The Spiral Path by Bill Davis and the Plastic-Experts

Imagine the position of a moldmaking company estimator faced with the most interesting of challenges; there is a project being quoted by a number of injection molding companies for a major player in the HBA market, and by the luck of the draw, no less than three shops have come to you to quote the job.

What makes it interesting is all three are in their own estimation "state of the art" operations, two independents and one a division/satellite to a conglomerate that is in a number of different businesses. All three have issued long laundry lists of declarations on how the mold must be built in order for them to have any chance of winning the bid and ultimately paying your bills.  Of course the three sets of specifications have absolutely no common ground except they are all aimed at producing the same product, which is in point of fact nothing more exciting than another variation on the theme of a "classy" cover for an aerosol can. The upside is that everyone wants to build a "good", permanent mold since the job is projected to run for several years. The downside is that the three sets of design specifications are so different that you as the estimator know immediately that there is no way for a couple of the choices to be competitive.

While all the facilities are modern with relatively new equipment, one independent runs only small presses and wants an eight cavity hot runner mold that they will try to run on a 12 second cycle, the other independent has bigger equipment and is requiring a 24 cavity tool with a planned 26 to 30 second cycle, but are adamant that only a 3 plate cold runner mold can work for this product. Meanwhile, over in Captains of Industry Land, the edict comes down that all they need are 36 toolsets to be built for one of their existing stack molds, with a projected cycle time of around 20 seconds. Happily they have also specified their price cap requirement for the toolsets based on prior buys, so you know you can meet their bid requirements and be a very happy camper.

As the moldmaker/estimator, your issues with all this are, as they say, legion. Do you follow strict procedures of impartiality, and just quote each customer exactly as per their requests? Do you tell the "Little Presses" guy that the product likely can't run at the speed he's expecting, since the wall section of the part and the material used are going to dictate an easily calculated minimum cure time pretty close to his total cycle estimate? Do you mention to the Three-Plate Mold guy that his runner scrap is going to be 50% of the shot weight, so over the years if he wins the bid he's going to have literally tons of regrind to deal with, and on a cosmetic part it's not all going to go back into the hopper? Worst of all since it's where the most money is for you as a toolmaker, do you let the toolset-only guy know that his mold expense is going to be way high compared to others you know of quoting the job, and with his high priced hourly rates on his huge Corporate Overhead machines he'll never get the price down to meet the more normal operations? Of course I know what we did in this case, being the fellow in the middle, as usual. Question is, faced with this range of options coming at you from three "state of the art" operations, all of whom have, shall we say, remarkably high self esteem and pretty positive views on "the only way this job can run successfully", what would you do?   

As we've tried to point out, "state of the art" can be pretty relative in injection molding. Being usually the outside guys called in to help fix things or just observers on the site, we see situations daily where one business or another is successful on the broad technical basis, but not making the return expected in spite of having all the newest and best hardware in place.

Here's a fairly recent example. The typical scenario, the  lucky moldmaker delivers a new mold, the injection molder tests the mold and finds performance nowhere near the projected results, and also way off from sampling results, which gets everyone into the predictable "who's at fault?" entertainment.

The job is of course behind schedule, the molder's customer is looming, and the molder's opinion is that SOMEBODY sold him a big boat anchor disguised as a mold. Again, picture a modern, clean floors, bright lights, bright young employees, well organized injecton molding facility. All the right stuff, except this new mold is making 50% scrap and running 25% slower than planned while doing it. Spend a day or two troubleshooting by phone, then of course you get to make the (hundreds of miles) trip out to try to solve the problem on-site.

Faced with a client who's facility and operation are without question in the upper class of injection houses, and who insists that every aspect of the setup and operation of this tool is perfect, how do you account for the mold running completely horribly here, when in final preshipment testing it was actually doing better than the projected/required production rates?

Back to the good old "state of the art" business again. Never assume a new facility that looks right and has all the proper looking bells and whistles on the plant floor is necessarily arranged in such a way as to operate efficiently. In this case the operation was compromised by a plant engineering decision made way back when the production floor layout was done. All machines were cooled by tower water to the heat exchangers, and all molds were cooled by chilled water from a huge central system running at a steady 40 degrees. Big water mains, big pumps, and a big mistake. Our poor mold, running a polypropylene material, needed high flow rates of 60 to 70 degree water to extract heat properly while not chilling the incoming melt so much that stresses and surface defects were introduced. With only chilled water available in this "state of the art" facility, the only way to fill the mold properly on injection was to restrict the flow of cold water to let the mold heat up, which slowed the cycle, and also affected shrinkage, so most parts were scrapped for dimensions out of spec. Incidentally someone decided to restrict incoming flow, not outgoing, so the return water mains actually vacuumed water out of the mold creating some really interesteing temperature fluctuations. Multi million dollar facility, $250,000.00 molding machines, our $50,000.00 injection mold, the people involved, the time, the engineers, etc. etc. all being victimized by  a plumber and a coin flip on which valves to close.

Happily, the law of unexpected consequences did apply here. Once we got our mold off the chiller and on its own little branch line from the tower, got everyone on board with "keep the water in the mold all the time", and got the promised production results, we had coincidentally grown for the Company a fresh crop of process technicians who were heavily into mold water flow and its impact on keeping one's job, which resulted in quite a few of their molds being re-plumbed to make life easier for the molds, the materials, and the guys who are judged by the production they get out the door.

Just another twist in the trail, out here on the Spiral Path..........