April 2007 Edition

Grinding

Job Shop Showcase

To stay ahead of the competition, companies have to seek innovations, but they also have to prove the change is worthwhile

Where once U.S. companies had to worry about domestic competitors, world markets have broadened rival companies to those across the globe. It takes constant innovation and investigation to remain at the top of the heap. For a carbide tool manufacturer, staying ahead of foreign companies meant learning and adopting what was new in grinding technology. Greene Tool Systems Inc. is a cutting tool manufacturer that produces specialty carbide tools for various industries. The company is a significant player in the diesel engine tool and job shop markets where high-quality tools in short runs are demanded with just-in-time de-livery.

Keeping Fresh

In the competitive cutting-tool industry, Tom Greene, owner of Greene Tool, Dayton, OH, looks for new ideas or technologies that keep his company a keen con-tender. For instance, the firm installed the first Walter Vision grinder in the U.S., a grinder that became the tooling industry’s best-selling unit. Enhancements for which Greene Tool opted included a tool loader, coolant filtration down to 1µ, a coolant chilling system, high-pressure cleaning nozzles, and steady rests for the longer tools. While advanced CNC machines let the company reduce costs and produce higher-quality tools, these capital investments were not enough since competitive pressures continued to squeeze profit margins. Greene, and Thane Buxton, Greene Tool plant manager, continued to investigate ways to improve company processes.

On-Site Assistance

Winterthur engineers Radu Coman and William Gelinas knew their products would be used in a slightly different manner than standard super-abrasive products, so they assisted Greene Tool in optimizing the feeds and speeds during testing.

As the Winterthur employees assisted in testing, they also educated Greene Tool plant manager Buxton in the proper speeds and feed rates for tool sizes, and types. They also demonstrated the proper procedures for truing and dressing the products to obtain maximum productivity at the lowest total cost per piece.

With this information, Greene Tool matched grinding wheel speed with higher in-feed rates. This allowed the wheel to grind at lower motor loads. The chips created during grinding kept the wheel in a free-cutting state so the wheels removed more material in less time. This also improved the number of pieces between dress cycles.

 To quantify the production improvements, Greene selected one tool which he would use to con-duct a full cost analysis. The tool was a four flute step reamer, with a flute length of 85mm, and 150mm long × 12mm diameter. The tool had primary and secondary relief grinds on the three O.D. step areas and end-face and chamfer areas.

Following its standard processes with the grinders Greene Tool was originally using, the grinding process took 24 minutes per tool.  

From 24 to 13

Winterthur engineers reduced grinding time for tool production by eight minutes. With program changes, Greene Tool took out another three minutes and 30 seconds from the cycle, for a total time savings of more than 11 minutes.

The number of parts produced between stick dressing went from 12 to more than 70. Less wheel breakdown also led to quality improvements.

In operation with the in-place grinders, the company would have to size every 30 pieces. The Winterthur grinders improved that. The biggest gain the company saw from the test was that it was able use an auto-loader, allowing one technician to monitor several machines.

As for other tools produced by the Winterthur grinding wheels, they showed significant improvements

:• Parts per truing increased from 40 pieces to up to 200 pieces.

• Machine adjustments were reduced from one to two size adjustments for about 30 pieces to one adjustment per 100 pieces.• A 25 percent reduction in cycle times.

• A 30 to 40 percent reduction in fluting time.“We ran a 30 or 40 part job and didn’t have to reset the wheel pack for size or re-truing,” Buxton said. “We loaded the next program and continued".  

Cost Drive-Down

A 24-hour tool production operation like Greene Tool required operators on each shift “buy in” to the changes. Training accommodated acceptance. Winterthur and Green Tool embarked on a continuous training program. All of Greene Tool’s operators were tutored on the fundamentals developed during the test.

“Training was the most important aspect of using the wheels,” Greene said.

With the CNC machine tools, the options, and the grinding wheels, costs were driven down by $17.19.

But, money wasn’t the only savings. A 200-piece order can be ground 26 hours faster. The cost analysis is for all of the grinding operations. The fluting operation saved almost 7 minutes of the cycle time.

Overall, by upgrading its CNC tool grinders, and by optimizing its machines, Greene Tool maintained its reputation for quality while staying competitive in this contentious market. The company also took advantage of new sales opportunities previously out of reach due to past cost or quality constraints. The company is now the prime provider of regrinding ser-vices for a large diesel engine manufacturer.

Visit www.rsleads.com/704mn-204 for more information

What do you think?
Will the information in this article increase efficiency or save time, money, or effort? Let us know by e-mail from our website at www.ModernApplicationsNews.com or e-mail the editor at pnofel@nelsonpub.com.