Plastic Injection Molding A New Industry

When it comes to excelling in the manufacturing industry, you need to be able to keep up with all of the current trends. When it comes to ideals, such as localism and working with companies in your own neck of the woods, you must understand that the rules of game are changing. We are talking here about the new global economy, which is changing the way manufacturing is performed. In the old days, it would have been less expensive to work with companies in your own country or even in your own region, but technology has changed this old bit of conventional wisdom. You can see these changes nowhere more clearly than in the plastic injection molding industry. Mold companies are now expanding their operations to include countries all over the globe.

If you are unfamiliar with the changes in the plastic injection molding industry, it might be because you are unfamiliar with the requirements of the industry. First, consider all of the functions that you would expect from the world-class mold companies. They are expected to perform injection tooling, injection molding, assembly, and finishing. Most companies can simply not afford to have an in-house operation. This would require a lot of real estate with many different facilities. From a purely economic standpoint, this is not a viable option in today’s economic landscape.

Instead, plastic injection molding is a several step process that reaches all across the world. For example, mold companies my start with injection tooling in America. They might then outsource their work to facilities in China for the molding and accessories. The process might come to a close with assembly taking place in Mexico or India. As you can see, this is an industry that spans the globe, creating a global market place where the best bids wind, regardless of location.

When you need to have plastic injection molding work done, make sure that you are looking at only mold companies that understand this new global model. This will mean that you are getting a quick turnaround and optimum cost effectiveness. When it comes to the needs of a competitive industry, this is exactly what you should expect. You will also find that these global companies have no problems dealing with your own global expansion. For example, if you need your parts delivered to your offices in China, a top of the line company will have no problem making this delivery happen in a timely manner.

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

What is Cast Aluminum

Cast aluminum is a specific metal that has gone through one of the several processes known as casting. Essentially, cast aluminum is created when methods such as die casting, mold casting, or sand casting are used to temper the aluminum for use in creating components for many different types of products. Cast aluminum is used for a number of items around the house, as well as machinery and other products that are necessary to the manufacturing of a wide range of goods and services.

One of the more common applications of cast aluminum is in the creation of cookware. Just as cast iron is used for skillets, baking pans, and other kitchen essentials, cast iron can also be used for these items. Usually created using the die cast approach, the cookware can withstand the high temperatures required to cook food properly and will remain useful for a number of years with no more than minimal care.

Cast aluminum is also used to create outdoor furniture. While not quite as popular as cast iron furniture for the lawn, cast aluminum patio furniture is somewhat more lightweight and can be moved around the space with greater ease. Patio furniture made with cast aluminum includes such items as chairs, gliders, and tables.

In addition to cookware and cast aluminum furniture, the cast metal is also used to create a number of motor parts for land vehicles as well as boats and ships. Components such as connecting rods, pistons, housings, radiator tanks, and other essentials can be created using both die casting and mold casting methods. Even components such as compressors and various types of gears may be created using aluminum of this type.

One of the main advantages to using cast aluminum is that the metal is often cost efficient in comparison to other cast metals. Along with the lower cost, the metal also retains a high degree of durability. While it is not necessarily true that cast aluminum will last as long as cast iron in some applications, the aluminum products do tend to hold up well for a number of years. The combination of lower cost and reliable durability makes cast aluminum an excellent choice for a number of metal components and products in domestic and commercial applications.

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

What are CNC Machines

Computer numerical control (CNC) machines are automated milling machines that make industrial components without human assistance. This is possible because CNC machines are fed a series of instructions that are delivered to an internal computer controller. These instructions are in the form of codes that belong to the numerical control programming language.

The code used to program CNC machines is generically called G-code. However, G-code instructions are only part of the programming language. Specifically, G-codes give CNC machines the coordinates from which to hold and engage the machining tool in order to cut and shape metal to certain specifications. The entire series of codes used to operate CNC machines also include M-codes and T-Codes, which manage the CNC machine and drill tool, respectively. Tooling speed and feed controls are dictated by S-Codes and F-Codes, while X, Y, and Z-codes determine absolute position.

A standardized set of control codes for CNC machines was developed in the early 1960s in the U.S. by a trade organization known as the Electronic Industries Alliance. Roughly 20 years later, the system was revised and dubbed RS274D. Although these codes are still used across the country to assist computer-aided manufacturing (CAM), variations and additions exist among operators and manufacturers of CNC machines. In fact, operators of specific CNC machines need to be educated about the differences between manufacturer’s models to avoid a conflict in programming compatibility.

