By Matthew Nipper, Spectrum Plastics Group, Director of Engineering
Laser micromachining is among the highest-precision processes utilized in medical device manufacturing. In fact, lasers are often the only option capable of producing certain delicate features, especially in thin or sensitive materials. Lasers can cut micron-sized features quickly with sub-micron tolerances, without defects—thereby reducing or eliminating secondary finishing processes, shortening cycle times, and expediting time to market. Because of these advantages, lasers are quickly becoming the preferred method to micromachine miniaturized and/or complex parts and products for medical devices, in virtually any shape or pattern.
Innovative product designs that require microscopic features are often best produced using laser machining—for example, catheters, medical balloons, and devices for neurovascular, cardiovascular, and diagnostic procedures. Features produced in polymers can be as small as 10 microns in width, with tolerances as tight as 1-2 microns.
Polymers are the material of choice for many medical devices. These materials are mechanically robust, bioinert, and have excellent insulative properties. Polymers can be engineered to exhibit specific mechanical and chemical characteristics, to improve biocompatibility and performance, and can be extruded, injection molded, or additively manufactured. Virtually any thermoplastic or thermoset polymer material can be laser processed with high precision, including polycarbonate, polyurethanes, ABS, FEP, polyamides, polyimides, PEEK, PTFE, PMMA, polyester, Nylon, PE and acrylics.
Laser Methods
As products become smaller and more complex, engineers must use their technical skills, material knowledge, and experience to design processes that can create tiny, high-precision features that enhance product functionality, which can ultimately enhance or save patients’ lives.
Examples of high-precision laser methods that are commonly used include:
Laser Ablation
Lasers can be programmed to ablate or “vaporize” material from surfaces with sub-micron accuracy. Ablation selectively removes layers of substrate or coating from the surface of manufactured parts, with little or no negative thermal or structural impacts to the surrounding material.
Laser Cutting
Laser cutting is ideal for manufacturing/industrial applications that call for a powerful, highly accurate cutting tool that creates clean, micro-scale features. As products become smaller, with more functionality, complexity, and tight tolerances, laser cutting is often the only method that can produce the high-precision features these devices require.
Laser Drilling
Many manufactured parts today call for microscopic features that can only be created with laser drilling. This highly adaptable, versatile, and reliable micromanufacturing process is used in a broad range of industries. Laser manufacturing and post-laser processing can be customized to match unique drilling needs, optimizing applications such as micro holes, hole arrays, blind wells, and specialized portals. Micron-scale holes can be laser-drilled in a variety of patterns with the highest precision, without burrs or residual material that can plug holes.
Wire Stripping
Wire stripping removes sections of insulation or shielding from wires and cables to provide electrical contact points for termination. Conventional wire-stripping methods make physical contact with the conductor, which can damage the wire and slow down processing speed. Laser wire stripping is much faster, provides excellent precision and process control, and eliminates contact with the wire, allowing for the processing of gauges as small as 46 AWG (0.0015 inches in diameter).
Ultra-fast Lasers
Ultra-fast lasers are in high demand because of their speed, precision, and lack of thermal or structural damage to the material being processed. With an average pulse width of 150 femtoseconds (150 quadrillionths of 1 second), there is virtually no heat transfer beyond the dimensions of the cut, making it a “cool” process. As a result, secondary processing is typically not required to clear burrs from cut features or enhance edge quality, saving time and cost.
Laser Components and Technology
Precision laser-processing can be used for extruded medical tubing, catheter and drug-delivery products, medical balloons, injection molding, and flexible films. For example:
- Extruded medical tubing. Lasers are high-precision machining instruments that cut micron-scale features in extruded tubing that enable specific medical applications, such as intravascular drug or stent delivery. Extruded medical tubing is a commonly used component in medical devices. It is manufactured from a variety of materials and in a wide range of shapes and sizes. Important chemical and mechanical properties include heat and chemical resistance, lubricity, flexibility, kink resistance, and drug-eluting capabilities.
- Catheter technologies. Lasers, which offer high speeds, incredible precision, and the ability to process without thermally altering the surrounding material, are ideal for removing material through ablation or drilling a variety of micron-sized features in catheter tubing and other materials. As medical catheters become smaller and more complex, lasers are often the only manufacturing technology capable of delivering the necessary accuracy.
- Medical balloons. Lasers play a critical role in creating detailed, high-precision medical balloon features that no other methods can duplicate including; texturing, grooving, and section thinning. With the latest laser technologies, tools, and materials, medical balloons can be manufactured with microscale features, from a large variety of materials, for increasingly innovative neurovascular, cardiovascular, gastrointestinal, urological, and catheterization procedures.
- Injection molding. For injection molded products, lasers can be used to create micron-sized features within molds, process molded ophthalmic implants, and improve osseointegration of injection-molded bioresorbable implants. Because ultra-fast lasers impart no heat damage, they are ideal for processing sensitive implantable and bioresorbable materials.
- Flexible films. Laser processing can be used for a variety of film applications. For instance, lasers can be used to create micro surface texture patterns on thin films increasing adhesion in delicate bonding applications. Lasers are also ideal for drilling small features, such as dense arrays of holes in filters or spargers. These are often made from thermoplastic materials, which are highly sensitive to heat.
Spectrum Laser Processing
As a full-service laser solutions provider, Spectrum can manufacture high-precision parts to exact specifications, in the most efficient and cost-effective way. Spectrum excels at turning even seemingly impossible designs into high-value products that exceed customer expectations.
Not only is Spectrum a laser contract manufacturer of high-precision products, we also provide off-the-shelf laser array tubing and laser cut marker bands online at webstore.spectrumplastics.com, which can be used to accelerate the development phase of your next project. For more information about Spectrum’s laser processing services and capabilities, visit www.spectrumplastics.com or call 404-564-8560.
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