Get the Most From Your Tooling – Plastics Technology via Nick.
The history and culture of the molding industry has been to pull out every trick possible to work around design, resin, tooling, processing, and testing issues once the mold arrives. It is time to rewrite history.
A pressure-loss study is a short-shot study on a mold to check the fill pattern for air traps, flow-front acceleration, uniform filling, and balance of fill. Note the high pressure loss in the sprue and runner. It’s good to find problems like these when the mold is still under warranty.
The arrival of a new tool always brings a certain level of excitement. Often it is late and everyone is in a rush and pressured to produce “good” parts. So the history and culture of the molding industry has been to pull out every trick possible to work around design, resin, tooling, processing, and testing issues. Burns? No problem, just slow the injection rate. Flash, color streaks, blush, shrink, warp, etc.? No worries. We spend hours on profiling, fixturing, trimming, and other tricks of the trade to get around these problems.
The result of this approach is often a few good parts but no real process that meets the production level, quality, or profits expected. Even worse, one of these good parts produced “by luck” is often waved around by your boss, who wants to know why, since the mold can “obviously” produce good parts, can’t you get the process to run? This leads to even more experimentation, which wastes time, resin, and money.
Is there a better approach? Sure, but since each tool is unique and has its own peculiarities, it’s tough to have a standardized way of doing things. That said, there are certain requirements and tests that all tools should pass before any parts are sent out.