CNC machines have evolved considerably since their initial introduction into the manufacturing industry. The earliest CNC machines received code instructions through hard-wired controllers, which meant that the programming format could not be altered. However, later models were programmed via mainframe cables and floppy disks, which permitted variations in programming. At present, most CNC machines are tied into a network of computers and receive operating and tooling instructions via a software file containing the “.NC” extension. Although, the file extension varies with each machine shop, depending on its ISO certification protocols.

Today, CNC machines have graduated to encompass entire “cells” of tooling machines that can operate independently of each other. They are driven by the direct upload of CAM software files, eliminating the need for design plans to be physically drawn up. Modern CNC machines are also capable of running overnight or for several days without human supervision. In fact, CNC machines are now so sophisticated that they can dial the chief operator’s cell phone to notify him or her when a tool part breaks, and still complete other parts of the program. These features make it possible to produce thousands of parts while the machine shop is closed or while the operator is performing other tasks.

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

What Is the Molding Pressure

Molding pressure typically refers to a measurement of force within an injection molding machine. In injection molding, plastic resins are melted and pushed into a steel or aluminum mold, fabricating small plastic parts. The mold pressure determines with what force the melted resin is forced through the machine and injected into the awaiting mold.

Solid plastic objects can be fabricated using a process called injection molding. An injection molding machine begins with a large hopper into which small plastic pellets, called resin, are loaded. The pellets are then heated to a certain temperature and melted. Inside the machine, molding pressure determines the speed at which material is passed by a large, rotating screw or ram and injected into the mold. A mold is typically a steel or aluminum block which is hollowed out in the reverse shape of the item to be molded. Then when the melted plastic is injected into the mold and subsequently cooled, it has conformed to the shape and created the part.

The amount of molding pressure should be enough to fill the mold completely, preventing what are known as short shots, or plastic parts that are not formed all the way. If this happens, the molding pressure should be increased. Once the mold is full, the pressure is reduced and stays level while the parts cool. Once the plastic cools, the mold is opened and the part is ejected from the machine.

The manufacturers of resin can assist machine operators with the complex task of determining optimum pressure for the plastic in the machine, but practically speaking, exact pressure is tested through trial and error. Molding pressure affects the velocity — or flow rate — which is another variable, along with temperature and time required to cool the plastic. Once the variables for optimum performance are established, an injection molding machine can be set to these levels for future runs, with minor adjustments necessary from time to time throughout the life of the machine and the mold.

The molding pressure on an injection molding machine is regulated by a pressure gauge and can be programmed to a certain pressure rate. The least amount of pressure needed to fill the mold should be used. This means the least amount of energy will be expended.

In the US, pressure is measured in pounds per square inch (psi). In many other countries, pressure is measured in bars. A bar is equal to 100 kilopascals, or approximately the measurement of the pressure of the atmosphere at sea level.

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

What Is a Plastic Test

A plastic test is any type of test done on a sample of plastic. These tests can be used to determine the strength, flexibility, or durability of a plastic and are often used as a measure of quality control. Laboratories that offer to perform plastic tests use a variety of different machines and techniques to determine the quality of the plastic.

One common type of plastic test is a test of how the plastic holds up under different temperatures. For this type of test, a sample of the plastic is placed in a chamber where the temperature is either raised or lowered at a slow but constant rate. Engineers watch for changes in the quality of the plastic, such as expansion, breaking, melting, or contraction, depending on the specifications of the test, and note the temperature at which the change took place.

Plastics may also be tested for how durable they are under stress. One plastic test that determines durability uses a machine that bends a piece of plastic until it breaks. In another type of test, a piece of plastic may be pressed firmly between two sides of a machine until it compresses or cracks with the strain. Engineers may also use a machine that hits the sample, testing the capacity of the plastic to resist the impact and slow it down. Examining the forces used in each of these types of stress tests gives engineers information about how strong a sample of plastic is.

Some plastics that are intended for use as lenses may also undergo a plastic test that determines how the plastic interferes with light that passes through it. In one such test, a light with a specific wavelength is viewed through the sample, and the color and quality of the light is compared to the color and quality of the same wavelength of light that has not passed through a lens. Haze, or the amount of visible light that is refracted as it passes through a plastic lens, may also be tested in a similar plastic test.

For plastics that are intended for use in different types of conditions, weathering tests may also be performed. A sample can be tested to see how much water it absorbs or to see at what temperature it will catch on fire. A machine that mimics the effects of weather over a long period of time may be used in a plastic test that determines how a sample will hold up over time and exposure to the elements.

