)

LCPs are cool, relatively new Injection Molding Plastic materials with interesting properties. They have tensile strength and modulus close to aluminum. Because of the highly oriented, rod like nature, of the polymer molecules, LCPs present some interesting design challenges. This is because the molecules will only form in straight lines. Additionally, the high orientation only occurs within about .040 of the surface of the part. Molecular orientation below this skin is random. As a result all of the strength of the material is in the skin. Good design data is not available for these materials, so prototyping is a must. prototypes must be molded, because of the molecular orientation mentioned above.

Applications: Electrical and Mechanical parts, Food containers, and any other applications requiring chemical inertness and high strength.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
12,000-32,000 psi 1,300,000-4,600,000 psi 1.1-11 ft-lb/in notched izod 430°-500° F Good to Excellent


Nylon 6-PA (Polyamide)

Nylons are semi-crystalline Injection Molding Plastics with a good range of properties. Nylons are widely used because they have a good cost to performance ratio. Lower numbered nylons, 6 ,6-6, 4-6, absorb moisture and change their properties as a result. Nylons have been compounded with reinforcements, fillers and additives to produce a very wide variety of properties. Nylon 6 has the lowest modulus of all nylon grades.

Applications: Automotive components, Bearings, Electronic Connectors, Gears, Consumer Products and Industrial products.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
6,000-24,000 psi 390,000-1,100,000 psi 2-8 ft-lb/in notched izod 200°-350° F Good to Excellent


Nylon 6/6-PA (Polyamide)

Nylons are semi-crystalline Injection Molding Plastics with a good range of properties. Nylons are widely used because they have a good cost to performance ratio. Lower numbered nylons, 6 ,6-6, 4-6, absorb moisture and change their properties as a result. Nylons have been compounded with reinforcements, fillers and additives to produce a very wide variety of properties. Nylon 6-6 offers better properties than nylon 6 without being as costly as nylon 4-6. It has the best abrasion resistance of all nylons. Verton, long glass fiber filled materials, by LNP, are excellent metal replacement materials.

Applications: Automotive components, electronic connectors, gears, consumer products and industrial products.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
8,000-24,000 psi 430,000-1,100,000 psi 2-8 ft-lb/in notched izod 220°-350° F Good to Excellent


Nylon 11-PA (Polyamide)

Nylons are semi-crystalline Injection Molding Plastics with a good range of properties. Nylons are widely used because they have a good cost to performance ratio. Lower numbered nylons, 6 ,6-6, 4-6, absorb moisture and change their properties as a result. Nylons have been compounded with reinforcements, fillers and additives to produce a very wide variety of properties. Nylon 11 offers better Impact Strength and dimensional stability than lower numbered nylons. It is also more flexible.

Applications: Automotive components, Electronic connectors, Gears, Consumer products and Industrial products.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
8,000-17,000 psi 170,000-1,200,000 psi 2-No break ft-lb/in notched izod 180°-250° F Good to Excellent


PBT Polyester (Polybutylene Terepthalate)

PBT polyesters are semi-crystalline. They are versatile Injection Molding Plastic materials with a good range of properties. They have excellent electrical properties and are abrasion resistant. PBT has been extensively compounded giving a very wide range of properties. PBT performs much like Nylon but can handle higher temperatures and does not absorb moisture. PBT has excellent impact strength but is very notch sensitive. PBT is very anisotropic in shrinkage, so it is difficult to mold to extremely tight tolerances.

Applications: Industrial equipment applications, business equipment, automotive housings-under the hood, power tool casings.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
6,000-13,000 psi 300,000-1,200,000 psi 1 ft-lb/in notched izod 250°-420° F Fair to Good



PC (Polycarbonate)

Polycarbonate is an amorphous Injection Molding Plastic material with excellent impact strength, clarity, and optical properties. It is very widely used and a wide variety of compounds are available. Polycarbonate has excellent mechanical properties, and can be molded to tight tolerances. It is attacked by solvents and petrochemicals, and its weatherability is only adequate.

