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Production on Demand

Nov. 27, 2007
Symmons Industries Inc. Braintree, Number of employees – 133 2007 sales – N/A Markets served – Plumbing fixtures for new construction and replacement markets. John Sandvik, manufacturing manager, said Symmons Industries is ...

Symmons Industries Inc.
Braintree, Mass.
Number of employees – 133
2007 sales – N/A
Markets served – Plumbing fixtures for new construction and replacement markets.

John Sandvik, manufacturing manager, said Symmons Industries is striving to eliminate time spent on set-up.

Symmons Industries Inc. realigned its machine shop six times in the past 15 years to move from having one person running one machine to one person running as many as five machines.

Those realignments were merely steps the company took along its way to keeping its 68- year-old manufacturing operations successful.

Symmons Industries produces plumbing fixtures. It buys 2 million pounds of brass and bronze and 400,000 pounds of stainless steel each year and generates enough brass and bronze chips daily to fill nearly 30 55-gallon drums.

Besides realigning its shop a half dozen times, Symmons Industries cut setup times, machining cycle times, and scrap rates and now keeps one-tenth of the inventory it had in 1998 to support sales that have nearly tripled.

“We had to think way beyond the traditional ways of thinking to keep the shop here,” John Sandvik, manufacturing manager for Symmons Industries, said.

One of the ways it went outside its normal course of thought was to spend a year to evaluate rotary transfer machines before deciding how to replace two aging rotary transfer machines for its production of plumbing valves. The result was a 30-page request for quotation, which led to the purchase of two new transfer machines. A Porta 43-axis transfer machine and a 12-station, 46-axis Buffoli Transbar machine from Italy.

On its previous machines, the company had a 12-hour setup time, and needed to produce 65,000 valves to amortize the cost and to support sales.

The new rotary transfer machines reduced set-up time to under two hours, and in some cases, to less than seven minutes. Also, the machines support current sales with 6,500 valves – a tenth of the previous inventory.

Another rethinking of its processes involved moving from a cast bronze billet for its shower valve spindle to a continuouscast bronze rod. The rod is not in near-net shape as the billet was, but the cast rod can be loaded into barfeeders that supply CNC machines that run 24/7 unattended. And, the cast rod costs less, is a better material than the cast billet, and has cut scrap rates from the nearly 25 percent that the company saw in 1994 to less than 1 percent today. The scrap rate was so high because the valve spindles require concentricity of 0.003 in., a tolerance that can be repeated on automated CNC machines using a ten-millionths resolution Renishaw probe.

“You need velocity in order to support a demand flow environment. If we can assemble a valve in 20 seconds, the longest machining cycle time for that valve has to be 20 seconds,” Sandvik said.

However, he noted that Symmons Industries has moved its machining cycle time from 36 seconds for a valve body that was produced by a machinist who ran one machine, to 8 seconds unattended using a robot vision system. He added that the machinist who is working today is running more than one machine, the 8-second cycle time is accurate for any one of 14 valve bodies that the company makes, and that machine changeovers from one valve body to another average less than 15 minutes.

The company also reduced production of the spindles that fit into its valve bodies to 20 seconds from 45 seconds.

“We had three machinists who made 80 pieces in an hour on five machines to produce a particular part. We use 50,000 of those parts a year, and we were running out of production capacity,” Sandvik said. One of the new rotary transfer machines – fed by an automatic loader – now makes the parts in nine seconds, and usually runs unattended.

“We have added nearly 28 percent more machine shop capacity by adding eight LNS quick loaders that are half of the price of traditional barfeeders,” Sandvik said.

Sandvik added that the shop also works to eliminate set-up times everywhere it can. It produces more than 14 versions of its spindles with no time spent on setup, he said, adding that production on demand gives the shop its edge.

“You don’t make money setting up machine tools. We got rid of hours and hours of set-up time,” Sandvik said.

Symmons conducted typical single minute exchange of die (SMED) events with its operators to target and identify throughout and its setup process.

Those events produced an 80 percent improvement the first time through, Sandvik said.

The shop also computerized the machines in its screw-machine department to move set-up times to average less than two hours from 10 hours. Those machines produce nearly 10 million parts a year.

“That resulted in much smaller lot sizes, contributed to running a visual Kanban system and eliminated work orders for about 1,500 SKU’s,” Sandvik said.

Cutting set-up time for some jobs to two hours from 10 hours led the company to cut its inventories to bare-bone numbers.

“Today, we don’t have to make 30,000 parts (to justify the set-up time required to produce a part) when we need 5,000 parts, and now we can make those parts at the last possible moment. We can make what we need when we need it,” he said.

Symmons Industries also has an extensive tool presetting and tool life management program for monitoring all of its tools constantly. The program includes electronic monitoring of a variety of parameters, including horsepower absorption, the amount of power that each tool requires to turn it in a cut, and monitoring axis thrust, the force required to push the tool into the workpiece, in each instance that the tool is used. When tools push parameters out of limits because they are worn or become broken, the operator is alerted and the tool is replaced with a one that is preset and on location.

“We investigated special coatings and innovations in tooling, and we’re not afraid to buy a more expensive tool, as long as we get the benefits from it. If we spend five times more for a tool and can get five times the life out of it, that’s five times our operators don’t have to change that tool,” Sandvik said.

Symmons by combining continuous improvement programs with a totally flexible workforce in conjunction with a managers measurement matrix’s focused on customer demand verse more traditional MRP/Standard Cost manufacturing systems has achieve astonishing performance. This has enabled Symmons to close their west coast and southern distribution centers with out interfering with customer demand. Units per hour have increased 40 percent over this time frame along with a continuous improvement in quality.

Contributing to a point of success, Sandvik said Symmons Industries has invested several million over 15 years. While doing so, Symmons has reduced finished goods inventory from $3.8 million to $50,000 while reducing customer order fill rate from 7 days to 2 days with 60 percent of the orders going out same day.

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