Back in early 2013, we received a phone call from a large OEM experiencing early wear out problems with the rubber-insulated bushings in their shaker machines. This was a very severe application with each of the three bushings in the machine, seeing continuous, radial, torsional, and conical loading.
The OE had been thru two (2) vendors, three (3) iterations of bushings, and several different bushing designs, and still had not achieved acceptable performance, which they defined as “required to hold up for a minimum of one year in the application”.
Bushings Inc. is happy to assist potential customers in troubleshooting these types of performance problems. Typically with the customers answers to a few simple questions we can help diagnose the root cause of the bushing problem in the application, and come up with a solution. A sample part is sometimes requested to assist in the analysis.
Some of the most common problems experienced are:
- High heat (this can be either ambient temperature, or the heat generated by the mechanical work being done in the application)
- Overloading (part size is insufficient for the load being carried)
- Ambient conditions (such as the presence of oil, solvent or lube in the application)
- Improper method of manufacture – (part not manufactured using the optimum method of manufacture for the duty cycle which the part sees in the application)
The graph below depicts results of our tests which we used to diagnose, and solve their application problem.
Part “A” was a fully mold bonded bushing, which the OE advised was de-laminating early on in the duty cycle. Parts “B” and “C” were silent-bloc bushings, part “B” worked fine in the application, but was seeing early wear outs (within 6 months of operation). Part “C” was a harder version of the silent-bloc bushing – but when this part was installed in the shaker, the machine would not start.
After the load deflection test, Bushings Inc. designed a center bonded bushing, molded in hardness slightly stiffer, than part “B” – we also molded a variant, in a slightly stiffer compound. Our initial part worked well in the application. Once we achieved the desired hardness for optimum function in the application, we tweaked the rubber formula to obtain greater tensile strength to further extend the life of the part.
After more than 18 months of testing in the application, we are happy to say, that this bushing was adapted by the OE for their shaker machines, and is working well, with no further complaints of short life.
Let us help you with your application problems, we can provide no charge assistance with your product design, or application troubleshooting.