Swiss Machines Power Shop's Growth

Wright Technologies, Rosemont, Illinois, is a contract manufacturer that specializes in turned and milled parts in prototype to production quantities. Two years ago, the shop quoted a job involving two relatively small parts, a valve body and stem, which made up a valve used to control oxygen flow. The customer liked the price and placed an order for 60,000 assemblies. However, when the shop produced some sample parts for the customer on its single-spindle CNC lathes, it discovered that it had significantly underestimated the costs for the job. The shop submitted a readjusted (nearly doubled) price to the customer, who declared it too high and withdrew the order. The job went to another vendor.

Wright Technologies president Kazimierz (Casey) Aleszczyk had mixed feelings about the chain of events. On the one hand, he was happy that he did not lose money because of the erroneous quote. On the other hand, the incident demonstrated that the shop was not competitive when it came to relatively small turned parts that required substantial milling and drilling operations. One year later, the same customer asked Wright Technologies to bid on a similar job, and Mr. Aleszczyk once again was confronted with the problem that he could not competitively machine that type of work on his existing equipment. He did not want to lose the business again, however, so he set about looking for the right kind of machine to do the job.

He wanted a machine capable of producing a complex turned and milled part complete in one setup. He had a CNC production lathe with a subspindle but only one turret, which meant that the machine could only work on the front or back of the part at any given time. He wanted a lathe that could machine the front and back of the part simultaneously to minimize cycle time. His search narrowed to CNC Swiss-style turning centers and, armed with the specs for the job he had been asked to quote, he visited the Precision Machining Technology Show in Columbus, Ohio, in April 2001, to see them in action.

Mr. Aleszczyk stopped at the booth of Hanwha Machine Tool USA Inc. He saw the Hanwha ML26H six-axis CNC Swiss turning center, with a subspindle and 16 tool stations, which was capable of simultaneously machining the front and back ends of a part. The machine has a 1-inch-diameter bar capacity, three cross-working stations, one off-center drilling station, four end-working stations, five turning stations and seven back-working stations. It appeared to be precisely what he needed. He explained his need for such a machine, showed the part prints to the Hanwha representatives and asked them to demonstrate the ability of the machine to handle the job by producing some sample parts.

Hanwha accepted the challenge, tooled up the job at its Pewaukee, Wisconsin, facility and invited Mr. Aleszczyk to view the parts being produced. He checked the dimensional and finish requirements of the sample parts and everything appeared to be in order. He then asked the vendor to set up the machine in his shop and run 5,000 pieces. If the run was successful, he would buy the machine.

"We ran 5,000 pieces, 10,000 pieces, 20,000 pieces . . . the machine performed flawlessly," Mr. Aleszczyk recalls. "So far, we've run 60,000 pieces. The machine is fast, holds dimensions and runs problem-free." Wright Technologies uses it to produce both parts of the valve in alternating batches.

The brass valve body is the more complex part. Operations include drilling and boring the ID and machining a fine (56-pitch) mating thread on the ID for the valve stem. From a practical standpoint, the most challenging features are two 1/32-inch-diameter holes, one drilled through the center of the part and the other at a 45-degree angle.

The valve stem is machined from 303 stainless steel. Main features are a needle that tapers from 0.035-inch diameter at the base to 0.026-inch diameter at the point, a 56-pitch thread machined on OD and a slot on the back end. The needle seats in the valve body to close the valve. Initially, Wright Technologies had trouble holding the required 60 microinch surface finish on the needle (required to seal the valve) because of tool wear; it had to change the insert every 400 pieces. Mr. Aleszczyk consulted with his local Kennametal distributor, who recommended a switch to Kennametal KC5010, a new high-performance titanium aluminum-nitride coated insert. As a result of the switch, tool life increased five-fold, to 2,000 pieces per insert.

A major advantage of the Swiss machine is its ability to run for long periods unattended. The machine is equipped with a Fedek Eagle 5-42 magazine bar feeder, supplied by MTA International (West Chester, Ohio), that automatically delivers 12-foot lengths of bar stock to the machine one at a time as needed. "We can fill the magazine with enough bars so that the Swiss machine can run for 8 hours without a problem," Mr. Aleszczyk explains. "When we go home at the end of the day, the machine continues to produce parts throughout the night. When we come back in the morning, we simply remove the finished parts from the parts bin and load more bars in the bar feeder."

Wright Technologies' experience with its first Hanwha Swiss machine has been so positive that the firm purchased a second machine, a Model SL32HP with a 1 ¼-inch-diameter bar capacity and more live tooling capacity than the first machine. The two-part valve job will be divided between the Swiss machines with each running one part. This will provide open time on both machines, which the shop is rapidly filling with similar work.

"The Swiss machines have created new opportunities for us," Mr. Aleszczyk says. "Before, we were geared primarily to large parts. Our Swiss machines have enabled us to take on smaller, more sophisticated parts, and that new business has kept us busy. The type of work we specialized in before is very slow now, however we are keeping busy with Swiss-type jobs."

— CNC Indexing & Feeding Technologies

— Greenfield Industries Inc.