For unmodified parts, we assign an internal number and name their model (if provided) with our number. We usually get PDFs of their prints, so we create our own slddrw file and insert the PDF into it so we stay consistent. Then we assign the COTS part number as the material so our procurement group knows what to buy.
For Modified parts, we create our own drawing as if it were a rework print. We put the COTS part number as the material and only indicate on the drawing what is to be modified (plus a few reference dimensions). In most cases we do not pull 2 separate part numbers, but if we used both the unmodified and the modified version of the COTS part, we would pull a number for both.
We also assign our own part number to downloaded parts from say, McMaster Carr. We list thier purchase part number on the data card and also on our drawing BOMs we pull in that purchase part number into a separate column.
In the case of modified (or make froms) we make a new number for the modified part and for us, we typically copy, paste as reference to the new part. An example, we buy some tubing BLK0001, and we then cut it to length. New Part number TUBE0001 which contains .25in of the purchased bulk item.
This works well when the purchased item does not have a model. For example, bulk wiring, we don't model the 100ft roll of wiring that we actually buy, so we create an "empty" or blank model, or you could use a virtual item as well. We will likely model the cut to length wire as it's used in an assembly. This makes your BOM accurate, and we export our BOMs into our ERP system so PDM serves as the Gospel BOM.
We are installing EPDM over the next couple months, so I am currently soaking in this forum category for the first time. I look forward to your recommendation as it related to EPDM.
In our current system we have to create a drawing with an internal company p/n, and it only references the vendor part number on the drawing. This way we can swap vendors without having to worry about changing our assemblies & BOMs. This is important because our parts are qualified for aircraft use, so if we design our vendor item control drawings correctly, we can do this without having to get approval from our customer.
Then if it needs modification, we can do it right on that drawing.
Anything we buy but do not modify is assigned a part number. If we modify a purchased item, we create an assembly, insert the part as the only item in the assembly and create any modifications as assembly level features. This approach gives the proper structure in SW BOMs. A BOM for the modified part will list the purchased part.
Here all vendor's have a CAGE code! And we use there part numbers so anyone can order the replacement part if needed. We use the existing vendor part number unless there is a modification we are doing to it then it becomes a new number and what is called an altered item. By using the vendor CAGE code and part number anyone can easily order replacement parts. But remember this is DoD we are not worried about making money on service orders. Just making sure the part can get to where it needs to ASAP.
For us it depends on what we buy. If we buy the vendor part and then we modify it, we use option 1 and have two part numbers. However we do not have much machining capability; mostly assembly. So if we buy the modified part from another shop and THEY buy the vendor part, we just note it on the drawing and use option 2 with one part number.
I have used a combination of your two options in EPDM over the last 7 years but the one I believe works most productively with all parties involved (from engineering, to supply chain, to production) is shown below:
- If you don't modify the part, keep the manufacturer part number.
- If you modify the part (own it), assign it a company part number.
Here are the highlights of what I've done:
- Create a separate folder structure "Parts Library" or "COTS Parts" in EPDM to keep it separate from your main engineering data.
- EPDM template to create a new "Vendor/Supplier" folder under the main "Parts Library" folder. Engineering can run this template.
- EPDM template assigns supplier name, address, CAGE code, website, phone, etc. to the folder card.
- Store all downloaded data for this supplier in this folder by the supplier/manufacturer part number. There is a possibility of duplicated numbers but pretty rare.
- If our company will alter these parts, engineers create a new internal company part number and store the data in the engineering project folder and note the supplier part number on the drawing such as "MAKE FROM SUPPLIER PART NUMBER XXXXX-XX-XXX" or something similar.
Lastly, engineering needs the freedom to move fast and drop the data they will use into EPDM. Having a one person role for this is rather cumbersome and creates opportunity for bottlenecks.
Hope this helps
The only thing I would do differently from what Tim described is have the folders by part type (e.g. Springs, Bearings, Screws, etc.). In my experience, the engineer looks for a particular type of component, but they don't know who makes it, or who supplies it. Creating folders by vendor or manufacturer requires some special knowledge to find the type of component you are looking for. Of course, you can use the search tool, but most people instinctively browse first.
As an engineer myself, I strongly agree with Tom on this. I have heard this input numerous times over the years and created something in a testbed.
I created the structure I mentioned above then created a secondary "Parts Library" folder with categories or part types. The idea is to have the engineer who creates the library parts in the "<Vendor>" folder then "Paste Shared" the parts into the correct part type folders at the moment of creation.
This way you have two searchable data sets and your engineers can peruse by vendor and by category.
There are probably much better ways to accomplish this using the data card and an addin...but this works.
Thank you all for your feedback. It's pretty much in line with my thinking but it helps to validate with others in the trenches.
The biggest issue I have is 'what to do with the files already in the vault' - I'm thinking move and rename.
Another thing I like to do with my part libraries is to utilize configurations for the specific sizes or materials, etc. of a family of parts (e.g. MS parts). Usually we try to find a balance point between materials and sizes by splitting them into separate files if there are hundreds of different sizes and several different materials. In those cases, we have a file naming convention to clearly indicate the scope of that file. All dash numbers follow the manufacturer's or standard's numbering convention. It might look something like this... MS21209-(-)L, where the "(-)" indicates the variations allowed within the file. Then the configuration names are the remaining dash numbers that fill in the blanks "(-)" of the filename, that make up the part number.
The advantages of this are:
- Clear communication between engineers on the scope of each file
- Quick, easy selection / changing of component sizes within a family of parts (no replace components & mates)
- Shorter set of files to browse through when looking for a component to use
- Leverages collaborative buildup of libraries