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

What Is a Hot Runner

A hot runner is a heated nozzle and manifold assembly installed on injection molding equipment. This assembly allows the plastic charge material left in the feed mechanism to remain fluid after injection while the part itself cools and solidifies. Injection molds equipped with hot runners are more economical, featuring faster cycle times and less material wastage. These savings are possible due to the fact that the manifold and nozzles keep the plastic in them fluid between injection cycles, eliminating the wasted time and material associated with the solidified “runners” in conventional cold molds. Installing a heated runner assembly adds significantly to the cost of any mold, limiting the viable use of the devices to high-production volume processes.

Injection molding is a production process where granulated materials, typically various grades of plastic, are melted and injected into a mold under pressure. Once the injection process is completed, the mold and parts are allowed to cool and solidify, allowing the product to be ejected from the mold cavity. The path within the mold followed by the melted plastic prior to reaching the actual cavity is known as a manifold or runner. Typically, these consist of one or more narrow channels. each ending in a nozzle which forms the cavity entrance. In conventional cold mold processes, the plastic left in these channels and nozzles cools and solidifies along with the molded part.

These solidified sprues or “runners” are then discarded prior to commencement of the next injection cycle. This not only represents material wastage, particularly in cases where the runners can’t be recycled, but also adds a production step to the process. This increases cycle times, cuts down on productivity and increases the unit cost of the parts produced. The use of a hot runner system almost entirely eliminates these problems by keeping the plastic in the manifold channels and nozzle fluid between injection cycles. This is achieved by including electrical heating elements in the manifold and nozzles, which keeps those parts at a constant temperature of approximately 550 to 590 °F (290 to 310°C).

Hot runner heating elements fall into two categories: internal and external types. External hot runner heaters are located withing the manifold body immediately adjacent to the channels and around the outside of the nozzles. Internal heater elements are located within the channels and nozzles. Although the internal heating method is used in some specialist applications and older machines, the more efficient external heating method has largely replaced it. While the use of hot runner systems represents significant savings, the high associated installation costs restrict their use.

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

What Is Coinjection

Coinjection is an injection molding process in which different polymers are injected into the same mold to produce a specific effect. In many cases, the desired effects include changing the physical properties of the polymers or reducing production costs. This process is also known as sandwich molding. There are two types of coinjection processes: machine based and mold based. Each type offers its own specific advantages and applications.

Machine based coinjection requires the use of two or more processing units. This is considered a cold-runner process. The molten plastic of each processing unit is forced through a manifold where it is combined and then exits through a single nozzle. By processing the plastic through this means, the result is a core product covered by a skin of polymer.

Mold based coinjection is a hot-runner process in which the two molten plastics are kept separate until the last phase. The streams are joined when they reach the mold, forming a part with a dual layered effect. This type of molding is commonly seen in household products such as toothbrush handles that have a clear outer surface surrounding a colored core. While this application is suitable for creating certain aesthetic effects, it is also useful in other ways. The combination of a core product with an overlay of polymer allows manufacturers to create a wide variety of different properties for products.

The reduced cooling time required in the coinjection process makes this method a practical technique for low temperature core products. By using an inexpensive recycled core material coated with a more costly polymer skin, the manufacturer can save production costs. In a similar arrangement, a strong core material, such as glass, can be used to add strength and rigidity to a more flexible polymer. In some cases, coinjection molding is combined with a foam core to create products with sound absorption properties.

Aside from the obvious benefits to the manufacturing side of the process, coinjection offers advantages from a consumer and environmental standpoint, as well. This process makes recycling of plastic parts and post-industrial materials possible. These materials are ground and used to form inexpensive cores for injection molded parts. By using recycled materials, it lowers the cost to consumers and eliminates waste products in landfills. The strength added by core choices can also result in more durable, long-lasting products.

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

What Is a Flow Mark

Sometimes known as flow lines, flow marks are a phenomenon that can occur during the process of injection molding. A flow mark is usually manifested as a line or series of lines which form a pattern that is slightly off-color from the rest of the molded material. There are several reasons why this type of pattern can appear, including issues with the speed that the injection is taking place.

The creation of a flow mark is usually an indication that there is some problem with the process used to created the plastics. Most commonly, flow mark patterns occur when the rate of injection is slower than it should be. When this happens, the plastic has time to cool during the injection, resulting in the uneven and somewhat wavy lines that appear in the molded material. Typically, increasing the injection speed will reduce the incidence of the flow mark patterns and allow the plastic materials to have an unblemished appearance.

