High-temperature resistant cups are mainly made of PP, PPSU, Tritan and PC materials. Such plastics feature high rigidity, stable shrinkage rate and strong mold adhesion, easily causing sticking, surface scratch, ejection whitening and cup deformation during demolding. Smooth product separation can be guaranteed through mold structural optimization, surface anti-sticking treatment, parameter adjustment and standardized operation, maintaining good appearance and high production efficiency.
1. Structural Optimization to Lay Solid Demolding FoundationDraft angle design is the key to reduce wrapping force. Side wall draft angle ranges from 0.5° to 1.5°, and angles at cup rim, bottom and textured positions increase to 1.5°-2.5°. Reinforcement ribs and buckles also adopt inclined transition to avoid demolding jamming. High-gloss cup cavities are finely polished to lower melt adsorption force. All sharp corners are modified into round arcs to prevent surface scratch. Ejector pins are arranged annularly at cup bottoms with reasonable spacing for uniform stress distribution and local crack prevention. Parting surfaces are arranged along maximum product outline to avoid visible friction traces. Sliding core pulling mechanisms handle embedded structures with synchronized stable movement.
2. Mold Surface Modification for Anti-sticking DemoldingSurface strengthening treatment effectively reduces material adhesion. Cavity surfaces adopt nitriding treatment, chromium plating or DLC coating to promote hardness and smoothness, adapting to repeated high-temperature molding and lowering sticking probability. Toxic oily release agents are forbidden in mass production. Food-grade dry anti-sticking coating is applied appropriately, achieving long service life without harmful precipitation. Fine scratches are polished regularly to keep smooth molding surfaces and stable demolding performance.
3. Precise Parameter Adjustment for Smooth DemoldingMaterial temperature is properly reduced to weaken melt adhesion. Moderate mold temperature accelerates product shaping and shrinkage, narrowing the fitting area between cups and cores. Even cooling pipelines guarantee consistent shrinkage and reduce demolding deformation risks. Excessive holding pressure and duration are cut down to avoid tight product wrapping. Segmented slow injection speed reduces internal residual stress. Demolding action starts only after complete product solidification. Ejection speed changes gradually to separate cups steadily without surface damage.
4. Operational Control of Mold Opening and Ejection ActionsMold opens slowly at initial stage to avoid instantaneous pulling deformation, then speeds up after complete parting separation. Closing movement slows down at final stage to protect mold precision. Ejection stroke is set accurately to prevent skew and collision damage. All ejection components keep synchronous movement to avoid unilateral stress defects. For slight sticking failures, staff adjust temperature and pressure parameters moderately instead of forced demolding. Fixed action parameters reduce abnormal demolding problems in batch production.
5. Daily Maintenance and Emergency Treatment of Demolding DefectsResidual scraps and carbon dirt inside molds are cleaned regularly, as protruding impurities cause scratch and demolding resistance. Worn ejector pins, springs and guide parts are replaced timely to keep flexible ejection operation. Cooling pipelines are dredged to avoid uneven shrinkage induced sticking. Different plastic materials are produced separately to stabilize adhesion characteristics. Severe core sticking is solved through temperature reduction and slow ejection. Scratch and whitening defects are eliminated by optimizing draft angle, surface smoothness and ejection layout respectively.
