A government contractor was challenged to find a small lot method to produce a hexagon boot clamp with a temperature performance requirement that was limiting their options. Traditional manufacturing techniques like injection molding and machining were too expensive for short run production. Initial AM methods used to produce these parts fell short on meeting the desired material properties, and failed testing conditions that they were subjected to.
Stereolithography (SLA) models were challenged by temperature limitations, and warped during thermal testing and heating. Each failure would compromise a week of testing for the application.
SICAM suggested to test out the feasibility of the latest AM technology by HP known as Multi-Jet Fusion (MJF). HP Multi-Jet Fusion Printer technology was used to produce a set of models of the hexagon boot clamp design. Using a Nylon 12 material, the MJF technology produced parts at a speed and level of quality that made them perform with traditional manufacturing processes capabilities, but at a reduced cost to meet the requirements of low volume production parts.
The MJF Nylon hexagon boot clamps were used to perform thermal load testing of clamping a silicone boot around a hex-nut. This critical application required long duration testing, and part reliability under a temperature range of -65 to 140 degrees F. Validation testing of the parts was carried out by submerging the clamp assembly in liquid nitrogen (~320 F) for about a half hour resulting in no deformation or cracking. Next, the clamp was put into a heat chamber at 160 F for about a 1 hour and clamped, under tension, and the results showed no deformation as the MJF Nylon parts. The parts performed their duty well and based on these positive results, additional sets of hexagon boot clamp designs are being fabricated, in small production batches, which suits the needs of this application to a tee.