{"id":3585,"date":"2026-10-29T14:26:07","date_gmt":"2026-10-29T06:26:07","guid":{"rendered":"http:\/\/www.circutor-rus.com\/blog\/?p=3585"},"modified":"2026-10-29T14:26:07","modified_gmt":"2026-10-29T06:26:07","slug":"what-materials-can-be-used-in-an-injection-molding-machine-4e28-f30c43","status":"publish","type":"post","link":"http:\/\/www.circutor-rus.com\/blog\/2026\/10\/29\/what-materials-can-be-used-in-an-injection-molding-machine-4e28-f30c43\/","title":{"rendered":"What materials can be used in an injection molding machine?"},"content":{"rendered":"

If you\u2019ve ever watched a plastic water bottle, a child\u2019s toy, or a automotive interior trim part roll off a production line, there\u2019s a good chance it was made on an injection molding machine. As someone who\u2019s been supplying and supporting these machines for over a decade, I get asked one question more than any other: \u201cWhat materials actually work in an injection molding machine?\u201d It\u2019s not a trivial question\u2014choosing the wrong material for your process can lead to warped parts, broken tools, or even machine downtime that costs you thousands in lost revenue. Today, I\u2019m breaking down the most common materials we work with, how they interact with injection molding, and what you need to know to make the right choice for your line. Injection Molding Machine<\/a><\/p>\n

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First, let\u2019s start with the basics: injection molding works by melting raw material pellets into a viscous melt, injecting that melt into a cooled mold cavity, and holding pressure until the part solidifies. The material has to flow smoothly enough to fill the mold, but it also needs to harden consistently to retain its shape. That\u2019s why not every material is a fit for every machine\u2014your machine\u2019s barrel temperature, injection speed, and mold design all factor in, but the material itself is the foundation.<\/p>\n

The most widely used group of materials in injection molding are thermoplastics. Unlike thermosets, which harden irreversibly when heated, thermoplastics can be melted and reshaped over and over, making them perfect for high-volume production. Within thermoplastics, we split them into two main categories: commodity plastics and engineering plastics. Commodity plastics are the workhorses for everyday products, while engineering plastics are chosen for their higher strength, heat resistance, and durability.<\/p>\n

Commodity plastics are the ones you\u2019ll see in mass-produced goods\u2014think packaging, disposable tableware, and cheap household items. The top three are polyethylene (PE), polypropylene (PP), and polystyrene (PS). Let\u2019s dive into each. Low-density polyethylene (LDPE) is soft, flexible, and cheap, which makes it ideal for plastic bags, stretch wrap, and squeeze bottles. But it has a low melting point (around 180\u00b0C to 220\u00b0C) and is not very heat resistant, so it\u2019s rarely used for parts that need to withstand high temperatures. High-density polyethylene (HDPE), by contrast, is stiffer, stronger, and more rigid, with a melting point of 120\u00b0C to 180\u00b0C. You\u2019ll find HDPE in milk jugs, plastic crates, and toy parts because it can handle impact and repeated use without breaking. Then there\u2019s polypropylene (PP), which is one of the most versatile plastics we work with. Its melting point is slightly higher than HDPE, around 160\u00b0C to 220\u00b0C, and it has excellent chemical resistance\u2014so it\u2019s used for everything from food containers and bottle caps to automotive battery cases and even some medical supplies. It\u2019s also relatively easy to mold, which means lower production costs for parts. Polystyrene (PS) comes in two forms: general-purpose polystyrene (GPPS) is hard, rigid, and clear, used for disposable cutlery, CD cases, and packaging peanuts, while expanded polystyrene (EPS) is foamed into lightweight insulation and protective packaging. GPPS melts at around 180\u00b0C to 260\u00b0C, but it\u2019s brittle, so it\u2019s not great for parts that will be dropped or handled roughly.<\/p>\n

Moving up, engineering thermoplastics are for when commodity plastics just don\u2019t cut it. These are used in automotive, electronics, aerospace, and industrial equipment, where parts need to be strong, heat resistant, or dimensionally stable. The most common engineering plastics we supply for are acrylonitrile butadiene styrene (ABS), nylon (polyamide, PA), polycarbonate (PC), and polybutylene terephthalate (PBT). ABS is a balanced plastic\u2014it\u2019s hard, impact resistant, and can be molded into complex shapes, which is why it\u2019s used for car dashboards, LEGO bricks, laptop shells, and toy guns. Its melting point is around 200\u00b0C to 250\u00b0C, and it can be pigmented easily, so it\u2019s perfect for consistent color-matched parts. Nylon (PA) is another staple, valued for its high strength, low friction, and resistance to wear. It\u2019s used for gears, bearings, conveyor belts, and automotive under-the-hood parts that need to withstand heat and vibration. Nylon\u2019s melting point is higher, around 220\u00b0C to 290\u00b0C, but it\u2019s hygroscopic, meaning it absorbs moisture from the air. That\u2019s a critical point for anyone running injection molding\u2014if you don\u2019t dry nylon pellets before loading them into the barrel, the moisture will turn to steam during melting, causing bubbles in your parts that weaken them. We always remind new customers to invest in a desiccant dryer if they\u2019re working with nylon. Polycarbonate (PC) is known for its exceptional clarity and impact resistance, so it\u2019s used for safety goggles, CD and DVD discs, water bottles (like Nalgene and CamelBak), and automotive headlights. It can handle temperatures up to 140\u00b0C, making it suitable for parts that need to withstand hot environments, but it\u2019s more expensive than commodity plastics, so it\u2019s reserved for high-performance applications. PBT is often used as an alternative to nylon for electronics parts because of its excellent electrical insulation properties and low shrinkage. It\u2019s used for connectors, switches, and relay components, with a melting point around 220\u00b0C to 240\u00b0C.<\/p>\n

