Faster Filter Design

Automotive Manufacturing & Production, Jan, 2000

The Situation: An automatic transmission filter was being developed by SPX Filtran. The component essentially consists of a plastic upper cover (nylon 6/6, 33% glass filled), a steel pan bottom and a felt filtering media in between. A prototype tool had been built to produce several hundred of the filters for purposes of testing.

The Need: The problem that was discovered was that the plastic outlet tube for the filtered fluid was shrinking to an unacceptable oval shape. Because the part was designed and tooling produced, the objective was to solve the problem with as minimal changes as possible.

The Solution: Experimentation and analysis were performed using C-MOLD software from C-MOLD (Louisville, KY). Essentially, the software permitted the engineers to characterize the distortion that occurred as a result of the shrinkage, and then to determine how this could be solved in the most cost-effective manner, taking into account not only the reduction of overall distortion, but in a cost-effective manufacturing operation. By using the software to predict the results of not only the behavior of the part as molded but also of the cycle time that would result from tooling modifications to accommodate changes to the part design, the solution was methodically determined in days, not the weeks of trial-and-error that would ordinarily be the case.