1. Metal Washer Question Selection
Metal Washer Question Selection ?. With so many washers to choose from, how does a
manufacturer select the best one for a specific application? While most often used to prevent
vibration loosening, washers also prevent joint relaxation and provide a common bearing surface.
Phoenix says manufacturers need to remember that washer thickness, diameter and strength
always impacts the length, diameter and capability of the fastener. In addition, they must factor
in space restrictions within the bolted joint and the environment where the fastened part is used.
Tight spaces might require the washer to be angled and custom-made. As for environment,
determine if the washer needs to allow conductivity or insulate the fastener from corrosion.
Finally, manufacturers have to decide if they want to install washers manually or with
automation. This decision should never be based on the assumption that every standard washer
can be installed with automation.
For example, a few years ago a water-pump manufacturer had batches of a custom washer that
could be automatically fed from a tube onto a fastener. The manufacturer had been using a
standard washer, which had ever-so-slight edge variations throughout each batch. The variations
caused some washers to get stuck in the feeding tube, disrupting production.
Another option for manufacturers is to use SEMS screws or Keps nuts, which have a retained
washer and can be installed manually or with automation.
A Smarter Future
Manufacturers love innovation and welcome it in all assembly processes, especially fastening.
That's great news for three Hong Kong teens who, this past May, unveiled their Smart Alert
specialty washer at the 2013 Intel International Science and Engineering Fair in Phoenix.
The washer is designed to lift a flag when the attached nut begins to loosen. It can be used in any
bolted joint.
The washer actually consists of two washers. One is a standard flat washer, but the other has a
small color segment connected to a spring. When the Smart Alert washer is installed, the loose
segment is hidden and held in place by the nut. If the nut becomes loose, the spring is released
and raises the color segment.
There's a growing awareness and appreciation for reliable bolted joints, and that's a great thing,
says Archer. This increases the potential for people to develop innovative bolts, nuts and
washers.î