8 Engineering Grade Plastic Specifications You Need to Know

08 Sep.,2025

 

8 Engineering Grade Plastic Specifications You Need to Know

Whether you are a factory foreman, engineer, or purchaser, you need to be aware of all your plastic options when it comes time to design and manufacture your custom, injection molding part.

What plastics are most resistant? Are there plastics that will show scratches and wear more than others? What type of plastic is most malleable? These are all important questions you need to consider when it comes time to order or design your next part. Many of these plastics are known colloquially by abbrevations (with several starting with the letter “P”) so even a seasoned industry expert can confuse them… we’ve seen it happen!

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At Buffalo Manufacturing, we want to make our custom injection molding process as simple as possible for our customers and our injection molding operators alike. Read through our list to make sure you have the appropriate product knowledge to equip yourself for your next custom injection molding part order.

1. Acrylonitrile butadiene styrene (ABS)

Acrylonitrile butadiene styrene, also known as ABS, is a popular choice for many in the custom injection molding process. Notability, there are two grades of ABS, ABS for injection molding and ABS for extrusion.

ABS has high impact resistance, rigidity, and temperature resistance compared to other plastic polymers. It is a highly stable plastic at both high and lower temperatures and maintains its integrity under large weight loads as well.

2. Polycarbonates (PC)

Polycarbonates (PC) is a commonly used polymer due to its durability, high level of impact resistance, and extreme temperature resistance. However, polycarbonates have low scratch resistance and many PC products require additional hard coating application to make up for this limitation.

Polycarbonates are malleable and can withstand several polymer deformations without the risk of cracking or bending. It can be molded and processed at room temperature and in some cases, does not require any heating.

Polycarbonates are excellent transmitters of visible light, commonly being used more effectively than glass in eyewear lenses and external automotive components. They are also a popular choice for prototyping parts where transparent or electrically non-conductive parts are required.

Polycarbonates are malleable and can withstand several polymer deformations without the risk of cracking or bending. It can be molded and processed at room temperature and in some cases, does not require any heating.

3. Polyamides (PA)

Polyamides (PA), most commonly known as “nylon”, are utilized for their high resistance to erosion from chemicals and abrasions, low friction surface, and their ability to be melted down and reused.

It is most commonly used in the production of fabrics and fibers, food packaging films, and in custom shape part production. Polyamides are diverse and can be mixed with a variety of different materials to achieve specific and customized product variations.

4. Polysulphone (PSU)

Polysulphone (PSU) polymers are rigid, strong, transparent, and are highly durable. It has a high compact resistance rating and is labeled as a “high-performance plastic”, commonly being used in injection molding, extrusion, and hot forming.

PSU is highly resistant to chemicals, acids, and bases on the pH scale from 2 to 13, allowing polysulphone-based parts and products to be cleaned with bleaches. However, it is soluble in dichloromethane and methyl pyrrolidone.

6. ULTEM Polyetherimide (PEI)

ULTEM Polyetherimide (PEI) plastics have high heat, solvent, flame resistance, and low smoke generation, and are most commonly used in the production of chemical and medical instruments. PEI plastics are also known to have high strength and rigidity.

7. Polytetrafluoroethylene (PTFE)

Polytetrafluoroethylene is also known as PTFE, or more simply, “teflon”. PTFE has high strength, toughness, and self-lubrication at extremely low temperatures.

PTFE plastics are frequently used in the pharmaceutical and chemical processing industries due to its slipperiness. PTFE is also widely used as a repellent to prevent bugs, insects, and small animals from climbing on an area coated with PTFE.

8. Polyoxymethylene (POM)

Polyoxymethylene is known by many names, but is most commonly referred to as POM or “Delrin”. POM is known for its high rigidity and hardness levels, low friction, and high stability and strength making it an excellent choice for precision part products in the engineering, automotive, and electronics industries.

It is also important to note that although POM is naturally white in color, it can be manufactured into a large variety of colors, making it suitable for custom part products.

