Apr 03,2026
Preassembly and Testing of Molds: Final Validation Before Delivery
Preassembly and Testing of Molds: Final Validation Before Delivery
Pre-assembly, Trial molding, Mold tryout, Debugging, Acceptance
From design to completion of manufacturing, countless engineers and technicians put in great effort. However, the value of these efforts can only be finally tested during the final pre-assembly and model testing stages. Pre-assembly verifies whether the various parts of the mold are well-coordinated and smoothly moving; model testing verifies whether the mold can reliably produce a qualified product under actual production conditions. These two stages are the “final test” of the mold before delivery to customers, and are also the last chance that any mistakes may be exposed.
Pre-assembly is a preview of the total mold assembly. Before assembling all the components into a complete mold, the pre-assembly of the components is usually performed first: fitting the mold core, mold cavity fitting into the template; fitting the slider into the slide socket; fitting the thimble plate and the thimble properly. The purpose of pre-assembly is to check: 1. whether each component is installed properly and whether there are any interference; 2. whether the guidance components (conducting column guide housing, diagonal guide column) are smoothly fitted; 3. whether the tip out system movement is smooth and whether the reset is in place; 4. whether the cooling water channel is clear and whether there are leaks; 5. whether the heat flow system wiring is correct. For problems discovered, such as overfitting, motion jamming, repairs or adjustments need to be made immediately. Only after pre-assembly fits can the total assembly be carried out.
Preparation before testing is essential. To hoist the mold onto the injection plastics machine, you need to confirm that the mold positioning ring matches the injection plastics positioning hole, and that the pressure plate is securely secured. Connect the cooling water pipe, heat flow power source, and temperature control box. Set the mold temperature, heat flow temperature, and preheat to the set value. Prepare the testing material, and confirm that the material has dried to the required water content. Set the injection process parameters: injection pressure, speed, retaining pressure, back pressure, screw turn speed, cooling time, and so on, usually starting with the parameters recommended by the CAE.
The model testing process is a process of gradual optimization. The first model often employs low-pressure, low-speed injection to observe the flow state of the molten fluid to prevent flying edges or damage to the mold. The pressure and speed are gradually increased until the mold cavity is basically full. At this time, the product is checked for defects such as defects, weld marks, and air marks. Process parameters are adjusted according to the phenomenon: defects increase the injection amount or pressure; flying edges reduce pressure or check the lock strength of the mold; and weld marks significantly increase the molten temperature or injection speed. The model testing process may require repeated debugging of dozens or even hundreds of models to find the optimal process window.
The key inspection items in the test model include: 1. Whether the product size and appearance meet the blueprint requirements; 2. Whether the removal of the mold is smooth and the tip-out marks are acceptable; 3. Whether there are adhesive mold and tearing phenomena; 4. Whether the moving parts such as sliders and slanted tops work normally; 5. Whether the cooling effect is good and the mold temperature is stable; 6. Whether the heat flow temperature control is precise and the pouring marks are qualified. For each model product, it should be labeled and the corresponding process parameters recorded for traceability.
The validation of the mold after the test is the final step. If the test product qualifies, and the mold remains stable and reliable after continuous production of a certain number (e.g., 100 models), it can be considered a successful test. At this time, the test report, including process parameters, product detection report, problem records, and solutions, must be compiled and delivered to the customer along with the mold. For problems discovered in the test, such as local wear, thimble marks, bad exhaust, and so on, model improvements must be made on the mold, and then the model must be validated again until all problems are resolved.
Model testing is not just verification, but also learning. Each model testing is a valuable practice, it reveals gaps between design and reality, accumulating experience for subsequent improvement of the mold. A mature mold manufacturer inevitably has a team of experienced model testing engineers, who can insight into the root cause of problems from the clues of model testing, and quickly provide solutions. Model testing is the final process of the mold going from blueprints to mass production, and it is also a witness to the final realization of the value of the mold.
Previous: None
Next: Cooling lubrication technology in mold processing: The secret to extending the life of knives
1013 Min'an Avenue, Xiang'an District Xiamen City, Fujian Province, China
+86-13225990951
2605949828@qq.com
