Not using GD&T? 10

[ctopher]

My last company, and current, have argued with me about using GD&T.
Engineers, purchasing, and managers have argued that it makes the parts more $$.
I tell them no it doesn't.
Last company had parts machined in China, current in Thailand and in USA.
China and Thailand have said not to use it because they don't understand it.
Often I see parts made that don't meet print with GD&T, but are bought off anyway.
I'm at wits end, tired of arguing with everyone.
I also find more people here in USA that don't understand it.
Anyone here run into this? If so, what do you do?

Chris, CSWP
SolidWorks '20
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[Burunduk]

Congratulations. This is exactly why some companies refuse to read a complicated standard that has generalized instructions that may or may not explain what is meant by symbols on a drawing. It's even more text in the standard to read through to find the portion that applies and it won't be specific so they also have to learn all the secondary theory that might be summed up with the procedure the inspectors typically write up anyway.

It's one thing to learn the standard once as part of the basic training of a newbie and then only having to look things up quickly by finding a related figure that visualizes the concept, and can point to the full definition if one needs it, all this while dealing with concise definitions on drawings that are made to the standard. Another thing is skipping that and having to deal with either a wall of text (not likely) or a poorly defined product geometry in every drawing.

 

[3DDave]

Since newbie is in a company that doesn't use it, after a while newbie forgets it. And since newbie never uses it and was only given a Powerpoint introduction and no copy of the standard, newbie has no way to look anything up.

Give newbie a step-by-step and he can follow instructions or the instructions can be reviewed one at a time, just like any other procedure for any other thing in the world.

Maybe your guys cannot read? Dunno.

 

[Burunduk]

3DDave,
I have encountered some lazy people, but I have yet to encounter a design engineer so unwilling to learn that he would prefer writing instruction lists instead of using a concise symbolic language. The same goes for the drawing users receiving them. Newbies or seniors.

 

[3DDave]

it must be nice to be in your world.

The instructions are for the shop-floor workers.

 

[CWB1]

And since newbie never uses it and was only given a Powerpoint introduction and no copy of the standard, newbie has no way to look anything up.

Sounds like someone that didnt attend either engineering nor trade school. Why would anyone allow such a person to interpret a print? Moreover, why would customers trust a shop that has such a person in that position? Hint: Most don't, they just take their business elsewhere.

This topic reminds me of companies that provide minimal info or really bad prints/models of their COTS parts to potential customers, they usually dont realize until the auction sale how their foot was shot.

 

[3DDave]

Funny - because 3rd party training is a huge market in the USA for 'Y14.5. Lots of people on the committee make their living not teaching at engineering or trade schools.

I wonder - wherever do they find students if everyone gets 200 hours of 'Y14.5 instruction in trade school or college?

 

[Burunduk]

The instructions are for the shop-floor workers

If from some reason the shop-floor workers can't read drawings they may need the instruction lists regardless of whether the drawing is per Y14.5 or an ambiguous one. There is the drawing and there are the instructions. The drawing can make the instructions redundant if the shop people are taught print reading and tolerance interpretation, but the instructions can't make a proper drawing redundant. The instructions better be written based on an unambiguous drawing, which means Y14.5.

 

[3DDave]

Y14.5 is all notes. Therefore it is ambiguous, as all written items are. If one doesn't have the standard then the drawing is incomplete. Which is why it costs more from some places.

Why do you say ambiguous when you mean "I didn't spend time learning to parrot anything else?"

 

[3DDave]

In the other thread

And my company standard requires ASME Y14.5-2018 but we can't look into the standard to which we have to comply. And they are against gd&t training because of cost-cutting reasons. Very sad.

I have yet to encounter a design engineer so unwilling to learn

NOW YOU HAVE. Another entire company of them.

 

[Burunduk]

Y14.5 is all notes. Therefore it is ambiguous, as all written items are. If one doesn't have the standard then the drawing is incomplete. Which is why it costs more from some places.

"All notes" doesn't mean ambiguous. It could mean well documented if the notes are written properly, but a product drawing or data set which is all notes is impractical. That is why there is a symbolic language available to be used. The "notes" in the standard define and explain that language.

NOW YOU HAVE. Another entire company of them.

