Surface Finishing for Plastic Parts

Huashuo provides injection molding surface finishing services for injection-molded and machined parts, covering polishing, texturing, coating, and marking processes. These solutions are selected based on your material, tolerance, and finish requirements, ensuring a consistent injection-molding surface finish from prototype to production.

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What is surface finish?

Injection molding surface finishing for plastic parts is a set of processes used to control surface appearance, roughness, and functional performance. It improves wear resistance, durability, and visual consistency, and is commonly applied to injection molded and machined parts requiring defined texture, gloss, or branding features.

At Huashuo, surface finishing options are selected based on your material, tolerance, and end-use requirements. You can submit your drawings or samples to receive a finishing recommendation with manufacturability and cost considerations.

Injection Molding Surface Finishing Options We Offer

At Huashuo, different types of surface finishing methods are selected depending on whether the priority is appearance, durability, or production efficiency.

Polishing

Polishing is used to create a smooth or mirror-like surface, often required for transparent or high-end visible parts.

Standard: SPI A1–A3
Roughness: Ra ≤ 0.05–0.2 μm
Materials: PMMA, PC
Best For: optical components, display covers
Limitation: sensitive to mold quality and increases cost

Typically selected when visual clarity or premium appearance is critical.

Sandblasting

Sandblasting creates a uniform matte surface that reduces reflections and improves visual consistency across parts.

Roughness: Ra 1.6–3.2 μm
Materials: ABS, Nylon
Best For: industrial housings
Advantage: hides flow marks and minor defects
Limitation: cannot achieve glossy finishes

Commonly used for functional parts where a non-reflective surface is preferred.

Painting

Painting allows flexible color control and adds protective layers, especially for consumer-facing products.

Options: UV / rubber / metallic coatings
Materials: ABS, PC
Best For: branded products and appliance panels
Function: visual + protective coating
Limitation: adds process steps and cost

Best suited for products requiring consistent color and brand appearance.

Silk Screen Printing

Silk screen printing is used to apply logos, icons, or interface markings with high positional accuracy.

Materials: ABS, PC
Best For: UI panels and branding
Advantage: precise and repeatable
Limitation: limited to relatively flat areas

Typically applied when functional markings or branding are required.

Electroplating

Electroplating gives plastic parts a metallic appearance and can add functional properties like EMI shielding.

Materials: ABS, PC+ABS
Finish: chrome, nickel
Best For: decorative + functional parts
Advantage: premium metallic look
Limitation: requires strict surface preparation

Used when both aesthetics and functionality need to mimic metal.

Mold Texturing

Mold texturing creates surface patterns directly during molding, ensuring consistency across large production volumes.

Standard: VDI 12–45
Roughness: Ra 0.8–6.3 μm
Materials: ABS, PP
Best For: grip surfaces, anti-scratch parts
Advantage: no secondary processing required

Ideal for mass production where consistency and cost control are priorities.

Surface Finish Comparison Table

Different processes vary significantly in cost, appearance, and production suitability, so comparing them helps narrow down options quickly.

Process	Finish	Roughness / Standard	Cost	Best For
Polishing	Gloss	SPI A1–A3 (≤0.2 μm)	High	Optical parts
Sandblasting	Matte	Ra 1.6–3.2 μm	Low	Industrial
Painting	Color	Coating-based	Mid–High	Consumer
Silk Printing	Marking	—	Low	Branding
Electroplating	Metallic	Smooth	High	Decorative
Mold Texture	Textured	VDI 12–45	Low (mass)	Grip

Surface Finish Standards

In practice, engineers select surface finishes based on both visual standards and roughness values.

Type	Standard	Roughness (Ra)	Effect
Mirror	SPI A1	≤0.05 μm	Optical clarity
Gloss	SPI A2–A3	≤0.2 μm	Smooth surface
Fine Texture	VDI 12	~0.8 μm	Soft matte
Medium Texture	VDI 24	~2.0 μm	Matte
Rough Texture	VDI 33–45	4.5–6.3 μm	Strong texture

Huashuo Surface Finishing Capabilities

Integrated Manufacturing

Injection molding and finishing combined for dimensional stability.

Consistent Quality

Batch-level control ensures uniform surface appearance.

Wide Process Range

Polishing, sandblasting, painting, silk printing, electroplating, mold texturing.

Engineering Guidance

Finish selected based on material, tolerance, and function.

Prototype to Mass Production

Support from small prototypes to high-volume parts.

Cost vs Performance

Optimized balance between finish quality, cost, and efficiency.

FAQS

Everything You Need to Know About Surface Finishing

Does surface finishing affect part dimensions？

Yes, slight variation may occur depending on the process.
In most cases, it is controlled within ±0.02–0.05 mm.

What is surface finishing for plastic parts?

It refers to processes that control surface appearance and roughness.
It is essential for achieving both visual quality and functional performance.

What surface finishing methods are commonly used?

Polishing, sandblasting, painting, electroplating, and texturing are widely used.
Each method serves different needs such as appearance, durability, or branding.

What is the difference between SPI and VDI finishes?

SPI defines polished surfaces, while VDI defines textured finishes.
They are selected based on gloss vs texture requirements.

Which surface finish is best for injection molded parts?

There is no single best option; it depends on application needs.
Engineers usually balance appearance, durability, and cost.

How do I choose the right surface finishing process?

Start with material, tolerance, and appearance requirements.
Then evaluate cost and production volume trade-offs.

Request a Quote

From mold design to mass production, we offer end-to-end solutions.

Tell us about your application, materials, and volume requirements. Our team will recommend the right process and deliver a tailored manufacturing solution.