×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Drawing standard - dimensions include paint or not

Drawing standard - dimensions include paint or not

Drawing standard - dimensions include paint or not

(OP)
I have a query - do engineering drawings include the paint thickness within the dimensions and tolerancing of a drawing?

IE if a drawing specified a dimension as 20mm +/- 0.002 but also called for a paint process should you make the part small to build in an allowance for the paint?

 

RE: Drawing standard - dimensions include paint or not

ASME Y14.5M-1994 2.4.1 addresses this "Where a part is to be plated or coated, the drawing or referenced document shall specify whether the dimensions are before or after plating."

So to American standards the drawing has to explicitly state whether the dimension applies before or after painting.  If the drawing doesn't say then it's ambiguous and arguably parts can't be rejected either way.

I'm not sure with ISO does though.

Posting guidelines FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

RE: Drawing standard - dimensions include paint or not

I'm thinking in machines and machines are assembled first and then painted. So I guess all dimensions in manufacturing drawings are without paint thickness (= paint thickness is added to drawing dimensions). I'm from Europe and I have never seen a manufacturing drawing with information about paint thickness. I saw drawing for parts which are coated after machining but that's something different.

If paint thickness was a critical value I would always add the information on the drawing. I learned that it is better to give information when important, regardless what the standard says. Who's benefit is it, if parts do not fit but the drawing complies to the standard?

RE: Drawing standard - dimensions include paint or not

You can not have a painted surface and a tolerance of +/-0.002. That tolerance 20 +/- 0.002 has to be on an unpainted surface. Period.
Next question: " Why would anybody specify +/- 0.002 on a painted surface"? Smells like the drawing was made by someone not having the slightest idea of 0.002 mm.

RE: Drawing standard - dimensions include paint or not

(OP)
Sorry the 20 +/- .002 was purely an example.  The actual case is a much larger frame, with a very thick paint process, that can cause the parts to run oot.  The problems it's causing now mean lots of rework and re-engineering a number of parts.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close