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Building a Better Mold - Part I Mold Cloning…Isn’t This Illegal?
By Steven Johnson, Maintenance Systems Manager The tooling engineer walked up to an old mold on the floor and blankly stared at it. He then rested his foot on it hoping the physical connection would somehow help recover faded memories of issues past concerning design and function. Although the images didn’t materialize, he did feel the heat of a dozen or so toolmakers staring at him, so he waved everyone over for a conference. It seemed several of the company’s products were gaining popularity and the increased sales would require adding a couple of molds to a product line to handle the volume. His mission was to investigate any issues and best determine what, if any, changes should be made to the existing mold design. His other option, and always the popular one, was to just clone this thing and be done with it. Mold cloning Mold cloning is simply building the exact same mold over and over. It is not uncommon for companies, in an effort to increase volume, to acquire a backup or simply replace an old mold to partake in cloning. And since the communication chasm from a designer’s computer to a press or mold repair bench is, unfortunately, still huge, not only is the mold replicated, but so are any problems inherent with the specific design or methods of fabrication. Here is a list of common reasons used to justify cloning: No accurate data is available. Accurate information concerning how a mold has performed (unscheduled stops, mold and part defects) and required maintenance (type of corrective actions necessary and tooling costs) is seldom available. Typical industry work order systems depend upon random, handwritten or typed journal entries that are incomplete, inaccurate or illegible. Few engineers are willing to make changes to a seemingly adequate mold design based on these scribbles, fading memories or shop floor hearsay. It’s easy. Cloning is an easy form of mold engineering. Just send your vendor the prints and have their team make another one just like it – and don’t forget my doughnuts in the morning. It’s safer. In a competitive engineering department, taking a chance creating a new lemon through bad decisions concerning fit, function and finish complicates the corporate climb more than replicating outdated technology, materials or mistakes from old molds. This is especially true if the new lemon turns out so bad it won’t run at all without first correcting the problems. “If it ain’t broke…don’t fix it” is a popular mantra for less-audacious engineers. Speed/Cost. Obviously there won’t be any time spent investigating new plating options, steels, existing shut-offs, alignment features or tolerances. New technology? No time – just build it. Less inventory hassles. Some companies who have yet to establish an organized, functional tool crib for storing mold replacement components don’t want the hassle of storing or tracking tooling that will only fit the new, improved mold. It is much simpler and there’s less chance of a mix-up if one keeps tooling universal between all like mold frames. It doesn’t always work As tempting as it is, cloning is seldom a good idea unless the DNA has come from a proven, reliable performer in the press that has also been well thought out from behind the bench. Most toolmakers will tell you they have never worked on a mold that could not be improved in some way or another, especially from the maintenance standpoint. Simple changes can save thousands of dollars over time in reduced labor hours and they make molds easier and safer to work on. With all the advancements in mold design today, you still can’t beat hindsight when it comes to disassembly, cleaning, repairing and reassembling mold components and plates. So the team huddled up and in less time than it took for everyone to get their feet up on the mold there was quite a discussion going on concerning the “junk factor” (problems with running and maintaining a tool) of this mold. It is common to have a range of opinions concerning the “junk factor” of any one mold because varying styles of hands-on work at a bench have a tendency to bias a repair technician through bites, cuts, pinches, crashes or increased anxiety levels with awkward procedures. These painful maintenance characteristics, although quite annoying, may or may not be the real high-cost roadblocks to producing quality parts on time. Data is needed to quantify. Many things, including hectic reactive shop cultures, can confuse the real issues for it becomes necessary over the years, when working in full firefighting mode, to become “tooling replacers” versus efficient troubleshooters. The junk factor This measurement is determined by the amount of physical frustration with overlooked features of old and new molds while being “pushed” to get them fixed. It can sometimes dictate how “professionally” a mold, die (or anything mechanical for that matter) gets worked on. With a top of the line junker, dealing with one too many unwieldy plates, cumbersome external components, a face full of water or oil along with thread stripping, knuckle busting, sharp edged tooling stuck fast into inaccessible pockets, can turn a normally calm, professional, church-going repair technician into a vein popping, wrench throwing, trash talking mold abuser. Some say it’s quite therapeutic. A different reaction has been seen in journeyman toolmakers that have walked into the repair shop in the morning, and upon seeing one of these high stress molds on their bench, gathered up all their tools and walked right back out, never to be seen again. The funny part is that a mold could start easily, run good parts at 100% cavity efficiency at the optimum cycle time and still be considered junk by the tool room. Ask a repair tech how they like working on a mold equipped with a hot manifold that must be completely disassembled simply to replace a single thermocouple, or a mold with dozens of water fittings protruding from the bottom of a mold or no access holes to shoulder/stripper bolts. Characteristics such as these are what make a mold repair memorable---not the fact that it always runs 32 cavities. So at the end of the day the “junk factor” of a mold could have less to do with how it performs than how quickly and painlessly it is repaired on the bench. The following items are just a sample of what a repair technician would like to see included on every mold’s spec sheet (if they have a spec sheet---which is another problem) before cloning takes place. These items concern ease of mold handling, disassembly, cleaning and assembly requirements versus mold function. A mold could be considered junk if there is/are no:
Other repair technicians and toolmakers will easily add to this list of simple maintenance oriented features that make a mold easier to maintain and work on, which translates to safer, quicker and more reliable methods of repair. So if a tedious procedure or laborious repair task costs you money why would you clone these problems into another mold? This is a simple question for a bean-counter. They will ask how much not having this feature really costing. Is it more cost effective to pay for the improvement up front…or to forget it and just deal with the cost of the task? There are many areas of maintaining molds that cost companies money in excess tooling and labor every day. Obviously, how much money is the question Due to the wide variety of opinions concerning how molds are run and maintained, determining what is really costing you needs to be verified by a more accurate method than simply taking a poll. Building a better mold does not always mean increasing every tolerance to a 4-place decimal or adding every type gear, cam, rack, rail or slick widget seen in an ad. Nor does it always mean doubling cavity count, adding a hot runner system or other expensive design features. Building a better mold means truly understanding how a mold performs in the press and what is required to keep it there. This can only be verified by putting a dollar amount to corrective actions necessary to clean, repair and maintain molds along with unscheduled mold stop reasons, defect types and frequencies. Many times it’s the simple things that get overlooked. The ability to accurately relate maintenance costs to specific performance and maintenance characteristics on every mold will give you the true picture of what needs to be addressed on any mold being considered for cloning. In Part 2 of Building a Better Mold, we will examine a mold’s history from different reports and see what the data has to say. In the meantime, if this article raises any questions, please feel free to contact author Steve Johnson at 419-289-0281 or Steve.Johnson@procomps.com. Be a TPN Guest Speaker! If you'd like to submit an article for a future issue of the TPN, please contact Editor Cyndi Kustush at editor@tooling-product-news.com for editorial guidelines. Be sure to provide complete contact information and any proposed topics or ideas. |
