Photo courtesy Norton | Saint-Gobain Abrasives
Giacalone of TGS noted that every grinding wheel is specific to a family of parts, and that is where a lot of wheel selection mistakes can be made. “Some job shops buy one wheel to grind different types of materials,” he said. “They can’t understand why they ground a great steel part to tight size, but when they switched to aluminum they can’t hold size at all. You don’t see that with large companies, such as Timken, or GM, because they are mainly grinding a certain process and a certain material.”
Balancing grinding wheels is also critical to successful centerless grinding. To increase throughput and improve part profiles, automatic balancing systems, once an option, have become standard equipment for dressing and grinding operations on many centerless grinders. “On a full CNC centerless machine, dressing the wheel is a piece of cake,” said Schürl. “All parameters are fixed; the operator presses a button, the wheel is dressed and compensated, and grinding resumes immediately. Manual dressing takes much longer, and after it is completed the operator has to zero the wheel in again. As a result, many operators put off dressing, leading to excessive wear on the grinding wheel. Also, with manual dressing the operator doesn’t really know how much of the wheel he is remov- ing. With automatic dressing, you can dress after a certain number of parts and know exactly how much of the wheel you are taking away.” In Schaudt Mikrosa’s system, the sounds that wheel dressing makes are made visible on the machine display via acoustic sensors and help the operator determine if the wheel is fully dressed. Giacalone agreed that automatic balancing systems are a must. “All of our machines get automatic balancers; I can’t remember the last time we built a machine without one. It’s the icing on the cake; if you have a great machine and the process is right, automatic balancing helps you trim off that last 0.25 µm. Also, if you’re having trouble balancing with your automatic system, say, five years down the road, it’s a
? Glebar Co. 201-337-1500 /
www.glebar.com
Norton | Saint-Gobain Abrasives 254-918-2313 /
www.saint-gobain-abrasives.com
Republic Lagun Machine Tool Co. 310-518-1100 /
www.lagun.com
Total Grinding Solutions Inc. 586-541-5300 /
www.totalgrindingsolutions.com
United Grinding North America Inc. 937-859-1975 /
www.grinding.com
June 2017 |
AdvancedManufacturing.org 59
Norton Century45 wheels, which are available with ceramic, aluminum oxide, silicon carbide grain and abrasive blends to maximize user grinding safety and efficiency.
good indicator that you probably have a spindle issue, not a balancing issue.” Today, centerless grinding is an interesting mix of old
and new, with some shops running decades-old manual machines and successfully making parts, while others use new, largely automated machines. But as tolerance demands grow and part volumes increase, the balance appears to be tipping toward modern centerless grinding.
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