When deciding what material to use when custom manufacturing plastic parts, there are many factors to consider. Different products have different application scenarios, required material properties, functional requirements, environmental conditions, costs, processing performance, etc. In addition, each plastic material has its own unique properties and advantages. Therefore, if you want to customize the right plastic parts, you must choose the right plastic material.
Points to Consider When Choosing Injection Molding Materials
To fully understand how to choose the perfect material for your plastic part, you need to understand your product. So, consider these questions when weighing your options.
What is the intended use of your product?
First, you need to consider how your product will be used. Will it be used with liquids? Will it need to withstand high temperatures or pressures? Will it come in contact with food or be used for medical purposes? Having a clear understanding of how your product will be used will be a major factor in determining what kind of plastic you need.
If you know you will be using your product to contain or withstand contact with liquids, then you need to choose a material that will stand up to the work.
How durable does it need to be?
Durability is another important factor to consider when determining which plastic material is best for your needs. If your product is sold as a disposable item, such as a disposable cup or plastic shopping bag, you can choose a less durable plastic material. On the other hand, if your product needs to stand the test of time, you will want to use a stronger resin that will not decompose.
Does it have standards or regulations that need to be met?
If you are manufacturing a product that must meet specific regulations or standards, you should pay attention not only to choosing the right plastic material, but also to choosing a certified manufacturer to produce it. If you are manufacturing a plastic medical device, you need to make sure that the material you use is biocompatible. In addition, the manufacturer you work with must be certified by ISO 13485. For plastic products in the pharmaceutical or food industries, you need to consider the material’s resistance to various solvents and heat. Some of the most common agencies that require detailed regulations include the USDA, NSF (National Health Foundation), 3A Dairy (Dairy Equipment), United States Pharmacopeia (USP), and Canada AG. The latter is important in Canada if you plan to sell plastic food containers there.
How do you want it to look?
Since the aesthetic quality of a product influences whether people buy it, you also need to consider how the finished product of a particular plastic material will look, i.e. what kind of surface finish is required? Do you want a matte or high-gloss finish? Should the material be translucent or opaque? Will the product need to be painted or glued after it is manufactured? The answers to these questions will help you determine the plastic you need to get the right look.
What are your production needs for your product?
For products in preliminary experiments, Urethane Casting or 3D printing can be used to save costs and ensure product quality. For different quantities of products, the choice of injection mold material will be different. The life cycle of injection molds is also different. Of course, Elimold engineers will choose the most suitable solution for you according to your ideal quantity. At present, we have 2 mold teams with 20 years of mold experience, each team has 10 people, just to make the best products.
The available options for manufacturing plastic parts are wide and varied. Therefore, it can be overwhelming to decide which material is right for your product. After answering these questions, contact a professional to discuss which material can meet all your needs. With the right advice and the right resin, you can ensure that you get the perfect plastic product.
Injection molding material types and application scenarios
General plastics
- Polyethylene (PE): divided into high-density polyethylene (HDPE), low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE). It has good low-temperature resistance, chemical stability and electrical insulation, good processing performance and low cost. It is often used to make plastic films, pipes, containers, etc., such as plastic bags and plastic bottles in supermarkets.
- Polypropylene (PP): It is a crystalline plastic that is colorless, odorless and non-toxic. It has high heat resistance and can be boiled and sterilized at 100°C. It has good fluidity, excellent molding performance, high yield strength and good electrical properties, but poor fire safety and poor weather resistance. It is widely used in automotive parts, home appliance housings, daily necessities, such as automotive interiors, plastic tableware, etc.
- Polystyrene (PS): It is an amorphous polymer, a colorless, transparent granular substance with high light transmittance, strong tinting power and high hardness, but the product is brittle, prone to internal stress cracking and poor heat resistance. Mainly used in the manufacture of packaging products, disposable medical supplies, toys, electrical components, such as electrical housings, foam plastics, etc.
- Polyvinyl chloride (PVC): has good chemical corrosion resistance, flame retardancy and electrical insulation, but poor thermal stability, and stabilizers need to be added during processing. It can be divided into hard PVC and soft PVC. Hard PVC is often used to manufacture pipes, door and window profiles, etc., and soft PVC is often used to manufacture wire and cable sheaths, films, artificial leather, etc.