Top 5 Considerations When Choosing the Right Plastic Resins for ...

There are several factors to consider when selecting a plastic resin for your medical device requirements. Understanding how medical devices will be used and navigating regulatory requirements is laying the groundwork – it shapes the material choice based on specific functions and ensures the devices we create are safe and effective for patients.

This article will review the most important considerations that every product designer should keep in mind when deciding which plastic resin would work the best for your healthcare devices. By understanding part function you can determine the necessity of biocompatible plastic resins and how they commit to the well-being of those who use your medical devices. Exploring the most common plastic molded medical devices will give us a glimpse into the diverse world of injection molding in the healthcare industry. These questions aren't just steps; they're guiding us toward safe, functional, and compliant medical device design.

Some key considerations when selecting the right plastic resin to use for your medical injection molding devices include;

  1. What is the intended use of Your Medical Device?
  2. What are the Regulatory Requirements for Medical Injection Molded Devices?
  3. What are the Most Common Plastic Resins for the Medical Industry?
  4. Do your Parts Require a Biocompatible Plastic Resin?
  5. What are the Most Common Plastic Molded Medical Devices?

Now, let’s delve into each of these aspects!

1. What is the intended use of Your Medical Device?

When choosing a plastic material, evaluating the level of contact the device will have with the human body is crucial. For single-use devices with direct or prolonged contact, such as Delivery Systems, choose a plastic resin that is biocompatible to prevent bad reactions. Check if it's safe for long-term use and won't cause allergies. Even for short contact, use materials that follow safety rules for overall patient well-being. Understanding how the device interacts with the body is key when picking the right plastic.

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Medical plastic products intended for multi-use have critical considerations such as; biocompatibility, sterilization compatibility, mechanical strength, and chemical resistance. Select materials with established track records in similar medical applications to mitigate risks and enhance patient safety.

2. What are the Regulatory Requirements for Medical Injection Molded Devices?

Consider whether your medical device requires manufacturing in a clean area. Certain devices, especially those sensitive to contaminants, benefit from white room molding.

A white room is a super clean space used in places like manufacturing facilities. They help keep out tiny particles and keep products clean of contaminants, these rooms are particularly important for making medical devices. A white room ensures that the production environment is controlled and free from particles that could affect the device's quality.

Confirm if your needs require high-quality standards. The top 3 most recommended regulatory requirements are;

  • cGMP
  • ISO certified
  • FDA Registration

Certifications like ISO : indicate that the manufacturer follows stringent quality management systems. This commitment to quality is essential for reliable and consistent production of medical devices. FDA registrations and adherence to Current Good Manufacturing Practices (CGMP) are also crucial. Manufacturers with FDA certification demonstrate that they follow the safety and quality rules set by the government.

IQ (Installation Qualification), OQ (Operational Qualification), and PQ (Performance Qualification) are essential components of the validation process for medical devices. IQ ensures that the device is installed correctly, OQ verifies that it operates as intended under various conditions, and PQ assesses its performance in the actual usage environment. These qualifications are crucial for ensuring the reliability, consistency, and safety of medical devices. Your company may require these validations to help manufacturers meet quality standards, mitigate risks, and ensure that medical devices perform effectively and consistently throughout their lifecycle.

3. What are the Most Common Plastic Resins Used in the Medical Industry?

Not all plastics are made equal, your product drawing needs to call out a specific material based on desirable characteristics – For example, polyethylene (PE) is a material that has considerable ‘flex’ and is great for medical devices that require bend and transparency. Polycarbonate and ABS are great for medical products that need a durable and strong feel; products like device housings and controllers are commonly associated with robust materials.

