Views: 0 Author: Site Editor Publish Time: 2026-06-22 Origin: Site
In injection molding production, mold clamping is one of the most critical processes that directly determines product quality, mold service life, and production stability. Poor clamping accuracy or irregular component installation will easily cause flash, short shots, mold damage, and even sudden production shutdowns. For mold technicians and injection molding operators, mastering standardized mold clamping requirements and correct component installation methods is essential for efficient and defect-free production.
This blog will systematically introduce the professional process requirements of injection mold clamping and the standard installation steps of core mold components, covering all key details from pre-clamping preparation to final commissioning.
Mold clamping is not a simple closing of the movable and fixed molds. It has strict precision and procedural standards to ensure tight mold fitting and stable operation.
The guide pins and guide bushes are the core positioning components of the mold. The single-side fitting clearance must be controlled within 0.02–0.05 mm. After installation, the mold opening and closing movement should be smooth without jamming or abnormal collision noise. The verticality of guide pins shall not exceed 0.02 mm per 100 mm to avoid unilateral wear and guide pin scratching during long-term production.
For the mold parting surface, no 0.05 mm feeler gauge shall be inserted after low-pressure complete clamping. The parallelism of the front and rear mold plates is controlled within 0.03 mm per meter. No sundries, burrs or warping are allowed on the parting surface, which is the key to preventing plastic flash.
All mold fixing bolts must be tightened diagonally in multiple steps instead of one-side full locking, which effectively avoids template deformation and clamping deviation. Standard torque values are adopted for different bolt specifications: 80–100 N·m for M12 bolts and 120–150 N·m for M16 bolts.
Low-pressure protection is a mandatory safety process for machine-mounted mold clamping. The clamping process is divided into three stages: slow start, fast clamping, low-pressure protection and high-pressure locking. The low-pressure protection distance is reserved 5–10 mm before the parting surface. It will automatically alarm and open the mold once foreign matters or unreset sliding blocks are detected, thoroughly avoiding mold crushing damage.
Clean the inner holes of guide pins and guide bushes to remove burrs before installation. Press the guide bushes into the fixed mold plate vertically with a press machine, ensuring the end face is flush with the template. Then install the guide pins on the movable mold plate, and monitor the verticality with a dial indicator during the whole process. After assembly, manually open and close the mold to check smooth fitting without deviation. The matching clearance of precision positioning tenons is controlled at 0.01–0.03 mm to improve the overall clamping accuracy of precision molds.
Check the direction and anti-error marks of mold cores and inserts before installation to avoid reverse assembly. Tap the mold core into the template gently with a copper rod. The parting surface of the mold core shall be 0.01–0.02 mm higher than the template surface to ensure complete fitting during clamping. Small inserts and pins are installed by sliding fit, with appropriate tightness: too tight will cause jamming, and too loose will produce flash. Finally, lock the fixing screws diagonally and install positioning pins to prevent displacement.
Install return springs with reasonable pre-compression, and reserve a 5 mm safety margin for the ejection stroke. After installation, perform repeated manual ejection and reset tests to ensure no jamming or eccentric wear. The single-side clearance between ejector pins and pin holes is maintained at 0.008–0.02 mm to meet precision molding requirements.
Equip limit screws and springs to ensure the slider is fully reset driven by angle pins during clamping. For large-stroke sliders, add wedge locking blocks to enhance mold locking rigidity and avoid flash caused by mold expansion during injection.
Mold clamping and component installation are basic but core skills in the injection molding industry. Every tiny precision error will be amplified in mass production, affecting product yield and mold service life. Abiding by standardized clamping processes and installation specifications is the most effective way to reduce mold failures, stabilize product quality and improve production efficiency.
