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FALL 2020

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Distributor's Link Magazine Fall 2020 / Vol 43 No 4


100 THE DISTRIBUTOR’S LINK LAURENCE CLAUS THE VALUE OF APPLICATION ENGINEERING from page 8 Although it is clear from this image that too much stress is detrimental to the plastic, I often use this to illustrate an application engineering point. I often ask the question whether the Type AB Screw could ever work in such an application. In other words, can we come up with a boss design that would allow the Type AB to work without cracking? The simple answer is yes. However, it would require considerably increasing the outer boss diameter. In fact, we might have to double the wall thickness to get the screw to work. In the event that the subtleties of this action escape the reader, consider for a moment the potential consequences: increasing the amount of raw material (material cost), increasing injection molding cycle time, increasing weight, and exposing visible surfaces to sink marks. An observer of this story may come away with another question, why did the OEM design it this way from the very start? The answer to that question is likely complicated but I believe there are several contributing factors; [1] Ignorance of a better option [2] Choosing the lowest price option [3] Failing to conduct any real Application Engineering activity Although this application was poorly engineered from the beginning, it does illustrate an important benefit of good application engineering. Many new innovations and technologies only become possible when other complimentary or enabling innovation occurs. In this previous example, a Type AB screw could be used in a plastic application but only when accepting risk or the inherent limitations of the technology. In this example, one sees that using application engineering skills to apply complimentary, new innovation allows the overall reduction of joint cost and improvement of joint quality with smaller bosses, less material, lighter weight applications, and elimination of sink marks. In fact, thirty-years later no one uses Type AB screws to fasten plastics anymore. Application Engineers have successfully educated the market allowing the innovation to take hold and evolve with the automotive engineered plastics market. In another example, several years ago I was hired by a distributor to conduct a walkthrough of one of their customer’s facilities with the purpose of discovering potential cost savings opportunities they could use to offset promised future price reductions. Although I knew better from personal experience, I was at first worried that I wouldn’t find much to help my client, making my efforts a costly misadventure for them. How wrong those fears were, this user, like almost every other large user of fasteners I have worked with over the years, was rife with continuous improvement and cost savings opportunities. One of the opportunities I spotted that day has long stuck out to me and I often use it as a teaching illustration. One of this company’s products was a large cabinet. They would ship it completely assembled from their manufacturing location to the site where it was to be installed. To prepare it for shipping they would raise it up and attach a two-by-four along the front and the back of the base. This effectively raised the base several inches off the ground and protected it during transportation and installation. When it was received on-site the make-shift two-by-four skids would be removed and discarded. The process of attaching these “skids” was pretty straightforward. They would lift the unit up, grab two twoby-fours, cut them to length, drill holes in a predetermined location, and then use a bolt and nut to attach them through holes in the base in four spots. I wandered over to take a look at the hardware they were using for this and was first surprised to see the length. They needed to clear a two-by-four on edge (1 1/2” thick) and the base (which was a metal band no thicker than 1/8 or 3/16 inches). The bolt, however was a good 3 1/2 to 4 inches long. As I further examined the bolt I was surprised again to find that it was a Grade 8. Clearly when they first started doing this they simply choose a bolt, nut, and a couple of washers from what they had laying around. These choices had quickly become “institutionalized” and they would continue ordering and using these fasteners for all such applications. The opportunity they were missing, however, was the threaded length and thus the bolt were probably about 40% longer than they needed to be and the bolt not needing to generate any real preload was way overdesigned as a Grade 8. In other words, they were paying for 40% more material than needed and a premium in raw material type and processing to achieve a Grade 8 state. CONTINUED ON PAGE 149


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