Breakage problem swivel wheel
Problems are there to be solves
One of our customer experienced that their injection moulded swivel wheels would shatter under high pressure. They found out about the problem, because the appliance where the wheels were confirmed underneath, fell over. They ran a test on similar injection moulded products and they found out that these products would bent under high pressure. The asked us how this difference between the products was possible and if we had a solution for the problem.
The current swivel wheel was produced with polypropylene. There exist different kinds of polypropylene, two kinds can be distinguished: homopolymer and copolymer. A homopolymer exists out of one kind of monomer and a copolymer exist out of multiple monomers. Due to this difference a homopolymer has a higher stiffness but a copolymer has a bigger impact resistance. This explains why the swivel wheels would splinter with a homopolymer and bent with a copolymer.
We conducted a material test, where we produced the swivel wheel with a copolymer instead. When we tested the product under pressure it bent instead of splintered. This meant the question of the customer was answered and in the future the wheels will be produced with a copolymer instead.