Views: 0 Author: Site Editor Publish Time: 2026-10-13 Origin: Site
Poor scratch resistance is one of the most common complaints for injection molded plastic products. Many base thermoplastics like ABS, PP and PA12 are relatively soft on the Mohs hardness scale. Fine dust, daily contact and friction will leave visible scratches easily.
There are multiple ways to boost scratch resistance for your injection molding parts. We can divide the solutions into 3 categories: material modification, mold & structure optimization, and post-mold surface finishing.
Changing or compounding the raw plastic is the fundamental way to upgrade scratch resistance.
Use higher-hardness engineering plastics: Replace soft PP or ABS with PC, PMMA, POM, PEEK if design allows.
Add scratch-resistant additives / hard filler: Add silicone additives, glass fiber or mineral filler into plastic pellets. It improves surface slip property and increases Mohs hardness.
Note: Glass filled material may cause more visible surface sink marks and reduce surface gloss.
Hard-coating grade plastic: Some PC/PMMA blends are specially formulated for hard coating.
A good mold design can reduce scratch risk during use.
Optimize sharp edges: Round off sharp corners and thin ribs. Sharp corners concentrate stress, coatings peel easily under friction.
Mold texture selection: Choose fine, uniform mold texture instead of deep coarse grain. Deep texture traps dust and gets scratched more visibly.
Control surface roughness of mold cavity: Polished or fine EDM textured mold creates smoother molded part surface, fewer micro-scratches coming from molding.
This is a transparent hard protective layer sprayed and UV-cured on plastic. Mohs hardness: 3~4H pencil hardness (Mohs ~3.5~4.5). ✅ Great for transparent PC/PMMA parts, high scratch resistance, keeps original plastic color. ❌ Extra production step, higher cost than normal spray.
If you need color (such as your matte gold tile), use scratch-resistant hard clear coat as top layer. Normal metal paint only Mohs ~2.5~3; upgraded hard top coat lifts it to Mohs ~3~3.8. ✅ Flexible color matching, works for complex rib geometry. ❌ Still organic paint film, heavy long-term friction will wear through.
Deposits real nickel/metal alloy layer on ABS plastic. Mohs hardness: 4.0~5.0. Much better scratch resistance than paint. ✅ Real metal feel, excellent anti-corrosion and scratch performance. ⚠️ Not recommended for repeatedly sliding / snap friction parts, rib edges may peel.
Hard film integrated during injection molding. The hard film is on the outer surface. ✅ No secondary painting, good scratch resistance, no paint peeling issue. ❌ Higher mold cost, high setup cost, complex fine ribs are hard to form.
Static decorative plastic tile (your gold tile sample): If you want matte gold appearance + cost control: Metallic gold spray + hard clear top coat. If you need maximum scratch & salt spray resistance: ABS electroplating.
Parts with repeated snap / sliding friction (lid latch tabs): Electroplating or spray coating both have coating peeling risk. Material modification + rounded corner design is more reliable.
Transparent plastic lens / cover: UV hard coating is the preferred choice.
To improve the scratch resistance of injection molded plastic parts, we have 3 directions: material compounding, mold structure optimization and surface finishing. For colored decorative parts, hard top-coat spray painting is a cost-effective option. Electroplating gives higher scratch resistance with real metallic texture, but it has limitations on sharp edges. When selecting the solution, evaluate your budget, appearance requirement and actual friction working condition together.
