GT & T in Solidworks models

[hoju6886]

I just received and e-mail stating that our drafting department is lobbying to get rid of the GD&T in the model files and leave it on the drawings only. Since I'm just starting to program offline, using models, how is this going to effect me, or is this going to effect me at all? Right now I don't think it means much to me at all, but as my skills develop, I'd hate to have this be something that I really wished I had fought to keep.

Any thoughts out there? (about this GD&T thing, not about you wishing you hadn't eaten that extra peice of pie or whatever.)

[Roger Kilpatrick]

I dont use any GD&T on CAD, it's usually not correct anyway. At least you can red line corrections on a drawing and take it to Engineering for an update.

[Wes Cisco]

I just received and e-mail stating that our drafting department is lobbying to get rid of the GD&T in the model files and leave it on the drawings only. Since I'm just starting to program offline, using models, how is this going to effect me, or is this going to effect me at all? Right now I don't think it means much to me at all, but as my skills develop, I'd hate to have this be something that I really wished I had fought to keep.

Any thoughts out there? (about this GD&T thing, not about you wishing you hadn't eaten that extra peice of pie or whatever.)

Well Tater, I think it just means more work and chance for error. If they go ahead with this it will be up to you make sure you find all of the proper GD&T callouts on the drawing and dimension them accordingly in your report. It terms of basic off-line programming of features it should not make any difference. If the GD&T is on the model, engineering must spend that much more time and attention on the project, which I would think means they are more likely to catch and correct mistakes before they get to you. Along with with new "plan" do they include a protocol for you to resolve conflicts between the CAD model and the print? Is one or the other specified as master? Why do they want to do this? I would be very afraid they are just trying to give you their headaches and will not give you the support you need to fix any problems you are almost certain to encounter. HTH

P.S. The goodnews is that your standup routine is a great success. Just don't start spewing hate, and you should be all set.

[Jan d.]

I don't think it makes any difference for you.

In the grand scheme of things, it is my personal opinion that your engineering department is making a mistake. There is no doubt that eventually the world will go "print-less" (meaning no more 2D representations of 3D parts). NOTE: I did NOT say paperless!!!!! And then the only way for you to implement requirements is to get them directly from the 3D model. Right now, the 2D print is what communicates the requirements. But like I said, it will disappear. Some time.

There are some serious developments in the STEP world that are trying to cut out the whole program generation step by working with info defined on the model (see http://www.steptools.com/ ). But having said that, the progress in that field is slow at best. But it is creeping forward. I think we are still decades away from this brave new "print-less" world. So I can understand that your engineering department doesn't feel it needs to keep spending money on things that are not available today.

But as long as they still give you a 2D print, you do not need any GD&T on the 3D model.



Jan.

[JamesMannes]

The only benefit of having the GD&T callouts on your CAD model at this time is if you have the IP module (Inspection Planner) for PC-DMIS. It allows the engineering group to "program" the specific callouts that they have made in their CAD package. This does not include moves, tip changes or any comments. Don't know if it adds reporting into the equation, but I can't see this becoming a viable product in the near future if at all.

[hoju6886]

These are all excellent points of view. I think planning for the future is a good thing. Most often we are far too shortsighted on these types of things and if a little more work on Drafting's part today will mean a lot less headaches in the future, then that makes a lot of sense to me. An ounce of prevention is worth a pound of hash, or something like that.

I also agree that making them put the GD&T into the model will make them look at it closer and most likely find problems that would not have been found otherwise.

Unfortunately, not THAT Ron White

[bw_bob]

These are all excellent points of view. I think planning for the future is a good thing. Most often we are far too shortsighted on these types of things and if a little more work on Drafting's part today will mean a lot less headaches in the future, then that makes a lot of sense to me. An ounce of prevention is worth a pound of hash, or something like that.

I also agree that making them put the GD&T into the model will make them look at it closer and most likely find problems that would not have been found otherwise.

Unfortunately, not THAT Ron White

I'll bring the pipe.....

[hoju6886]

Well, first we have to find an ounce of prevention........

[craiger_ny]

Did someone say "pound of hash"? An ounce of prevention is worth the same as a pound of hash? So if I am reading this right an eight ball of prevention is worth two ounces of hash correct? I gave up on prevention a long time ago but if you would be interested in unloading some of that hash I'll take whatever you are willing to part with.

In regards to the GD&T like the others said it is a long ways away. My guess is the transition will involve model and print GD&T overlapping for quite some time. Even when the "printless" era is conventionally accepted (and reliable) it will only be for conveying design engineering requirements. Process requirements will still need to be communicated to the those on the floor and will continue to be in a 2D format (my opinion) so if you need to communicate to the shop floor guys as well as the designers you will have to do it in a language that coincides with both types of communication. In other words 2D drawings will be here a long time even after design goes 3D exclusively. In my experience it is the quality guy that in many instances catches model/drawing mistakes so it will actually bennefit you and your organization to be able to speak both languages (3D and 2D). Don't worry about not being the first to be exclusively 3D, that would be kind of like being the first to be exclusively 4.0 let them iron the bugs out while you ease yourself into it.

The hash on the other hand we should dive right into.

Craig

[John Kingston]

I just received and e-mail stating that our drafting department is lobbying to get rid of the GD&T in the model files and leave it on the drawings only. Since I'm just starting to program offline, using models, how is this going to effect me, or is this going to effect me at all? Right now I don't think it means much to me at all, but as my skills develop, I'd hate to have this be something that I really wished I had fought to keep.

Any thoughts out there? (about this GD&T thing, not about you wishing you hadn't eaten that extra peice of pie or whatever.)

It looks like your Engineering department is taking a step backwards. As Jan points out, someday in the future, there won't be a 2d paper print. If they've left the GD&T off the 3d model, where is the GD&T once the paper print is obseleted.

engineering department is making a mistake.
Jan.

Jan,
Isn't that statement redundant?!

[kbotta]

There is already a standard in place for this. ASME Y14.41, Digital Product Definition Data Practices.
This is also where some of the confusion over the "circle U" for profile erupted from, as it was apparently released in Y14.41, but not in Y14.5 (yet, I have been told by many...)

....from ASME....
With Y14.41, the documented 3-D models can be used instead of, or in addition to, conventional 2-D drawings.

The areas of industry that are expected to gain the greatest benefit from the Y14.41 standard include tolerance analysis, inspection machine programming, machine tool programming, preparation of installation manuals and cost estimation.

.....

It's already out there.
Kev

[Andrew Gardner]

I've worked with RDD (reduced dim drawings) before, where as the model had all of the GD&T notations on it. The paperwork that went with this was just basically telling you what the flag notes meant, and the other tolerances. It was alright, but I prefer having a print that I can look at - the whole thing at once.

The RDD drawings usually caused us more work due to the fact that we had to create check sheets for the machine operators. With no prints to put out on the floor, the operators could basically follow the set-ups sheet and walk away without checking one dimension. What's faster for the engineer, is not always the best for the whole process.

[cmmguy]

.... our drafting department is lobbying to get.....

Oh great, just what we need, another lobbying group trying to get something for less work....