Designing/Engineering directly in CAD software? 2

[CADtrainer]

Hello,

I'm interested in the way people look up to Designing issues in a Cad environment (especially Mechanical design but I think the issues are always the same - also in other disciplines).
I hear a lot of managers complaining that the engineer spends to much time in putting his ideas en calculation results into the cad software. It would be more interesting to do a lot of the designing and engineering in “an other way”. This then should give the advantage that in a late state of the design process the proper cad/cae/cam tool could be chosen. Another advantage that we are looking for is that a senior engineer could do the real design/engineer work a pass this on to a junior engineer who could do the detailing of the engineering. The problem in this context is the transfer of the knowledge between the senior en the junior engineer. This sometimes costs so much time (and is a source for errors) that in practical terms the senior engineer very often also does the detailed work…

My question to you is now:

Do you have experience in this matter? Or does may be somebody know some kind of study cases that cover this issue?

I would also find it very interesting to hear your opinion in this matter.
Please feel free to react!

 

[ctopher]

In my experience, usually the Senior Engineers are the ones with Masters or PHD's. They have the original ideas, pass them down to the Engineers who do the design/testing. Then passed down to the Designers for details design, then do the Drafting themselves or pass on to Drafters. Some Engineers do the prelim CAD work then pass to the Designers to complete it and draft them. It all depends on the size of the company and the type of work. With SolidWorks/Cosmos it works well.

 

[drawoh]

CADtrainer,

At the mechanical level, I do everything from design concept to fabrication drawings and specification controls.

Back in the days of drafting boards, I concluded that the way to be efficient was to at least try to generate final, official documentation from the very start. I would plan would plan to convert my design layouts into assembly drawings or arrangements. One of the big failures with mechanical design from what I see is that people fail to generate assemblies and parts lists. For design layout, there is no substitute for scale drawings and models.

If you are doing to do all your design outside of CAD, you might as well buy the cheapest edition of AutoCAD. Your drafter can read the napkins the engineer has been scribbling on, and transfer the information to a pretty drawing.

For the $5K(US) it costs to bring in medium level 3D parametric CAD, you should anticipate that design gets done.

JHG

 

[jdo2ley]

From my point of view - the engineer aquires the work and provides the concept, the designer makes the concept physical (develops a 3D model which includes routing pipe and fitting choices, etc) and the drafter takes care of document production (editing, refinement and revisions).

 

[CADtrainer]

Hello,

Thank's for your replies.
What I would like to add to my question is how dou you setup a efficient way to share information/knowledge between for example the designer and the drafter?
In my environment a lot of work is done by the designer because in the time he has handed over the work to a drafter all the work allready could be done...

Thank you for your reactions,

Pw

 

[TheTick]

In my environment a lot of work is done by the designer because in the time he has handed over the work to a drafter all the work allready could be done...

For that matter, I have worked with too many drafters where it took more time to check and correct their work than to just do it myself.

Such seems to be the case in many places. My theory is that competent drafters quickly become designers, while less-than-competent drafters...


"Customer satisfaction, while theoretically possible, is neither guaranteed nor statistically likely.--E.L. Kersten

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[gmarken]

How many companies still have drafters? Every company that I have worked for in the last 10 to 12 years, the engineers do the design and drafting of new products. If the company had any Draftsmen they were usualy dedicated to document control and handling ECO's. With the advent of CAD and especially Solid Modeling the need for Draftsmen has diminished.

I started out as a Draftsman right out of High School in 1976. Back the in the pencil and paper world, there was more of the traditional structure, Engineer, Designer, and Drafter. In the early part of my career I did work for companies(commercial and military)that had this hierarchy.

Most of the companies I have worked at within the last 12 years have tended to be smaller and the Engineers did thier own detailing. Actually, I worked at Lucent for a time before the Telecom bubble burst and I still did my own details.

 

[MadMango]

I have been saying for the last 8 years that the concept of a drafting pool is a dead one. This was proved two years ago at my company where we had a new Engineering Director, one with a DOD and General Electric background. He proceded to restructure the department into something he was familiar with. He took a lot of good designers and bumped them down to "drafters" to create a drafting pool. He then took all engineers and made them Design Engineers, regardless of experience.

He wanted all Design Engineers to do the designs and the drafters to do all the detail drawings, with redlines being used as the means to correct problems. It did not work, but we suffered through it for several months. Many of the newly created designers were not familiar with the CAD system, some having no experience at all. Many of the drafters were happy to correct redlines, considering that they were still being paid $20-25 an hour.

The Director resinged a few months later (we think forced) and the department was reverted back to the was it was, sans a few good people that left during the turmoil. In this day and age of 3D design, Engineers need to be CAD Operators and the traditional Drafter needs to not only be a CAD Operator but be willing to do learn and apply a little engineering as well.

I'll agree with TheTick, competent drafters often become good designers. The ones that fall short soon find themselves stuck behind a stack of ECO changes to process.

[green]"I think there is a world market for maybe five computers."[/green]
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[cvengr]

Computer Aided Drafting?/Design?/Documentation?/Development?

Also what area of Mechanical?

In construction of facilities, mechanical designs vary considerably.

Older engineers tend to design on the back of a napkin then give to a secretary or draftsman to place into AutoCAD/MicroStation.

Younger engineers are probably more intuitive with PC based tools and FEA software.

Recent college graduates probably can communicate more efficiently via AutoCAD if they comply with past drafting and filing standards.