The OP of that thread indicated that he is willing to learn and implement standardized tolerancing, so this is already one employee out of his company that cares about what he is doing. I'm sure there are others like him there. The management there, on the other hand, seems to think that acquiring and implementing tolerancing knowledge is a waste of money, an approach you seem to continuously provide support for in this thread by different dubious arguments.

 

[3DDave]

Oh, now you have moved to "impractical." I didn't say "all notes" and I have no idea what you mean by that. You need to explain your ambiguous statement.

You assured me that "I have yet to encounter a design engineer so unwilling to learn that he would prefer writing instruction lists instead of using a concise symbolic language." Maybe the rest are avoiding you.

Their suppliers are telling them they will charge more for the product. Why would you support a more expensive item if it works? Are you under the impression that additional constraints on the supplier will reduce the costs, that more requirements is cheaper?

Again, you must live in a magical world if that's how it works.

I suggest you join a training company that can extol the benefits without a single example to support it. I think there can be but, unlike you, realize that just because you own a hammer that not every single problem is a nail.

 

[Burunduk]

I didn't "move" to anything. I've been consistent in what I've been saying throughout. In my post from 29 Aug 22 17:37 I mentioned that a drawing would have to be overloaded with notes in order not to use GD&T (tolerancing practices per Y14.5 or other product definition standards) and yet remain unambiguous. I mentioned a few times that it is not likely to encounter such a drawing in the industry - obviously because it is impractical. What are the odds that notes that replace datum feature symbols and feature control frames would be specified by everyone in a clear, not to mention uniform, manner?

You assured me that "I have yet to encounter a design engineer so unwilling to learn that he would prefer writing instruction lists instead of using a concise symbolic language." Maybe the rest are avoiding you.

I can't make any sense of what you try to say here. Yes, as I said engineers prefer to use agreed upon symbols than lengthy literal descriptions for stating requirements. And drawing users too, unless they have no idea how to read a print, in which case they are in the wrong job. You only reinforce my point by bringing up an example of someone who stated he would rather study the standard and have access to it at work, despite a stupid policy of his company trying to economize on tolerancing training and copies of the standard they reference.

How did you conclude that his company deals with suppliers that charge more for a part defined per Y14.5? He said "And they are against gd&t training because of cost-cutting reasons. Very sad".
Nothing about vendors bids.
You seem to support their policy of "We don't need to get a hammer because we don't even know what nails are for".

If you think that this kind of cost-cutting is understandable, as you indicate in some of your posts, why cut costs only on tolerancing courses? Why not avoid training in other areas of the profession, such as maybe an in-house training on material properties? A vendor will charge more for a product with a unique metallurgical treatment specification than for something that can be machined from as-fabricated stock...

 

[3DDave]

You aren't consistent. How would a drawing be "overloaded" when the same text is in a standard? But then you say it's "impractical," which isn't "overloaded." And you imply that the notes would be "ambiguous". So that's three different complaints about doing the same thing as 'Y14.5 does. The description doesn't have to be any more uniform than that all parts have to be identical.

Is it convenient for large, integrated organizations? Sure. Is symbolic shortcutting required to accomplish that task? Not at all.

I support whatever they want to do to maximize their profits rather than doing unnecessary work that, for them, has no benefit.

You have now encountered two companies with many engineers who have not been willing to learn. Whatever else you have said is just as baseless.

Material properties? Stay on topic.

 

[ctopher]

From my experience, people have become lazier. Add a bunch of notes on a dwg, they don't read them. It's like sending someone an email, they only read the first sentence.
More people have shorter attention span.
I think all engineers/designers/drafters/managers should have some experience in the machine shop.
Then have GD&T and drawing training. It only needs to be 1-2 weeks, just some basics/common sense stuff.

My son is an engineering professor (not naming college). He teaches his students some GD&T. Some don't get it, but at least they leave some knowledge of what it is.

Chris, CSWP
SolidWorks '20
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[Burunduk]

3DDave,
The standard is not overloaded because it serves a different purpose than a drawing. The standard defines the meaning of symbology, and the drawing uses that symbology to define geometric limits for a part.
Perhaps some paragraphs in the standard could be shorter, but that's beside the point. You need words and sentences to describe rules and define the meaning of symbols. Symbols take much less time to write and read than instruction lists and have universal meaning.

