Flexible wear protection
For flexible materials to successfully protect against wear, they need to be elastic enough to change their shape as well as having sufficient space around them. These materials rely on their ability to internally redistribute the forces applied to them from rocks falling or tumbling over their surface.
And tumbling really is a key word in describing materials sliding or washing across an elastomer surface. As long as the particles bounce and turn as they hit the surface, wear is minimal and the materials will last a long time.
Photo: WT7000 Rubber Plate
To achieve this, the wear material needs to act as a spring or a trampoline. Instead of permanently absorbing the energy from the rock particles, the wear protection moves and then bounces back. If the particles start digging into the elastomer material, causing tears and erosion, wear life will be significantly reduced.
Contrary to the tougher category of materials, the basic principle is, the softer the better. However, this basic principle is very simplified, and a soft material that doesn’t have the ability to bounce back is of no use.
For heavy impact applications – where these materials generally perform extremely well – it’s worth having a slightly stiffer material, for practical and financial reasons. To go back to the trampoline analogy, the most important factor is to stop the jumper from hitting the floor. A trampoline is thus designed according to a maximum weight and jump height.
To translate this into minerals processing, the wear protection should be designed according to a certain drop height, particle size and density. The thickness and physical properties of the wear material must correspond to these demands.
You need to have a corresponding wear material thickness, together with carefully chosen material properties, to avoid crushing polymer chains which will lead to rapid wear.