Drafting Standards, GD&T & Tolerance Analysis

sheet metal drawings

sheet metal drawings

mfalk99

(Mechanical)

(OP)

19 Oct 11 14:48

I am looking for some ASME standards for sheet metal drawings.... any help??

Mike.

RE: sheet metal drawings

pmarc

(Mechanical)

19 Oct 11 16:21

Not that I am aware of any ASME standard specifically dedicated to sheet metal drawings, but what kind of information are you expecting to get from such document?

RE: sheet metal drawings

drawoh

(Mechanical)

19 Oct 11 17:39

   I do lots of sheet metal drawings.  I am not aware of standards for them, separate from any other kind of fabrication drawing.  

   Sheet metal shops can bend to tolerances of ±.015" or ±0.4mm.  Your tolerances to and from bends should reflect this.  

   I have never checked the accuracy of the punching or laser cutting or whatever.  I assume they are pretty good.

   I keep claiming here that any idiot can prepare drawings for machining.  Sheet metal, casting and weldming is more difficult because the fabrication process will not automatically do the tolerances required to make your part work.  You are going to have to think out your drawings and your design.  Your design will have to work with the sloppier tolerances imposed by the process.  

   Go back and read the GD&T standard and any manuals you may have.  This is where good GD&T becomes useful.   

mfalk99,I do lots of sheet metal drawings. I am not aware of standards for them, separate from any other kind of fabrication drawing.Sheet metal shops can bend to tolerances of ±.015" or ±0.4mm. Your tolerances to and from bends should reflect this.I have never checked the accuracy of the punching or laser cutting or whatever. I assume they are pretty good.I keep claiming here that any idiot can prepare drawings for machining. Sheet metal, casting and weldming is more difficult because the fabrication process will not automatically do the tolerances required to make your part work. You are going to have to think out your drawings and your design. Your design will have to work with the sloppier tolerances imposed by the process.Go back and read the GD&T standard and any manuals you may have. This is where good GD&T becomes useful.

               JHG

RE: sheet metal drawings

juergenwt

(Mechanical)

19 Oct 11 20:24
I know it is in German but if you look at the DIN/EN/ISO numbers listed you should be able to find it in English.
If not - you could have someone translate the important parts of the table.

mfalk99 - I believe you are looking for something like this: http://www.tmf.de/bilder/Toleranzen.pdf I know it is in German but if you look at the DIN/EN/ISO numbers listed you should be able to find it in English.If not - you could have someone translate the important parts of the table.

RE: sheet metal drawings

MechNorth

(Mechanical)

20 Oct 11 10:21

A Y14 standard for sheet metal has been proposed several times, but there hasn't been enough interest/participation for it to move forward. If there is a base of people ready to work on such a standard, ASME would be the right forum to get it going. There has been significant cross-pollenation, historically, between DIN/ISO/ASME, with each basing some aspects of their standards on the others (or pretty much copying them entirely).

Jim Sykes, P.Eng, GDTP-S
Profile Services  www.profileservices.ca
TecEase, Inc.  www.tec-ease.com

RE: sheet metal drawings

CheckerHater

(Mechanical)

21 Oct 11 06:47
To the best of my knowledge there isn't any.

ISO might have something in the works, and I also heard about French NF standard, but I've never seen it translated.

Genium manual has chapter on sheet metal, but it based on "accepted practices" rather than specialized standard.

Nevertheless all the dimensioning, tolerancing, and other general drafting standards still apply.

If you are looking for things like general tolerances / acceptable accuracy, there are people on this forum, who can help.

Also, there are few good recources online:

http://www.precisionsheetmetal.com/home/tolerances.htm
http://www.vista-industrial.com/services/manufacturing-engineering-sheet-metal-fabrication-tolerances.html
http://www.vista-industrial.com/docs/VIP_Default_Tolerances.pdf

To the best of my knowledge there isn't any.ISO might have something in the works, and I also heard about French NF standard, but I've never seen it translated.Genium manual has chapter on sheet metal, but it based on "accepted practices" rather than specialized standard.Nevertheless all the dimensioning, tolerancing, and other general drafting standards still apply.If you are looking for things like general tolerances / acceptable accuracy, there are people on this forum, who can help.Also, there are few good recources online:

RE: sheet metal drawings

fsincox

(Aerospace)

21 Oct 11 10:27

CH & juergenwt,
Thanks for the information.
Frank

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