In the long run, it is less expensive and risky to train people to understand and communicate requirements in a uniform language than not doing it and relying on notes. These notes won't happen. Do you actually believe that people who never learned what a datum is, and what a tolerance zone is as they were never trained or did any voluntary self-studying, are capable of writing sensible notes for specifying geometrical requirements? You think notes written by these people can capture functional considerations as well as provide the allowance that manufacturing needs? Heck, I would trade my "magical world" by yours any time. A designer who only understands "distance X mm" +/- "Y mm" and "angle Alpha degrees" +/- "Beta degrees" won't even try to specify any notes. And If the company does invest in training for those whose job is to make the drawings to avoid garbage specifications, It may as well invest in educating those that read those drawings, and let the two groups communicate concisely.

You have now encountered two companies with many engineers who have not been willing to learn.

Maybe so, but they are probably even more unwilling to do what you suggest - writing and reading instruction lists that would make their work tasks much more time-consuming and grunt than they are. Perhaps there are a few exceptions to that in the form of note writing enthusiasts, but their output doesn't sound promising:

We do have one engineer that has been working here a very long time, way before my time. He clutters the dwgs with notes. Most notes either don't make sense or can be interpreted various ways.

 

[CWB1]

I wonder - wherever do they find students if everyone gets 200 hours of 'Y14.5 instruction in trade school or college?

The same place HR, PM, engineering, CAD, and other consultants find most students - annual training quotas/budgets. I grew up in a job shop so had a decent knowledge before taking it in trade school, again as an undergrad, and have taken ETI’s basic course twice and tolerance stacks once for work.

 

[ctopher]

I have only worked with very few that have had actual training in it. It's mostly learn on the job.

Chris, CSWP
SolidWorks '20
ctophers home
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[Burunduk]

"Learn on the job" is also a type of training. It works if the more experienced personnel mentor the newer workers. But the company should at least make copies of the standard available for everyone who needs them, and be ready to spend some time resources because the time spent on teaching and learning is time at which both workers are not making drawings or parts, or inspect parts.

 

[3DDave]

Burunduk,

Now a fourth dodge - they won't want to write? I already mentioned they wouldn't have to as a company will rapidly collect notes that apply to them.

They really won't want to read a nearly 400 page book either.

I think notes will be used for suppliers who have expressed a desire to increase prices or refuse to work if they see even one geometric tolerance. This situation, where an individual feels there is a need for the controls, can write those controls as notes to get what they want.

Trying to be reductionist is embarrassing you. If there is a need for controlling the relationships between features, then it's first necessary to identify just how that should occur, being able to put that into words, and then, if possible, there is the potential to find some method to express that control. See that "put that into words" step?

I find most often that the people who have problems with the symbols (you know, the ones who are trained or are trained on the job) skip that "put that into words" step.

"it is less expensive and risky to train people to understand and communicate requirements in a uniform language "

Do you only write Chinese or Hindi? You expect to give up all the other languages in favor of just one? Are you pushing your management to demand a change in the language the company uses? Are you refusing to speak your native language?

What about the ISO standards? Should those be ignored or is it Y14.5 that isn't the uniform language source?

Are there standards to make symbols of all the other notes on drawings? Why not? Why are you putting any notes on any drawings? If no one wants to write them, where do they come from?

 

[3DDave]

CBW1 - that sounds good.

Are you also dealing with suppliers who don't want to use Y14.5?

The areas I'd see as most likely are automotive, military, or design for hire as the big three for having extensive in-house Y14.5 training.

If you have a stress analysis department, do they get the same training so they can analyze the effects of tolerance and tolerance accumulation based on the geometric tolerances? Does procurement get the same training so they can better control bids?

Are the tolerance analyses statistical - that is, based on comparing known production variations and then looking at the allocations to be 3 or 6 sigma or are they done using actual costs to create fixtures and particular processes? Did ETI cover that?

Were I making 500k vehicles I would want as much control as possible. And I would want to avoid arguments about how parts will be inspected - as a result they write their own overlays of the Y14.5 standard to limit a lot of the variety.

As I mentioned before, desperation is what causes adoption and training. Putting 100k vehicles into a recall program because someone didn't do a tolerance analysis is the sort of desperation I'm talking about. If there's no desperation then there isn't a clear cut benefit, though it does create it's own self-sustaining make-work employment.