Different applications may demand specific mechanical properties such as strength, flexibility, or rigidity. Choose a resin that aligns with the mechanical needs of the device. Common Injection molding materials and characteristics for medical devices include;

Strength:

  • Polycarbonate (PC)
  • Acrylonitrile Butadiene Styrene (ABS)
  • Polyethylene Terephthalate (PET)

Flexibility:

  • Polyvinyl Chloride (PVC)
  • Polyethylene (PE)
  • Thermoplastic Elastomers (TPE)

Rigidity:

  • Polypropylene (PP)
  • Polystyrene (PS)
  • Polyoxymethylene (POM)

4. Do I Need a Biocompatible Plastic Resin?

Biocompatible materials are designed to interact with biological systems in a way that is safe and effective, without triggering an immune response or causing harm. Think about how long the device touches the body and if it's inside or outside. If the plastic is inside of a body for a long time, like a mouth guard, it needs special materials to avoid adverse reactions or cause any harm to the patient. Additionally, it is important to avoid things like irritation or allergic reactions. Government agencies, like the FDA, have rules that require certain medical devices to be made with materials that won't make people sick.

UL Prospector is a great tool for picking the right plastic resin with biocompatibility in mind. It gives a lot of information about different resins, like technical details, how they perform, and if they follow regulations. When you're working with things like medical devices, biocompatibility is super important. UL Prospector helps you check if the resin you're thinking about using meets the strict standards for how it interacts with living tissues. It tells you about things like cytotoxicity and sensitization, which are crucial factors. This tool is easy to use and helps make a tough job easier by giving you all the details you need to choose the best biocompatible plastic material for your project.

Based on favorable results and resin testing, the FDA will approve materials for medical devices. Some common materials that are often approved by the FDA for medical devices include;

  • Polyethylene (PE): It is widely used for containers, tubing, and orthopedic implants.
  • Polypropylene (PP): Commonly used for containers, closures, and flexible packaging in medical applications.
  • Polyvinyl Chloride (PVC): PVC is used for tubing, blood bags, and medical devices.
  • Polycarbonate (PC): Used in applications such as incubators and medical equipment housings.
  • Polyethylene Terephthalate (PET): Often used for packaging, such as bottles for pharmaceuticals.
  • Polyurethane (PU): Used in catheters, wound dressings, and other flexible medical devices.
  • Polyoxymethylene (POM): Used in components like gears and connectors in medical devices.
  • Polyethylene Glycol (PEG): Used in various medical applications, including drug delivery systems.
  • High-Density Polyethylene (HDPE): Commonly used for laboratory containers, specimen cups, and prosthetic components.

5. What are the most common Plastic Molded Medical Devices?

Plastic injection molding is a popular method for making important medical devices. Very often, an engineer may be designing a part and not know the best way to manufacture it or what material to use. To make an informed decision when choosing a plastic resin, it is important to know what healthcare products are the best fit for plastic injection molding.

Syringes and needles, crucial for precise medication administration, are typically crafted and designed for injection molding because of the scalability and dimensional compliance of this manufacturing method. Housings for diagnostic equipment, like blood glucose meters and thermometers, are efficiently produced, showing the cost-effectiveness of injection molding. Surgical instruments, such as orthopedic implants, benefit from precise molding of biocompatible plastics for durability and compatibility within the human body. Drug delivery devices, like insulin pens and infusion pumps, use plastic injection molding for intricate and reliable components. Lastly, dental devices, such as impression trays and brackets, highlight the method's importance in ensuring the quality and precision of these critical medical tools. These precision healthcare tools used in various medical procedures allow for the creation of durable, and sterile components essential for successful surgeries.

About Stelray

Stelray Plastic Products’ offers numerous advantages for medical device manufacturers, including high-quality and precise products, cost-effective manufacturing, and plastic design flexibility. With the ability to produce complex and intricate designs with tight tolerances, injection molding is the preferred choice for medical molding solutions.

As technology continues to advance, we can expect to see even more innovations in medical injection molding, making it an essential process in the medical industry.

Contact us to discuss your requirements of Advanced Engineering Plastics. Our experienced sales team can help you identify the options that best suit your needs.