In medical industry, manufacturers never stop applying medical grade liquid silicone rubber for the best products with cost saving, high quality and extend lifetime performance. Furthermore, they should also focus on long-term cost and price stability to guarantee sales revenue and profit. The medical device market requires professional skill and research, especially in the area of material selection and manufacturing process.
The material performance in medical industry are different between health and injury. Consequently, once you evaluate metal, plastic, ceramic or Liquid Silicone Rubber (LSR) for medical device, the most critical aspect to consider is the compatibility of material with functionality. Engineers need to consider some key factors in materials selection for new medical equipment and devices, such as bio-compatibility, qualification, cost and regulation.
Silicone medical devices have the durability to withstand tough conditions, like heat, high pressure, chemical exposure and bio-compatibility. LSR is a perfect material for customer silicone molded components and assemblies. Medical-grade LSR molding parts are widely used for dental and surgical applications, healthcare products and other medical devices.
Liquid Silicone Rubber
LSR is a highly flexible thermosetting plastic with a wide range of composition and hardness, designers and engineers can select the most appropriate LSR material with specific characteristics for various applications. LSR materials start out in liquid form, then heat curing into solid state. The molded LSR parts remain solid once it cures. Therefore, this feature will make LSR the ideal choice for medical applications. The key attributes of LSR including: hardness, tensile strength, compression set and fluid resistance.
Comparing to other elastomer, medical-grade LSR has many benefits:
- Bio-inert material according to ISO 10993, RoHS standard.
- Sterilization with different methods, like Autoclave, E-beam, Gamma radiation, ETO.
- Excellent stability in a wide range of temperature -65℃to 250℃.
- Self-adhesive LSR can adhere chemically to plastics without priming.
- Maintain flexibility, resiliency and mechanical force transfer capability at extreme temperatures.
- Superior electrical insulation quality under severe conditions.
The Importance of Medical Grade Liquid Silicone Rubber
Various silicone materials satisfy the standards of medical device manufacturing, these standard including medical non-implantable, medical restricted implantable and medical unrestricted implantable. The primary reason make silicone as the key material for medical application is its bio-compatibility.
Non-implantable grade LSR is able to contact with skin, but not inside tissue of the body. While, innovations in silicone material science have encouraged non-implantable silicone materials commonly available in different hardness. We are able to produce medical devices with varying hardness levels.
ISO 10993 is a standard to evaluated material bio-safety in worldwide, LSR meets the medical application standard in ISO 10993 requirements. Normally, medical grade LSR is in three categories: limited exposure, prolonged exposure, permanent contact.
Limited Exposure:
This level devices are only allowed to contact with skin, mucosal membrane, breached and compromised surfaces, it has service life of 24 hours or less.
Prolonged Exposure:
This level also referred as healthcare grade, it is based on test of heamolysis, toxicity, genotoxicity, intramuscular implantation in histopathology. It has implant contact more than 24 hours and up to 30 days.
Permanent Contact:
This level also known as long-term implantable, this silicone rubber should pass physio-chemical and biological testing, including chronic toxicity, developmental toxicity, carcinogenicity.
If you are looking for a new application with benefit of inertness, low compression set or temperature in medical industry, medical-grade LSR is the most suitable material. Miwo has the ability to produce any type of housing, dampener, seal, valve, coupler, membrane button for medical device and equipment.
Medical LSR Advantages
Medical-grade LSR for skin contact medical applications has tremendous stability and water resistance, in order to prohibit cured LSR parts from affection by skin contact. LSR is different from latex materials, it is non-allergenic and never affect human skin. In addition, its water resistance also can prevent sticking on wound areas. The hygienic quality of medical-grade LSR can resist bacteria and fungi growth, its inherent flexibility and softness can ensure patients’ comfort.
Regardless high temperature resistance, LSR also remains elastic at extreme low temperature. Its flexibility depends on compound nature, and typically very high. Such as its highest break elongation can reach to almost 900%. LSR has low compression set and low permanent deformation in force application and removal. LSR can also withstand ultraviolet radiation. All these benefits can prolong LSR product’s shelf life. Although LSR material has higher cost than other resins, and longer cycle time in molding process. LSR production allows multiple components’ combination, this will reduce overall cost of production.