For the most part, the presence of a flow mark is seen as a defect. This means that manufacturers will normally monitor the efficiency of the equipment used in the injection molding process to make sure the injections are occurring at a speed that is in keeping with company standards. Quality inspectors usually examine samples from every lot of plastic goods produced in order to determine if there is any presence of flow mark patterns, and call for adjustments before the next lot is poured using the same equipment. When there is some sort of malfunction and a piece or several pieces are produced with prominent flow lines, they are often sold as second-quality goods, even though the pieces can normally be used with no apparent decrease in efficiency.

Businesses generally attempt to keep the incidence of those marks as low as possible. This is true when the production process calls for the production of plastic goods that are intended to have smooth surfaces with no lines or patterns in the plastic itself. There are instances in which the creation of the flow mark is intentional, adjusting the speed of the injection so that the plastic does have the chance to cool and form the pattern. By managing the injection at various speed throughout the process, it is possible to create an interesting pattern on the finished piece.

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

Cost Effective Injection Molding Tips from a Design and Engineering Firm

Injection molding is one of the most popular and effective manufacturing processes, because it is capable of producing high quality parts in large numbers, and generally very quickly. In a nutshell, injection molding is when a material (generally plastic) is heated until pliable, forced into a mold made for a specific purpose, allowed to cool and harden, and then ejected from the mold. Depending on how the mold is made (and what material is being injection molded), this process can be repeated over and over in order to create large numbers of a given product. Although popular and effective, injection molding is not a cheap process; projects typically cost between $10,000 and a few hundred thousand dollars to manufacture. Let’s look at some ways to ensure that cost effective injection molding is a reality for your project.

Tips for cost effective injection molding 

Make sure you’re using the right material. Did you know that there are hundreds of plastics (let alone other materials) that can be injection molded? It’s important to consider what function you want a particular piece to accomplish, and which material is most appropriate to make that happen. Does a piece need to be pliable or rigid? Will it be exposed to heat or extreme temperature deviations? How does Factor of Safety affect the materials required for design? It’s a common mistake to assume that a state-of-the-art, top-of-the-line material is the right one to utilize, but if its good qualities aren’t pertinent to your project, then they are essentially useless – and may cost more money overall. For instance, why use a 40% glass filled nylon when polyethylene would do the trick just as well? The best material for injection molding is the one that best fits your requirements and is not simply the better material overall.

Identify where processes can be consolidated. There are a lot of secondary processes involved in producing a part from scratch. Such processes (like custom inserts, label printing, painting, etc.) can prove to be time consuming, as they require extensive setup – and in injection molding, time is money. All those extra costs – and the time that could have been saved with better production management – ultimately drive the part price up. The best practice is to try to combine all of these processes into one single robust process.

Be selective when choosing who does the injection molding. Like most industries, the injection molding industry is full of small, mid-size, and large companies. One or the other may be more appropriate depending on your project. Smaller companies will generally offer more flexibility and lower costs, whereas prices may be driven up with large companies due to higher overhead, higher salaries, and sometimes more advanced technology. In general, it’s best to choose a company that has experience molding your type of product, as it will save time during the research and development part of the project. Remember that bigger and more expensive does not necessarily equal better quality.

Consider bulk production. Molding operations are rarely personal projects or projects that will produce small numbers. In the research and development phase alone, some projects produce hundreds or thousands of prototypes, as many benefits come from extensive testing and feedback. When the product moves into the production phase, it is even more important to be able to mold as many parts in one shot as possible. Molds for production should also have as many cavities as possible without compromising the quality of the parts produced. In a competitive market, a product must be the best it can be while also being affordable. That is why it is advisable to produce as many parts as possible at one time – because it spreads the setup cost out over more parts, thus leaving you with a lower price per piece. You can now sell your product in a competitive market. 

Is the mold design optimized for cost effective injection molding? In mold design, as in bulk production, it is beneficial if you can produce as many parts as possible in a single shot. For mold design, it is also very important to be able to eject the plastic product quickly and to be ready for the next shot without wasting movements. Rods, an air blast, or a plate are typically used for the ejection stage of injection molding. Every second in the injection molding process translates into money, so it is critical to minimize the mechanisms of molding to as few and as fast as possible. A design and engineering firm that is familiar with the nuances of injection molding will create parts that will lend themselves to optimized mold design.

