Drawing Quality
Drawing Quality
(OP)
This is a question for fabricators, inspectors and manufacturers. thread1103-265767: Engineering Drawings and Tolerances is drifting off topic, so I am starting this thread.
How good are the drawings you are being sent? Do they make sense as per drafting standards? Are you willing to promise to meet the dimensions and tolerances?
How good are the drawings you are being sent? Do they make sense as per drafting standards? Are you willing to promise to meet the dimensions and tolerances?
JHG





RE: Drawing Quality
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Drawing Quality
I think companies have become lazier and have less employees that understand drawing standards and GD&T.
It's more of a 'cost cut' in management minds.
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion
RE: Drawing Quality
Thank you for moving this. I would love to know peoples impressions, I suspect there are lots of drawings out there that people will laugh in your face if you applied too much GD&T. My wife is an engineer in a company who constructs water treatment systems, again not mass production stuff. they DO NOT use GD&T. All bent brackets, weldments and lots of tubing all fabricated outside they make nothing in house. They are booming now, just the right leading edge American industry.
Frank
RE: Drawing Quality
CAD and CAM have contributed to the downward spiral, in both the frontend and backend of the process.
"Art without engineering is dreaming; Engineering without art is calculating."
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RE: Drawing Quality
RE: Drawing Quality
Just last week I was working in an assy file someone else had created and noticed some holes didn't line up.
3D CAD gives improved tools for finding these problems up front but no package I've ever used makes it impossible.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
"Art without engineering is dreaming; Engineering without art is calculating."
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RE: Drawing Quality
Matt Lorono
Lorono's SolidWorks Resources & SolidWorks Legion
&
RE: Drawing Quality
Do you feel the tolerances on your fabrication drawings, (castings, weldments, formed parts) acurately reflect the tolerances achieved on your parts?
Frank
RE: Drawing Quality
Fast forward to mid/late 1980's owner companies, on hard times, decide to drop whole design/drafting groups, & a majority of their senior engineering people. Now opting to replace the Sr. people with wet behind the ears engineering students fresh out of school with only afew Sr. types to ride heard over the Jr. people.
Now AutoCAD pokes its head into things, with the new "Computer Revolution"! Now it's a whole new/different way to do drawings and lot of the Sr. people in design/drafting opted to retire early as appose to have to learn a new way of doing their job. SO now it's more important as to what computer program you know and developing your computer capabilities as apposed to developing your designer capabilities. This goes on this way for about 15 to 20 years. These days 3D is the "optimumal" way to document projects! Why? ...because with 3D you generate a "pictures" where it doesn't require anybody to be able to "read" a technical drawing. IF you're thinking this is not true, I'm here to tell you it's already happening, I've seem it! Projects are done 3D and "pictures" (with shading) are passed out to the welders. This is done because the cheaper welders don't read drawings too well and do better with pictures!
This is the reason us "older guys" have heart ache with this whole thing. When I was taught mech. & piping drafting, it was hammered into you that your drawings WILL LOOK one way! That doesn't happen these days. What these computer programs put out would be unacceptable pre-1985 ...they DO NOT follow accepted drafting standards & convention! ...SO WHY are they acceptable now!?? ...Welcome to the Computer Revolution of the 1990's!
RE: Drawing Quality
If I communicate with the machinists and explain the drawings each time, yes. Too many machinists these days that can't read drawings. I used to give it to them and walk away, then receive good parts.
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion
RE: Drawing Quality
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Drawing Quality
Matt Lorono
Lorono's SolidWorks Resources & SolidWorks Legion
&
RE: Drawing Quality
But coming back to OP's questions; I am working for automotive company that has many plants all over the world: US, Europe, India, Asia-Pacific. Different sites use different drawing and GD&T standards - US follow ASME Y14.5, Europe works according to ISO. We are of course using CAD system and producing hundreds of drawings per year, but I am very sad to say that I have not seen a single drawing that could be considered as fully done according to any of mentioned standards. Designers/drafters simply put remarks like 'Dimensioning and tolerancing according to ASME Y14.5M (or ISO 1101)' in general title block without thinking what are the implications of it. What is even worse, they do not use GD&T almost at all. And I am not talking about very simple parts like rectangular blocks or similar - geometry of our products is usually quite complicated. We have some internal rules saying that to avoid too complicated and unreadable drawings only functional dimensions should be presented, and I am OK with that, but engineers here are not even able to show these functional dimensions properly. Good example can be when symmetry of two features (let's say rectangular) is considered. Everybody will specify their widths, but nobody will care that geometrical relation between them is still missing. Most of guys will say: 'They are shown symmetrical on a drawing, so they are symmetrical, and that's all. If we add symmetry or position control on the drawing this will increase final costs of a product'.
