Product data management (PDM) is the process behind automatically managing all the design data contained in engineering shop drawings and associated documents regardless if they are digital or paper.
Back in the day, It was the collective bills of material on a set of shop drawings that were the primary source of all the procurement information. That Bill of material often got turned into spreadsheets so that the data could be entered into a companies purchasing system. The parts and assemblies were numbered and the data entered into the companies production information system
One of the drawbacks to this, is that a lot of information was not always captured by the bill of material. The paint colour, the material finish, special instructions for fasteners were often contained only in notes on the drawing and this information had to be tediously copied one at a time into a companies production information system.
Sometimes there were no actual shop drawings at all. Every bit of information about making a particular product was spread across varied spreadsheets, word documents and handwritten paper sheets in 3 ring binders. In some cases it was all contained in the head of one key employee who had been around long enough to learn every conceivable detail about the products manufacture.
Product data management is the system that tries to replace that single key employee, and all the documents as well with a single source of data entry that takes products from creation to shipping to after sales support. Tracking all the data and archiving all the steps along the way.
Modern CAD systems create the files, archive them and provide revision and version control. Systems like OnShape store their files in the cloud so and certain files can be given permissions so that vendors and design engineers can actively collaborate on any given design using tools such as Zoom or Teams conferences.
This video from OnShape shows how this collaboration takes place.
Multiple designers can work on different aspects of a product at the same time and be able to see what each other is doing. Alternatively they can branch the part they are working on and then save it back to the main model so everyone can see the changes. If changes to externally referenced files are made, the software the lead designer that there is a new version and to update the design.
The engineers give access to the 3D model and post it live on the conference so that the vendor can redline specific areas that need to be changed in order to improve the design or integrate it with a specific part. The changes can be recorded as separate versions within the CAD software so that they can be evaluated. The versions are archived in case they need to become product revisions in the future.
Finally the model can be shared with outside vendors so they can be sure the parts they are supplying will work. This is analogous to texting pictures of a broken part to get the right replacement except the vendors have the ability to manipulate the CAD model to make sure the geometry of the new part is correct.
Once the product has completed all design detailing it's ready to release to PDM as revision 0 release to manufacturing.
There are also plenty of industries where drawings are the primary control document for products. The pharmaceutical industry for example may have dozens of products and thousands of ingredients, all tracked by spreadsheets, emails and Teams and Zoom conferences.
The first step in unified product data management is to keep every bit of product information in a single place or database. There should be only one location for the product description, part number ,SKU number and so on.
Every department, shipping, engineering, sales through administration refers back to this single database for whatever product information they need
Built into this single database is change management and revision control. When a part or a process gets changed for any reason each revised part is treated as seperate and distinct and complete history is recorded to keep track of what versions were used and with which customers.
This kind of information is essential if you are going to be supplying spare parts and have to know if there are compatibility issues that may arise from shippping the customer a Revision 4 part when he or she may have originally purchased Revision 1.
The PLM system database records dates and times for purchases and for manufactured items which makes it possible to forecast requirements based of previous years demand.
Since I started working in engineering in 1982 always had an interest in the whole process of making a product. I was fortunate to start working a company with an early MRP (Materials Requirements Planning) system and especially an enthusiastic professional engineer who devised a standardized BOM (Bill of Materials) for our line of end load cartoning and packaging machinery.
That 20 page standardized BOM was a printed Microsoft Word document that made creating a Cartoning machine easy. Because it recorded all of the drawing packages and parts lists of every type and size of packaging machine the company had built going back twenty years. All organized by type and size of machinery.
The single best thing about the standardized BOM is that you only had to engineer that which had to be customized on any new machine. Usually 90% of the machine you were building could be put together just by checking off assemblies and parts lists of machines that had gone before. It eliminated waste that could be caused by drawing things over and over again that had been done before.
Tony the Engineer understood the value that existed in in all the legacy drawings and how important it was to catalogue them and most importantly filter out those assemblies and parts lists that could be reused any time a new order arrived.
He made drawers full of old hundreds of old paper drawings wonderfully productive. Tony understood the principles of Lean Manufacturing long, long before there were dozens of tutorials on YouTube.
Fast forward to the 2020's and there are still plenty of engineering departments using the latest CAD tools with storage capabilities we could not even dream of back in the 1980's.
I still remember the myself and the whole engineering department mobbing around an IBM XT with a newly purchased 40 megabyte hard drive and declaring it was a veritable "black hole" of data storage!
But even with these new tools 3d models of the same bracket thats been used in potentially hundreds of machines is recreated by almost every new hire and given a new part number. Modern CAD systems even encourage the creation of duplicates by allowing you to create parts in context.
The standardized BOM has never been needed as badly. It's a solution when CAD users dont even realize they have a problem.
As good as the standardized bill of material is, it's use typically is most important in the engineering department. It is fundamentally a user guide to getting critical information into the BOM database across all of the engineering disciplines used in the project and preventing duplication.
New I deliberately say database because in no way do I want to create the idea that the engineering Bill of material is just some spreadsheet that gets filled in following the guidance of the standardized bill of material.
Spreadsheets are inherently one dimensional and the multi level part/assembly relationships shown by the standardized bill are more than just indented tabs on a spreadsheet. They need to be tables with relationships in a relational database of dataset.
Once a set of drawings and its associated bills of material are released to production, manufacturing is going to want to reorganize a whole new set of relationships in the BOM database that best suits the way they plan to go about manufacturing the parts.
Every designer has heard the phrase, that part is released now you cant be making any changes to it. Yes but there's the rub ! It's almost a given that that there will be changes and additions necessary as manufacturing and purchasing moves forward.
In many companies that use enterprise requirements planning (ERP) systems there is usually a Bill of Material (BOM) module or database that initially gets populated using the parts and assembly lists from the standardized bill of material.
Aside from preserving the drawing BOM structure the ERP BOM module prompts for more information related to the parts and assemblies in its product master file such as which which vendors were used to specify the component, or if a component needs machining, welding, finishing or other processes.
Its important to understand that manufacturing may want to add new relationships to the tables containing engineering drawing information to produce their own manufacturing bill of material (MBOT). This MBOT might contain lists of parts for each machine center and lists of parts and assemblies for subcontract processes.
Similarly if the engineering bill of material is being released to production, The sales department may want to create new relationships by building spare parts kits with lists of parts that added to the company website for sale.
In much the same way accounting will want to interface bill of material information with its own software for client billing, as well as checking estimates against actual hours and dollars spent.
Inventory drift could be caused by unexploded multi-level BOM's
There is no way a single Bill of
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Breaking free from legacy workflows