VDI 3400 标准，Bayer Plastics has some good Information about surfaces and injection molding available on their web- Site.在拜耳塑胶的网站上有一些关于表面处理以及注塑成型的好资料According to a (German) Document the VDI surfaces correspond to the following Ra / Rz Values and require the following drafting angles:依据一份（德国）文档，VDI 参数对应的 Ra，Rz 及拔模角度如下VDI; Ra; Rz; DA-PA; DA-PC; DA-ABS12; 0,40; 1,5; 0; 1,0; 0,515; 0,56; 2,4; 0,5; 1,0; 0,518; 0,80; 3,3; 0,5; 1,0; 0,521; 1,12; 4,7; 0,5; 1,0; 0,524; 1,60; 6,5; 0,5; 1,5; 1,027; 2,24; 10,5; 1,0; 2,0; 1,530; 3,15; 12,5; 1,5; 2,0; 2,033; 4,50; 17,5; 2,0; 3,0; 2,536; 6,30; 24,0; 2,5; 4,0; 3,039; 9,00; 34,0; 3,0; 5,0; 4,042; 12,50; 48,0; 4,0; 6,0; 5,045; 18,00; 69,0; 5,0; 7,0DA-PA = Drafting Angle for Polyamide（PA 拔模角度）DA-PC = Drafting Angle for Polycarbonate（PC 拔模角度）DA-ABS = Drafting Angle for Acrilnitrile-Butadiene-Styrol（ABS 拔模角度）glass reinforced materials require more drafting（玻纤？）强化材料需要更大的拔模角Lorenz Wiedemar- Langendorf, Switzerland+VDI 换算方式如下：VDI = 20log(10Ra)James Lai- JB, Malaysia+Conversion scales from VDI.RA.UM.RMS.I have a VDI Scale. Does anyone have such a conversion scale.Is the um a separate scale from the RA scale or is it part of it? If not how is the um expressed.PinocciJoe Pinocciequipment supplier - Warwick, RI+VDI Table（完整的 VDI 表）In the following, you can determine the roughness for your application according to VDI table.根据下表，你可以得到你的产品的表面粗糙度VDI3400 Ra = AA = CLA ISO1302 Rt0-45 m inch N3-N10 m- - - - -0 | 0.1 | 4 | N3 |1 | 0.11 | 4.4 | |2 | 0.12 | 4.8 | |3 | 0.14 | 5.6 | |4 | 0.16 | 6.4 | |5 | 0.18 | 7.2 | N4 |6 | 0.2 | 8 | |7 | 0.22 | 8.8 | | 8 | 0.25 | 10 | |9 | 0.28 | 11.2 | | 10 | 0.32 | 12.8 | | 11 | 0.35 | 14 | N5 |12 | 0.4 | 16 | | 1.613 | 0.45 | 18 | |14 | 0.5 | 20 | |15 | 0.56 | 22.4 | | 3.216 | 0.63 | 25.2 | | 17 | 0.7 | 28 | |18 | 0.8 | 32 | N6 | 519 | 0.9 | 36 | |20 | 1 | 40 | |21 | 1.12 | 44.8 | | 7.522 | 1.26 | 50.4 | | 23 | 1.4 | 56 | |24 | 1.62 | 63 | | 1225 | 1.8 | 72 | N7 |26 | 2 | 80 | |27 | 2.2 | 88 | | 1628 | 2.5 | 100 | |29 | 2.8 | 112 | |30 | 3.2 | 125 | N8 | 2031 | 3.5 | 140 | |32 | 4 | 160 | |33 | 4.5 | 180 | | 2534 | 5 | 200 | |35 | 5.6 | 224 | |36 | 6.3 | 250 | N9 | 3737 | 7 | 280 | |38 | 8 | 320 | |39 | 9 | 360 | | 4640 | 10 | 100 | |41 | 11.2 | 448 | |42 | 12.6 | 500 | N10 | 6043 | 14 | 560 | |44 | 16 | 640 | |45 | 18 | 760 | | 85Qijin Wu- Nanjing Jiansu Province, P.R.ChinaApril 4, 2011Nr is the number of roughness or the class, using VDI dNr=20*log(10*Ra)Try with the equivalence table.AitorAitor Ruiz- Basq Country (north of Spain)-MORE DETAILS ,PLS REFER TO BELOW LINK http:/www.finishing.com/307/63.shtml