Injection Mold Mirror Polishing
Injection mold mirror polishing refers to progressively grinding and polishing the surface of a mold cavity to achieve a mirror-like finish. This ensures the molded parts have a smooth appearance, easy demolding, and extended mold lifespan.
1. Purpose and Benefits
Improves the appearance of molded parts: Mirror-polished molds can produce transparent or high-gloss parts with a flawless surface in a single molding cycle, eliminating the need for post-processing steps like sanding.
Reduces demolding resistance: The smooth surface minimizes friction and adhesion between the part and the mold.
Extends mold service life: Reduces residue buildup and wear during injection molding.
2. Process Flow
1. Rough Grinding
To remove deep scratches, machining marks, or weld seams, use coarse sandpaper (240–400 grit) or silicon carbide grinding wheels.
2. Intermediate Grinding
Gradually transition to 600–800 grit sandpaper to flatten surface grooves and blend grinding marks.
3. Fine Grinding
Refine the surface texture with 1000–1500 grit sandpaper to prepare for polishing.
4. Initial Polishing
Use a soft felt wheel with a polishing compound at medium-low speed for uniform polishing.
5. Final Polishing
Switch to a wool or cotton wheel with an ultra-fine polishing compound (e.g., cerium oxide). Polish at low speed and high pressure until a mirror-like reflective surface is achieved.
3. Tools and Materials
Abrasives:
Sandpaper/sanding cloth (240, 400, 600, 800, 1000, 1500 grit).
Grinding wheels/grinding heads (corundum grinding wheels, diamond grinding heads).
Polishing Tools:
Polishing wheels (felt, leather, wool, or cotton wheels).
Polishing compounds (aluminum oxide, chromium oxide, cerium oxide in coarse, medium, and fine grades).
Equipment:
Power tools: Angle grinders, polishing machines, portable micro-polishing pens.
Auxiliary tools: Ultrasonic cleaners, protective gloves, masks, goggles, etc.
