Bayer Plastics has some good Information about surfaces and injection molding available on their web- Site. According to a (German) Document the VDI 3400 texture surfaces correspond to the following Ra / Rz Values and require the following drafting angles:
VDI 3400 defines surface texture standards for mold-making. It categorizes roughness classes using Ra values. German engineers played a crucial role in developing the VDI 3400 standard, ensuring consistent texture quality and improving product performance.
VDI3400RaRzDA-PADA-PCDA-ABS120.40 1.50 0.5 1.0 0.5 150.56 2.40 0.5 1.0 0.5 180.80 3.30 0.5 1.0 0.5 211.12 4.70 0.5 1.0 0.5 241.60 6.50 0.5 1.5 1.0 272.24 10.50 1.0 2.0 1.5 303.15 12.50 1.5 2.0 2.0 334.50 17.50 2.0 3.0 2.5 366.30 24.00 2.5 4.0 3.0 399.00 34.00 3.0 5.0 4.0 4212.50 48.00 4.0 6.0 5.0 4518.00 69.00 5.0 7.0 6.0
DA-PA = Drafting Angle for Polyamide DA-PC = Drafting Angle for Polycarbonate DA-ABS = Drafting Angle for Acrilnitrile-Butadiene-Styrol glass reinforced materials require more drafting.
VDI 3400 TableIn the following, you can determine the roughness for your application according to VDI 3400 table. Surface roughness is a critical factor in the VDI 3400 standard, influencing the performance of various components.
VDI3400 0-45µm µinchN3-N10ISO1302 Rt µm00.10 4N3 10.11 4.4 20.12 4.8 30.14 5.6 40.16 6.4 50.18 7.2N4 60.20 8 70.22 8.8 80.25 10 90.28 11.2 100.32 12.8 110.35 14N5 120.40 16 1.6130.45 18 140.50 20 150.56 22.4 3.2160.63 25.2 170.70 28 180.80 32N65190.90 36 201.00 40 211.12 44.8 221.26 50.4 231.40 56 241.62 63 12251.80 72N7 262.00 80 272.20 88 16282.50 100 292.80 112 303.20 125N820313.50 140 324.00 160 334.50 180 25345.00 200 355.60 224 366.30 250N937377.00 280 388.00 320 399.00 360 464010.00 400 4111.20 448 4212.60 500N10604314.00 560 4416.00 640 4518.00 760 85