BOM's On/OFF The Drawing - What do you do?

[leeave96]

BOM's On/OFF The Drawing - What do you do?

How do you handle your BOMs for assemblies?

Do you put them on the drawing or in a separate database?

What are the pros and cons of why/what you do?

I have worked where the BOM was ON the drawing, though manually created vs. CAD created. That worked great.

I have worked where the BOM was OFF the drawing in a database, though manually created.

Now days, the 3D package (read Alibre) will generate the BOM for the drawing and I suppose you can export that out to a spreadsheet and then to a database system. Problem is that sometimes, in my experience, not everything on a BOM is CAD generated. For example there might be reference documents that would be manually added to a drawing’s BOM and also lots of times, one doesn’t have time to populate the model with all of the fasteners required for an assembly. This causes a problem with CAD generated BOMs where in the old days one could edit the BOM to show the correct amount – more of a time driven/dead-line kind of thing.

Further, if you use CAD to generate a BOM and export it out, you’ve lost associativity with the original assembly. Sooooo, if you delete something, and try to re-export, your item call-outs could be out of sync with your database BOM.

Here’s what I am thinking.

Keep your “official” BOM in a separate database and not have it shown on the drawing. But, make a CAD driven BOM at the beginning. Use it to populate your database BOM – first time. Put the BOM on the drawing, but hide/suppress it and then use it as a reference/check for the future. Manually update the database BOM as changes require. Still lots of trouble and time, but it’s just a thought.

What are you doing?

Thanks!
Bill

 

[swertel]

I really wish there was an emoticon for "opening a can of worms." I guess this one is pretty close :twisted:

For those of you who don't want to read about my soapbox <insert soapbox emoticon> musings, just read the following line.
Parts lists go on the drawing, BOMs don't.

So now everyone is telling me to stop being such a smart-a$$ and explain why symantecs are such a big deal. In short, a BOM is a tool and you need to use the right tool for the job. Granted, my line in bold above is just a matter of symantecs, but it helps to clarify the difference.

A parts list is just that, a list of parts. Typically, these are the parts that are contained in an assembly, thus shown on an assembly drawing. You put the parts list (P/L) on the drawing so you don't have another sheet of paper to have to refer to, and potentially loose. Parts list do not contain assembly instructions, specifications, or purchasing information other than what is required to guarantee the engineering approved part is fully defined for ordering.

Bills of materials, on the other hand, do contain this information. There are many MANY BOMs: purchasing, production control, and product baselines just to name the most common.

For example, the engineer puts together the drawing package based on manufacturing requirements, including all subassembly definitions. Purchasing doesn't buy subassemblies created in-house, they just buy the components to those assemblies. Their BOM won't show the subassemblies. Production control needs to know which assemblies levels get built and stocked. They need a BOM that they can assign work orders to stockable part numbers. Product baselines capture the as-built condition. These include all parts, assemblies, specifications, and other documentation that is used to create the end-item deliverable.

Purchasing and production control can take a CAD developed BOM and import it into a spreadsheet for manipulation. Product Baselines are more intense and require a database as the back end. Even better would be a PDM system that ties into your ERP system. The link would allow the engineer to seed the database with the parts list. Document control would attach all the specifications, requirements, and other documents to each part in the parts list, creating a product baseline. Purchasing and production control would tag the items from the product baseline that they need for their BOMs and publish a report. That's how it works in theory, anyway.

 

[leeave96]

Wow! Great reply!

I have worked for companies with such structure and I guess it worked. Made things real inflexible. Reminds me of the time a guy told this engineer, "Theory strikes again."

I find in my neck of the woods (with respect to small business) there is never enough $$$ to have the software and staff to implement the BOM vs parts list deal.

What is am seeing is an all out effort to rid cost - at almost any cost! That means that a lot of times the engineer is drafter, designer, clerk, manufacturing go to guy for how something goes together and info gatherer for purchasing!

Sooooo, to save time (maybe) and keep it simple, I am courious as to how NOT to duplicate info.

That is why I ask this question. What are you doing with your BOM/parts list. On the dwg, off the dwg, in a database or both?

Thank!
Bill

 

[jwknecht]

I think that the assy drawing requires a parts list to define the content. Or, you could note each part with a text note, but that does not take advantage of the "BOM" functionality built in to Alibre Design.

When it comes to most mid to large size companies, you end up using another system for BOMs and all the associated functions (purchasing, manufacturing, etc.). However, take a look at the fields built into the Alibre BOM. There may be a good way to link the Alibre BOM to a live database that drives the company orders, etc. If so, this would eliminate duplication of at least the design content of the database.

So, to answer your question: Parts list on the assy drawings.

 

[swertel]

The history of my full-time jobs has mostly been in the defence industry. I know all about stringent and inflexible specifications. But in reality it is quite flexible. Every department adds the information that they are responsible for, no more no less. Everyone gets a BOM in the format they want. Also, everyone is pulling the BOM information from the same location. There is no duplication and there is a reduction in errors.