All in all, the overall capability of LSR encourage it the most smart choice for medical device applications. The benefit to select medical-grade LSR over other materials, including:
- FDA bio-compatibility
- Bacteria and chemical resistance
- Transparency and clarity (light transmittance and illumination)
- Gas permeability
- Superior dielectric strength
- Functional ability in extreme temperature
- Superior tensile strength, elongation, tear strength at extreme temperature
- Low compression set at wide temperatures
Comparing to high-consistency rubber (HCR) and other elastomer, LSR is a better material choice for high-precision medical components and devices with detailed geometries.
Medical Devices by LSR Injection Molding
LSR is a critical material used in medical devices fabrication. Some medical components require multiple molding process. We need to evaluate different manufacturing variations, like production life-cycle, production volume, part geometry and LSR type.
Two compounds of LSR are mixed in static mixers, then transfer into the screw. The screw will force mixed material into mold in shot size. This injection molding process are automotive with high quality and volume. Miwo produce a wide range of medical silicone parts and devices, our specific medical field by LSR medical injection molding include:
- General surgery
- Oncology
- Cardiology
- Plastic surgery
- Bariatic surgery
- Ophthalmology
- Dialysis
- Neurosurgery
- Ear, nose and throat
- Wearable health monitoring devices
If you are choosing a suitable material for your medical project, LSR is the best choice with improved quality and better performance. In a long-term vision, medical LSR can withstand all challenging conditions.
Over-molding Medical Devices with LSR
In medical and healthcare industry, LSR manufacturing can create medical products and devices with tighter tolerance, sterilization capability, soft-touch surfaces, and various colors.
LSR over-molding is a fabrication method, which add another layer of LSR over a substance part. It also has different names like: multi-shot, double-shot, hard/soft overmolding, twin-shot molding, 2K molding. As product-makers realize the tremendous benefits of LSR over-molding, this technique has changed drastically medical products of aesthetics, design and functionality.
Surgeons and other clinicians prefer surgical devices and instruments with soft-touch handles to improve the grip. LSR over-molding can fabricate handles into ergonomic shapes, in order to fit end user hands or interact with attachments. The transparency of LSR material is able to create seamless surfaces with no gaps and eliminate contaminants. This will assist surgeons look through the instruments and work with high precision.
LSR over-molding technology is a viable process in medical market, it works well for devices and products with handle, bio-compatibility, heart and chemical resistance requirements. Furthermore, LSR has far outweighed properties than other materials, like cold, heat, chemical and UV light resistance. It also has unparalleled flexibility and mold-ability.
Cost Saving of LSR Manufacturing
Miwo are trying to mold as much functionality into device part, in order to minimize material cost and secondary operations assembly. In addition, structural ribs and frames are applied to improve functionality. For surgical instruments, over-molding of LSR and metal are preferable to machining entire instruments from metal alloys.
Over-molding manufacturers will trim cost by molding required metal parts like cutting areas, casting the remain instrument with LSR. Therefore, this method is conductive for high-volume production and cost less than normal machining, especially for intricate geometries.
Brand Identification for LSR Medical Devices
Many companies prefer to brand company name, logo, color or other characteristics into LSR products. LSR over-molding is a perfect solution, it can produce solid surface on both top and bottom with high thickness. LSR molding also eliminate the priming step, LSR material only need to add on functional purpose, without cover additional surface area. This will encourage LSR over-molding to fabricate parts in a more economical way with less material and time.
Competitive Edge of Medical-grade LSR
The innovation of medical industry encourages medical-grade silicone rubber to manufacture products from tubes to life-saving devices. High quality and repeat-ability of LSR molding is most suitable for flash-less products in high volume production. LSR injection molding, LSR over-molding, LSR 2-shot molding in Miwo can catapult you above all your competitors.
Conclusion
In conclusion, Miwo has more than 20 years of experience and expertise in large quantity product orders, we are able to produce high-quality products consistently.
Contact Miwo now to learn more about medical-grade Liquid Silicone Rubber.
