An abundance of materials is accessible for injection molding, one of the most frequent manufacturing methods for industrial parts. Materials like PC-ABS and injection-molded PEEK are included in this collection of engineering materials.
The material you choose for each component should be considered. It’s essential to think about the part’s utility, efficiency, and cost when making this decision. While some materials may be more popular than others, production does not have a one-size-fits-all solution. Ultimately, the application of your part will dictate the material you use. It can be crucial to distinguish between “desires” and “requirements” in a manufacturing project to keep costs and schedules in check.
What to consider when selecting the suitable material for injection molding
1. The flexibility of the injection molding material
The most excellent load that a material can withstand or the application dictates which material to use. While certain materials are hard and durable, others are pliable and readily broken. While some materials can endure significant loads and stresses, others are brittle and prone to breaking under pressure. Stiffness testers on a scale of 0 to 100 can be used to measure the flexibility of a material. The content becomes more difficult as the score rises. ABS and PC are two examples of hard materials, while HDPE and PVC are soft ones.
2. The degree of chemical exposure
Chemicals have varied effects on different plastics. Certain plastics are resistant to strong chemicals, whereas others degrade even in the presence of weak chemicals. You must choose a material that can tolerate oils, chemicals, cleaning agents, etc. depending on the use.
3. The Temperature range
This term relates to a material’s behavior under conditions of severe heat or cold. At elevated temperatures (or, in the case of thermoset materials, burning), certain materials may begin to deteriorate or even melt, while others may become more brittle in extreme cold.
4. The material resistance to UV resistance
UV resistance is just as critical as temperature resistance in outdoor applications. UV resistance is a material property that indicates its capacity to maintain its qualities — strength, form, and appearance — when exposed to ultraviolet sunlight.
5. The viscosity of the material
It is common practice to use a low viscosity material for complex components to facilitate the flow of material into molds. This ensures that the cavity is properly filled with material. As a result, viscosity is an important consideration when selecting a material.
6. The Materials hardness and density
Consider the types of forces to which your parts may be subjected throughout their use when developing your design. If material is subjected to a variety of stresses, it will function differently. Density affects the strength of a material. Thus you must choose a material based on its intended use.
7. The cost of the materials
A variety of materials are available to choose from. Polyethylene and Polypropylene, two of the most common commercial plastics, are high-density and low-heat, easy to obtain, and relatively inexpensive. Engineered plastics, such as PEEK and PEI, fall into the second category. These are extremely expensive and hard to come by, but the tradeoff is that they provide a lot of heat and stiffness.
8. The Regulator requirements and guidelines
As the cost of your part increases, it’s crucial to determine what is necessary and what isn’t essential in terms of compliances. You need to determine whether or not your part must be food-safe and meet FDA regulations. Does it have to meet medical standards, ISO requirements, or other standards?
9. The Cosmetic Requirements of the project
Are there any restrictions on the transparency of the portion, or can it be any color? You may have to do color matching if your part is part of an assembly that needs to match other components. Using finishing standards, such as SPI, you may have a good idea of what kind of surface treatment you should use for your parts, from optically polished SPI-A1 to coarse matte SPI-D3. MoltTech’s mold texturing, for example, is another method for creating cosmetic faces.
Some efficient injections molding materials to select from
Thermoplastic Material types to select from
1. Polypropylene Injection Molding (PP)
Low-cost, light-weight, and chemically resistant, PP is an ideal material for use in packaging. Plastics made from Polypropylene are resistant to fatigue, strong, and reinforced with glass fibers or minerals to improve mechanical performance.
2. High-Density Polyethylene (HDPE)
This flexible thermoplastic polymer can benefit from toys, storage containers, sporting items, appliances, and milk crates.
3. Low-Density Polyethylene (LDPE)
Softer than HDPE and widely used in consumer and industrial items, LDPE is a popular choice.
4. Polyvinyl Chloride (PVC)
Most other types of plastic are lighter than PVC but heavier than metal pipes that they have replaced. Water, sewer, windows, siding, and other building materials are commonly made of PVC.
5. Polyethylene Terephthalate (PETE)
Despite its low weight, PETE is surprisingly robust. Known by the trade name “polyester,” it is the most widely used thermoplastic polymer globally.
Office items, food processing and storage, consumer products, and construction are all common uses for this material.
7. High Impact Polystyrene (HIPS)
HIPSis a versatile, inexpensive, and impact-resistant material that may be used in various applications.
Engineering material types to select from
1. ABS Plastics Injection Molding
In injection molding, ABS is a popular thermoplastic because of its high impact strength and toughness and its mechanical and electrical qualities.
2. Acrylic Injection Molding (PMMA)
Polymethyl methacrylate, or PMMA, widely known as Plexiglas® and Lucite ®, is a glass alternative with numerous excellent qualities when used in plastic injection molding applications.
3. Polyurethane (TPU)
Thermoplastic polyurethane (TPU) is a flexible, versatile, and robust material available in ether and ester-based formulations.
4. Nylon (PA)
nylon is one of the most versatile, cost-effective, and high-performance plastics on the market. The PA 6 and PA 66 varieties of Nylon are the most widely used. Good heat resistance, wear resistance, and lubricity are among the many advantages of Nylon.
5. Thermoplastic Elastomer (TPE)
TPE blends the practical and adaptable features of rubber and plastics into one material.
6. Thermoplastic Polyurethane Elastomer
In applications that require the flexibility of rubber and high tensile and tear strengths, TPU is an excellent choice.
7. A thermoplastic alloy for engineering
Alloys with increased strength and toughness across a wide range of attributes
It is a tough, engineering-grade thermoplastic that provides high impact resistance and strength in many demanding applications, such as bulletproof glass.
8. Terephthalate Polybutylene (PBT)
With strong chemical resistance to a wide range of chemicals such as aliphatic hydrocarbons, oil, grease, dilute acids, and bases and detergents, PBT is a good choice for a wide range of applications.
Some materials with great performance
1. Polyetherimide (PEI)
PEI is a high-performance polymer with excellent dimensional stability and extensive chemical resistance that can be used in medical, electronic, and other industries that require outstanding strength and stiffness in high-heat applications. PEI is well-suited to settings that are both hot and wet.
2. Polyphenylene Sulfide (PPS)
Engineered thermoplastic PPS offers the broadest chemical resistance of any thermoplastic. As a result, PPS is an excellent thermoplastic for use in highly corrosive and high-temperature situations, as well as chemically stressed.
There are additional considerations to keep in mind, such as the simplicity of processing, the availability of materials, and the environmental impact of your choice. Machining services providers will always be ready to assist you if you’re unsure what type of plastic you should use for your injection molding job. Get in touch with one today.