Surface Finishing Service

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Injection Mold Surface Finishing Standerds

Zhongde has access to a diverse marketplace of molding suppliers and all standard mold surface finishing options. Mold finishes can range from glossy to matte to even patterned. Finishes applied to the surface of the mold cavity transfer to the surface of the molded part. For example, a mold surface that is polished to be reflective will make a reflective (or transparent) part. Mold finishes differ from CNC machined or 3D printed parts, where each component is treated individually. Adding a finish or texture can change the tool’s price depending on the process required, but it does not alter the price of the individual parts.

Our standard mold finishing includes the following:

Society of Plastics Industry (SPI) Mold Finishes
VDI

SPI Finishes vs VDI Finishes

SPI Surface Finishing Standard

SPI Finish (SPI Finishes) is also known as “SPI Mold Finish (SPI Mold Finishes)” or “SPI Surface Finishes“.

The SPI Surface Finishing refers to the American surface finishing standard set by SPI (Society of the Plastics Industry).

SPI A Finishes

SPI A-1

Diamond buffed with grade #3, 6000 grit for a highly polished finish. Also suitable for producing optically clear parts. Has an average surface roughness of 0.012-0.025µm Ra.

SPI A-2

Diamond buffed with grade #6, 3000 grit for a high polish finish. Also suitable for producing transparent parts. Has an average surface roughness of 0.025-0.050µm Ra.

SPI A-3

Diamond buffed with grade #15, 1200 grit for a high-to-medium polished finish. Also suitable for producing non-optical transparent parts. Has an average surface roughness of 0.050-0.100µm Ra.

SPI B Finishes

SPI B-1

A 600-grit sanded finish for a medium polish with a surface roughness of 0.05-0.10µm Ra.

SPI B-2

A 400-grit sanded finish for a medium polish with a surface roughness of 0.10-0.15µm Ra.

SPI B-3

A 320-grit sanded finish for a medium-to-low polish with a surface roughness of 0.28-0.32µm Ra.

SPI C Finishes

SPI C-1

A 600 stone finish for a low polish with a surface roughness of 0.35-.40µm Ra.

SPI C-2

A 400 stone finish for a low polish with a surface roughness of 0.45-.55µm Ra.

SPI C-3

A 320 stone finish for a low polish with a surface roughness of 0.63-.70µm Ra.

SPI D Finishes

SPI D-1

Dry blasted with glass bead for a satin finish with a surface roughness of 0.80-1.00µm Ra.

SPI D-2

Dry blasted with #240 oxide for a dull finish with a surface roughness of 1.00-2.80µm Ra.

SPI D-3

Dry blasted with #24 oxide for a dull finish with a surface roughness of 3.20-18.00µm Ra.

VDI Surface Finishing Standard

VDI 3400 Surface Finish (known as VDI surface finish) refers to the mold texture standard Verein Deutscher Ingenieure (VDI), the Society of German Engineers. The VDI 3400 surface finish is mainly processed by Electrical Discharge Machining (EDM) when mold machining. VDI is an international standard for mold texturing of matte surfaces. The EDM surface gives a fine-to-coarse grain depending on the selection.

VDI (EMD) Finishes

VDI 12

A 600 stone low-polish finish with an average surface roughness of 0.40µm Ra.

VDI 15
A 400 stone low-polish finish with an average surface roughness of 0.56µm Ra.

VDI 18

A glass bead blast satin finish with an average surface roughness of 0.80µm Ra.

VDI 21

A #240 oxide dry blast dull finish with an average surface roughness of 1.12µm Ra.

VDI 24

A #240 oxide dry blast dull finish with an average surface roughness of 1.60µm Ra.

VDI 27

A #240 oxide dry blast dull finish with an average surface roughness of 2.24µm Ra.

VDI 30

A #24 oxide dry blast dull finish with an average surface roughness of 3.15µm Ra.

VDI 33

A #24 oxide dry blast dull finish with an average surface roughness of 4.50µm Ra.

VDI 36

A #24 oxide dry blast dull finish with an average surface roughness of 6.30µm Ra.

VDI 39

A #24 oxide dry blast dull finish with an average surface roughness of 9.00µm Ra.

VDI 42

A #24 oxide dry blast dull finish with an average surface roughness of 12.50µm Ra.

VDI 45

A #24 oxide dry blast dull finish with an average surface roughness of 18.00µm Ra.

Mold Surface Texture: Techniques, Standards, and Applications in Injection Molding

Explore the world of mold surface texture in injection molding, where the visual and tactile qualities of a part are

Secondary Surface Finishing

Here is a list of optional super surface finishing. For custom high metal surface finishes such as electroplating or polishing, please contact sales@zdcpu.com.

As Machined

For as machined all sharp edges are removed and parts are deburred. Tool marks are visible.

Smoothing

A finishing CNC machining operation can be applied to the part to reduce its surface roughness. Machine marks are less evident but still visible.

Material Compatibility: All plastic as and metals

Bead Blasting

Bead blasting adds a uniform matte or satin surface finish on a machined part, removing the tool marks. This is used mainly for visual purposes and comes in several different grits which indicate the size of the bombarding pellets.

Material compatibility: All metals Color: Uniform matte of raw material color

Powder Coating

Powder coating is a strong, wear-resistant finish that is compatible with all metal materials and can be combined with a bead blasting to create parts with smooth and uniform surfaces and excellent corrosion resistance.

Material compatibility: All metals Color: Black or any RAL code or Pantone number.

Anodizing Color (Type II)

Type II anodizing is mainly used to produce parts with a uniform, aesthetically pleasing surface and provides good corrosion and limited wear resistance.

Material compatibility: Aluminum alloys Color: Black, clear or any RAL code or Pantone number

Anodizing Hardcoat (Type III)

Type III anodizing provides excellent corrosion and wear resistance, suitable for functional applications.

Material compatibility: Aluminum alloys Color: Black or clear

Electropolishing

Electropolishing is an electrochemical process used to polish, passivate and deburr metal parts. It is useful to reduce surface roughness.

Material compatibility: All metals Color: Natural metal color

Black Oxide

Black oxide is a conversion coating used to improve corrosion resistance and minimize light reflection.

Material compatibility: Stainless steel and copper alloys Color: Black

Chromate Conversion Coating (Alodine/Chemfilm)

Chromate conversion coating is used to increase the corrosion resistance of metal alloys while maintaining their conductive properties.

Material compatibility: Aluminum and copper alloys Color: Clear or yellow

chromate conversion coating surface finishing

Brushing

Brushing is produced by polishing the metal with grit resulting in a unidirectional satin finish. Not advisable for applications where corrosion resistance is required.

Material compatibility: All metals

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