Here is one real-life example of how tweaking the dressing process can significantly improve grinding performance. The part was a hydraulic sleeve and Meisterʼs customer was dissatisfied with the results he was obtaining from a bore grinding process using a vit-bonded CBN wheel.
The customer was looking for a cycle of less than 37 seconds but was only getting 42 seconds.
Immediately after the dressing cycle, he was seeing (+) taper and an unacceptable drop in bore size, which only corrected itself after grinding 2-3 parts. After reviewing the grind process, wheel, and dresser designs, Meister engineers decided to have a closer look at the dressing process.
It was determined the dress process was unnecessarily dulling the CBN wheel, causing it to build too much pressure during the grind cycle. This resulted in quill deflection which, in turn, caused the taper and size control issues. Also, the customerʼs dressing process had a dulling effect that prevented the wheel from grinding at its full stock removal potential.
The following chart shows the steps that were taken to improve the dressing process.
Results: Moving from a counter-directional to a uni-directional dress (both wheel and dresser rotating in the same direction) exerted more crushing force on the abrasive bond, resulting in a more open and aggressive cutting wheel, so the customer was able to increase feed rates and get the cycle time down from 42 seconds to 36 seconds.In addition, taper and size control dramatically improved, so there were no more dimensional issues after dressing. As a bonus, since the wheel was cutting more efficiently, the customer found he could increase skip dress from 10 to 15 parts, allowing a much improved wheel life
Want to Know More about dressing techniques for vit-bonded superabrasive wheels? Download Meister Abrasiveʼs Dressing Tutorial PDF: Click Here.
