Complete Trial Process and Acceptance Standards of Chinese Injection Molds

In China’s injection molding industry, mold trial serves as the most critical verification link before mass production. It is a standardized inspection procedure formulated according to domestic mold manufacturing specifications and production quality requirements. The main purpose of mold trial is to comprehensively verify the rationality of mold structure, processing accuracy, cooling system, exhaust system and ejection system, eliminate hidden dangers in design and processing, optimize and lock stable injection molding parameters, and ensure that the mold can achieve high-quality, stable and high-yield mass production. Standardized trial process and unified acceptance standards can effectively avoid repeated mold trials, prevent defective molds from being put into production, and reduce mass scrap and rework costs.

1. Pre-Trial Preparation Work

Before the formal mold trial, comprehensive inspection and preparation of the mold, equipment, raw materials and technical documents must be completed in accordance with Chinese factory standard procedures. Workers need to thoroughly clean the mold cavity, parting surface, flow channel and exhaust groove to remove iron filings, residual glue and polishing dust. Inspect the flexibility of thimbles, sliders, lifters and guide components to ensure no jamming or loosening. Check the cooling water circuit for smooth flow and no water leakage. Lubricate all moving parts and conduct empty mold opening and closing tests to ensure stable mold operation.

Select a suitable injection molding machine according to the product projection area and mold tonnage. Strictly dry and dehumidify the plastic raw materials to prevent moisture from causing silver lines and bubbles on the product surface. Prepare precision measuring tools such as calipers and micrometers, and check 2D drawings, tolerance standards and appearance requirements to clarify key size control areas, ensuring traceable and standardized trial work.

2. Mold Loading and Initial Parameter Debugging

After the mold is hoisted and fixed on the machine and the water circuit is connected stably, set the basic process parameters including barrel temperature, mold temperature, injection speed, holding pressure and cooling time. The first filling adopts low-speed and low-pressure molding. The priority is to check the filling balance, exhaust smoothness and ejection effect, instead of pursuing perfect product appearance.

Technicians adjust process parameters according to actual molding defects. Reduce injection speed to eliminate air lines and burning marks; increase holding pressure and holding time to improve shrinkage and sink marks; optimize clamping force to improve flash; adjust cooling parameters to improve warpage and deformation. Gradually eliminate basic molding defects and lock the preliminary qualified molding process parameters.

3. Continuous Production Stability Verification

After the initial parameters are qualified, conduct continuous production of 30 to 50 consecutive shots for stability verification, which is a necessary procedure in Chinese mold trial standards. Continuously observe the reset state of sliding blocks, lifters and thimbles to avoid jamming and abnormal noise. Inspect intermittent defects such as exhaust carbon deposition, unstable ejection and occasional filling shortage.

Randomly sample products to detect appearance quality, dimensional accuracy and deformation consistency, focusing on controlling weld lines, sink marks, top whitening and size fluctuation. Verify the long-term stability of mold cooling and exhaust system, and finally lock the standard mass production process parameters to ensure that the process has good stability and fault tolerance.

4. Full Item Inspection and Mold Acceptance Standards

The final acceptance of Chinese injection molds covers mold operation state, product appearance, dimensional accuracy and assembly performance. In terms of mold operation, the mold opens and closes smoothly, all moving mechanisms reset accurately, there is no water leakage, no abnormal wear and no jamming, meeting long-term mass production requirements.

In terms of product appearance, the surface is free of bubbles, silver lines, shrinkage, scratches and obvious weld lines. The parting line and gate position are flat and uniform without obvious defects. In terms of dimensional inspection, all key assembly sizes and appearance sizes are within the drawing tolerance range with small batch fluctuation. In terms of assembly performance, the sample fits tightly without interference and loosening, meeting product assembly standards.

5. Trial Rectification and Final Filing

For unqualified items found in the trial process, classify and rectify mold structure problems, processing precision problems and process problems in a targeted manner. After modification, conduct repeated trial verification until all defects are eliminated. After the mold is fully qualified, clean and maintain the mold, spray anti-rust agent, and complete the filing of trial reports, process parameters and test data to form complete mold production technical documents.

Summary

The complete trial process and acceptance standards of Chinese injection molds are standardized systems integrating preparation, debugging, stability verification, full inspection and rectification. Strict implementation of domestic mold trial specifications can effectively check mold manufacturing defects, stabilize molding quality, ensure mold mass production consistency, and provide reliable technical guarantee for subsequent long-term and efficient injection molding production.