Applications: Automotive Headlights, Business Machines, Consumer Products, Telecommunications, Medical Products and Mechanical Goods.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
9000-23,000 psi 340,000-1,400,000 psi 2-18 ft-lb/in notched izod 150°-300° F Poor to Fair



PEI (Polyetherimid)

PEI is an amorphous, high temperature Injection Molding Plastic material with relatively low cost compared to other high temperature materials. It has excellent elongation and Impact Strength, and can be molded to tight tolerances. Its chemical resistance is not as good as crystalline materials but is excellent for an amorphous material. PEI behaves similar to polycarbonate, but can perform at higher temperatures.

Applications: Commercial aircraft interiors, healthcare products, cooking utensils, fiber optics, electrical and electronic applications.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
14,000-28,000 psi 480,000-1,300,000 psi 2 ft-lb/in notched izod 375°-420° F Fair to Good


PE (Polyethylene)

Polyethylene is a widely used, inexpensive, Injection Molding thermoplastic. It has good inherent lubricity, and is easy to process. Polyethylene has good to excellent chemical resistance. It is also soft and cannot be used in temperatures much above 150. As a family, they are light in weight and possess toughness, chemical resistance, impermeability as well as excellent electrical insulating properties.

Applications: Consumer products, houseware items, electronic wire/cable insulators and medical products

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
1900-4500 psi 40,000-105,000 psi 2-No break ft-lb/in notched izod 130°-150° F Good to Excellent


LDPE (Low Density Polyethylene)

Polyethylene is a widely used, inexpensive, Injection Molding thermoplastic. It has good inherent lubricity, and is easy to process. Polyethylene has good to excellent chemical resistance. It is also soft and cannot be used in temperatures much above 150. As a family, they are light in weight and possess toughness, chemical resistance, impermeability as well as excellent electrical insulating properties. Low density polyethylene is the softest and most flexible version of this material. It has high elongation giving it excellent impact strength. This is offset by its permanent deformation upon impact.

Applications: Consumer products, houseware items, electronic wire/cable insulators and medical products.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
1,200-4,000 psi 35,000-48,000 psi No break ft-lb/in notched izod 130°-150° F Good to Excellent


HDPE (High Density Polyethylene)

Polyethylene is a widely used, inexpensive, Injection Molding thermoplastic. It has good inherent lubricity, and is easy to process. Polyethylene has good to excellent chemical resistance. It is also soft and cannot be used in temperatures much above 150. As a family, they are light in weight and possess toughness, chemical resistance, impermeability as well as excellent electrical insulating properties. High density polyethylene is the hardest and stiffest version of this material. It does not have the impact strength of low density, but is more resilient.

Applications: Consumer products, houseware items, electronic wire/cable insulators and medical products

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
3,200-4,500 psi 145,000-225,000 psi .4-4 ft-lb/in notched izod 130°-150° F Good to Excellent



PET Polyester (Polyethylene Terepthalate)

PET polyesters are semi-crystalline. They are versatile Injection Molding Plastic materials with a good range of properties. They have excellent electrical properties and are abrasion resistant. PET has not been as extensively compounded as PBT because it is more difficult to process. PET has a higher modulus than PBT. Like PBT, PET is very anisotropic in shrink, therefore it is difficult to mold to extremely close tolerances.

Applications: Reusable bottles, Pacifiers, Sippy cups, Bottle sterilizer lids, Medical devices, Housewares.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
7,000-23,000 psi 350,000-3,000,000 psi .45-8 ft-lb/in notched izod 250°-420° F Fair to Good



PP (Polypropylene)

Polypropylene is a widely used, semi-crystalline Injection Molding Plastic material. It has been extensively compounded to provide a wide range of properties at a wide range of costs. In general, polypropylene is a low temperature Injection Molding Plastic material with excellent chemical resistance. It has no known solvent at 73 F. Polypropylene is difficult to mold to extremely close tolerances.

Applications: Packaging, industrial components for fluid processing, household goods, automotive and electrical hardware.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
4,500-18,500 psi 210,000 -1,500,000 psi 1.4-5.5 ft-lb/in notched izod 150°-300° F Excellent



PPA (Polyphthalamide)

PPA is a relatively new, semi-crystalline Injection Molding Plastic material, with an excellent cost to performance ratio. PPA bridges the performance gap between nylons/polyesters, and higher priced, high temperature materials such as PEI and PEEK. PPA has excellent impact strength and is not notch sensitive. PPA does absorb moisture, and its properties change as a result. This change is not nearly as great as 6-6 nylon. Despite its relatively recent introduction, good design data is available for PPA.