Sometimes I wonder how lucky this company is that no serious problems caused by ambiguous dimensioning has happened so far. This might sound weird, but from my point of view (as a great supporter of using GD&T) I would like a situation to happen that somebody will come to us and say: 'Hey, there is no sufficient information on your drawing. Please fix it.' or 'You haven't specified it on the drawing, so we did as we thought, and you can not have any complaints to us that this doesn't work. If you want any modification you have to pay'. Maybe then our management would somehow realize that the company spends hard money on licences for sophisticated CAD systems to product worthless pieces of paper which instead of bringing huge profits can bring serious financial troubles.
RE: Drawing Quality
I think you and I must work for the same company/boss. It is good to hear I am not alone out here.
Frank
RE: Drawing Quality
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
I think that is about it. I was once told the difference between an engineer and scientist was something like a scientist is on a long search for the real truth an engineer needs just to get close enough, good enough, strong enough, fast enough to get the job done.
Basically, companies only want to get the work out. Walt says: "remember, companies are in buisness to make money".
It is people like us here who care enough and are interested in perfect drawings.
Frank
RE: Drawing Quality
Shall I assumue you are refering to the times when real people made real prints, a little before my time? When I first started, I worked with a guy who shaded his drawings it was beautiful art, they would shoot the guy now. Most of my time, before CAD, their was mylar repos they were pretty ugly generally and not to scale usally either, I would not call that the golden age either. I was glad to leave it, frankly
Frank
RE: Drawing Quality
CAD is so much more than a few lines on a piece of paper, it has driven so many things forward and things are produced today that would simply be impossible without it.
Of course none of this alters the fact that the skill of the operator is still key, be that at a CAD station or on a drawing board.
RE: Drawing Quality
The lesson, that it seem almost everybody has lost, is drawings STILL need to be as simple as possible to insure that just about any body can use them down the line! Two axioms that just about says it all are as follows"
"NOTHING is make better by making it more complicated"!
The other lesson written between the lines here is...
"IF good work is not recognized, then poor work will follow!"
RE: Drawing Quality
Much of it is adding capabilities that some people will find very usefull. However, often for most situations it just ends up with more than one way to achieve something, some of these ways are very complicated.
I've certainly opened files made by others that I needed to change and found it a real pain to do so, some because of bad practices, some because of complicated practices.
At our place the situation is complicated because we have a lot of 'part time' users, and a lot of interns who typically haven't used our CAD package before.
So, KISS rules to help future users, but it does sometimes limit how much advantage we can take of the CAD's capabilities, and yes, even I occasionally get carried away.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
Yes, for the sake of other users, you have to keep things simple. On the other hand, you can dumb things down well below the minimum level to do actual design. CAD is user friendly enough that dull, stupid people can perform most operations. That does not mean that they can make design decisions, or understand assembly requirements well enough to communicate requirements on the documentation.
There is a minimum level of intelligence and knowledge for someone to be able to do drafting and design.
Whining and crying about how things used to be so much better, definitely can be tracked back as far as Socrates. Perhaps someone will dig up a Mesopotamian tell and find a cunieform tablet complaining that today's makers of machines are idiots. The point of my post is that I am curious about what sort of average drawing the fabricators and inspector here are encountering. The older guys can comment on what it looked like thirty or forty years ago.
RE: Drawing Quality
The rise of CAD coincided with the fall of the drawing checker. After all, CAD makes things so easy to do, anyone can do it! And that led to the downsizing or elimination of entire drafting departments, leaving drawing creation to the engineers. This could have worked out well, if they had kept the drawing checker, but he was part of the drafting department and had to go.
