Silicone Extrusion Process Guide
While your medical grade tubing may look simple to the untrained eye, you know the critical role it will perform. Others in the industry may view it as simply a tube, but to you it’s a shield or a feeding device or a medical delivery system. And for that reason, it must be perfectly designed and properly manufactured. Use this process guide to ensure that your silicone extrusion is the best it can be. Because at Lubrizol Life Science Health we know that anything less is simply not acceptable.
Silicone Extrusion Basics
The silicone extrusion process begins with blending a two-part silicone gumstock on a two-roll mill to produce a homogeneous medical-grade silicone. The silicone is then formed into strips and fed continuously into the extruder. A variable-speed screw feed maintains proper pressure at the pin and die, and a laser micrometer monitors the OD throughout the process. Finally, the medical grade tubing passes through an oven that cures the product with radiant heat.
Optimizing Every Aspect of Silicone Extrusion
The aspects of silicone extrusion that may affect the cost and clinical outcome of your medical device include:
- Quality Control
The quality of your silicone extrusion is largely determined before manufacturing begins. The toolmaker, technician and quality control inspector should all provide their input during the early stages of medical device product development. This collaboration helps the silicone extrusion process flow smoothly the first time, without the need for reruns, saving time and money. Quality control inspection plans must target the critical dimensions and be easy to use during the extrusion process.
- Silicone Specifications
There are many variations of medical-grade silicone gumstock — also referred to as HCR (high consistency rubber). You must specify the right one in order for your silicone extrusion to function properly at the point of care. For example, the components of a feeding catheter should be made of silicones with different durometers that exhibit the right physical properties. Specifying the wrong type of silicone may cause discomfort for the patient or application difficulty for healthcare professionals. Likewise, specifying certain nonsilicone substrates for reinforcement or coextrusion may be necessary to ensure product functionality.
- Product Design
Your medical device design affects manufacturability as well as performance at the point of care. It’s important to discuss your design with a manufacturing expert who can suggest refinements that will reduce your costs without sacrificing functionality. Examples of complex design specifications for silicone extrusion include extremely small bend radii, sharp corners, asymmetrical shapes and ultrahigh-precision callouts.
- Facility Design
Be sure your silicone extrusion takes place in a clean room environment with adequate space for processing. Modular equipment, flexible connections and interchangeable extrusion heads allow the facility to accommodate your needs with efficiency.
- Equipment Capabilities
Verify that the most advanced equipment available will produce your silicone extrusion. But not every machine works for every silicone extrusion; the medical-grade silicone you specify must be matched to the right extruder and screw. Machine calibration and wear must be closely monitored to minimize costs and to ensure optimal clinical outcome.
- Operators and Training
Silicone extrusion is a true skill and craft. Operators must be thoroughly trained, or their mistakes could affect the quality or cost of producing your silicone medical device. The best operators are those who utilize automated statistical process control and are also experts at manual in-process inspection.
- Process Controls
Control issues such as the pulling speed, level of automation and feedback loops can significantly affect the clinical outcome and cost of your silicone extrusion. Advanced in-process controls like laser micrometers ensure that all measurements meet the specifications. Together, the right operators and controls keep the process flowing smoothly and according to budget.
Finding the Right Silicone Extrusion Partner
A qualified silicone extrusion partner provides expertise in all of the above aspects of silicone extrusion. Be sure to work with a company that demonstrates understanding in the critical demands of the medical device industry, QSRs, product manufacturability, dimensional layout, tolerance stackup and quality control inspection plans. The right partner for you is someone who can do all of that while also offering insight into industry trends, such as the increasing demand for the following:
- Smaller diameters and thinner walls for neurovascular applications
- Custom tubing and exotic shapes
- Biocompatibility and long-term implants
- Antimicrobial silicone extrusion
- Complex tubing that requires secondary applications
- Reinforced extrusion
Finally, the right medical device outsourcing partner will always put your needs first, delivering a cost-effective silicone extrusion that succeeds in the marketplace.
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