Applications: Automotive applications, Housing for high temperature electrical connectors, Multiple other uses as a replacement to metals.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
9,000-33,000 psi 270,000 -2,700,000 psi .6-22 ft-lb/in notched izod 300°-450° F Good to Excellent



PPS (Polyphenylene Sulfide)

PPS is a high temperature semi-crystalline Injection Molding Plastic material. It has good mechanical properties and excellent chemical resistance at elevated temperatures. PPS has been compounded extensively and many different types of properties are available. PTFE filled PPS is one of the best bearing materials available. Unfilled grades of PPS have poor properties, so components are usually made from glass filled or glass/mineral filled grades. PPS is very sensitive to molding conditions and must be processed properly to achieve its maximum potential.

Applications: Hydraulic components, bearings, cams, valves and electronic parts

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
14,000-28,000 psi 550,000 -2,900,000 psi .5-6 ft-lb/in notched izod 450°-500° F Good to Excellent



PS (Polystyrene Crystal)

Crystal polystyrene is the cheapest Injection Molding thermoplastic available. It has properties to match its price. It is transparent and has good optical properties. It has very low Impact Strength.

Applications: Household Goods, Containers, Furniture, Housings and Packaging.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
5000-7500 psi 380,000 -480,000 psi .35-.45 ft-lb/in notched izod 100°-150° F Poor



HIPS (High Impact Polystyrene)

High Impact Polystyrene is what its name implies. A few cents more than crystal styrene, to pay for the rubber modifier. HIPS is opaque and very widely used. It has a lower modulus, better elongation, and is a lot less brittle than crystal styrene.

Applications: Household Goods, Containers, Furniture, Housings and Packaging.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
7,500-10,000 psi 160,000 -370,000 psi 3-7 ft-lb/in notched izod 100°-150° F Poor


PSU (Polysulfone)

Polysulfone is a high temperature amorphous Injection Molding Plastic material with relatively low cost. It is transparent and can be used at temperatures of up to 300 F. Polysulfone has been compounded, with glass and mineral filled grades available.

Applications: Appliance parts, electronic parts, automotive parts, medical components, business Equipment, aerospace and insulators.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
9,500-18,000 psi 390,000-1,500,000 psi .65-7 ft-lb/in notched izod 300°-350° F Fair to Good



PU (Polyurethane)

Polyurethane is a resilient, extremely tough abrasion and tear resistant elastomeric Injection Molding Plastic material that is available in ether and ester based formulations. These diverse formulations cover an extremely wide range of stiffness, hardness, and densities. These Injection Molding Plastic materials offer good chemical resistance, and are transparent in unfilled grades.

Applications: Gaskets, Seals, Bushings, Connectors, Electrical parts

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
6,500-33,000 psi 230,000-2,000,000 psi 1.5-10 ft-lb/in notched izod 150°-230° F Good



PVC (Polyvinylchloride)

PVC is one of the oldest and most commonly used Injection Molding thermoplastic materials. The material is a colorless polymer of vinyl chloride. PVC can have numerous properties and the characteristics can be altered by the use of additives such as stabilizers, lubricants, softeners, pigments, fillers or static agents. PVC offers similar properties to ABS at a slightly reduced cost. However, the appearance of PVC cannot come close to ABS. In its plastic phase, PVC is corrosive to molds and molding machines. In its solid phase, PVC is non corrosive.

Applications: Medical/Healthcare Products, Automotive Applications, Household Items and Electronic Extruded Wire Covering.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
10,000-12,000 psi 350,000-600,000 psi .8-1.4 ft-lb/in notched izod 120°-170° F Fair to Good



PVDF (Polyvinylidene Fluoride)

PVDF is a melt processable fluropolymer Injection Molding Plastic. It is similar in properties to other fluropolymers, but has better strength and lower creep than the other members of this family. PVDF has good wear resistance , and excellent chemical resistance. But does not perform well at elevated temperatures.

Applications: Aircraft applications, Computer components, Protective coverings, Seals, Electrical parts, Diaphrams.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
3,500-7,200 psi 170,000-1,200,000 psi 2.5-8 ft-lb/in notched izod 170°-300° F Good to Excellent



SAN (Styrene Acrylonitrile)

SAN is ABS without the Butadiene. It does not have the Impact Strength of ABS, but can be crystal clear. Injection Molding Plastic, Styrene Acrylonitrile has better general chemical resistance than polystyrene and is cheaper than acrylic. It has a good combination of rigidity, strength, toughness and transparency.

