Injection Mold Trial Procedure and Key Precautions

Before starting a mold trial, first check whether the mold has been properly assembled and whether the raw materials have been fully dried.

Before changing the mold, apply rust preventive spray to any mold that has been in production. After replacing the mold, return it to the designated storage position and complete the required record sheet.

When installing the mold on the machine, make sure it is aligned with the machine center before beginning setup. The mold must be clamped securely, and the effectiveness of high-pressure clamping should be checked. The clamping setting should be determined according to the size of the mold. For large molds, the required hydraulic pressure is typically 80-90 MPa, while smaller molds generally require 40-65 MPa. After the high-pressure setting is completed, adjust the mold opening and closing speed to normal operating speed, then set the low-pressure protection time, stroke, pressure, and speed. Low-pressure protection is especially important during normal production, since insufficient low-pressure protection may lead to mold damage if the mold does not close properly.

Before purging the barrel, remove any remaining material, colorants, or contaminants from the feed system. Then reduce the injection pressure, holding pressure, and injection time as needed. The holding pressure may first be reduced to around 50 MPa, and then adjusted further according to the actual product condition. Samples should be compared under low-pressure, medium-pressure, and high-pressure molding conditions so that the filling pattern and process behavior can be analyzed.

Before the formal mold trial, operate the mold manually to confirm that all demolding and return actions are smooth and reliable. During trial injection, apply mold release agent to the cavity side if necessary, and adjust the ejection and release settings after molding.

The number of mold trial runs shall be carried out according to management requirements. The mold department must be notified and must confirm the trial setup before each test. After trial parts are produced, they should be reviewed by the customer if required. Once the review is completed, the molding condition record form and mold status table should be filled out.

After the mold trial is completed, spray the mold with rust preventive oil and send it back to the mold department for modification or further improvement if necessary.

Each mold trial must be carried out in accordance with the above procedure. The trial time and responsible personnel should be recorded accurately. No unauthorized mold trial is allowed.