September 24, 2009
Lean manufacturing and an integrated transfer press cell conversion helped deep-draw stamper Truex, Pawtucket, R.I., to diversify its product mix and expand into new markets.
Deep-draw stamper Truex, Pawtucket, R.I., was founded in 1976 to supply brass garden hose fittings for hose manufacturer Teknor Apex. Although garden hose fittings still are the company's biggest product line, Truex diversified its product mix and made the foray into other markets as a result of a four-year-long lean journey coupled with an integrated transfer press cell conversion.
The new process increased productivity so substantially and freed up capacity and space so as to enable the company to expand its product line—including its entree into stainless steel part manufacture—and to reduce costs, lower prices, and increase profitability.
"We started to reduce our costs through lean and ended up in a very cost-competitive position. So it led to the thinking � 'we have increased capacity now more than ever; what are we going to do with it?'" said Stacey E. Alsfeld, vice president and general manager. "So we said, 'Let's go capture some stainless steel business.'
"We supply garden hose fittings to many garden hose manufacturers around the world, but we've also expanded into custom stampings for many other applications and other markets, such as plumbing—which is where a lot of the stainless fittings are going," Alsfeld said.
"In terms of units, we have increased our stainless steel parts business this year by 83 percent, and sales dollars have more than doubled," Alsfeld said. "That's over the average of the three prior years—and in a recessionary environment."
Altogether, the company produces about 10 million units a month, including fittings, ferrules, and stampings for many types of hoses, plus automotive and industrial applications.
Process improvements resulted in:
Alsfeld said the company embarked on its lean journey in 2005 with a 5S program (see 5S Sidebar), which led to value stream process mapping. "Lean manufacturing is all about reducing waste in all of its forms—including movement of equipment, of material, of people �"
All the transfer presses (the company's deep-draw stampings are performed on transfer presses) were at one end of the building. The assembly equipment was in the middle, and the raw material storage was on the opposite end of the building, Alsfeld said. "From a process flow standpoint, it was very inefficient.
"The lean teams came up with suggestions in terms of how to reduce the waste, because they know best where a lot of the waste is inherent. Most of the great ideas that we've been able to implement have come from the employees, the 5S teams, which is the whole point," Alsfeld said.
The company then engaged in value stream mapping to isolate wasted movement. "So we asked, 'Why do we have presses here and materials there? And why are we outsourcing cleaning and bright annealing of the stainless parts? Let's put them all in one area so that we can have two operators for the entire cell, and they can do the parts cleaning and bright annealing in-house as well.' And that's also where we store the stainless steel," Alsfeld said (see Figure 1).
"Every time you move material, it takes time. It risks damage to the metal or the parts. It just takes longer to get through the whole process. What we wanted to do is make the operation as efficient as possible by reducing the movement of men and material. This reduced cycle time."
Engaging in value stream mapping freed up space, as well, Alsfeld said. "Since then we've added several new presses—and without having to add additional space or people."
Tool Crib. "The tool crib had been at the furthest possible end of the building. That resulted in employees making numerous trips down the length of the building to the tool crib. When they'd get down there, sometimes they'd discover the tool crib attendant wasn't there. So back they'd go again. And this would necessitate another trip. All this was a tremendous waste of time," Alsfeld said.
"The first time we value-streamed it, we moved the tool crib to the middle of the building so that it would be equidistant everywhere, with an open caged area so everyone could see if the attendant was there or not.
"The next time we value-streamed—this is an ongoing process—we got more into the cell concept, and asked, 'Why do we have a central tool crib anyway? We should have the tools near the manufacturing cells themselves.' So now the tool cribs are in several areas near their manufacturing cells."
Shadow Boards. "The shadow boards are another cost reduction [see Figure 2]. It's a very simple concept. Tools are either mounted on the shadow board or in the operator's hand, so you only need one set. The first-shift operators don't have their own; the second-shift operators don't have their own. Prior to the shadow boards, everybody would have their own tools all over the place. We reduced the number of tools and supplies needed, as well as the time wasted looking for misplaced items."
Point-of-Use Storage. "We're big on point-of-use storage. The raw material that operators need for the equipment, as well as the tools, are all there. Our folks don't have to traverse the length of the building several times a day looking for what they need," Alsfeld said.
The stamper's integrated cell incorporates three transfer presses that were moved from one end of the building. It is dedicated to stainless steel parts. "When you run different types of metals, they require different types of lubricants and cleaning solutions. And what we don't want to do is set up, run a job, and then have to change over the lubrication system and cleaners to run a different type of metal, because that's just not efficient. That's not lean. So we try to concentrate the presses by types of metal to reduce the amount of changeover and setup time from one job to the next."
The cell has a parts cleaner/washer and a separate bright annealing furnace. "Most of the stainless products have to be bright-annealed to soften them up, to achieve a certain temper, and to look like stainless steel again—clean and without stains or oxidation," he said. Previously the company had been outsourcing its parts washing and bright annealing.
"So all the money that was spent on parts washing and bright annealing has been eliminated. It's a nice cycle time and cost reduction," Alsfeld said.
"Through all of that, we were able to reduce our costs and cycle times, improve our quality, and increase the inherent equipment capacity. With the same labor costs, same fixed costs, and lower overhead costs over many more units produced, obviously the unit cost drops appreciably. So that allowed us to be more cost-competitive. That was why we could expand and grow the business now.
The stampings are produced on transfer presses ranging from 3 tons to 135 tons.
"Flat strip—typically 4 to 6 inches wide, of various gauges—goes into the transfer press. The first station blanks it. It's now in individual pieces; the remaining strip webbing exits out the opposite side of the press. The second station forms a cup, and the cupped part is transferred with finger tooling and is carried from station to station with a 30 to 40 percent maximum reduction at each station. There are as few as four and as many as 12 stations. Then the part comes out the other end as a semifinished product and is loaded into bins for cleaning, heat treating, and assembly, if required.
"The advantage for us in using transfer presses is that the tooling is reasonably inexpensive; on average, $5,000 to $15,000 to tool up a new part, whereas a progressive die can cost hundreds of thousands of dollars," Alsfeld said.
"The beauty of the transfer press is that if a customer needs to make a modification, we don't have to change the whole die, just one of the stations. Let's say he wants a larger pierce hole. It's a very simple change. All we have to do is take that one particular station and change it, rather than an entire die set.
"The limitation is that the technology and press size we use limit product size and shape to round or oval," he added. "The largest component we make is about the size of a coffee can," Alsfeld said.
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