Applications: Battery cases, Dials, Knobs, Switches, Lenses, Trays, Containers, Covers, Autoclavable devices, Dental & Medical light diffusers

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
10,000-18,000 psi 500,000-1,200,000 psi .3-3.0 ft-lb/in notched izod 140°-200° F Poor to Fair



TPE (Thermoplastic Elastomer)

Thermoplastic elastomers (TPE) are a combination of polymers (usually a plastic and a rubber) which consist of both thermoplastic and elastomeric properties resulting in a product that is extremely easy to use in manufacturing a variety of products. TPE Injection Molding Plastic require little or no compounding and no need to add reinforcing agents, stabilizers or cure systems.

Applications: Automotive Fluid Delivery Systems, Household appliances, Sporting goods, Electrical and Medical components.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
1,000-7,000 psi 5,000-800,000 psi 2.5-No Break ft-lb/in notched izod 200°-300° F Fair to Good



TPU (Thermoplastic Polyurethane Elastomer)

Injection Molding Thermoplastic polyurethane elastomers exhibit excellent abrasion and wear resistance and high tensile and tear strengths. TPUs are tough, durable, easy to clean and well-suited to applications that demand the elasticity of rubber combined with high stability. In addition, the inherent translucency of these products makes it easy to color and that is an added benefit in many applications.

Applications: Automotive and Aerospace Applications, Medical and Optical purposes, Electrical Wire and Cable Coverings.

Tensile Strength Flexural Modulus Impact Strength Max Temp. Chemical Resistance
6960-12,000 psi 260,000-340,000 psi .80-10.1 ft-lb/in notched izod 160°-250° F Fair to Good
From Website
Edited by Leafly Mould Provides Injection Mold, Plastic Mold, Injection Molding, Die Casting Mold, Stamping Mold

Design for Manufacturing

Injection molding your  plastic parts just got a whole lot easier.

  • Minimize Tooling Costs
  • Reduce Design Changes
  • Expedite the Manufacturing Process
  • Ensure Better Part Quality

Design for manufacturing Injection Molding

Design for Manufacturing, or DFM service that Xcentric provides to all of its customers free of charge.  At the time of quote your parts are ran through our DFM process.  Even More, our customers are experiencing tremendous cost saving by minimize tooling costs and design changes.  As a result, we are putting production parts in your hand faster than anyone else.

When you submit a quote for plastic injection molding we will provide you a detailed report that provides you important information about the design of your custom parts.  The DFM report highlights  potential problem areas noted by our experienced plastic sales engineers and tooling designers.  That means you have real eyes on your project.

It is also helpful to eliminate potential issues before the quote stage.  Use our extensive resources to help make your part ready for the injection molding process.  By following our online Design Guidelines your part is sure to be a success and the cost saving will be priceless.

From Website
Edited by Leafly Mould Provides Injection Mold, Plastic Mold, Injection Molding, Die Casting Mold, Stamping Mold

Knit Lines

The injection molding process is on the surface is fairly simple, plastic resin is heated to its melting point and forced into the cavity of the mold to produce a plastic parts.  As the plastic travels through the cavity it wants to naturally cool.  This is because the melt temperature is much higher than the mold temperature usually between 150 -300 degrees Fahrenheit.  To further complicate matters, if the molten plastic meets an obstruction it must travel around and meet at the other side.  Obstruction are those that create windows or core outs in the part.  See the illustration above. If the plastic has cooled too much during the injection process it can lead to knit lines in plastic parts when they meet past an the obstruction.

Some plastics are more prone to knit line than others.  Usually materials with lower flow rates such as ABS are prone to knit lines.

Knit lines are most common downstream of holes created in parts where the molten material meets. While knit lines can be present it does not always mean the structural integrity of the plastic part is compromised.

It is important when selecting an injection molder that the right process conditions are used to reduce or eliminate the effects of knit lines in your plastic parts.

From Website
Edited by Leafly Mould Provides Injection Mold, Plastic Mold, Injection Molding, Die Casting Mold, Stamping Mold