Plastic Injection Molding is one of the most versatile operations for the manufacture of high-quality plastic parts. When developing a new product, the material selection usually factors in the end-use, cost, color, availability of the resins and ease of use. Today, we explore the many categories of applications that developers might use plastic parts for and evaluate some of the most important considerations for each class of project application.
Food Grade
Food grade plastics are generally plastic resins that are considered and certified safe for use in food packaging, cooking and production. Because of how delicate food is, these plastic parts must not be sterile, non-biodegradable, non-absorbing and not impart any additional flavors to the food item stored within them.
One of the most common options here is Polyethylene terephthalate (PET) packaging. Another is the Low-density polyethylene (LDPE). PET is commonly used for storing non-carbonated and carbonated soft drinks, water and other foods. These plastics are tough, breakproof, abrasion-durable, lightweight and recyclable. LDPE is used for making cling films to cover food and other food bags such as Ziploc bags. High-density polyethylene (HDPE) is used in making plastic chopping surfaces while polypropylene can be used to make coffee and yogurt cups.
Engineering grade
Engineering grade plastics include Polyetheretherketone (PEEK), Polyoxymethylene (POM), Acrylonitrile butadiene styrene (ABS) and Polyamide (Nylon). These are high-grade crystalline polymers that have strong mechanical properties. They are durable and tough like metals but offer the advantage of being lightweight and more affordable to produce.
Asides plastic injection molding, all of these materials can be 3D printed. They have low friction and are usually temperature resistant. Engineering grade plastics would often be employed in the production of gears, shafts, plastic gun parts, switches and ball bearings. Their high strength and lightweight makes them the perfect candidates in both aerospace and automotive industries.
Fire-retardant
As plastics are used in a variety of industries, there is always a need to make components that may be required to be fire-retardant. Plastics will naturally burn in the presence of fire, however, not all plastic are flammable.
Some plastic materials are actually self-extinguishing such as PVC (Polyvinyl chloride). This is because the chlorine helps to rid the flames of oxygen. Others will simply not burn depending on the type and extent of treatment they have received. Because of the need to use plastic parts in automobiles or airplanes and other confined spaces, manufacturers have to select fire-retardant and self-extinguishing plastic parts and coat them with other substances and impurities that will disrupt the normal burning process in the case of a mishap. The ULVO-40 is the most popular fire-retardant plastic resin known today as it will not burn or drip molten plastic on the floor.
Bio-compatible/Medical
The medical industry has undoubtedly seen an increased application of plastic resins over the last 10 years. Today, resins can be used in making prosthetics, heart monitors, infusers, pill dispenses, valves, artificial joints, bone replacements, cranium caps, blood stents and more. Because of how delicate these project applications are, there is a biological risk that must be efficiently mitigated before any plastic resin can be used.
Each type of plastic resin serves an array of function including skin contact areas, internal medicines and those used for medical parts/equipment such as PEEK, PVC, HDPE, PMMA and POM. PPSU, PMMA and HDEP is ideal for internal medicine while PE, Nylon, Teflon, PEEK, PP and PPSU are great for skin contact. Epoxy is the ideal solution for dental implants.
Impact resistant/Flexible/Elastic
ABS and High-impact polystyrene are the kings of this category. Projects that require elastic plastics and impact-resistant resins are those where the end-part will be exposed to repeated forces and return to its original shape without losing its elasticity or breaking.
These categories of plastic can be used in the sport industries to make mannequins that can take a lot of punches and force. ABS and HIPS can also be used in making tool boxes and power tool housings, or as alternatives to glass as transparent plastic. Polycarbonate (PC) can also be used to make windshields for motorcycles or eye glass lenses for plastic frames.
For project applications requiring a significant amount of flexibility, Polypropylene is the most suitable material for making parts that will repeatedly flexed during the lifespan of the product. These may include items such as pill dispensers, shampoo bottle caps and more while Thermoplastic polyurethane can be casted to make sealing rings, gaskets caster wheels, skateboard wells and other sporting equipment. TPU is stretchy and rubber but still boats of decent strength and durability.
High-quality Plastic Injection Molding and CNC Machining in China by FirstPart
At FirstPart, we offer an extensive variety of in-house prototyping and manufacturing service that helps all our customers achieve all their project applications for plastic injection tooling parts. We deliver high-quality injection molding, urethane casting and CNC machining that can be used with the best combination of plastic resins to deliver the best results on your project. Click here to contact us today and request a quote for both low-volume manufacturing and mass production. Our designers are always available to work with you to help optimize your design for optimal yield.
