INJECTION MOLDING PROCESSES

>INJECTION MOLDING PROCESSES
INJECTION MOLDING PROCESSES 2020-09-17T11:14:46+00:00

PLASTIC INJECTION MOLDING SERVICE

At RJC , we specialize in high-quality custom plastic injection molding and mold tool making. Plastic injection molding is by far the industry’s most common way to manufacture plastic parts, especially when making larger quantities. We provide custom molding for 50 to 100,000+ injection molded parts as well as a wide range of other manufacturing and finishing services to complete your project.

WHAT IS PLASTIC INJECTION MOLDING?

Plastic injection molding involves melting granular plastic pellets into a liquid form and then compressing this liquid into the empty cavity of a mold tool. The plastic will retain the shape of the mold as well as the surface texture of the walls of the cavity. After an optimized injection and cooling phase, the now solidified plastic part is ejected and the molding cycle is repeated. This molding cycle can take from as little as a few seconds to several minutes depending upon part size, molding resin and part design.

In addition, Insert molding and overmolding are other kind of molding in injection processes. RJC can support your next projects with dedicated molding process.

ADVANTAGES OF PLASTIC INJECTION MOLDING

• We have thousands of different types of plastic available for you to choose from, for a wide range of mechanical and cosmetic properties.
• Plastic injection molding is great for larger volumes with production mold (Reasonable lifespan Of Mold Tool) . For smaller volumes we might recommend Soft Mold ( sampling Mold ) depending on the needs of your project.
• Hundreds of thousands of parts can be produced from a single mold tool.
• Your part can have excellent surface quality finishes in a wide range of polishes and textures.
• Injection molding allows you to do overmolding to combine different types of plastic in one piece. It is ideal for lightweight parts that are immune to corrosion.

Injection Molding Plastic Materials RJC Use

  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    5000-7500 psi270,000-380,000 psi3.0-7.5 ft-lb/in notched izod140°-200° FPoor to Fair

    Advantages

    • Good impact resistance with toughness and rigidity
    • Metal coatings have excellent adhesion to ABS
    • Excellent processability and appearance

    Disadvantages

    • Poor solvent resistance
    • Low dielectric strength (not a good insulator)
    • Low continuous service temperature (melts easily)
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    6400-9150 psi300,000-400,000 psi8-12 ft-lb/in notched izod140°-210° FPoor to Fair

    Advantages

    • Good impact resistance with toughness and rigidity
    • Metal coatings have excellent adhesion to ABS
    • Very good indoor UV light colour stability
    • Excellent processability and appearance

    Disadvantages

    • Poor solvent resistance
    • Low dielectric strength (not a good insulator)
    • Low continuous service temp. (melts easily)
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    6000-22,000 psi120,000-170,000 psi.8-2 ft-lb/in notched izod180°-300° FExcellent

    Advantages

    • High tensile strength with rigidity and toughness
    • Good impact and solvent resistance
    • Glossy molded surface
    • Low static and dynamic coefficients of friction (slippery)
    • Many grades have FDA and NSF approvals on food and water contact
    • Replace die–cast metal components

    Disadvantages

    • Difficult to bond bond
    • Poor resistance to acid and bases
    • Subject to UV degradation
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    2800-10,9000 psi221,000-534,000 psi.22-1.1 ft-lb/in notched izod183°-217° FExcellent

    Advantages

    • Excellent optical clarity
    • Excellent weatherability and resistance to sunlight
    • Rigid with good impact resistance
    • Good light transmission

    Disadvantages

    • Poor solvent resistance
    • Subject to stress cracking
    • Slightly absorbs moistures
    •  Continuous service temp. (melts easily)
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    6,000-24,000 psi390,000-1,100,000 psi2-8 ft-lb/in notched izod200°-350° FGood to Excellent

    Advantages

    • Temperature capability 600°-700° for short term
    • Excellent chemical resistance
    • High resistance to abrasion
    • Tough and withstands repeated impact

    Disadvantages

    • Absorbs moisture (can affect the electrical and mechanical properties)
    • Requires UV stability
    • Attacked by strong acids/bases
    • High notch sensitivity
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    8,000-24,000 psi430,000-1,100,000 psi2-8 ft-lb/in notched izod220°-350° FGood to Excellent

    Advantages

    • Temperature capability 600°-700° for short term
    • Excellent chemical resistance
    • High resistance to abrasion
    • Tough and withstands repeated impact

    Disadvantages

    • Absorbs moisture (can affect the electrical and mechanical properties)
    • Requires UV stability
    • Attacked by strong acids/bases
    • High notch sensitivity
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    6,000-13,000 psi300,000-1,200,000 psi1 ft-lb/in notched izod250°-420° FFair to Good

    Advantages

    • Good flow
    • Tough
    • Hydrollysis Resistant
    • High impact
    • Easily Processed

