Assembly drawings package question

[A.DelNegro]

Ok, so here's a question...

I have an assembly of 20 parts. I will need machine drawings for most of them. Is it better to create ONE drawing file with a page dedicated to each part OR a separate drawing file for each part.

I have always created a separate drawing for each part and a separate drawing for the assembly. I had a contractor in who put all the drawings in one file. We argued over the merits of each method.

I'm wondering if there is a 'suggested' way or possibly a 'better' way or is it like a lot of things in Creo, you can do it both ways and you pick which way works best for your.

T



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[nrollins]

If the design is a tool or a prototype, I don't see a problem keeping it on
one drawing ** if you want to deal with rev control that way. Sounds like a
hassle to me. If it is production, I would _never_ put multiple parts on
one drawing.



So, tell us, what are the advantages claimed for having all the drws on one
multi sheet. I don't see an obvious pro.



Nice Friday discussion.



Happy long weekend for all you fellow U.S. users (Memorial Day Weekend -
yay!)



-Nate

[mpeterson]

I think it is better to have one part drawing per part with an assembly
drawing including a BOM for all the parts. I worked for a company that had
some manufacturing fixtures with around 30 parts per assembly and put them
all in one drawing document with near 30 sheets. They liked the convenience
of having all the details in one document for sending to the vendor and that
seemed to be the ONLY benefit. It does take a little time to round up all
the part drawings and files to send out for fabrication, but that effort is
done very few times during the entire design process.



These large multi sheet drawings get really large. Single part drawings are
smaller and easier to deal with.



If one part cannot be found you cannot open the drawings and have to start
playing games to create a dummy part to even open to start fixing the
problem part. If a part cannot be found on a single drawing all the others
are fine.



If you need to make a similar part and drawing you and do a quick save as
and get both part and drawing with the right config settings



If all the parts are in one document only one person can work on the drawing
and parts at the same time. Multiple users can work on a project with
individual drawings.



Revision control is much simpler with single part/drawings.



Those are the benefits I can think of off the top of my head. I am sure
there are more.



Use the KISS principle. Keep It Simple Stupid



I am interested to know if there are some other REAL benefits to multi sheet
and multi part drawings. Currently I don't think that is the way to go, but
it can be done if desired.



Sincerely,

Mark A. Peterson

Mechanical Design Engineer / Industrial Designer

-

[drichards]

I've seen the "composite drawing" thing while working at two, maybe threecompanies, frankly I think it clearly shows the stupidity of the person who started the practice, and the foolishiness of the company to continue it. I've seen a lot of cases where people who are "entrenched" in a company do this stuff just to do as he pleases or to exert his influence.

Far too many companies get stuck in repeating the same foolish practices forever, apparently thinking if it was done previously, it has to, or shouldbe continued. Or, if someone provided instruction to do it that way, it's better to blindly continue doing it that way than toengage the brain.

[A.DelNegro]

So... A heated discussion it becomes... Just so you know, we are a small company with only 2 seats of Creo. We don't have a PDM system or any other means of managing files.

I asked my contractor why he uses multi-sheet drawing and what he feels are the pros. Here's what I got back. I don't really agree. I think the hassle they can cause would overcome any benefits gained. Also he mentions revision control, but I simply have a parameter in each part that automatically updates the assembly drawing, so I'm not really sure why he thinks reckon control is so much easier in multi-sheet drawings.

[DonSenchuk]

I gotta say his response looks to be following the PHD method of slinging BS; Piled Higher & Deeper. Nothing about what he talks about makes sense. Our Tool Design department uses that method and even they admit the only reason is to make it easier for vendors to keep components together. Everything has the same drawing number, so they know everything goes together (12345-1, 12345-2, 12345-3, etc.) Not the best reason but they don’t make the attempt to justify it with some sort of ridiculous revision control argument.

In the end it’s your decision. If he’s a contractor, he does what you tell him to do. No discussion, no argument, no reasoning it out.

In Reply to Anthony DelNegro, P.E.:

So... A heated discussion it becomes... Just so you know, we are a small company with only 2 seats of Creo. We don't have a PDM system or any other means of managing files.

