Tech Talk Blog

In surface science, the use of a goniometer (contact angle meter) is common to determine the wettability of a surface. What is clear is that every material has a specific surface energy. But, may not be clear is that the surface topography of that material also effects the contact angle.

Surface roughness can change the contact angle without plasma or other surface treatment. When a device is molded or machined, the surface finish of the device can have a functional as well as a aesthetic purpose. The functional purpose can be microscopic capillary channel as in microfluidic devices. The aesthetic purpose can be feel or finish of the part as in grips or sunglasses. The data below shows the effects of surface roughness in RMS versus natural, plasma treated hydrophilic, and plasma treated hydrophobic.

Notice the general trends in contact angle relative to surface roughness.

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It is more a standard than an exception to bond dissimilar materials in industry these days. Many adhesive manufactures have responded with a variety of liquid treatments to facilitate this trend. Though many of these primers work well, they have safety, shelf-life, and disposal issues. So, what now!

Plasma combines with aqueous (water) based post treatments provide a broad range of environmentally safe and stable surface activation primers. The plasma and corona pre-treatments open the types or polymers that can be primed for the specific chemistry to react with a particular adhesive or paint like rubber to metal. If you would like to improve your current process of metal treatment prior to rubber overmolding or polymer treatment prior to adhesive dispensing, then this technique should be tested. If you have a specific question about your application, Ask The Experts.

There are many options when it comes to cleaning parts; solvent wiping, soaking, ultrasonics, abrasion. But, more and more are considering plasma treatments, specifically plasma cleaning. Granted that plasma cleaning is horrible at removing bulk or globed on gunk from a device simply because it would take a very long time for all organics to be eliminated. But, to use plasma as the final step in complete organic removal, nothing is better.

Plasma cleaning of critical parts like medical implants, electronics, or diagnostics is one of the best methods. The operational cost and chemical use is very low making this technique environmentally friendly. The plasma technique is completely 360 degree cleaning organic residue from the smallest feature. The surface will be hyper-clean, uniform and ready for packaging or to some other critical step where pristine surfaces are necessary. Learn more about plasma treatments in our Shooting Star eLetter and be sure to check out the archives!

Rulon 142 is an excellent material for high load, high speed linear guideway liners for machine tools. Commonly used as an inexpensive insurance policy to possible lube failures on machines, Rulon 142 is bonded to the dynamic component on the X-Y-Z tables of some of the world’s leading machinery builders. Rulon 142 is also an excellent material for rebuilding machine tools where the efficiency and tolerances have been lost over time. Easy to install using CE211 or CE211FC adhesives available from stock. Rulon 142 is commonly used as an cost effective alternate to Turcite B and is fabricated using the same techniques. For more information on Rulon 142, visit www.tstar.com and check out our Shooting Star Archives for a number of articles on Rulon and more!

Rulon J is a polymer reinforced PTFE material with extremely low friction and long wear life. Developed by Dixon Industries over 40  years ago, Rulon J is best used in light duty, high speed bearing applications. Operating temperatures of -400 to +550F are attainable with Rulon J as with all Rulon materials. Rulon J is commonly used in applications where absolute minimal stick slip can be tolerated, no lubrication can be used and speeds are running as high as 500 sfpm. Rulon J can be found in office machines, X-Y-Z guides on analytical instruments, fine movement aerospace components and similar types of equipment. For more information Rulon J visit www.tstar.com or simply Ask The Experts your direct question.

TriStar’s CJ bearings are filament wound composite bearings with various liner materials for specific applications. CJ bearings are able to operate from cryogenic to +350 temperatures with NO LUBRICATION. CJ bearings are primarily for high load, medium speed linear or oscillating applications such as lift and tilt points on equipment. The FCJ and Super CJ are designed for high loads and high speeds with 400 sfpm attainable without lube. CJ bearings are truly maintenance free bearings and cost effective even when compared with bronze bushings. For more information on CJ bearings visit www.tstar.com. And don’t forget to contact TriStar to learn how CJ bearings can help with your product performance.

Rulon 641 is an FDA cleared bearing material that has excellent wear resistance in non-lubricated bearing applications. It is non-abrasive so works well against soft metals like stainless and aluminum. Rulon 641 is white in color so pleasing to the eye for food and pharmaceutical applications. Excellent material for linear, rotary or oscillating applications with very low coefficient of friction a K (wear) factor. There are two new FDA cleared materials compatible with the 641. Rulon 1439 is advised if the bearing is in a submerged or wetted environment. Both materials are inert to chemicals including all new sanitizing technologies in food and drug industries. For more information visit www.tstar.com and click on Rulon Bearings.