A course to teach drafting to engineers who can do CAD 3

[Sparweb]

Some of you will understand what I'm asking right away (or have bemoaned this themselves) but for the rest I will explain what I'm considering and why I'm asking:

There is a difference... in fact there is a very wide gulf... between the ability to select and place the drafting icons on your CAD screen, and the ability to produce a clear, concise, and adequately detailed drawing that a fabricator can use to produce the part or assembly correctly. The distinction is important to me. Many students come out of school knowing the former. Few are taught the latter, formally. I wasn't either, but I was lucky that I started in workplaces with people prepared to teach and they set me on the right track. I think it's my turn to do the same for my younger co-workers. They are currently churning out crap.

I work with a large (~30) team of engineers who, for the most part, have a lot of experience with CAD, mostly CATIA and Inventor (SW and AutoCAD take strong runner-up places) but few of them have any training at all in preparing good drawings. Sure, they know what a hidden line is, but few know when to use it for effect and clarity. What I want to do is to create a drawing class for this group so that they can produce better, more clear drawings for the fabricators that use them. I have just completed a project where the average rate of shop error, query, revision, or change notice rate is roughly 10 per drawing. The time wasted on these frequently exceeded the original drawing time. While I don't believe that the engineering dep't has to take responsibility for all production errors, I have personally seen many errors that could be traced back to confusing instructions on drawings.

I have started preparing to give a course that does the following:[ul]
[li]Teaches good techniques for detail, assembly, and installation drawings[/li]
[li]Shows examples of good drawings and bad, and discusses the reasons[/li]
[li]Gives the engineers strategies to prevent omissions on their drawings[/li]
[li]Prepares the engineers to lay out a drawing package in a logical order before making the first drawing[/li]
[/ul]
...and by the way, I do not want the class to:
[ul]
[li]Teach the minutiae of the company's drawings standard - they can read that for themselves[/li]
[li]Teach where to click the button to make a feature appear - that course already exists[/li]
[li]Hold their hands (or their mice, either) - the point is to make the hand-holding stop[/li]
[li]Point fingers at anyone who has more difficulty than others[/li]
[/ul]

I have been looking for such a course and have yet to find one. The courses I find all seem to be about "how to click the button". So I decided to start designing a course of my own.

I confess that I'm old enough that I can say I took 3 drafting courses, with boards, pencils, rulers and such in school. I think I'm the beneficiary of that, and I'd like to pass it on, just in a way that doesn't force these kids to use a #2HB. There won't be much point in trying this if I start off on the wrong foot giving them the impression that "my way is better" or that something archaic is good for them. I love CAD and I know that CAD can be used to make excellent drawings because I've seen it done.

For those tempted to remind me that management has to care before all of this happens, I agree. I have been laying the groundwork in the minds of my superiors and their superiors for a few months, and "taking the temperature" before I make my case. I believe I am ready to do that, with facts and numbers of dollars saved by the company, or cost if not done.
Also made a few allies.

Does anyone have suggestions for making this course a success?

STF

 

[3DDave]

I would probably make examples from existing drawings and their subsequent changes to show where things were left confusing. It might also be of worth to take the original versions of drawings that were found to be incomplete or confusing and have them build CAD models from them to see where they get stuck.

For procedure based (history) models, having people create drawings one feature at a time as a discipline for checking that the drawing reflects a minimum of the model structure is helpful.

Other than that, good luck. The people who get drawings out fast, but garbage, are typically more rewarded than the ones that have to come back an fix the damage. I'm not sure how to fix that.

 

[MikeHalloran]

Amen to fast garbage. One of my employers' "best" designers never erased anything. Need a new feature? He'd add a new bracket. ... to an existing bracket. ... which was attached to another bracket, etc. Our fastener costs were outrageous. ... but the Drafting Super loved the guy.

;--

I tend to use more liberal tolerances and/or smarter design on my home projects, where I am both designer and sole fabricator.

Sort of along those lines, it might be educational to assign a project, say a multipart assembly, where everyone in class designs a single one of the parts and produces a drawing. Then they rotate, and everybody checks somebody else's work. After working out the resulting disagreements, everyone gets to fabricate a part that they neither designed nor checked, then the music plays for a bit, and everyone inspects a part that someone else made. Then the class tries to assemble the end product.

The first thing that came to mind was a Shaker Candle Box, or something similar, made from a softwood like pine, with a fine tooth pull saw, a coping saw, a combination square, a utility knife, and a 1/4" wood chisel. I.e., no power tools allowed. I made a pretty crude one that way in about 3 afternoons last summer, so six people might be able to make one in a long afternoon. There are six parts in all, including some stopped rabbets and some handcut dovetails. The rabbets are pretty loose. The dovetails are more of a challenge; I'd allow an angle gage or a protractor or maybe a template for them.



