Category Archives

A technician asked me this question yesterday… Jason What is the best way to correct for part warpage? My Response Typically, part warpage is the result of variable shrinkage. In most cases, the variations in shrinkage causes the part to buckle, bow, or twist. Unfortunately, there are many causes which will contribute to this including […]

I was at a customer site recently and they were encountering intermittent contamination throughout the plant but could not isolate the source… The Culprit Upon review, the company has instituted very effective procedures for cleaning all of the material delivery, storage, and drying systems. I observed the entire cleaning process and realized they forgot to clean the feedthroat shut-off. […]

A blog reader emailed me this question… GW How can you theoretically calculate the necesary contact force between the nozzle and the sprue bushing? My Response The theoretical necessary contact force is based on multiplying the cross sectional area of the sprue bushing or nozzle opening (whichever is largest) by the injection pressure (in plastic pressure). Force […]

A blog reader asked a follow-up question to a previous blog posting… MJ If I don’t level the machine, what will happen? My Response Failure to properly level a molding machine can result in premature wear, equipment damage, and even clamp failure. Any twist or non-levelness of the clamp system results in non-linear movement of the platen and uneven […]

This concludes the three-part post regarding a reader’s question about machine maintenance… Tim What is the best method of measuring tie bar strain? My Response The most common method of measuring this is to follow the procedures of measuring parallelism as discussed in the previous post on measuring platen parallelism. The difference between the parallelism before and after clamping will give you important information […]