Engineering Plastics
- Nylon (PA): Also known as polyamide, it has high crystallinity, high mechanical strength, good toughness, high tensile and compressive strength, outstanding fatigue resistance, wear resistance, corrosion resistance, heat resistance, non-toxicity, and excellent electrical properties, but poor light resistance, easy water absorption, and acid resistance. It is widely used in automobiles, machinery, electronics and other fields, such as automobile engine parts, gears, bearings, etc.
- Polycarbonate (PC): Commonly known as “bulletproof glass”, it is non-toxic, tasteless, odorless, transparent, flammable, but can self-extinguish after leaving the fire. It has special toughness and hardness, the best impact strength among all thermoplastic materials, excellent creep resistance, good dimensional stability, high molding precision, and good heat resistance. It is often used to make automobile lampshades, building doors and windows, optical lenses, electronic and electrical housings, etc.
- Polyoxymethylene (POM): also known as steel material, has a high degree of crystal structure, excellent mechanical properties, high elastic modulus, high rigidity and surface hardness, low friction coefficient, excellent wear resistance and self-lubricating properties, second only to nylon, but cheaper than nylon, good solvent resistance, but not resistant to strong acids, strong alkalis and oxidants. Commonly used in the manufacture of mechanical parts such as gears, bearings, sliders, valves, etc.
- Acrylonitrile-butadiene-styrene copolymer (ABS): synthesized from three monomers of acrylonitrile, butadiene and styrene, with high mechanical strength and good “tough, tough, steel” comprehensive properties, easy to process, stable in size, and has good comprehensive physical and mechanical properties. Widely used in automobile, small appliance housing injection molding, electronics, toys and other industries, such as automobile housing, appliance housing, toys, etc.
Special plastics
- Polyetheretherketone (PEEK): It has extremely high heat resistance, chemical corrosion resistance, mechanical strength and wear resistance. The long-term use temperature can reach 260℃ and can be used in harsh environments. It is often used in aerospace, medical equipment, electronics and other fields, such as aircraft parts, artificial joints, electronic connectors, etc.
- Polyphenylene sulfide (PPS): It has excellent high temperature resistance, chemical corrosion resistance, flame retardancy and mechanical properties, and can be used for a long time in high temperature environments above 200℃. It is mainly used to manufacture automotive engine parts, electronic and electrical parts, chemical pipelines, etc.
- Polytetrafluoroethylene (PTFE): Commonly known as the “King of Plastics”, it has an extremely low friction coefficient, excellent chemical corrosion resistance, high temperature resistance and electrical insulation, and is almost insoluble in all solvents. It is often used to manufacture seals, bearings, pipes, valves, etc., such as coatings for non-stick pans and linings for chemical pipelines.
Thermoplastic Elastomers
- Thermoplastic Polyurethane (TPU): It has good elasticity, wear resistance, oil resistance and weather resistance, and can be used in the temperature range of -40℃ to 120℃. It is widely used in the fields of shoe materials, pipes, films, automotive parts, such as sports shoe soles, automotive oil pipes, etc.
- Styrene-Butadiene-Styrene Block Copolymer (SBS): It has good elasticity and processability and can be blended and modified with a variety of plastics. It is often used in the manufacture of rubber products, adhesives, waterproof materials, etc.
- Thermoplastic Vulcanizate (TPV): It is a dynamically vulcanized thermoplastic elastomer with excellent elasticity, wear resistance, aging resistance and oil resistance, and can be recycled. It is often used in automotive parts, building seals, wires and cables, etc.
Conclusion
Choosing the right plastic material in injection molding is the key to ensuring product quality and performance. When choosing plastic materials, multiple factors need to be considered, including product functional requirements, environmental conditions, cost, and processing performance. Understanding the characteristics of different plastic materials, considering product functional requirements and environmental conditions, evaluating cost and processing performance, and referring to existing successful cases and experience are all important steps in choosing the right plastic material. At the same time, communicating and cooperating with professional injection molding manufacturers can obtain more professional material selection advice and support. Only by scientifically and rationally selecting plastic materials can we ensure that the product has good quality and performance during the injection molding process.