Mike Halloran
Pembroke Pines, FL, USA

 

[Sparweb]

Musical chairs, I love it.
Don't know if I'll be granted enough time to do it, but if I set time limits for each step, it might be possible.
The practical fabrication would be a difficult sell, though... Might be more direct to have the assembly on a table for them to inspect, and CAD models of each part ready in advance. That way the lesson only concerns drawing the parts, checking their neighbours' work, and inspecting the original parts against the resulting drawing.


STF

 

[TheTick]

Put them in a shop and force them to make parts from their drawings.

 

[berkshire]

Sparweb,
Maybe you should take them back to some of the old drafting books such as " Basic Technical Drawing." MacMillan. or Mechanical drawing em960 These books pre date Y14, but they have a common theme: The working Drawing is a complete set of drawings such that the object represented can be built from it/them alone without additional information.

The Tick ,
I really like your idea, That way they put their money where their mouth is.

In the drawing office where I first started drafting, ( I came to the office from the shop floor ), was a large sign on the wall it said " Questions are free, nobody gets paid for them."

B.E.

You are judged not by what you know, but by what you can do.

 

[CheckerHater]

The working Drawing is a complete set of drawings such that the object represented can be built from it/them alone without additional information.

Haven't seen it for a long time. Nowadays drawings represent "function" whatever that means. Generations of professionals are raised, who are not only tolerant of their complete ignorance of how parts are made, but proud of it.

Star to you for bringing back the old truth.

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

 

[score33]

I took a GD&T class from where we were taught to think of inspection and fabrication when dimensioning our parts, not necessarily only function. I think this went a long way to help me become a better design engineer. Understanding how the parts were made and inspected is not something I learned in school so found that part of the course extremely useful...

 

[Sparweb]

Berkshire, "...old drafting books..."
How about "Ye Olde-Tyme Draughting Course"

These guys are millennials. I don't want to frighten them!


STF

 

[MintJulep]

Combination of Mike's and Tick's ideas, in recognition that getting a class of designers in front of bridgeports is unlikely.

Everyone gets a part to model and make a drawing.

Musical chairs: Everyone gets to model someone else's part from nothing except the drawing.

Continue: See what the final CAD assembly of the second generation models looks like.

 

[mkcski]

Let me add my two cents.

Remind the class the purpose of a engineering drawing (Y14.5 is for engineered parts) is to communicate design intent, NOT make pretty pictures or tell someone how to make or inspect the part. Also, explain that drawings/CAD "show" the perfect part, and since nothing is prefect, that tolerances tell how bad it can get/be. Next, like in grade school, we learn to communicate by reading first and writing second. Making drawings is writing. I bet few have had a print reading class before CAD classes.

As TheTick post eluded too, let them be the audience (reader) for a while not the presenter (writer). Get a machinist AND inspector in the class to show them how he/she reads (interprets) what they have written. This will help them understand what drawing information is needed by shop personnel to make parts for a profit and keep them having a job. A bit simplistic, and getting a class together to do this is complex, but I believe this is what is missing.

Certified Sr. GD&T Professional

 

[cowski]

Also, explain that drawings/CAD "show" the perfect part, and since nothing is prefect

I see what you did there...

 

[berkshire]

Sparweb,
"Ye Olde-Tyme Draughting Course"

I am a bit long in the tooth, but I did not want to go there
Non the less when I started in the Draughting office as a detail Draughtsman, I knew from Technical college how to do an orthographic drawing, or so I thought. I quickly got that beaten out of me, I was told in no uncertain terms that a drawing was not just a pretty picture, it was a set of technical instructions to the shop floor in Graphic form, you now have to learn to write them. The lead draughtsman then proceeded to ride herd on me until I got it,
This is the position you are now in, you have to go beat some pre conceived notions out of a bunch of guys who " Know how to draw.", but really don't. You started at the bottom of the barrel like me, and had a set of mentors who kept you on the right track, now like it or not, its your turn in that barrel .
B.E.


You are judged not by what you know, but by what you can do.

 

[robertib]

Another variation on what's already been said.

Before the class, create a series of drawings.

In the class, have them create a model from a drawing - retrieve the drawings after use, so that they can't be used as templates.

Then have someone else create the drawing for the model, and print the drawings.

Delete (or hide) the model, and give the original person the new drawing to see if they can recreate the model - without informing them that it's the drawing you originally gave them.

The frustration of trying to create a model from an incomplete drawing should teach them why they need good drawings.

