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

Injection Molding Definitions and Terminology

Tooling

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.

Gate

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

Vestige

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

Shear

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.

Runner

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.

Sprue

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)

Slide

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

Gibbs

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

CAM/HORN PIN

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)

Undercuts

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.

Core

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)

Cavity

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.

SLA

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

FDM

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.

Operator

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.

Boss

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

Ribs

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)

Warp

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.

Draft

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.

 

From Website
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

Internal & External Threading

Internal & External Threading

Injection Molding Threading

Adding threads to your injection molding project gives you the ability to fasten your plastic parts to other components securely with relative ease.

At Xentric we can handle any thread design.  Currently we are making threaded injection molded parts for all industries including; medical, aerospace, defense and Automotive.

Give us a shot on your next injection molding project.

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

Surface Finishes

No matter what kind of surface finish you desire, Xcentric will be sure to exceed your expectations.

Available Surface Finishes from Xcentric

  • B3 320 Paper
  • B2 400 Paper
  • MT-11020 Heavy Bead Blast
  • MT-11010 Light Bead Blast
  • A3 Smooth Finish
  • A2 Optical Smooth Finish

During the part design consider the relationship between cost, lead time and surface finish. Typically higher level finishes like A3 or A2 will increase the tooling cost significantly.

Surface finishes play a key role in both function as well as the look and feel.  Parts that are hidden in the assembly may not require a surface finish at all.  In contrast, exposed components might need to be visually appealing.

If your parts will not be visible in the end product a lower finish option is typically selected.

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Flash

Parts with flash boil down to one or two issues.  First, Flash is when material seeps beyond the boundary of the part.  There are three causes. Either the tool is damaged,  the part is being over packed or the molding machine is too small to hold the mold halves closed while under pressure..

Tool damage requires an experienced tool engineer  to make a repair.  Sometimes this can cause extensive delays in delivery.

Over packing a part is generally not enough to cause it to flash.  However, when extra pressure is trying to force more plastic into the cavity, even a .003 gap in the shut off can leak.

Wrong sizing of the molding machine can result in the mold blowing open while under pressure.  Be sure that the correct tonnage is calculated.  As a  general rule of thumb, 2 to 5 ton of clamp tonnage per square inch of projected part area.  For example, if you have a part that is 3 inches x 5 (depth is not calculated in area) that is 15 square inches.  So that is between 30 and 75 tons of clamping pressure needed.

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Sink & Warp

Warp in injection molding is caused by the part wall sections being inconsistent.  As the part cools the thick sections will shrink more than the thin sections.  As a result the thin section will be pulled in toward the thick section thus resulting in warp.   Additionally, if the part is informally thick it can cause sink issues and unstable dimension caused by excessive shrink.

Sink Marks in injection molding can also be caused by features adjacent to nominal walls.  For example, if a wall has a rib or a boss protruding from it ant the width of the boss or rib is greater than 60% it can result in a witness or sink mark on the opposite side of the adjacent wall.  The above illustration is a part that has 2 bosses on the reverse side.  Bot of these bosses are larger than 60% of the wall section they are attached to.  Causing sink marks on the reverse side of the part.

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Close Tolerances

When designing parts with tight tolerances it is important to consider the tolerance of the plastic being used.  This is one mistake many design engineers make when designing a part for the injection molding process.  For example, if the shrink tolerance on a materiel is between .004 and .008 per inch.  Then it would make no sence to require your injection molder to hold less than .004 as the range is .004.  When tighter tolerances or repeatability is required try choosing a material  with low stable shrinkage.

If your project has tight tolerances usually less than .004 per inch or .1 mm.  It is advised to leave key dimensions stock safe and later groom those dimensions into tolerance.  This will save a lot of money in tooling cost as stock safe changes are much cheaper than adding stock.

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