German Prints - No GD&T ?

[umatrix]

I've noticed that 2D prints from Germany (one that I have seen) do not have GD&T , is this common ?


The print calls out this ISO 1101 spec, which is GD&T. Just not sure why symbols not shown on drawing.

ISO 1101
Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of form, orientation, location and run-out

 

[greenimi]

What other standards that german print(s) calls out? Could you, please advise?
ISO2768, maybe?

 

[TheTick]

EVERY German drawing? I've been to Germany. It is a big place. Many people. Many companies, some of which are undoubtedly creating engineering drawings.

 

[Wuzhee]

There are tons of companies that don't utilize GD&T and stick to the old fashioned ± tolerancing.
Even if the company directive refers to an international standard (ISO, ASME etc.) the people who make the parts and drawings usually doesn't have the knowledge or the willingness to learn GD&T.

Knorr Bremse for example still orders parts from suppliers based on digitized handmade drawings from the late 40s and 50s. Those parts go unchanged since so why should they bother with it at all?

 

[greenimi]

Wuzhee,

Knorr Bremse for example still orders parts from suppliers based on digitized handmade drawings from the late 40s and 50s. Those parts go unchanged since so why should they bother with it at all?

Are you working for them? If yes, maybe you can change their habit, procedures, culture

 

[Wuzhee]

No, I don't, my friend's company is a contractor to Knorr and they receive these drawings every now and then. These are very simple basic parts like steel disks, sleeves, cups, etc. Very basic geometry. Even the company he's working for uses old drawings from prehistoric ages of the standard.

 

[ctopher]

Over the past 20 years I have seen a decline in the use of GD&T. Mainly because most people getting into engineering do not have training in GD&T, or general drafting practices. Engineers/Designers are thrown into CAD design without proper training. I see it all the time.
I also argue with others all the time, they think GD&T will raise the cost of parts.
We just had GD&T training here the past two weeks. I hope they use it.

Chris, CSWP
SolidWorks
ctophers home

 

[3DDave]

Until software as I proposed here becomes cheap (free) and widely available, the struggle will continue.

 

[Wuzhee]

Our company enrolled new employees for GD&T training few years ago. Now they say they have to cut costs and proper training is less important than actually good and functional products it seems ?!

I just got a request from my colleagues to basically teach them on GD&T because I'm the one here who's constantly scrolling through the standard whenever a question arises. But I'm not sure about a ton of things either. CEOs and execs just makes excuses like pandemic, rising lithium prices, competition etc.

 

[CheckerHater]

Over the past 20 years I have seen a decline in the use of GD&T.

Over the past 20 years some technologies become widely available: 3D CAD, CNC, CMM.

Producing parts that fit each other well is becoming trivial.

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[looslib]

Over the past 20 years some technologies become widely available: 3D CAD, CNC, CMM.

Only 20 years? I first used CAD in 1977, 3D wireframe. It has come a long way to the solid modeling we do today.
CNC programming has been around since the late 1970's, maybe not as nice as the conversational controllers of today, but still more than 20 years. NC programming goes back another 20 years to the mid-1950's.
CMM was in use in the mid-1970's, too, we had some Bendix Cordax machines where I worked in 1978.

"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli

 

[ctopher]

I was using 2D/3D CAD, 3D printing, CNC/PLC programming back in 1985.
GD&T was barely used, not until 90's we starting doing more of it.
Because of advanced machining, engineers/designers have become more on relying CNC/CMM to do the detail work, checking against 3D models.
GD&T is still needed to control how the parts are made/dimensioned.
I wish I could share here some drawing I come across daily. Such cr*p. I don't know how the part are made. No 3D models, most in 2D ACAD.

Chris, CSWP
SolidWorks
ctophers home

 

[Burunduk]

Often I look at drawings that use geometric characteristic and datum feature symbols and think they would better off not using any of it at all. Geometric tolerances applied in a way that doesn't make sense is much worse than "no GD&T".

The problem is that most people that don't know what they are doing probably been at some time in a study class where the symbols were shown, and they see them in other people's drawings that are often just as bad, so they think it is something that is supposed to be on the drawing, and they are expected to use it. This means that bad "GD&T" is not going away, and the only way to fight it is proper training.

 

[3DDave]

"proper training" won't work. There has to be accurate feedback from an automated source, preferably one written and distributed for free by the relevant agency as the sole source of "truth."

The reason "proper training" won't work is that GD&T (sic) is a programming language and people suck at programming unless there is a compiler to examine the validity and a computer to run the code. The compiler and computer have no opinions to manipulate. No one does "code reviews" line by line anymore independent of compilation and running the code. But that is still tolerated in GD&T (sic.) Even then the better programmers run extensive tests on varied inputs to ensure the outputs are what is expected.

In software, a programmer might write 10-50,000 lines of code a year**. A drafter/detailer might put down 50-1000 FCFs a year. Which one is likely to truly understand the subject when the drafter/detailer never sees all the possible variations his code might produce? Feedback is how one gets experience. Sitting in training doesn't produce experience.

That's why I want Y14.5 to be a picturebook, so that no one has to think about the outcome to typical cases at all. And ASME to provide a software tool to generate variations that are acceptable per the GD&T (sic) so that users have immediate feedback and can push those variations to tolerance analysis software and to FEA software.

**Most are rewrites when the software doesn't work as expected. Many more are deleted when a better solution comes up. Still, the programmer has considered each line and what it will do and they still need the compiler to verify their understanding is correct.