Canadian Plastics

In-House Mold Testing Saves, Makes Bucks

Canadian Plastics   

If your mold shop is testing molds on in-house presses, you're part of a growing trend to on-site tryout. In fact, one third of Canadian moldmakers listed in the Canadian Plastics Industry Association...

If your mold shop is testing molds on in-house presses, you’re part of a growing trend to on-site tryout. In fact, one third of Canadian moldmakers listed in the Canadian Plastics Industry Association’s Plastics Machinery and Molds Directory list in-house mold tryout as a featured capability. Injection equipment used by moldmakers is generally a mix of new and used equipment, with multi-press operations often mixing several different brands.

The decision to add in-house capability often depends on geography, in particular, the distance between moldmaker and customer. While first shot success is always the goal, the reality of fine tuning a mold (and last minute engineering changes) often involves shipping a heavy, expensive mold back to the builder for rework. If the moldmaker does export work, and the numbers suggest that many do, delays and shipping costs can spiral to the point where the job becomes unprofitable.

Joe Claxton, vice-president, technical services for Tradesco Mold, (Rexdale Ont.) a typical larger Canadian mold exporter, says: “We export all over the world: Asia, Europe, Africa, and the U.S. Test room machines are essential. We’ve had our own test facilities since 1980, and now have six machines in-house from 300 tons all the way up to 600 tons.” Tradesco uses Husky, Sumitomo, and Klockner-Windsor presses with an Engel on order. The firm buys new equipment to match customer capabilities and to optimize more complex projects in thin-wall molding.

In-house tryout offers several advantages to the moldmaker. The first and simplest is the ability to get molded parts to the customer ahead of mold delivery for fit checks, dimensional tolerancing, and validation of the mold design. Again the important saving is time. Rework to deal with sink marks or knit lines discovered before shipment, for example, could be negotiated under an existing contract, often preserving delivery guarantees and performance incentives. From a quality perspective, the time savings can also reduce or eliminate the “quick fix” which preserves delivery guarantees at the cost of increased maintenance or slower cycle times. Another advantage is the ability to track mold performance after several hours of operation at actual running temperatures and pressures. This break-in period can also pinpoint flaws in components subject to higher “infant mortality”, such as sensing electronics.


Michael Ryan, president of Ryka Blow Molds, (Mississauga, Ont.) explains another good reason to test in-house: reduced customer machine downtime. “Many of our customers do not have their own R&D or test centres. They have to break into a production run to test their molds, and sometimes they end up doing it on a weekend because their own production requirements are so heavy. This sometimes results in an accelerated, incomplete test, so they don’t get the results they should.” Ryka does extensive in-house testing with “state of the art” equipment. The clear warning for moldmakers who don’t test in-house is that they are ultimately captive to the molder’s test procedures. If the tests are imprecise, then the moldmaker may take the hit for a run-time problem over which he has little control.

Larger operations take in-house capability as a given, and many test on the same equipment their customers use for ultimate mold certification. Smaller moldmakers, however, are surprisingly reluctant to talk about in-house capability, especially where it is based on older, used or rebuilt equipment. One Southern Ontario shop which requested anonymity told Canadian Plastics: “We have a machine (a ten-year-old 60 ton press from a major manufacturer) but we don’t really talk about it. It works well, and we use it constantly. Our customers know about it.” The fact is, smaller shops can add considerable value to their service with simple equipment, but like any other piece of shop-floor capital equipment, injection molding machines need to run to make money. A good start is to offer pilot quantity production as a separate service to the agreed test quantities. These smaller runs usually don’t require lightning fast cycle times, and overloaded processors are often willing to cooperate with personnel, quality, and shipping issues. Simple gravimetric loaders, a clean, well-lit machine environment, and basic SPC capability can make older equipment a significant profit centre, as well as the ultimate arbiter of mold quality.

Fortunately for smaller operations, machine pricing is very competitive, and opportunities to run production can turn a tryout machine into a profit centre. Moldmakers don’t mince words, and Joe Claxton is no exception. He puts it simply: “It’s a non-issue in our industry. If you don’t have it, you don’t get the work.”


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