A certain amount of professional wherewithal also dictates what elements are included in a biddable design and what's considered a shop drawing. Depends on the client, owner, customer, situation.

AIA/CSI A/E/C CADD standards don't even comply with database normalization standards which a graduate IT/CompSci student from Stanford might associate with Donald Gray's Transaction Processing. Those standards, though, are detailed enough that a separate documentation/draftsman is probably required to keep the layers, groups, elements, and other information well organized per contractual requirements with government entities.

Practically, The engineering professional must retain wherewithall in the design process. The final drawings and specifications are merely formal methods of communication publicly recognized as professional correspondence.

One problem with computerized designs is the same as architects had with 'cut & paste' for many years after the copier came out and before computer technology. Each particular project needs a professional to devote due diligence in assessing the problem and communcating thew proposed and designed solutions.

Today, there are many, many off-the-shelf solutions to problems which used to require professional problem solving.

Many of the designs I see today in facilities are off-the-shelf designs which either require a seasoned engineer in multiple disciplines to troubleshoot or accept without question. The codes and regulatory issues tend to dovetail into one another, so there is little difference in suburban New England, suburban New Mexico or Hawaii. Some have more micromanaged regulations or local codes, but it never substitutes for simple professional wherewithal.

Ideally, today's engineer needs a $200/year CAD program subscription to install on whatever machine he can access. He needs to be able to access a pricing/estimation database such as Mean's or Sweets, run schedules attached to his designs, compose details with attached LISP or macro based Excel spreadsheets to run a standing cost estimate, a separate linkable Calculation Design space parallel to Model space and Paper/Plot Space.

At present, AutoCAD still has the entire industry racked up on a constantly changing overpriced application inhibiting professional growth, which doesn't even normalize the elements of information and data management. It's a good package, but considering they've been around for over 20 yrs and have never charged less than about 10 times market rates, I have no doubt Autodesk has done more to impede the professions than to promote professional wherewithal.

Mean's is far more respectable IMHO. MS Office has become a defacto standard, but if I did it,..I'd get AutoCAD, Office, Access, Mean's and tool up accordingly. Use Linux where possible and keep your eyes open for something that will generate a .dwg/.xls/.doc/ file format in ODBC for your professional tooling-up at least cost with the most open design.

Next big step I see is digital cameras and photogrammetrics coming into play. 2 shots and generate an AutoCAD As-built in 3-D.

PEs and Architects still needed for the professional wherewithal to identify the actual problems and communicate appropriate solutions.

 

[MechCT]

MadMango, I agree with your last statement.

However... I believe that you just can't be a good drafter without some engineering knowledge. The several places I've been employed as a drafter, it was not only expected that we should create the drawings, but also that we should know how to do tolerance studies, how to decide what kind of geometric tolerances to put on a part or assembly, the whole ECO riggamaroll, AND we were also encouraged to check the designs for flaws!

I don't think the drafting position is going anywhere. I think that the expectations of drafters is changing.

I see the Engineers doing the number crunching and much of the conceptual stuff (although not all of it) and the Drafters doing the rest (solid modeling, fine tuning of the designs, drafting, etc.). Designer... Drafter... Who know's which is which anymore.

 

[MadMango]

I agree with you MechCT, you must have missed a line in my 31DEC04 (so long ago) post.

In this day and age of 3D design, Engineers need to be CAD Operators and the traditional Drafter needs to not only be a CAD Operator but be willing to do learn and apply a little engineering as well.

Rereading this topic, I see that we never did answer one question:

What I would like to add to my question is how dou you setup a efficient way to share information/knowledge between for example the designer and the drafter?

We handle this transfer of knowledge by using a Project Notebook that contains all design notes, sketches, communications and other data, but nothing beats good 'ol verbal communication and comprehension.

[green]"I think there is a world market for maybe five computers."[/green]
Thomas Watson, chairman of IBM, 1943.
Have you read faq731-376 to make the best use of Eng-Tips Forums?

 

[RedPen]

Because of CAD and especially 3D parametric solid-modeling, most of the local companies have more-or-less eliminated the Drafter position over the last 20 years. The line between Engineer and Designer has been blurred for the same reason. Many Senior Designers do much of their own engineering (number-crunching, spec-writing, tolerance-analysis, etc). Many older Engineers prefer to do the engineering work themselves but leave the modeling (CAD) work to Designers. Many of the younger Engineers do at least some of their own modeling, especially at the conceptual stages.

The system that works the best, IMO, is when the Engineer and Designer are both included in a larger team (Mfg Eng, Purchasing, etc.) from the beginning of a project. Each person from each group works to their strengths and contributes to the success of the team and project as a whole. Working together, from the start, the Engineer can focus on the engineering and the Designer can focus on creating efficient models that capture design intent and all the Design For "X" requirements. There is no "hand-off" or "throw-it-over-the-wall" senario to garble communication. The Project Manager (sometimes this is the Engineer) keeps a project binder(s) where all the specifications, documents, redlines, sketches, notes, etc are kept. Everyone is "on the same page" because they've been involved from the beginning. As a bonus, sometimes excellent design ideas/solutions come from team members not directly involved in design.

Granted this explanation is extremely oversimplified but I hope you understand the relationship I'm describing.

Any senario in which I've worked that involved bringing in any person or group part-way thru the project caused delays and errors primarily due to poor communication.