Optimize product design and materials. You can save a considerable amount of money, especially in material consumption, with an optimized product design. Using ribs and gussets to reinforce a product, for example, will save on material consumption, as well as ensuring that the product has uniform wall thickness that is neither too thin nor too thick. Incorporating adequate draft is also essential, as it allows for quick ejection of the product from the mold, saving time and money. If there is a need for a mechanism in the product, there are quite a few to choose from. Many can be incorporated into the molding process without the need for secondary processes or machining. Some mechanisms, such as living hinges, take advantage of the properties of the material that was used to mold the plastic part. These mechanisms can be made directly from the molding process versus spending extra time and money on other processes, such as stamping.

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

5 Different Design Methodologies in Solidworks

Five design features in Solidworks that every design engineer should know

Designing in Solidworks starts with a 2-dimensional sketch. From a 2D sketch one can create 3-dimensional objects using built-in tools called “features.” Features are simply different ways of converting 2D outlines into 3D objects. Two of the most common tools (methods) for doing this are extrusions (the “extrude” feature) and revolutions (the “revolve” feature).

  1. Extrusions: The Extrude feature takes a 2D sketch in the x-y plane and gives it thickness or depth by developing it linearly in the z-axis. For example, a sketch of a circle would be extruded into a cylinder. A sketch of a square would be extruded into a rectangular block (or a cube in the event the thickness were made to be the same as the x and y dimensions).
  2. Revolutions: solidworks tips for design engineersThe Revolve feature takes a 2D sketch in the x-y plane and gives it thickness or depth by rotating it about one of the two sketch axes (i.e. the x or y axis). A commonly known item that demonstrates the utility of the revolve feature is a pawn from the game of chess. An otherwise extremely intricate piece to design, the revolve feature allows the designer to develop a 2D profile which is rotated about the vertical axis for 360 degrees and easily completes the part.

Although extrusions and revolutions are some of the most common features used to design parts in Solidworks, they are nowhere near the only available options. Here are three more features that help round out a basic inventory of design tools:

  1. Sweeps: The designer can create parts using multiple sketches on perpendicular planes. One sketch will act as the profile and the other will act as the path. The profile sketch is dragged along the path to create the 3 dimensional object. The sweep feature is very effective for things like handles or pipes.solidworks tips for design engineers
  2. Surfaces and Lofts: Surfaces typically work similar to sweeps in that they utilize profile and path sketches but they also introduce guide curves. Guide curves act as a second path of sorts in the event that the surface is not going to be symmetric about the path. Surfaces are great for things like handles or nozzles. Additionally, surfaces are hollow by default (the designer simply applies a thickness to the shape which is different than most solid parts). Lofts are typically used to connect different pieces into a single part by using mathematical equations that blend the curves between parts according to the designer’s inputs.
  3. Sheet Metal: Sheet metal drawings are the most effective way to design parts that are actually manufactured by sheet metal forming (adding flanges and bends to a flat “sheet” of metal).solidworkstips.png

In truth, even these five features are only the beginning. There are a great many other tools to design and refine the design of various parts such as patterns (linear and circular are very common), holes, and a built-in toolbox for off-the-shelf (OTS) components. When determining which tools and/or features to use in your design, it is often useful to think about how the part will be fabricated once you are finished with the design. Some processes are subtractive (such as CNC), while others, like sheet metal work, manipulate a flat surface in different ways. Sometimes it is easy to buy components from manufacturers that make their Solidworks files available on the web. Sometimes parts are combined via fasteners and in other instances they might be welded together. Solidworks has powerful design tools for all of these decisions and more.

Pro Tip: Once you’ve settled on the right design, think about how you’ll display it to your clientele. What types of files do you want to export when you are finished with your design? The three most fundamental file types are .sldprt (the basic file extension for a part designed in Solidworks), .sldasm (the basic file extension for an assembly of multiple parts designed in Solidworks), and .slddwg (the basic file extension for a Solidworks drawing). But are these the right files to send to a customer?

  1. Sending files to customers: Oftentimes when we send files to a client it will be as a .STP or .STEP file. The interesting thing about this file type is that it doesn’t display the individual features that were used to build the part but rather simply displays the part as a single piece. E-drawings are another good way to send pictures or videos of the design to individuals who do not have Solidworks on their computer. Functional depictions of designs can be exported in multiple formats such as html, .exe (executable files) or .zip.
From Website
Edited by Leafly Mould Provides Injection Mold, Plastic Mold, Injection Molding, Die Casting Mold, Stamping Mold