Are you turning a shiny finish to a matte or frosting a clear surface to diffuse light? MicroBlasting is an excellent method for altering the finish on a base material by adding texture. Surface texturing is not just a cosmetic application. MicroBlasting is also widely used to enhance the adhesion characteristics of a surface for improved bonding.
- Angioplasty balloons
- Cannulae – selective texturing of the tube surface prior to over-molding and light abrading to impart an echogenic or etched surface finish
- Catheters – preparing surfaces to promote bond and coating adhesion
- Lens molds
- Nitinol stents
- Orthopaedic implants
- PEEK implants
- Vascular stent
- Orthodontic bands
- Implants – roughening the threads increases the surface area for the tissue to take root, improving osseointegration
- Surface prep of alloys prior to opaquing
- Bonding HUD optics
- Injection mold cavities – texturing the surface of a cavity on a new mold to hide splay lines, flow lines, knit lines, blush marks and other molding flaws
- Load cells
- Flex circuitry – texturing provides adhesion enhancement for bonded components and increases the peel strength of material when it is attached to other substrates
- High performance capacitor cans
- Laser flow tubes
- Load cells
- Solar glass – texturing to increase reflectivity on backside
- Underwater fiber optic cables
- Load cells – texturing surface for better bond adhesion
How To Texture with MicroBlasting
MicroBlasting produces accurate and uniform surface finishes. Surface finish creation begins with identifying the ideal surface properties for your part and then selecting the best abrasive for the job. Three factors impact surface finish creation:
Type of Media
The chemical and physical properties of abrasive effect your part’s surface finish. For instance, angular materials tend to leave a matte finish on most surfaces and spherical media tend to leave a satin finish. The more energy a media can store, the rougher the surface it creates.
Size of Media
Basic principle: the larger the abrasive particle, the rougher the finish. Pit size on your part’s surface directly correlates with the mass of the particle that strikes it.
Speed of Media
The speed at which the abrasive particles travel is determined by many factors: blast pressure, nozzle design, propellant or gas type, and nozzle distance. The faster a particle travels, the larger a crater it leaves in the targeted surface.
Different materials will react differently to the blasting process. These materials can be divided into two groups:
The Ra is a combination of the depth of the crater and the displaced ring around the edge. Depending on the abrasive selection and composition of the ductile surface, micro-abrasive blasting can produce either a satin or a matte finish.
There is no displaced ring. Ra is typically determined by the fracture mechanics and grain size of the substrate. Blasting on brittle materials only produces a matte finish.
How to Get a Consistent, Repeatable Surface Finish
Look Beyond Ra
Ra is a measurement of peak amplitude on textured surfaces. It does not account for peak density or spacing– two variables that matter in most texturing applications. Combining Sdr (developed surface ratio) with Ra can provide a more accurate understanding of your part’s surface and bonding properties. Mechanical bonds generally require more spacing between peaks, whereas organic bonds tend to require tighter spacing. Large abrasives at low pressures yield low peak densities. Fine abrasives at high velocities yield high peak densities. Learn more and see examples in our post on improving bond strength.
Specify and Control
Learn more about surface texturing from our Chief Engineer, Mickey Reilley. Watch his presentation, “Microblasted Surface Finishes: How to Specify – How to Control.“
Manual and Automatic Systems
Apply texture uniformly with either a manual or an automated MicroBlasting system. A manual system is a great starting point. It gets you into the process. You can achieve desired results without having to invest heavily in fixturing and technology.
Automation is ideal for applications where large areas of a part need to be textured uniformly. MicroBlasting roughens these large surface areas without leaving lines or bands. Automation also delivers on applications that require very tight tolerances or localized and focused texturing, like a dental implant that requires a sharp delineation between textured and non-textured areas.
The surface texture of a dental implant is a critical design component, as it determines how quickly and smoothly the implant integrates into a jaw bone. Studies indicate that the surface of the dental implant needs to be more than just rough. Several characteristics impact the rate of integration. MicroBlasting controls two of these characteristics: Ra, the size of the peaks and valleys, and the developed surface, or the amount of surface area created through the texturing process.
Automation delivers ideal results for surface texturing dental implants. It provides careful control over particle velocity and coverage, which together create a consistently uniform surface. With automation, you can create surfaces as smooth as 10 µin or as rough as 200 µin.
While surface texturing with MicroBlasting is most commonly used on bone screws and dental implants; it is appropriate for most implants that depend on a rapid fixation process, even some spinal implants.
Load Cells and Flexible Circuitry Bonding
Load cells and flexible circuitry need to bond to a metal substrate, either chemically or mechanically. MicroBlasting suits both texturing applications. Each application can be done manually or using an automated system.
MicroBlasting roughens the surface of a load cell to keep it glued to the substrate.
MicroBlasting improves gripping power by creating large peaks and valleys on a flexible circuit.
Sodium bicarbonate is an effective abrasive for roughening polyimide film, like Kapton. Sodium bicarbonate is also water soluble and easily washes off the device during the cleaning process.
Rework Injection Molds
Molds gradually lose their surface finish in production. Some molded parts change appearance and stick in the mold. Proper mold maintenance extends the life of mold cavities.
MicroBlasting creates a uniform finish without degrading the mold cavity. A focused micro-abrasive stream delivers consistent results, especially on small and intricate molds.
Glass bead is an effective abrasive for this application. Its spherical shape forms smooth craters in the mold cavity and cleans out any residual material.
- MicroBlasting for Texturing and Cleaning Molds – Article in Plastics Machinery & Auxiliaries
- Customizing Surface Abrading for a Perfect Finish – Article in Products Finishing
- Need to Improve Bond Strength?
- Need a Consistent Surface Finish?
- Uniform Removal + Sharp Delineation? You’ve Got This.
- Surface Texturing for Dental implants (VIDEO)
- MicroBlasted Surface Finishes: How to Specify, How to Control (VIDEO)