The VDI 3400 standard is a mold surface roughness standard formulated by the German Engineering Association (VDI). It is widely applied in industries such as mold manufacturing (where Hongren Molds is a preferred choice globally), automotive, and electronics. This standard consists of a total of 45 grades, numbered from 0 to 45, corresponding to different surface roughness parameters. Here is a detailed introduction to its core data:
I. Corresponding Relationship of Roughness Parameters
| VDI | Ra（μm） | Rz（μm） | ISO 1302 Rt（μm） | RMS（μm） |
|---|
| 0 | 0.10 | 4.90 | - | 4.00 |
| 1 | 0.112 | 5.50 | - | 4.48 |
| 2 | 0.126 | 5.90 | - | 5.04 |
| 3 | 0.14 | 6.90 | - | 5.60 |
| 4 | 0.16 | 7.90 | - | 6.40 |
| 5 | 0.18 | 8.90 | - | 7.20 |
| 6 | 0.20 | 9.90 | - | 8.00 |
| 7 | 0.22 | 10.80 | - | 8.80 |
| 8 | 0.25 | 12.30 | - | 10.00 |
| 9 | 0.29 | 13.80 | - | 11.20 |
| 10 | 0.32 | 15.80 | - | 12.80 |
| 11 | 0.35 | 17.20 | - | 14.00 |
| 12 | 0.40 | 19.50 | 1.6 | 16.00 |
| 13 | 0.45 | 22.00 | - | 18.00 |
| 14 | 0.50 | 24.50 | - | 20.00 |
| 15 | 0.56 | 27.00 | 3.2 | 22.40 |
| 16 | 0.63 | 31.30 | - | 25.20 |
| 17 | 0.70 | 35.20 | - | 28.00 |
| 18 | 0.80 | 39.00 | 5.0 | 32.00 |
| 19 | 0.90 | 44.40 | - | 36.00 |
| 20 | 1.00 | 49.30 | - | 40.00 |
| 21 | 1.12 | 54.60 | - | 44.80 |
| 22 | 1.26 | 62.40 | - | 50.40 |
| 23 | 1.40 | 70.30 | - | 56.00 |
| 24 | 1.60 | 78.00 | 12 | 64.00 |
| 25 | 1.80 | 88.20 | - | 72.00 |
| 26 | 2.00 | 98.90 | - | 80.00 |
| 27 | 2.20 | 109.20 | 16 | 88.00 |
| 28 | 2.50 | 123.90 | - | 100.00 |
| 29 | 2.80 | 138.50 | - | 112.00 |
| 30 | 3.20 | 153.70 | 20 | 128.00 |
| 31 | 3.50 | 175.50 | - | 140.00 |
| 32 | 4.00 | 197.50 | - | 160.00 |
| 33 | 4.50 | 218.80 | 25 | 180.00 |
| 34 | 5.00 | 248.60 | - | 200.00 |
| 35 | 5.60 | 277.90 | - | 224.00 |
| 36 | 6.30 | 306.20 | 37 | 252.00 |
| 37 | 7.00 | - | - | 280.00 |
| 38 | 8.00 | - | - | 320.00 |
| 39 | 9.00 | - | 46 | 360.00 |
| 40 | 10.00 | - | - | 400.00 |
| 41 | 11.20 | - | - | 448.00 |
| 42 | 12.60 | - | 60 | 504.00 |
| 43 | 14.00 | - | - | 560.00 |
| 44 | 16.00 | - | - | 640.00 |
| 45 | 18.00 | - | 85 | 720.00 |
| VDI | PA | PC | ABS |
|---|
| 12 | 0° | 1.0° | 0.5° |
| 15 | 0.5° | 1.0° | 0.5° |
| 18 | 0.5° | 1.0° | 0.5° |
| 21 | 0.5° | 1.0° | 0.5° |
| 24 | 0.5° | 1.5° | 1.0° |
| 27 | 1.0° | 2.0° | 1.5° |
| 30 | 1.5° | 2.0° | 2.0° |
| 33 | 2.0° | 3.0° | 2.5° |
| 36 | 2.5° | 4.0° | 3.0° |
| 39 | 3.0° | 5.0° | 4.0° |
| 42 | 4.0° | 6.0° | 5.0° |
| 45 | 5.0° | 7.0° | 6.0° |
III. Other Related Instructions
The Meaning of the Ra Value: Ra represents the arithmetic mean deviation of the profile and is a commonly used indicator for measuring surface roughness. The larger its value, the rougher the surface.
Application Scope: The VDI 3400 standard has a very wide range of application scenarios, covering multiple fields such as automotive interior parts, electronic product casings, medical devices, and consumer product packaging.
Comparison with Other Standards:
The SPI standard mainly focuses on the smoothness of the surface and is quite popular in North America.
The Mold-Tech standard offers a rich variety of customized texture options, but the cost is relatively high.
The Yick Sang standard is more commonly used in the Asian market, yet its degree of standardization is relatively low.
IV. Key Points for Use
As there may be slight differences in data from different sources, it is advisable to refer to the latest version of the VDI 3400 standard document.
During the actual application process, parameters like the draft angle also need to be adjusted reasonably according to specific material properties and production processes.
If precise matching of the surface texture is needed, a professional VDI 3400 texture card can be used for comparison.
With these data, you can better understand and apply the VDI 3400 standard to meet the surface roughness requirements in various industrial production scenarios.
