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Precision Mold Gap Matching Technology: How Scientific Clearance Control Eliminates Flash and Burrs

OkMold Views：109 Release time：2026-08-05
Flash and burrs are the most common and stubborn defects in precision injection molding. Most manufacturers attribute burr problems to poor machine parameters, but the real root cause is unreasonable gap matching of the precision mold. High-quality precision molds rely on ultra-precise clearance coordination between cavities, cores, sliders, inserts and parting lines. Scientific mold gap control can completely eliminate overflow material and ensure zero-burr mass production.
Our factory adopts professional precision gap matching technology for every custom precision mold. We set differentiated clearance standards according to plastic fluidity, mold temperature and product precision requirements, realizing tight sealing at parting lines, reasonable sliding clearance for moving parts, and perfect fitting for insert positions. This advanced mold making process effectively solves flash problems that plague most mold manufacturers.

Quality Problems Caused by Unreasonable Mold Clearance

Excessively large gaps on parting lines and insert joints will allow molten plastic to penetrate during high-pressure injection, forming obvious burrs and flash. Tiny burrs on precision electronic and medical parts will lead to assembly jamming, sharp edges and product disqualification. Manufacturers have to spend extra time on manual trimming, greatly reducing production efficiency.
Conversely, overly tight clearance without reserved expansion space will cause mold jamming, scratching, poor mold closing and component wear after thermal expansion. Unbalanced gap matching makes the precision mold unstable, resulting in fluctuating product quality and frequent mold maintenance.

Our Precision Mold Clearance Calibration Process

We formulate dynamic gap standards for precision mold manufacturing instead of fixed static values. For high-fluidity materials such as PA, PP and ABS, we adopt ultra-tight sealing clearance to prevent overflow. For high-temperature engineering plastics, we reserve thermal expansion gaps to avoid mold clamping interference.
All parting surfaces, insert joints and slider fitting positions are precisely grounded and manually calibrated. We conduct repeated mold closing tests and high-pressure injection simulation to fine-tune gaps, ensuring zero flash under long-term high-pressure production while maintaining flexible mold movement.

Advantages of Zero-Burr Precision Molds

Precision gap matching technology enables the precision mold to achieve fully automatic production without manual trimming. It reduces labor costs, improves product surface quality, and maintains consistent dimensional accuracy in long-cycle mass production. Stable zero-burr mold performance is the key to high-efficiency and high-yield precision part manufacturing.


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