Rub Rails and Washers
Rub rails and bumpers are “sacrificial” guards that are placed in high-impact areas to absorb the shock and wear from contacting walls and other objects. They are usually placed in such a way that they protrude slightly from the housing or cart they are meant to protect to make sure they come in contact first with any obstacles.
Desirable material properties are softness for impact absorption, a low coefficient of friction to make the guard slide and deflect obstacles easily and lastly it should be non-marring in order to not leave marks and streaks on walls or other surfaces.
Materials of choice are mostly HDPE , Polyamide and Acetal and. These polymers are not affected by corrosive environments and stand up well to common cleaning agents, fuels, oils and other chemicals.
Since bumpers and guards are wear items they need to be cheap and easy to replace. In most cases these guards are custom made for specific applications and in small volumes which rules out injection molding or thermoforming because of the high upfront costs for molds and fixtures.
This is why our zero-tooling process is ideally suited for these kinds of parts. Not just because of the low upfront cost, but also because it is our policy of indefinitely retaining CNC files and bills of material for all our customers and projects. This means that even years or decades later we are able to manufacture replacements to the original specifications with short lead times and no non-recurring engineering charges.
Lastly, there are washers and guides that fulfill a similar purpose by reducing friction and wear. Rotating arms, drawer rails, chutes, skid plates and funnel guides benefit from the same properties that make for a good rub rail or bumper. In these cases sometimes graphite filled Polyamides ( Nylatron ) are used to further reduce friction. We carry these grades for those specialty applications.