Now, beyond basic thermoplastics, many customers come to us looking for specialized materials to meet specific needs. Two of the most popular types are filled thermoplastics and biodegradable plastics. Filled thermoplastics are thermoplastics mixed with additives like glass fiber, carbon fiber, or talc to improve strength, stiffness, heat resistance, or dimensional stability. For example, glass-filled nylon is three times stronger and stiffer than regular nylon, making it ideal for structural automotive parts or machine components that need to hold their shape under load. But there\u2019s a catch: filled materials are more abrasive than neat plastics, so they can wear down your injection molding machine\u2019s barrel and screw faster. We always recommend using hardened tool steel barrels and screws if you\u2019re running filled materials, and we can modify our machines to include those components as standard for that type of work. Biodegradable plastics, meanwhile, have grown a lot in demand over the last decade as customers look to reduce their environmental footprint. The most common biodegradable injection molding materials are polylactic acid (PLA) and polyhydroxyalkanoate (PHA). PLA is made from corn starch or sugarcane, and it biodegrades in industrial composting facilities in a few months, making it perfect for single-use items like cutlery, food containers, and packaging. Its melting point is around 150\u00b0C to 160\u00b0C, which is lower than many other plastics, so it\u2019s important to adjust your machine\u2019s barrel temperature and injection speed to avoid burning it. PHA is similar, but it\u2019s made by bacteria, and it\u2019s more flexible and durable than PLA, so it\u2019s used for items like food packaging and disposable gloves. One thing to note with biodegradables: they\u2019re sensitive to moisture, just like nylon, so drying is non-negotiable to avoid defects.<\/p>\n

There are also high-performance thermoplastics for extreme applications, like polyether ether ketone (PEEK), polyimide (PI), and liquid crystal polymer (LCP). These are used in aerospace, medical devices, and oil and gas parts, where they need to withstand temperatures over 200\u00b0C, harsh chemicals, and heavy loads. PEEK, for example, is often used for surgical implants because it\u2019s biocompatible and strong, and it can be sterilized repeatedly. Its melting point is around 340\u00b0C, so your injection molding machine needs to be able to reach and maintain those high temperatures, and you need to handle it carefully to avoid degradation. These materials are more expensive, but they last much longer than standard plastics, so they\u2019re a worthwhile investment for customers with specialized needs.<\/p>\n

Now, I can\u2019t talk about materials without mentioning what causes problems\u2014because even the best material will fail if you don\u2019t handle it right. Common mistakes we see new injection molding operators make include not drying hygroscopic materials (like nylon, PC, and PBT), which leads to splay marks or brittleness; setting the barrel temperature too high, which burns the material and causes discolored, weak parts; or injecting too fast, which can cause air traps or flash (thin, unwanted plastic edges on parts). That\u2019s why when a customer comes to us with a machine for a specific material, we don\u2019t just sell the machine\u2014we walk them through material handling best practices, recommend the right drying equipment, and even offer training for their operators. We\u2019ve had customers come to us with a machine that worked for LDPE but struggled with PEEK, and we helped them adjust their barrel heaters, screw design, and injection pressure to get consistent, high-quality parts.<\/p>\n

Another important factor is material consistency. All pellets are not created equal, and inferior raw material can lead to inconsistent melt flow, which causes defects in parts. We partner with trusted material suppliers, and we always advise customers to use high-quality pellets that meet industry standards. If you\u2019re running a low-volume job, custom color-matching or material blending is also an option\u2014many of our customers work with us to adjust their process to incorporate colorants or additives directly in the barrel, which saves time and reduces waste compared to pre-blending pellets.<\/p>\n

At the end of the day, choosing the right material for your injection molding machine is a balance between part requirements, production volume, cost, and machine capability. Commodity plastics are great for high-volume, low-cost parts, while engineering or high-performance plastics are necessary for specialized, durable applications. Specialized materials like filled plastics or biodegradables offer benefits, but they require adjustments to your machine and process to avoid issues.<\/p>\n

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If you\u2019re in the market for an injection molding machine and you\u2019re not sure which materials you\u2019ll be running, or if you have a specific material in mind but you\u2019re not sure if it\u2019s a fit for your current setup, I\u2019m here to help. Every machine we sell is built to adapt to different materials, but the best results come from pairing the right machine with the right material and process. Don\u2019t hesitate to reach out to our team to discuss your needs\u2014we can walk you through material options, machine modifications, and best practices to ensure your production runs smoothly and your parts meet your standards.<\/p>\n

Injection Blowing Machine<\/a> References<\/p>\n

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  1. Rosato, D. V., & Rosato, M. G. (2011). Injection Molding Handbook. Springer.<\/li>\n
  2. Harper, C. A. (2002). Modern Plastics Handbook. McGraw-Hill.<\/li>\n
  3. Giles, H. F., & Wagner, J. R. (2010). Extrusion: The Definitive Processing Guide and Handbook. William Andrew Publishing.<\/li>\n
  4. Kutz, M. (2002). Applied Plastics Engineering Handbook: Processing and Materials. Elsevier.<\/li>\n<\/ol>\n
    \n

    Shenzhou Machinery Co., Ltd.<\/a>
    As one of the most professional injection molding machine manufacturers and suppliers in China, we’re featured by quality products and good price. Please feel free to buy advanced injection molding machine made in China here from our factory. We also accept customized orders.
    Address: Fenghuang Town, Zhangjiagang City, Jiangsu Province, P.R.China
    E-mail: sale@shenzhoumac.com
    WebSite:     https:\/\/www.shen-zhoumachinery.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

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