In a perfect world, every component would be manufactured exactly to specification. But perfection drives costs higher so it makes sense to accommodate variations — tolerances —as long as they do not compromise the finished assembly.
But there is a catch. If a device features four or five nested components, the components may be at the “worst case” limits of their design. Tight-fitting parts make assembly difficult and slow, and excessive friction and sticking, often called “stiction” can degrade the operation of the finished device. These accumulated “stacked tolerances” can be very difficult to resolve in manufacturing.
A cost-effective way to address stacked tolerances is to use a dry lubricant based on polytetrafluoroethylene (PTFE) like Duraglide™. PTFE is a powder and is mixed into a carrier fluid. The mixture is applied by dipping the parts into a liquid bath. The carrier fluid then evaporates away leaving a smooth, dry PTFE coating on the part.
Dry lubricants such as Duraglide™ are versatile. They are compatible with most plastics and metals. They conform to virtually any surface; they readily penetrate into complex shapes and blind vias. Duraglide™ is safe, clean, non-migrating and is ISO 10993 certified. A brief heat-treating process can turn the coating into a hard, durable and attractive finish.
But most importantly, dry lubricants improve the performance of a finished device. They can instantly reduce the coefficient of friction on a treated part to as low as 0.06. This translates into a 25-30% reduction in actuation forces, greatly improving performance. Many medical devices would not be commercially viable without a dry lubricant.
For additional information about dry lubricants in general and Duraglide™ lubricant in particular, contact your MicroCare representative.