Production Machining

OCT 2018

Production Machining - Your access to the precision machining industrial buyer.

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productionmachining.com :: 19 ,ĞůƉŝŶŐWƌĞĐŝƐŝŽŶDĂĐŚŝŶĞ^ŚŽƉƐĞDŽƌĞWƌŽĚƵĐƟǀĞĂŶĚWƌŽĮƚĂďůĞ of assuring that we have the correct tool to make the job trouble free and a "steady runner?" Minimized Cycle Time or Optimized Process? Which point of view is in control of your shop today? Is your shop's philosophy minimized cycle times? Or do you prefer to run no-surprise optimized processes? ÜÕVVÕ`>Óx«iÀViÌÀÀiVÀi>Ãi production time with virtually no increase in labor be worth to your shop? You can run the numbers. Alternatively, you could do what some of your sharpest competitors are doing—slow down, optimize for process (not for lowest cost inputs) and run lightly attended. Change in Demand: Time to Change Your Thinking Continued from page 17 Optimized Process by Optimizing Material and Tooling Material.7iwÀÃÌV>iÌÕÀ`ÕÃÌÀÞ>Ã>ÃÕ««iÀ of steel, I was fascinated by what I have come to call, "the fastest cycle time—cheapest material paradox." The paradox was that my customers, the machine shops, emphasized how important having the fastest cycle times was for them. However, when I offered them a freer cutting, faster cutting material (at a slightly higher cost per pound), they abandoned their demand for fastest cycle times in favor of what I called the "lowest price per pound" heresy. Purchasing agents were the high priests of the business in those days, and they were rewarded for lowering the costs of the steel and tools they purchased (as opposed to being rewarded for their role in increasing the throughput of their shop). Today, with shops at or near capacity, lead times extending and material availability even more of a challenge, it is critical for the purchasing agent to be a partner in optimizing ë«iÀvÀ>Vi]ÃÌi>`vLi}Ìiºw`iÀvÌiVi>« ÃÌÕvvvÀÌi«iÀ>ÌÃ}ÕÞÃÌw}ÕÀiÕÌÜÌÀÕ°» As that young steel guy, I wrote a computer program that was able to determine the cost impacts of choosing a more expensive, more machinable grade on the total cost-per- thousand parts produced. (Spoiler alert: it reduced the cost substantially on most parts!) By evaluating not just the raw material cost (the cost of the steel), but also by calculating the change in the cost to actually machine the «>ÀÌVÕ`}«ÀÛi`ivwViVÞ>`Õ«Ìi]VÀi>Ãi` speed [SFM] or feed rates [IPR], etc.) from the different candidate grade. The math was compelling, but it remained >`vwVÕÌV>ÃiÌ>i]Õ>VVi«Ì>LiÌ«ÕÀV>Ã}>}iÌà whose bonus depended on ever-lower costs of inputs. Yet it often was convincing to the shop owner, who understood that more parts at the end of the shift was the goal, or the operations manager, who understood that 'good machinability' was whatever didn't shut his machines down for unplanned outages. Tooling. It was not just about the material. The choice of tooling also fell under the low-cost incentive to purchasing. ÀiiLiÀÌiwÀÃÌÌiÃ>Ü>ÌÌ>ÕÌÀ`iV>Ìi`] VÀVÕ>ÀvÀÌ°ÌÕÃÌ>ÛiÜi}i`£ä«Õ`Ã°Ì was being used on a multi-spindle screw machine at a government arsenal to make projectile blanks (talk about high-volume production) out of free machining steel. I asked, "Why on earth are you using such an expensive tool to make these screw machine parts out of free-cutting steel? Certainly, this is over-engineered?" The reply was priceless, "Young man, if you knew how much we are billing the U.S. government for an hour of machine time, you would do everything possible to assure machine uptime too." In today's market, where our shops are running at or near capacity, are we doing enough to assure uptime of our production processes? How many of us err in the opposite direction, going for less expensive tooling instead In a recent straw poll of PMPA member contract manufacturing shops, over two-thirds of respondents reported some lightly attended jobs. In many cases, these jobs were reengineered to slower cycle times, but higher CPK, assuring that they would get the most advantage from their lightly attended operations. Is having a low cycle time important? We can all agree that what we sell is the time on our machines. We can agree that having a low cycle time looks like one way to maximize the V>ÃyÜvÀÌiÌiÜi>ÀiÃi}° There is another way. That way is to assure more uptime, higher process capability and the ability to add additional hours with virtually no labor cost to increase the number of sellable parts produced in our shop each day. This is accomplished by optimizing our process. Are you ruled by cycle time? With today's technologies for >ViÌÀ}]ÌÃÌ>ÌÕÃÛiÀwV>Ì]>ÕÌ>ÌVL>À loading and more robust tools, substrates and coatings, we think you have another option. The two graphs shared previously should convince you that perhaps now might be a good time to change your thinking.

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