Summary for charmille surface finish chart Discussion
Charmille surface finish chart questions center on how Charmilles EDM finish numbers compare with Ra, RMS, SPI, VDI, and molded textures like Ford stipple 002. Gale asked whether a conversion chart exists, and later Kal B and Vincent Giglio asked specifically about the VDI equivalent for Ford 002 stipple when using a Charmille sinker EDM. John Muldowney pointed readers to Charmilles technology sheets and gave example conversions from XS25A.TEC, including CH 29 = 112 Ra, CH 27 = 88 Ra, CH 25 = 72 Ra, CH 21 = 44.8 Ra, and CH 15 = 22.4 Ra. He also suggested contacting Charmilles directly. Another contributor noted that if the Ra values are in microinches, the Charmille number matches the VDI number. John McSwiggen then shared a downloadable EDM surface finish chart link for further reference.
Q. Is there a chart showing the difference between Charmilles surface finish and that of RMS or SPI or any other? Thanks! Hope to here from someone.
Gale T [last name deleted for privacy by Editor]
Omaha, Nebraska
Q. I would like to know the VDI equivalent for a (Ford) stipple 002 texture. We prefer to EDM our texture using a Charmilles sinker EDM. Can anyone help please?
Thanks,
Kal B [last name deleted for privacy by Editor]
– Reading, Massachusetts
2006
Q. Hello Kal,
Did you get an answer to the Ford 002 Stipple question? We have a customer asking for us to mold a part with this finish and we also have a Charmille sinker that I need a conversion to a Charmille finish for. If you have any info I would appreciate it. Thanks,
Vincent Giglio
– Toms River, New Jersey USA
October 8, 2012
Q. I am trying to get a surface finish comparison chart from a Charmille EDM finish to an Ra. If anyone can lead me in the right direction, I would appreciate the help.
Hank Walton
– Lafayette, Louisiana
A. How nice of Charmilles to have their own surface finish standard…
Look at their “technology sheets”; which list different material types, thickness of material, wire type, amperage, etc. If yours are the same as mine they have a translation of at least a few of their numbers. XS25A.TEC lists:
CH 29 = 112 Ra
CH 27 = 88 Ra
CH 25 = 72 Ra
CH 21 = 44.8 Ra
CH 15 = 22.4 Ra.
Or you may try contacting Charmilles…
John Muldowney
– Hamel, Minnesota
July 2, 2009
A. If the Ra value in the above list is in µin then the Charmille number is the same as the VDI number.
That’s good to know. Thanks for the info.
VDI | Ra(µm) | Rz(µm) | Ra(µin) | ISO 1302 | Rt (µm) |
0 | 0,10 | 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 | 0,20 | 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 | 0,40 | 1,5 | 16 | 1,6 | |
13 | 0,45 | 18 | |||
14 | 0,50 | 20 | |||
15 | 0,56 | 2,4 | 22.4 | 3,2 | |
16 | 0,63 | 25.2 | |||
17 | 0,70 | 28 | |||
18 | 0,80 | 3,3 | 32 | N6 | 5,0 |
19 | 0,90 | 36 | |||
20 | 1,00 | 40 | |||
21 | 1,12 | 4,7 | 44.8 | 7,5 | |
22 | 1,26 | 50.4 | |||
23 | 1,40 | 56 | |||
24 | 1,62 | 6,5 | 63 | 12,0 | |
25 | 1,8 | 72 | N7 | ||
26 | 2,0 | 80 | |||
27 | 2,24 | 10,5 | 88 | 16,0 | |
28 | 2,5 | 100 | |||
29 | 2,8 | 112 | |||
30 | 3,15 | 12,5 | 125 | N8 | 20,0 |
31 | 3,5 | 140 | |||
32 | 4,0 | 160 | |||
33 | 4,5 | 17,5 | 180 | 25,0 | |
34 | 5,0 | 200 | |||
35 | 5,6 | 224 | |||
36 | 6,3 | 24,0 | 250 | N9 | 37,0 |
37 | 7,0 | 280 | |||
38 | 8,0 | 320 | |||
39 | 9,0 | 34,0 | 360 | 46,0 | |
40 | 10,0 | 400 | |||
41 | 11,2 | 448 | |||
42 | 12,6 | 48,0 | 500 | N10 | 60,0 |
43 | 14,0 | 560 | |||
44 | 16,0 | 640 | |||
45 | 18,0 | 69,0 | 760 | 85,0 |
John McSwiggen
– Ramsey, Minnesota
A. You can download an EDM surface finish chart at:
highperformancemachinery.com/yahoo_site_admin/assets/docs/Surface_Finish_Charts.270113339.pdf
John griffiths
– Orange, Massachusetts
October 22, 2009