Automatic Lathes Provide Zero Defects, Three-Shift Production

Case Study From: Production Machining, ,

Posted on: 1/17/2013

Being competitive these days is essential, yet becoming more difficult.

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Wiscon runs square stock for a ballscrew nut. The part starts with a center hole, and runs as fast as 4,000 rpm on the tooling.

Wiscon produces this solar industry part that is produced at the rate of 800 per day, every day of the week, on Wiscon’s automatic lathe. It takes about 35 tools to make it complete.

Being competitive these days is essential, yet becoming more difficult. Customer parts are more complex with tighter tolerances. They also want cost-effective analysis and competitive pricing, according to Torben Christensen, president of Wiscon Products Inc., Racine, Wisc.

To keep up with customer needs, this family owned and operated contract precision machining job shop is aggressively investing in equipment and improving. Three INDEX multi-spindle CNC lathes and six INDEX C Series automatic lathes occupy the shop floor and all are busy.

“We’ve just had several years of growth, investing more than 30 percent of our total sales in new equipment,” Mr. Christensen says.

With a highly skilled workforce of 50 employees averaging more than 15 years with Wiscon, the company, established in 1945, produces a range of flat and shaft-type parts such as hydraulic components, powered hand tools parts, oil field parts—an eclectic mix of complex parts and challenging materials—many automotive.

Wiscon operates three shifts, not only picking up 4 extra hours during the day, but also increasing production efficiency because there is no start/stop and related warm-up time, first piece runoff and start-up procedures. Scrap rate also is reduced significantly.

One of the parts running at Wiscon is a steel automotive camshaft end piece. The shop is making four different parts for the customer on several different machines in the shop.

“We package these and ship them to China for our customer’s car manufacturing facility there,” Mr. Christensen says. “They are confident they can just put our parts in and they will be good.”
He explains that another company that had the job did it out of a saw cut blank, machining two sides, then knurling. The part went through several operations and handling, resulting in unacceptable tolerance variation and bad quality. “Labels on dunnage from other shops show how many times some of the parts had to be inspected and repaired before acceptance,” he says. “It’s a shocking number. How do you make money on that?”

Wiscon’s quality range gets a lot of credibility with its customers. “I started as a supplementary supplier with this part, and we now have four parts from this customer,” Mr. Christensen says.
Mr. Christensen points out the quality management room, which includes a new Zeiss CMM. “We were getting to the point where we could not prove how good the parts really were, so we invested in the quality equipment,” he says.

Wiscon develops the process for each different customer part, fully utilizing the productivity of the INDEX equipment. It starts on the desktop. The shop uses INDEX VirtualMachine process design and simulation software for at least 90 percent of what it does. It uses it to develop cycle time analysis, and that has been highly beneficial. No CAM system is necessary or would tell us more.

“We found that the more time we spend with VirtualMachine to design realistic tooling for each step of a process, the process will be much more efficient and the parts much more accurate from the get-go,” Mr. Christensen says. “Production can happen immediately with faster start-up times because we can fully optimize the process and cycle times before we cut a chip.” Another positive result of VirtualMachine is that Wiscon avoids using up to 12 hours of machine time trying out a new part process.

On one of the C100 automatic lathes, Wiscon runs square stock for a ballscrew nut. “With the C machine, we can maintain all the orientations. The part starts with a center hole, so it runs as fast as 4,000 rpm on the tooling. For square stock or hex stock, the INDEX bar loaders are the only ones that work efficiently and quietly,” Mr. Christensen explains.

Because the C100 is configured to complete a range of parts, small to large batch sizes, Wiscon reports high machine utilization rates, which allow the machine to be very cost effective. Parts can be unloaded from the main or counterspindle.

Simultaneous machining with two Y axes at the main spindle or a Y axis at the main spindle and also one at the counterspindle—each with 70-mm travel—gives Wiscon the option to divide machining operations for optimum machining efficiency and flexibility. This freedom also is a key to reduced cycle times. Wiscon can machine simultaneously with as many as three driven tools for complete machining in a single setup, including heavy milling and backworking with as many as five tools.

Mr. Christensen says, “I feel the C100 is the only machine that could do this part, which is used by the solar industry—800 per day, every day of the week. It takes about 35 tools to make it complete. The part has a lot of detail, and many times the customer will change it on the fly. That’s why we find the versatility and quantity of the tooling on the C axis—up to 42 tools live or stationary —is key. We are now the customer’s largest supplier of machined parts.”

Another of the C100s uses 34 separate tools (half are live tools) to make a stainless part in a single setup. “Not many pieces of equipment could handle that many tools, especially with that many live tools,” Mr. Christensen says. “When you are using 34 tools, chip-to-chip time becomes important: It’s less than 1 second each on the C100. This saves an amazing amount of time.”

Dealing with a competitive environment is much more manageable when working with a reliable machine tool company. INDEX has been that company for Wiscon through the years. “We feel we selected the right partner to create a production capability that has grown and is now unusual in the precision parts industry,” Mr. Christensen says.
 


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