Drawing for part with multiple common features

[liegev]

thread1103-411884

So it's been some time now and KENAT's suggestions seems to be the next logical step for me.

What would the best way to call out the more generic drawing within the more specific drawing.

Say there is bend and a hole location that is on the specific drawing but not called out because it is generic. Would something like this work?

<-----SEE DRAWING X123-4567

(apologies if the referenced thread does not show and this post makes absolutely no sense - I will update if needed)

 

[MintJulep]

This seems like a good use of "Make from".

As in "Make from X123-4567".

Or the "Material" could be X123-4567.

 

[jassco]

Hi, Liegev:

I think this is a question of part no. You standardize your part no. and create relationship between them.

Part A
Part B
Part C

You can have a part C made from part B which is made from part A.

With relationship, you can do anything you want.

Best regards,

Alex

 

[liegev]

Mintjulep,

That's perfect. I tossed a callout on there and it makes a ton of sense.

jassco,

I'd like to dig a little deeper here. X makes the bends and the common holes. Y1 has all the features for that specific product.

What I'm missing is the way in which you would annotate the drawing in order to communicate that to manufacturing.

If X makes Y1, ideally X should have no mention of Y1 in it. If it did, I would have to update X every time I make a new Y1 or Y2.

Is there a term for this kind of part to part relationship? I'd like to look into this some more. Maybe there is good document control manual out there that I need to be a bit more familiar with? I have Watts Engineering Doc Control Handbook, but I can't see a mention of that kind of "makes" relationship.

As always. Thank you all so much.

 

[jassco]

Hi, liegev:

You have a raw material to make this part. Let's call it "RAW".

You will make "X" from this "RAW" as material above;

Then you will make "Y1" from "X"; (Note: "X" is essentially material to make "Y1")

You can also make "Y2" from "Y1" if necessary. As a matter of fact, you can make anything from "RAW", or "X", or "Y1", or "Y2".

The term is Material for an item. If you use Solidworks, it is called "derived" part. Other CAD software have something simiiar.

I hope this makes sense to you.

Best regards,

Alex

 

[3DDave]

Typically this would be a single drawing with a note on the feature that one part number has the hole and the other part number does not.

Going the "make from" route means adding an additional step to the manufacturing process and one more drawing to be managed.

Instead of one Drawing Y documenting Part Y1 and Y2, you have Drawing Z documenting Part Z and Drawing Y documenting the changes to Part Z to create Part Y.

In typical operations that means when manufacturing gets an order for Part Y they need to then generate an order for Part Z which means getting both drawings. Part Z is fabricated, run through QA/QC, and then turned back to manufacturing to be modified, then run through QA/QC again for the new features, risking that the part is mishandled and no longer conforms to Drawing Z when it's put on the shelf.

This is a problem for documentation systems where Drawing means Part in one-to-one correspondence. People like that system because revisions cannot propagate; the disadvantage is that it causes the exact difficulty originally mentioned. There's no universal solution, just ones that hurt in different ways.

 

[drawoh]

liegev,

KENAT was describing the ASME Y14.100 process of tabulating your drawing. Your drawing is number X123[&#8209;]4567. It describes two parts, X123[&#8209;]4567[&#8209;]01 and X123[&#8209;]4567[&#8209;]02. You have a table (hence "tabulation") describing the difference between your parts. If the difference is the position of a hole, the table can show the two dimensions. If the difference is a hole that may or may not be present, the table can refer to an alternate drawing view.

Are you using 3D[&nbsp;]CAD? How does it support alternate versions of parts?

How will your manufacturing manage two different versions of your part? MintJulep's suggesting is that your primary fabrication drawing is X123[&#8209;]4567. Drawing X123[&#8209;]4582 calls up that part and lists modifications. Maybe that suits your manufacturing!

Always ask yourself what you are trying to accomplish. A tabulated drawing with 98% of features common is easy to manage if commonality was your design intent. A sheet metal part tabulated RH and LH shows the fabricator that the flat layouts are common.

If I have a tabulated drawing and I want to modify one part only, things can get complicated, especially if it has to be implemented by CAD[&nbsp;]monkeys.

--
JHG

 

[3DDave]

The nightmare fuel of one-drawing-tabulated parts is from "I only want to revise the exact part that changed, not create revisions of all the tabulated parts at the same time, so I want to keep all the parts on individual revisions but force them to be in lockstep except when they aren't."

Usually this causes the PDM guys to get unhappy and that ropes in the order management people who get all bent out of shape because they have to cancel the Rev C orders for Rev D, but product conforms to both, and they marked the "C" revision on the parts so now they have to throw it all out.

Having lived the alternative, which meant updating thousands of nearly identical drawings because a new note had to be added to what would have been a 1-hour job on a tabulation, I don't get it.

But every situation is different.

For example, ask me about using parts created as mirror parts to "save time" when the reality is that the mirror part stays mirrored for about 10 seconds before someone asks to add a new flange to just the left-hand one and now the mirror fails and needs to be built from scratch and get into all the places in next assemblies that no longer have the same references and all done in 4 hours before the next change board. Good times.

 

[liegev]

jassco,
Absolutely perfect. The incorrect concept that "material" and "raw material" are synonymous was keeping me from seeing how obvious this was. The second I stopped thinking about it that way, everything fell into place. I've got a drawing "X" that documents the 20 or so features that are common across all those products. Now I've got one super clean "Y" drawing that calls out "X" as the material and documents the 20 or so other features that are specific to that product. Honor is due.

3DDave,
Love the quote "There's no universal solution, just ones that hurt in different ways." I know the manf. folks, I'm confident this is a massive improvement. It's be confirmed when I toss this over there to see what they think. The last drawing we were using was a dozen pages dues to all the features (not just holes) that were changed from one product to another. This is clearly the least painful approach for everyone. As an added bonus, the tools seem to reflect this philosophy. They stamp the blank and a bunch of the holes, then bend a few times, and then the custom stuff comes last.

drawoh,
That older post used holes as an example, which lends itself to a table really easily. Some of the other more complex feature do not. The "material" seems like the best choice for this particular application. But I hear what you are saying. Much appreciated. Also, what's a CAD monkey?

P.S. This website is second only to Wikipedia in term of how much useful knowledge it contains. Thank you all so much.

 

[drawoh]

liegev,

A CAD[&nbsp;]monkey is a person who knows how to operate CAD, and who knows bugger all else. In general, CAD[&nbsp;]monkeys are assumed to be idiots. 3D parametric CAD is not the least bit idiot resistant. They are not compatible with tabulated drawings. Ask yourself how easy your tabulation is to administer. Keep things simple.

3DDave,

This is I brought up the modify-one-part-only scenario. I didn't word it very well. It is design intent. I may be designing a Meccano style frame, where left and right designation is reliable, and an opportunity for fabrication to save time and money. If I am designing a chassis with all sorts of mount points, one side will get modified. Tabulation quickly becomes a bad idea.

--
JHG