Engineers need to see their drafting mistakes, omissions and poor practices in red. Handing the drawing off for a peer check does little as far as good drawing practice is concerned (just re-inforcement of poor habits), and (in my experience) engineers often self-check because "it will get the parts out the door" quicker. Proceedures in many places have become more lax, and drawings are often signed off and released without anyone skilled at drafting having any input.
Yes, there were poor board drawings back in the day, but there were also many more good drawings, depending on the company cuture. It was a hell of a lot harder to correct your mistakes then than it is now on CAD, and those lessons tended to stick.
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Drawing Quality
Anyway, there's no room for Checkers in the modern commercial world, what value does preventing errors in advance while educating folks have? The engineers just need to be trained properly; we can rely on their professionalism to self-check and do it right. Then rely on Scrap & Rework to speed up product development. That's the way forward.
As to the OP, I do occasionally get actual drawings from vendors and generally they are pretty woeful, rarely enough info on them to do a tolerance check against for instance.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
Now that you got me pegged as some "old Fart" that has computer phobia you are wrong again! I don't think anything has come along in this industry that has so much potential! However it has come with growing pains.
...People in positions without a "proper" education for that position.
...No national standards or conventions on how a computer makes the presentation.
...The number of different drafting programs that have divided up the work force.
...The fact that the major emphasis now is to up grade your computer skills as apposed to up grading your designer skills.
...AND the one that really causes me heart ache is as KENAT pointed out (and what I was hinting with my story about shading nozzles), computer guys like to go overboard on how they generate drawings! Because it's "fun" for them to intricately weave computer programs/commands/X-ref.s to generate a drawing ...so complicated that it takes the I.T. department or the original author to un-ravel it so some lesser qualified employee can use the file on another job! This is where the KISS principal needs to be implemented! ...AND where I point to on the first axiom I stated..." "NOTHING is make better by making it more complicated"!
All this goes hand in hand for the computer age, as it has done for the "old days" on the board with pencil and paper ...like it or not.
RE: Drawing Quality
I'm not at all claiming that it is a perfect standard (neither is Y14.5 though), but it is a starting point.
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Drawing Quality
It seems more telling the CAD programmers what to develop rather than so much telling CAD users what to do. Also it doesn't really define modelling best practices so much as how to apply anotation in a model to replace a drawing and or how to have a model/drawing pair.
I agree it's a start point but there's a long way to go.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
I started around 1980, am left handed and a perfectionist. Drafting was a chore for me as I always rub my hand accross my printing and got bad hand/arm cramps from it. I was really excited about CAD now my drawings could look like everyone elses. I love the information I can get too.
Frank
RE: Drawing Quality
Is what I was referring to. Not sure what being left handed has to do with that, and who says I'm not a lefty anyway?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
Frank
RE: Drawing Quality
When you cut a section on CAD it cuts through ribs, impeller vanes, bosses, etc like a saw. That is not the correct representation according to the old standard drafting manuals, mil or ASME standards rules on section projection. I have yet to find an easy way around this, yet it is so basic to drafting practice and I felt may contributes to some of the "bad practice" mentioned here earier.
You don't have that?
Frank
RE: Drawing Quality
I don't know about specific CAD systems, but I remember that section views can be cut from a "cutting plane line" that is not always straight across -- it can zig zag, or turn on an angle as in the aligned section that I mention. However, when you see the section view, it makes it all appear as if it's in the same plane; you have no sense that the saw turned a corner.
Not sure if that's what you are referring to...
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: Drawing Quality
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
I guess I am not describing this very well.
Kenat,
Sorry, I am not at work now and I do not happen to have a copy of that standard here in my pdf collection.
Take a section through the center of a 5 spoke pulley wheel, I can cut the section so the spokes roll down into proper opposing places, but, the spokes then are also not supposed to be shown as cut through/sectioned.
