Benefits of injection moulding for medical parts

Plastics have revolutionised the medical industry. Not only does plastic lower the spread of infection, but it’s also an affordable material and when used in the injection moulding process, they can deliver precise, lightweight and durable devices.

The different polymers available are vast and can be formulated specifically for healthcare applications. These plastics don’t harbour pathogens and can stand up to different sterilisation processes. Plastics have given us one-time-use tools and devices, such as surgical gloves, syringes and IV tubes. These materials are also used for durable applications, such as hospital beds and medical equipment.

The benefits of plastics in medical fields, from dentistry to orthopedics, are many. So are the advantages of the medical injection manufacturing process. If you’re not familiar with plastic injection moulding, we suggest you read In-depth: the injection moulding process. We’ll give a quick summary of the process here:

1. A mould is made from metal and precision machined to match the geometries and measurements of the product you’re manufacturing.
2. Plastic resins are fed into a heated barrel and mixed.
3. Heating bands melt the resins.
4. The molten plastic is then injected into the mould cavity, where it cools and hardens.
5. When the plastic solidifies, the part is ejected from the mould.

You can learn more about this process in The future of injection moulding and in the video Injection Moulding: How does it work?

Plastic insert moulding is a close cousin of injection moulding. This takes an already fabricated component, such as a surgical knife blade or surgical tube, and encapsulates it in molten resin to manufacture a finished product. Plastic injection moulding involves injecting one or more molten plastic resins into a mould to produce single, finished parts.

Examples of products made with plastic injection moulding for the medical-device industry:

• Beakers
• Test tubes
• Lab and clinic housings and casings
• Implantable components
• Surgical blades
• Surgical tools
• Pacemaker parts
• Orthopedic and dental instruments
• Needle housing
• Instrument handles
• Suture delivery devices
• Prosthetics

Now the question is, why produce your plastic components for medical devices with plastic injection moulding, versus another process? The reasons vary:

Compliance

In order for any medical device to reach the market, it has to satisfy EU (MDR) regulations, which recognise ISO standards. Plastic injection moulding is a controlled process, which makes it easier to meet ISO compliance. Examples include the tight controls on materials and measures taken to prevent contamination. Even the manufacturing facility itself is controlled to help regulate temperatures.

Note, in order to meet plastic injection-moulding standards, the manufacturer must be ISO 13485 certified, which sets out standards for quality management systems.

Cost efficiency

Plastic-injection-moulding medical parts offer significant cost benefits. The moulding tool and die require a high up-front cost compared to other manufacturing processes, but the mould only needs to be created once. After hundreds of thousands of runs, it may need to be replaced, but this will be easier and cheaper to recreate.

The benefit is in the overall costs. Injection moulding is efficient and fast. You can do high-volume production runs with lower per-part costs. In other words, the more parts you produce, the lower the cost. If you’re manufacturing components or devices in bulk, plastic injection moulding will almost always be the most cost-effective option.

Precision

There is no official designation of medical-grade plastic, but for plastics used in medical devices to be considered as such, it must be compatible with our body’s biological system. The overall device, which includes materials, must satisfy regulatory requirements in order to reach the market. Part of those requirements include specifications.

Medical injection moulding enables devices to be manufactured to your exacting specifications. Tolerances in medical device moulding are tight. As technologies continue to advance, those tolerances become even tighter. The more complex the part, the tighter the tolerance should be to ensure a uniform performance at scale, which makes plastic injection moulding the ideal manufacturing process for critical parts.

Design flexibility

Plastic injection moulding does have a few restrictions, such as the need to avoid sharp corners, which increases stress concentration. Also, wall thickness should be uniform to prevent inconsistencies in the cooling process, which can cause defects.

Still, you have a lot of leeway regarding your design. Medical plastic moulding allows complex geometries and intricate designs, for example. Medical plastic parts form in the mould cavity, so you can achieve different features with just one injection. Designing for different features with another process would take costly, multiple assemblies.

Reduced weight of device

Plastics in the medical field possess unique mechanical properties designed to improve the performance of medical devices while reducing their weight. This is critical, as it diminishes the fatigue surgeons experience while performing long procedures.

Medical injection parts also enable patients who depend on continuous monitoring with wearable medical devices to go about their daily lives. Another benefit to lightweight medical plastic parts is the convenience they offer EMTs, who have to carry them to attend patients in emergencies.

Durability

Plastics that must be biocompatible are formulated for those properties. As the resins are to be used in injection moulding, they also contain another quality: durability. Plastic-injection-moulding medical parts are incredibly strong and can stand up to heat in autoclaves, which is necessary for sterilisation. These materials also resist impact and vibration, making them versatile for medical applications.

Plastic injection moulding vs other processes

Is the medical injection manufacturing process the most appropriate for your application? To help you make the right decision, we’ve devised the table below.

What else should you know?

The more you know, the better decisions you can make. These topics provide in-depth information to help you learn more:

Medical material standards

Medical-grade plastics

You’ll also need components for your design. These guides tell you about solutions already being used in the medical industry, from handles to cable management.

Patient-care equipment

Medical furniture

Laboratory equipment

Download free CADs and try before you buy

Download free CADs and request free samples, which are available for most of our solutions. It’s a great way to ensure you’ve chosen exactly what you need. If you’re not quite sure which product will work best for your medical device, don’t worry. Our experts are always happy to advise you. Whatever your requirements, you can depend on fast despatch.

Request your free samples or download free CADs now.

Questions?

Email us at sales@essentracomponents.co.uk or speak to one of our experts for further information on the ideal solution for your application 0345 528 0474.