Medical Molding: High Quality Molded Parts for Medical Device

Medical device injection molding can be performed on plastics, metals, silicones, thermoplastic elastomers (TPE), or composite materials. Although there are many different kinds of injection moldable plastics, depending on the purpose, medical device designers frequently select polypropylene, polyethylene, polystyrene, or polyetheretherketone (PEEK). Additionally, silicone elastomers come in a variety of materials and combine chemical stability with sterilizing support. Metals facilitate medical molding, are strong, and can withstand microbiological development.
There are six primary forms of injection molding that are utilized in medical devices in addition to traditional plastic injection molding: Thin wall injection molding, Gas-assisted injection molding, Overmolding, LSR injection molding, HCR injection molding, Metal injection molding.

We go over each of these medical molding techniques, and if you’re seeking for details on how to develop molded parts for medical devices.

Thin Wall Injection Molding

Thin wall injection molding is employed to create thin, lightweight parts, reducing material costs and speeding up production cycles. This technique is commonly used in medical molding manufacturing for small, intricate parts demanding high precision. The thinness of the wall is vital, although it’s constrained by the size of the part. Typically, parts with a wall thickness of less than 1mm are considered thin-walled. This approach is especially cost-effective for high-volume production and suits applications like small medical device enclosures. We offer economical steel molds for medical device prototype development and low-volume manufacturing, offering an alternative to 3D printing for functional samples, ensuring suitability for high-volume production.

Gas-Assisted Injection Molding

Gas-assisted injection molding is a low-pressure plastic injection molding process that employs pressurized nitrogen or carbon dioxide gas in addition to heated plastic. The gas aids in filling the mold’s extremities, producing thicker walls with hollow sections. This method is suitable for plastic parts with large surface areas, requiring intricate textures and superior surface quality. Like thin wall injection molding, gas-assisted injection molding minimizes plastic usage, shortens cycle times, and reduces material costs. It also enhances part appearance by reducing imperfections, and because molding pressures are lower, there is less residual stress on parts and less wear on molds.

Overmolding

Overmolding is an injection molding process that applies a polymer layer over a substrate, eliminating the need for post-molding assembly. It is utilized for creating handles on surgical instruments and can be employed in medical molding products without metal components, using materials like silicones or thermoplastic elastomers (TPE) overmolded onto thermoplastic substrates. Overmolding involves the formation of chemical and mechanical bonds at the molecular and physical levels between the substrate and overmold material. Two-shot molding is a two-step continuous process used for prototyping and low-volume production.

LSR Injection Molding

LSR injection molding utilizes liquid silicone rubber (LSR), a two-component elastomer that requires curing to achieve its final properties. This process involves mixing LSR components, feeding them into an injection unit with further mixing, and injecting the material into the mold. Curing, which lasts about 30 seconds, crosslinks polymer chains to achieve the desired properties. Platinum-cured LSR is employed for high-purity applications, such as spacers for asthma inhalers, due to its greater optical clarity, tensile strength, and tear resistance.

HCR Injection Molding

HCR injection molding utilizes high-consistency silicone rubber (HCR), or heat-cured silicone rubber, which requires heating the raw material and injecting it into a mold under high pressure. Preheating the gum rubber before injection reduces its viscosity and aids in filling the mold cavity more rapidly. HCR injection molding offers better overall properties than LSR but can be more complex due to its higher viscosity. Proper tool design and experience are crucial for maintaining consistent shrink rates, especially for applications like gaskets and O-rings in medical devices.

Metal Injection Molding (MIM)

Metal injection molding (MIM) involves mixing powdered metal with a thermoplastic binder, heating the mixture, injecting it into a mold, and removing the thermoplastic binder. Subsequent sintering compacts the material, resulting in a net-shape or near-net-shape part. MIM supports high-volume production of medical molding parts with complex shapes, strength, and an excellent surface finish. It offers a cost-effective alternative to CNC machining for challenging-to-machine metals like stainless steels, cobalt-chromium alloys, and titanium alloys. MIM-produced parts have dimensions and properties comparable to wrought and cast materials, making them suitable for surgical instruments and implants.

Benefits of Medical Molding

Medical molding plays a critical role in the healthcare industry, contributing to the development of safe and effective medical devices and equipment that improve patient care, diagnostics, and treatment. Key features of medical molding include:

Material Compatibility: Medical molding employs materials specifically designed to meet the strict safety and biocompatibility standards required for medical applications. These materials are often tested for their resistance to chemicals, sterilization methods, and body fluids to ensure they are safe for use in medical devices and contact with patients.

High Precision: Medical molding processes are capable of achieving tight tolerances and exacting specifications, ensuring the reliability and functionality of medical components. Precision is crucial in applications like implantable devices and diagnostic equipment.

Cleanroom Manufacturing: Many medical molding facilities operate in cleanroom environments to maintain a controlled and sterile production environment, preventing contamination of the medical devices being manufactured.

Regulatory Compliance: The medical molding industry adheres to strict regulations and quality standards, such as ISO 13485 and FDA requirements. These regulations ensure that the produced components meet the highest standards for safety and effectiveness in healthcare applications.

Versatility: Medical molding can produce a wide range of medical components, including syringes, IV connectors, surgical instruments, diagnostic equipment, catheters, and more.

Cost-Effectiveness: The scalability of injection molding allows for cost-effective production of medical components, making it a preferred choice for high-volume manufacturing.

Medical Molding for Complex Medical Parts Production

Medical molding involves the precise injection of medical-grade materials, typically thermoplastics, into molds to create parts and products that meet stringent quality and regulatory requirements within the healthcare industry.
However, is medical molding required for high-volume, low-volume, or prototyping production? Inadequate drying or incorrect processing techniques can result in increased injection molding costs and hazards, which can be avoided with a well-thought-out plan and an experienced manufacturing partner.
No matter how complicated your designs are, we have the cutting-edge manufacturing operating system and production specialists you need to get high-quality medical injection molded parts. Additionally, we are equipped with the knowledge and abilities to help you from part design to production and prototype.

We offer comprehensive medical molding solutions. Contact us without hesitate!

Related Resources:

What is Medical Device Contract Manufacturing?

Medical CNC Machining: CNC For Medical Parts And Products

Applications of Injection Molding in the Medical and Pharmaceutical Industries