Frank
RE: Drawing Quality
Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services
www.infotechpr.net
RE: Drawing Quality
Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services
www.infotechpr.net
RE: Drawing Quality
Thanks, Yes, that is right except in the old days and per ASME Y14.3-2003, as Kenat has kindly provided above, the other rib should be rolled into place but not "sectioned".
They used to refer to it as true view vs. sectioned. To my OP they really need to work on sectioning or more likely the standards must be changed, I would hate to see the later though it may be more likely.
Frank
RE: Drawing Quality
Though, looking in the standard it appears use of true Geometry is allowed, or am I misunderstanding the intent of the last para of seciont 4.2.1 and figure 45?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
It would be good if the latest made that a sugestion instead of a mandate. While the CAD system I use can be cajoled to meet the '94 standard, it is much more involved than a simple section. As for rotating into plane, I don't even try. The cutting line would have to reflect exactly where the section is taken, no feature rotation.
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Drawing Quality
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Drawing Quality
Frank
RE: Drawing Quality
I somewhat judge a company on their drawing (rightly or wrongly), the better looking drawings generally are the best done as far as accuracy and content.
I drew on the board for 10 years before going to CAD, and I still try my best to have the best drawings, and I get many complements from them.
RE: Drawing Quality
RE: Drawing Quality
The type of product manufactured and frequency of changes made a big difference, but good drawings were more prevalent then than now, at least in my experience. YMMV
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Drawing Quality
RE: Drawing Quality
Frank
RE: Drawing Quality
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
I realize now you have come from a later time. All the profile tolerances talked about here would have been laughed at when I first started. You have come to accept a whole new level of GD&T than when I started, it was mush more like some of the comments we get now, "what do we need to go to that for". I see the same thing in resistance to the 2009 standard, for example, it's statement that +/- is basically only good for features of size. Make no mistake some checkers were my mentors in many other ways, no doubt. Change is a given, resistance to change did them in.
Frank
RE: Drawing Quality
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
Everybody seems to have their own idea of who should do design checking, and how. In the offices of Dominion Consolidated Widgets Incporated, the design checker may be a highly qualified professional that everybody respects and relies on, or he could be some goof that everybody wanted kept away from the drafting board or CAD station.
This sort of thing depens massively on who you are working for.
RE: Drawing Quality
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
I really do not believe the majority of old checkers knew GD&T. I would like to believe we would be much farther ahead if they had. I once refered to the people you are refering to as the best and the brightest of their time, someone took issue with that statement when I made it before. I would still maintain that the people you know were the best and brightest of their time. Unless you just mean they knew the words like: parallelism, perpendicularity, concentricity and symmetry. those checkers I knew, too. Parallelism was like a snake.
Frank
RE: Drawing Quality
While a sample of 3 folks isn't that large, they were very good.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
I do not and cannot claim that a majority of checkers back then knew the standards very well, but I can claim that most of the ones I worked with did, and what they did not know they were willing to learn as it was presented to them.
Again, YMMV.
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Drawing Quality
Frank
RE: Drawing Quality
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
Kenat,
Are you English originally; You mentioned you worked there when we first talked, but now, after reading back it appears different.
Frank
RE: Drawing Quality
Regarding certification, I looked into this when I got landed the checking role, I even got the study guide.
However, having looked at it a little (not enough) and talked to some others, I have the perception that they perhaps set the bar too high for the initial level of certification. The amount of time & effort I'd have to spend to get it didn't seem commensurate with the benefits. I haven't seen many job adds asking for GD&T certification, just for experience with ASME Y14.5 etc.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Drawing Quality
The checkers I worked with then, did not know any standards but "company standards". They had no interest in national standards any more than if they were ISO standards. Now I work in areospace and I see a nominal interest by management in at least looking like we adhere to standards because the apperance of it is good for buisness so I do see the difference.
Frank
RE: Drawing Quality
I am reading your thread 1103-192933 on GD&T parts costing more. Powerhound's comments about bad GD&T stand out in particular as he references his perspective. That and many other threads here indicate to me from the outside world that you were very lucky to have a good friend/mentor. I did too, he was a checker also, Art.
Frank
RE: Drawing Quality
RE: Drawing Quality
Frank
RE: Drawing Quality