    Disadvantages

    • Low Max. Use temperature
    • Lower Stiffness than similar PET
    • Lower Strength than similar PET
    • Attacked by Strong Bases
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    9000-23,000 psi340,000-1,400,000 psi2-18 ft-lb/in notched izod150°-300° FPoor to Fair

    Advantages

    • High impact resistance
    • Clarity
    • Good flammability performance
    • Dimensional stability
    • Chemical resistance (PC blends)

    Disadvantages

    • Only fair solvent resistance
    • Subject to stress cracking
    • Degrades if not processed correctly
    • High processing temperature
    •  Yellowing after long term exposure to UV light
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    14,000-28,000 psi480,000-1,300,000 psi2 ft-lb/in notched izod375°-420° FFair to Good

    Advantages

    • High heat resistance
    • Exceptional strength and impact modulus
    • High dielectric strength
    • Broad chemical resistance
    • Biocompatible
    • Excellent machinability and finishing characteristic
    • Outstanding processability on conventional molding equipment
    • Flame resistance with low smoke evolution

    Disadvantages

    • Translucent and opaque-clear is not available
    • High cost
    • Notch sensitive
    • High processing temps required
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    1900-4500 psi40,000-105,000 psi2-No break ft-lb/in notched izod130°-150° FGood to Excellent

    Advantages

    • Low Cost
    • Impact resistance from -40° to 194° F
    • Moisture resistance
    • Food grades available

    Disadvantages

    • Poor weather resistance
    • High thermal expansion
    • Subject to stress cracking
    • Difficult to bond
    • Flammable
    • Poor temperature capability
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    1,200-4,000 psi35,000-48,000 psiNo break ft-lb/in notched izod130°-150° FGood to Excellent

    Advantages

    • Low cost
    • Impact resistance from -40° to 194° F
    • Moisture resistance
    • Food grades available

    Disadvantages

    • Poor weather resistance
    • High thermal expansion
    • Higher cost
    • Subject to stress cracking
    • Difficult to bond
    • Flammable
    • Poor temperature capability
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    3,200-4,500 psi145,000-225,000 psi.4-4 ft-lb/in notched izod130°-150° FGood to Excellent

    Advantages

    • Low cost
    • Impact resistance from -40° to 194° F
    • Moisture resistance
    • Food grades available

    Disadvantages

    • Poor weather resistance
    • High thermal expansion
    • Subject to stress cracking
    • Difficult to bond
    • Flammable
    •  Poor temperature capability
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    4,500-18,500 psi210,000 -1,500,000 psi1.4-5.5 ft-lb/in notched izod150°-300° FExcellent

    Advantages

    • Excellent moisture resistance
    • Food grades available
    • Mold–in hinge possible
    • Good impact strength

    Disadvantages

    • Degraded by UV
    • Flammable (retarded grades available)
    • Attacked by chlorinated solvents
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    9,000-33,000 psi270,000 -2,700,000 psi.6-22 ft-lb/in notched izod300°-450° FGood to Excellent

    Advantages

    • Heat resistance
    • Chemical resistance
    • Can resist infrared soldering environments
    • Relatively low moisture absorption
    • Strength or physical properties

    Disadvantages

    • Not inherently flame retardant
    • Requires good drying equipment
    • High processing temperatures
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    14,000-28,000 psi550,000 -2,900,000 psi.5-6 ft-lb/in notched izod450°-500° FGood to Excellent

    Advantages

    • Capable of extended usage at 450° F
    • Good radiation resistance
    • Good solvent and chemical resistance
    • Excellent dimensional stability
    • Flame retardant
    • Low water absorption

    Disadvantages

    • Difficult to process (high melt temps)
    • High cost
    • Fillers required to obtain good impact strength
    • Attacked by chlorinated hydrocarbons
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    10,000-18,000 psi500,000-1,200,000 psi.3-3.0 ft-lb/in notched izod140°-200° FPoor to Fair

    Advantages

    • Heat Resistant
    • High Clarity
    • High Flow and Rigidity
    • Dimensionally Stable

    Disadvantages

    • Low impact strength
    • High processing temps
    • Flammable-smoke generation
    • Yellows quicker than other PS
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    1,000-7,000 psi5,000-800,000 psi2.5-No Break ft-lb/in notched izod200°-300° FFair to Good

    Advantages

    • Low compression and tension set
    • Easily processed
    • Fatigue resistance
    • Good tear strength

    Disadvantages

    • Flammable but flame retardant grades available
    • Extensive heat aging causes severe change in mechanical properties
    • High cost
  • 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 StrengthFlexural ModulusImpact StrengthMax Temp.Chemical Resistance
    6960-12,000 psi260,000-340,000 psi.80-10.1 ft-lb/in notched izod160°-250° FFair to Good

    Advantages

    • Chemical Resistant
    • Low temp. flexibility
    • Abrasion and wear resistant
    • Easily Processed

    Disadvantages

    • Shorter shelf life
    • Lower Stiffness than similar PET
    • Drying required pre-processing
    • Narrow hardness range