Now the typical installation is a combination of my soapbox rants and raves. For example, how many columns do you want to show on you parts list? The engineer should be specifying the specifications for all materials, finishes, and other manufacturing info. Put all that information in the part/assembly properties and link it to columns in a parts list. Show as many or few fields as you want on a drawing.

You can add a make or buy flag in the part models. Purchasing can use AD BOM tool to create a custom BOM from the Alibre models listing only those items with a BUY flag. Production control can do the same for MAKE. No database required, no PDM, no ERP, just Alibre Design with structured and disciplined use of file properties.

 

[scarr]

Re: BOM's and Parts List

If you populate the part Properties information under the General Tab in Properties, and select the material under the Materials tab, Alibre will import this information into the Alibre BOM on your drawing. You can then export the information as a .csv (comma separated value) file and open it directly in Excel. Sadly there's no direct link back to the BOM on the drawing so if something changes a new export will need to be created, but this does savea lot of retyping and does lessen the chance for transpositional errors.

 

[cherkey]

I don't think of the 'BOM' in my drawing as a BOM, rather I consider it a parts list. I create as exploded assembly view drawing for use in Production which they can use as reference while following the Work/Assembly instructions. I create a separate 'system level' BOM and send that over to be entered into our inventory system. There's too much involved with trying to use an Alibre created 'BOM' with our inventory system - they just wouldn't work well together. Soooo...my parts list on the drawing is just that - a tool to reference the callouts on the drawing.

 

[indesign]

:cry: Sadly we have not implicated using Alibre's BOM to sync with the purchasing software. We are a job shop where we have a high turnover of jobs and we have many that are repeated.

The trouble comes down to being able to incorpoorate the BOM from one program into another. They both need a common database and they both would need to be capable of changing from either the purchasing software or the developing software. I am still unsure of how and when we could implement this though.

I have not looked into how Alibre's BOM can be correctly incorpoorated to the Excell database or how the purchasing software can do the same but maybe I should.

 

[Oldbelt]

scarr wrote :"If you populate the part Properties information under the General Tab in Properties, and select the material under the Materials tab, Alibre will import this information into the Alibre BOM on your drawing.".

This does not function at least not at a seperately generated bom.
The materials column is not filled in.
Funny, because the Weight column is.

kind regards

Oldbelt
Do it right first time.

 

[moyesboy]

If you want to put things in your parts list and don't want to model them in 3D, then just add in an appriately named blank alibre part file to the assembly so it shows up how you want it in the parts list (or BOM depending on the outcome of your discussion with Swertel).

If you can't abide the hassle of inserting all the fasteners then just duplicate them with zero offset so they are coincident with the appropriate quantity so the numbers are right in the BOM. Yuo can also hide them if they are not in the right place.

Many shortcuts are available to get to what you want.

You can manually insert lines in the parts list too, but I'd prefer to always call the same part the same thing by referring to the external file. That way if you add additional info in that part description all BOMs that call it will update.

 

[swertel]

Re:

If you can't abide the hassle of inserting all the fasteners then just duplicate them with zero offset so they are coincident with the appropriate quantity so the numbers are right in the BOM. Yuo can also hide them if they are not in the right place.

I've tried several shortcuts in several CAD packages to not have to place all the fasteners. In the end, it was just easier to put all the fasteners into the right locations.
1) Proper mass/weight of the assembly
2) Proper CofG location of the assembly
3) Proper interference checking
4) Someone downline always seems to want to show the detail in the area of the model that I shortcut for things like assembly instructions, marketing flyers, etc.

Rather than deal with shortcuts, perhaps creating enhancement requests to simplify your tedious operations would be more beneficial, not just to you, but other users as well.

--Scott

 

[Oldbelt]

Please inform, all of you discussion the "proper" use of the BOM
functionality, have you the material, you specitfied in the parts property,
in the material column at the BOM.
I do not think this it function, at least not here.

kind regards
Oldbelt

Do it right first time.

 

[scarr]

I'll check the functionality again and get back to you. This was with a BOM attached to a part/drawing.

 

[scarr]

Oldbelt,
I'm back and I made a mistake, something I do at least once a day minimum. The material has to entered in the Material block under the General tab in order for it to show up in the BOM. Selecting the material under the Material tab will give you the weight in the BOM, just as you observed. Try this and see if it works.

 

[scarr]

It would be nice if the material fields inside the Properties panel were combined - select once, get the material and weight in the BOM.

 

[Oldbelt]

Hello Steve.
Thank you for the hint.
Once apon a time I asked Alibre to make the
connection between the property data and the the BOM,
but nothing have happend with 9.1, a shame.

regards Oldbelt

Do it right first time.

 

[scarr]

Hi Oldbelt,
The folks at Alibre do listen to what's said here in the forum, and I'm sure this is on their to do list - but I know that everything get prioritized, and there were/are probably bigger items they're working on, but we'll keep asking for things like this and I'll bet eventually we'll get them. I think an indented parts list that follows the structure of an assembly would be a great addition too. Have a great day.