 

[Tunalover]

berkshire:
Your statement "The working Drawing is a complete set of drawings such that the object represented can be built from it/them alone without additional information." is WAY off the mark. The engineering drawing (see the definition in ASME Y14.100) is an engineering and inspection document that is intended to portray the end-item. It may be used to make an end-item without additional information but that is often not the case. The drawing must be concise and sufficient and, except for special processes that are not widely known in the industry, needs to be free of process (manufacturing) details as much as possible. The drawing says WHAT to make not HOW to make it.

For example, there are industry specs (SAE perhaps now that so many mil standards are coming under their stewardship) that describe in detail the proper installation of helical coil inserts. This process may be involved and it takes a lengthy spec to cover all the bases. But those installation details are left OFF the drawing so the drawing does not need a long, tedious note or two to explain how to install the helicoil. For a complex end-item, if the drawing must include all the necessary "HOW TO" information then that drawing becomes a living, breathing beast chock full of notes that will be under constant revision to fix this process detail or that process detail. Let the specs work for you! If information can be obtained from a spec under the purview of a formal standardizing organization, then that organization will insure that the process information is clear and sufficient to successfully carry out that process.

I just came from a company who required that, for a purchased custom transformer, for example, all electrical requirements be stated on the drawing with no other separate requirements specs called out in the notes. The E-sized drawing had the first three sheets filled with notes and tables laying out the electrical requirements. It would have been MUCH easier to have a separate A-sized spec called out in a note that spelled out the electrical requirements while leaving the rest of the drawing to describe the form and fit. This way the drawing could have been one, maybe two C-sized sheets. It is much easier to make revisions with a word processor than with a CAD system. And the person doing the revisions doesn't have to be a well-paid engineer or designer (a typist can work from a redline provided by the EE). At this company, how drawings were prepared was controlled by top management, not Engineering. That was pretty obvious by looking at their custom component drawings!



Tunalover

 

[drawoh]

tunalover,

On my drawings in SolidWorks, when I specify tapped holes, I delete the tap drill specification. When I call up any thread inserts, I specify that they are to be installed as per the manufacturer's specifications. My drawings show that there are tapped holes and that there are thread inserts. It is assumed that the fabricator knows how to implement them. My drawings describe what I will accept from the fabricator. I think this meets Berkshire's description.

--
JHG

 

[SwinnyGG]

when I specify tapped holes, I delete the tap drill specification. When I call up any thread inserts, I specify that they are to be installed as per the manufacturer's specifications.

This is exactly how I do it too.

 

[KENAT]

SparWeb,

I learned to draw on the job by asking questions, looking at examples, looking up the standards and most importantly having my drawings bled over by folks that new what they were doing. This drawing check also involve some chastisement (mostly in the form of being given a good ribbing) enough that it made it painful to submit a bad drawing so driving me to give good ones. Not sure you'll be able to really address it in a class but...

I'd love to give a diatribe but haven't been able to find time so a few ideas:

1) Give them some general appreciation/guidelines of what helps make a good drawing beyond just doing exercises. You may choose to do an initial exercise first before giving them guidelines but still.

a. General appearance - cramped drawings with uneven dimension spacing and random font size & orientation ... make it harder to use.
b. Overlapping dimensions
c. Avoid dimensions in the field of view whenever possible
d. Don't randomly change template settings etc. (assuming your templates and pre sets etc. are correct)
e. Think about subsequent users of the drawing, not just the machinist & inspectors etc. but what about the Engineer or draftsman that is looking at it in a few years time because of some problem in production

I'm sure you have a more complete list.

2) How about giving them some guidance on how to review their own work for completeness? For instance when I used to check drawings and still on my own for simple part drawing I basically take the print and give or take do the following using yellow pencil to indicate 'good' and red to make corrections (and occasionally blue for non mandatory suggestions or check calculations etc. when checking someone else work):

a. Read the notes.
b. Check for datum structure and general dimension scheme & make sure they reflect function.
c. Check all the dimensions for the outline/primary geometry of the part are given and tolerances are appropriate - start with the overalls then work my way down finishing with rads & chamfers. I don't always do a full on tolerance stack - just where it matters otherwise I do it by 'feel' and while taking into account typical process capability etc.
d. Check all the dimensions for internal features are given - e.g. do each hole pattern one at a time checking off both location dims and the size dims & FCF.
e. Check the rev block & title block are filled out properly

Ideally I leave the drawing for a few hours or over night between 'finishing it' initially and coming back to do the above check but that's not always practical.

Once I have my marked up drawing I methodically go through incorporating the red lines initialing each change as I go (green pencil) and making sure to save regularly.

If there were a lot of changes or it's really complex I may repeat the check process but generally just make sure I incorporated all the redlines.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[mkcski]

Might I suggest a review of Y14.5-2009, paragraph 1.4(e).

Certified Sr. GD&T Professional

 

[CheckerHater]

I like use of "should" and "shall" in that paragraph

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