I asked my contractor why he uses multi-sheet drawing and what he feels are the pros. Here's what I got back. I don't really agree. I think the hassle they can cause would overcome any benefits gained. Also he mentions revision control, but I simply have a parameter in each part that automatically updates the assembly drawing, so I'm not really sure why he thinks reckon control is so much easier in multi-sheet drawings.

[JonathanHodgson]

I've used this type of approach in the past for fabricated items ("weldments" if you prefer), but in reality I suppose I considered them to be not so much individual parts, but rather details or stage drawings for elements of the single finished part. I think this is similar to previous comments about use with jigs and manufacturing fixtures.

If they really are separate components, then I'd only even consider putting them on a single drawing if there's no possibility at all of ever wanting to re-use any of them in a different assembly. And probably also only if I could guarantee that they would all be made by the same supplier. In practice, there's little chance of both (or even either) of those being satisfied.

Jonathan

[davehaigh]

At a previous company we did telecom equipment. Rivets and spot welds for the card cages and exterior cabinets. The item sold was the top assy, so that was the drawing.

All the individual parts were detailed on one drawing. Some of the larger cabinets would have 25 or more pages. One design was so big we had to break it up in to two drawing files of 15 pages each. But it was the same drawing number.

David Haigh

[StephenW]

I have done both at several different companies.

Years ago I worked for a company who switched from single part drawings to "composite" drawings. The reason was revision control on sub-level parts when the top level part was what was ordered from an outside vendor.

For example, say a weldment was farmed out to a weld shop. After the purchase order was issued for the weldment (at a specific revision), one part of the weldment was revised for whatever reason. The change was considered inconsequential to the assembly so it was not revised. Since the buyer is tracking the revision of the assembly, not the piece parts, he did not realize he need to send the new revision to the weld shop. They would build the assembly to the correct revision of the assembly but not to the correct revision of all the parts.

Now, you could say the buyer should be watching all the parts of the assembly to make sure they didn't change. I basically agree. But, if, as a buyer, you are responsible for say a 1000 purchase orders at any given time, you better have a really good method or system that warns you of revisions. This specific company was a small-medium size company with limited resources. They did not have access to million dollar systems. Heck, I think at the time, they were using microfiche for drawings.

Each company can have their own perfectly valid reason for doing it one way or another. I would not consider it "stupid" or "foolish" or any other derogatory term. I would say they found a reasonable solution to their specific problem. Sometimes you have to step outside of the engineering box and look at what the other people in the organization do and what their challenges are.

[jlippeth]

Fun topic

So back in the day using a 486 Pentium with an AccelGraphics 8MB AGP video card, Win XP with the 3 gig switch.

Large assemblies and a 100 sheet design with a 45 minute regen time, yea we needed to split up the drawings.

Much easier to do with the computing power available today.



With that said,

For me a multi sheet design makes sense

We typically can have 25 – over 100 sheets for one project

We report the sheet number on the BOM (Detail 2200 / Sheet 18)

Question, How does one do this on a single sheet per comp drawing file when all the sheets will be Sheet 1 of 1?



On larger jobs we may start off with several drawing files, mold_asm, mold_plates, molding_comps, mics_comps.

If needed several people can detail at the same time.

Once complete the lead designer can merge the drawings together, click the custom mapkey “Rename Sheets”, an all the sheets get renamed in secs.



Having the multi drawing sets is ok, but trying to manage the sheet numbers where one set leaves off and the other begins can be a pain, not to mention making a PDF, with a single drawing file with multi sheets it’s a “One Click” PDF button and you’re ready to print.



Note: On the multi sheet drawing file, one comp per sheet, format sizes to vary **

** I do not use an “A” size drawing format, primarily because the wide format printer is setup with two rolls 17” and 34”

Having an “A” size drawing will alarm the printer, with this setup I make a PDF, Print, Done. It’s that easy!



Just my point of view

Hope this helps





Jeff Lippeth ▪ Mold Design Engineer

NyproMold, Inc.

▪ P 847.855.2226