Preparing CBN Wheels for Use
Superabrasive grinding wheels, such as diamond and CBN wheels require a little work and effort to set up and make them ready for use. This involves three main steps mounting, preparing (truing) and dressing the wheel so that they work as they should and give you the best possible grind. All three steps are important, but none so much as truing your CBN wheel.
What is Truing?
Truing allows for the face of the CBN wheel to be presented to the work piece properly and give you the best possible performance. After all, a wheel that is untrued can provide a surface finish, stock and removal capability that is undesirable. If you go through the truing process, and choose the right options based on your particular device and the product you are working with, you will get the highest possible performance of your grinding wheel. Additionally, the wheel life will be greatly reduced costing you much more effort and cost in the long run.
The Truing Process
The truing process occurs after you have already hand mounted your CBN wheel to the minimum runout. There are a number of techniques you can utilize to obtain the maximum truing level. Two of the most common include:
1) Multiple point (14 - 40 mesh) or impregnated (40 - 100 mesh or finer) diamond-type dressing tools.
Offers 0005" infeed for each pass (.01MM)
Not recommended for single point & cluster diamond tools
Finer mesh diamond - This technique allows better initial work piece finish
2) Truing brake or motorized dresser
Coarse grit (ranging from J to M hardness)
Silicon carbide or aluminum oxide wheel
001” Infeed per pass (.025MM)
You will apply the truing device to the wheel until contact is made with the entire face of the CBN grinding wheel. Whenever it is possible, you want to use flood coolant as this will extend the life of the CBN wheel. Heavy-duty water-soluble oils will also help add life.
It is important to remember that a resin-bonded wheel is not necessarily ready to go after it has been trued. Properly dressing it is very important as well. If you do not work through all the steps of the process, you will not get the best possible results and you may find yourself changing your wheel again much sooner than you planned to in the future.
Taking the proper preparation steps with your CBN wheels is not necessarily the easiest part of the grinding process, but it can make a big difference in the effectiveness of your wheels as well as with helping them to do their job for a longer length of time. For most factory and workshop applications, it is worth the effort and cost up front. After all, a CBN wheel is one of the most important tools you use on a daily basis, so why not take the time with the process?