We at Rebling Plastics work hard to ensure that the quality of our products’ quality is consistent and that our employees get the training that they need to keep up with the demands of the industry. We realize that not everyone has a cursory understanding of our industry and the that go into creating and maintaining quality product and, to assist, include steps that we use for training purposes.
Rebling Plastics’ Quality Manager writes an inspection plan for each operation- plastic injection molding, secondary operations, etc. for each new product. Typically, the inspection plan consists of measuring critical dimensions and visual inspections of the plastic injection molded part or assembly. A copy of each inspection plan, which is stapled to a drawing with corresponding numbered dimensions, is organized by mold number and filed on the shop floor. Each time a plastic injection molding or secondary operation is started, setup technicians post the inspection plan with the shop traveler and setup instructions at the plastic injection molding press or secondary equipment. The operators record their own measurements at specified time intervals, and the Quality Manager audits the inspection records throughout the day. Special inspection requirements involving inspection fixtures or testing of electrical and mechanical requirements such as Hipot, dielectric, and torque testing are performed offline in our QA Lab.
Employee training begins with basic blueprint/drawing reading. Employees can read dimensions from the inspection plan and understand where the measurement should be taken on the part.
The next stage of the training process involves using basic measurement devices such as calipers, micrometers, gage pins, fixtures, etc. Employees must understand how to take the measurements properly for repeatability. Unlike with metals, some plastic injection molding materials are soft, and some are even considered elastomers. When inspecting these parts, it is very critical to not squeeze calipers and micrometers on the part. This is because squeezing may cause deflection in the part and make measurements inconsistent. Gage pins may also appear to “go” when they are actually a “no go”, because a thin plastic part stretches. That is why our employee quality training program uses examples of different plastic parts to illustrate the point. By learning the proper technique early on, our employees can make consistent measurements.
In the last stage, everyone receives special training for spotting specific defects which are unique to the plastic injection molding process. Employees can quickly identify sinks, gas marks, flow marks, flash, short shots, splay, knit lines, etc. which is critical for assuring quality.