7 Replies Latest reply on Mar 18, 2016 4:28 PM by Reed Anderson

    Drawing Standards Question

    Reed Anderson

         I am new to Solidworks and CAD in general.  I started using Solidworks about 18 months ago and I am decent at parts modeling and using assemblies.  The requirements for my job are of a very basic level as all the parts I create are machined for internal use and are usually quite simple.  I passed the CSWA recently and am working towards the P in the future but my current skill set is more than sufficient for my employers needs, I want to advance myself for personal reasons.  One area I know needs to be improved, both for personal and professional reasons is drawings.  My company is small and has no CAD department and no internal drawing standards.  My drawings were nightmares when I started out but with time and research I have vastly improved from where I started.  I know basic ANSI standards and good practice but with no formal classes or education I am sure the drawings I create would greatly benefit from an experienced opinion.  That being said, I was familiar with GD&T but have never employed GD&T standards (nor has anyone at my company) as I have no clue how to and the precision we need has never been a problem.  I am aware of situations where GD&T can prevent 'accumulating' tolerance (not sure what the proper vocabulary is there) but with the simplicity of our parts and use of ordinate dimensions, this has not yet been an issue. 

         The issue I am having is an individual at our company saw a drawing I created with no datum reference symbols.  She says that without these the drawing is not usable and is surprised our vendors would even accept the drawing.  It rubbed me the wrong way as this statement was made in a very public way.  Our vendors often re model the drawings we send and send back their own drawings which we then sign off on and they create the part we need.  None of the drawings that have ever come back from a vendor have had datum reference symbols and the only issue they ever had was due to some egregious mistakes I made in the beginning.  2 questions :

       

          1.  Is GD&T and the use of datum reference symbols a requirement? 

          2.  I would like to seek out more formal education drawing standards, are there companies that have these types of classes or should I look at local universities?

       

        Thank you very much.

        • Re: Drawing Standards Question
          Glenn Schroeder

          Hello Reed,

           

          Your situation is very similar to mine a few years ago.  Where I work I'm pretty much a one- man show.  We also didn't really have any formal drafting standards until I established some, and they're constantly evolving (although the rate is much slower than it used to be).  And I know next to nothing about GD&T, or datum reference points.  It's my belief that the purpose of a drawing is to convey the information needed to accurately fabricate or manufacture the product.  As long as that's covered I don't worry too much about it.  I realize that many industries require more formal, widely recognized standards, but I've never had any issues with the drawings I send to vendors or clients either (although I cringe when I look back at some of the ones I did when I was starting out).

           

          And it sounds like your co-worker needs some classes on dealing with people.  If she disagrees with how you're doing something she should have discussed it with you in private. Unless of course she sees you as a threat, or is just generally insecure and feels a need to put others down in public to make herself feel better.

            • Re: Drawing Standards Question
              Reed Anderson

              Thanks Glenn.  We are basically a 2 man show.  I have learned a lot from the original SW user at our company as he has many years of experience.  He also had no formal education on drawing standards but his drawings today are clean, concise and easy to read.  A lot of the parts I model are variations of ones he created before and I often update his original part and original drawing if it is appropriate and I like the drawing.  That and looking at vendors drawings and other online drawings has been very helpful.  I appreciate your feedback.

                   I will continue to search out more formal education in drawing standards in case I end up in a job someday where that is required. 

               

                 The co-worker is another story.  She's middle management, I'm further down the ladder.  It is frustrating when someone higher on the food chain makes decisions on issues they truly do not understand because I am not in a position to call them out on that.  I just need to defend my actions to the best of my ability.  Thanks.

            • Re: Drawing Standards Question
              Mark Kaiser

              I second a lot of Glenn's and your opinion Reed.

               

              When I started at my current employer... over 15 years ago... our drawings did not even have tolerances on dimensions that should have.  I came in with some knowledge, but it really evolved from what the company wanted, and having the drawing be the bible to create the product by, and the drawing be able to be understood by the employees who manufacture the product.  Well, most of them anyhow.

               

              1.  We do not use any GD&T or datum symbols.  We even spell out dia. instead of the symbol.  Even on vendor drawings.  Everyone understands the drawings we put out.

               

              2.  You could probably find GD&T and ANSI books and get as much out of it as any class.  Apply to your work as needed.

               

              Ignore the middle management as much as you can.

                • Re: Drawing Standards Question
                  Jim Steinmeyer

                  Reed,

                  I would ask this individual how many people on the floor she expects to be able to read the GD&T symbols. In some industries GD&T is very important. I would guess your co-worker has recently come from one of these industries. Of the 6 companies I have worked at I don't know of more than 2 co-workers that had any idea what they meant. We have never used them an any of the companies.

                  Should you start placing them on the drawings and the shop employees have no idea what they mean they will view them as extra fluff and just ignore them. This would start a bad example as they could expand the items ignored and then miss vital information. Of course I have been places where the entire print is ignored but that is a whole different problem.

                  If this individual is adamant that GD&T is used she needs to sponsor a class to train both the designers and the shop personnel as to what symbols are to be used and what their meanings are so that everyone will be on the same page.

                • Re: Drawing Standards Question
                  Greg Rupp

                  Hi Reed,

                   

                  1) Absolutely not. We make thousands of prints a year with little to no GD&T callouts.  GD&T is not required but it certainly solves a number of problems inherent with standard plus and minus tolerancing.

                   

                  2) There are a lot of technical colleges around the United States that will formally train on this. I have a BS in Mechanical engineering from a university and to be honest, they glanced over the importance of how to create a good drawing. There are a number of components that make up a good CAD drawing, like creating templates & title blocks, proper views, revision control, dimension placement, and of course tolerancing.

                   

                  If you are looking for more information on methods of tolerancing I would highly recommend ADVDM. We hired ADVDM to help train our quality, manufacturing and engineering groups on tolerance stackups and to review the statistical significance of a tolerance. Personally, I thought they did an excellent job.

                   

                  If you are looking more for best practices on how to make a drawing, then google will be able to help you out. Just search for "dimensioning ppt". If you really want to get crazy you can read NASA's standard here.

                   

                  Lastly, if she really said " ... that without these the drawing is not usable and is surprised our vendors would even accept the drawing." you can take pride in knowing that whoever "she" is doesn't know what she is talking about.

                   

                  Regards,

                  Greg

                  • Re: Drawing Standards Question
                    Jim Sculley

                    Reed Anderson wrote:

                     

                     

                    1. Is GD&T and the use of datum reference symbols a requirement?

                    Absolutely not.

                     

                    2. I would like to seek out more formal education drawing standards, are there companies that have these types of classes or should I look at local universities?

                     

                    Thank you very much.

                    For a few hundred dollars US, you (or better yet your company) can buy a few relevant ANSI/ASME standards that cover most of what you would need:

                    ASME Y14.1 -- Decimal Inch Drawing Sheet Size and Format

                    ASME 14.100 -- Engineering Drawing Practices

                    ASME Y14.5 -- Dimensioning and Tolerancing

                     

                    14.5 is mostly GD & T but the first chapter covers plain vanilla dimensioning.

                      • Re: Drawing Standards Question
                        Reed Anderson

                        Thanks everyone for the input.  I am greatly relieved to know that I was ignorant to a 'required' standard.  Do to the nature of our parts and their use, the precision gained by GD&T would not be beneficial to our company.  That being said, setting an internal standard would.  I will do some research in regards to the resources mentioned above. Thanks again for the feedback everyone.