POOR PART QUALITY AT START-UP

If you begin a production run and immediately notice problems that you suspect are due to a heat-transfer problem, here are a few questions to ask:

oWas the cooling system checked? It sounds ridiculously simple, but is your heat-transfer system actually working? Check that all hoses are properly connected and that there are no leaks. Then, starting at the mold, make sure all the components in the system are working correctly. If you have a mold-temperature control unit (TCU) between the mold and the chiller, make sure the heater and pump are working. Until the mold is up to temperature, the TCU will need to heat the heat-transfer fluid and it can’t do that if the heater isn’t functioning. Then check the cold-water source (chiller or cooling tower) and make sure they are operating correctly.

oWas the tool changed? If so, then make sure that all temperature and flow rates are optimized for the new mold. Different molds often require different heat-transfer settings and if the tooling was changed but the heat-transfer settings from the previous job remain, the system won’t be able to produce good parts. It is also possible that a TCU that works well with one tool or process may not be capable of handling a larger tool effectively. And don’t forget to make sure that the mold cooling lines have been purged completely of any air before start-up. The air in the tool will inhibit proper heat transfer.