This video documents a Wear Resistance Accelerate Test.
The purpose of this test:
1. To prove the following statements corrected in general principal and theory of tribology.
a. Metal-to-metal wear, or adhesive wear lead to the following list of surface characteristics and the processes that produce them.
- Micro-rough due to tractive stresses resulting from "ADHESION".
- Macro-rough causes severe "ADHESION", at least as an initiator of damage.
- Shiny, a very thin (or perhaps no surface film) of e.g., oxide, hydroxide, sulfide, chloride, or other species.
Quoted from "Friction, Wear, Lubrication"(see appendix) A Textbook in Tribology by Kenneth C Ludema, Publisher : Boca Raton : CRC Press, c1996.
b. In theory of Tribology, same metal with same crystal lattice type, same atomic plane distance and same electron density. Those materials carry similar characteristics in electrochemistry. Their mutual solubility in same materials becomes greater. They easily bond together and cause wear damage. But metal and non-metal e.g. example nylon, plastic, graphite etc., the mutual solubility is relatively small, the tendency to coherence of two materials is greatly reduced.
Quoted from"Materials in Engineering & Its Applications"(see appendix)
Course Outline of Professional Degree in Mechanical & Automation Engineering Design published by University of Xian Electronic & Technology Publication, c2008.
c. High degree of miscibility between same metals has a high adhesion and bonding capacity. Therefore, we should try to avoid using the same material in composition of sliding friction system. Aluminum and aluminum alloy wear with different loads also have two different mechanisms. At low level of loading, the metal itself induces minor wear or oxidation wear with thickness up to about 2µm on the surface. For the role of friction, this layer oxidative film being ruptured and peeling off with debris and flake.
Quoted from "Materials for Wear Resistance in Tribology" (see appendix)
Textbook of Materials in Mechanical Engineering & Its Application published by China Machine Press.
Test Products : Original FMC Aluminum Rollers and New Composite Nylon Roller
- A Loader Platform Simulator should be constructed using the FMC transfer desk as reference. Four FMC roller clusters should be installed in the simulator. Each of the clusters will be fitted with 24 new FMC Aluminum rollers given by Hactl in first round and do the same test with 24 new Composite Nylon Rollers in 2nd round.
- A 70 cm diameter circular steel plate with its bottom fitted with a metal plate, the same type of metal (American Standard # 7050) as per the cargo box bottom plate. This is to simulate the actual metal / roller contact condition. The test is carried out by putting a 450 kg metal weight on the circular plate, i.e. each roller shares a load of 112.5 kg, 2.5 kg more than the standard maximum loading of 110 kg per roller.
- The clusters are recorded as group A to D. They rotate at 160 r.p.m. in same directions which is 4 times of normal rotation rate.
- The test is expected to conduct 10 hours per day, i.e. a total of 100 hours each round of testing.
- Every 20 hours, the rollers are measured to record the wear occurred. The roller diameters at the centre and at both ends are measured (see the arrow pointing locations in Figure 2.11). The smallest diameter over the circumference obtained is recorded.
- After each 10 hour operation and measurement, the device is started again running in reverse direction.
Result & Summary :
The wear on the new composite nylon rollers is much less than on the traditional aluminum roller, while the test on aluminum rollers was only lasting for 2 hours. Its surface started peeling off after 30 minutes and serious deformation and started damaged to housings in 2 hours.
For test of Nylon Rollers, it is discovered that there was no serious loss of material at the surface and two ends after 20-hour test which is 10 times of test hours of Aluminum Rollers. It can even run more than 20 hours but we stopped the test when the machine engine found overload.
The result to compare two kinds of rollers is very obvious to support the theory of tribology in selection of materials in composition of sliding friction system. Metal-to-metal contact is not a good arrangement and easily gets wear & tear of both the aluminum rollers and the aluminum pallet plates as well.