The CMDC Advisor:
The Device Master Record



What does it take to manage the Device Master Record effectively?


There are several aspects to this fundamentally important question. How these aspects are addressed impacts company operations far more than most people realize. The effectiveness of the document control system depends on what documents go into the DMR, how those documents are linked or related to each other, and the content (text or graphic) of each document. Every department and activity involved in manufacturing a product from design to shipment is affected.

So, what should the DMR contain? - The FDA defines the content requirements of the DMR in Sec. 820.181 of the Quality System Regulation. The FDA also excluded internal and supplier audits from the DMR (but still requires management to certify that they were done). Regulations aside, we feel the only practical approach of effectively managing the DMR is to include any and all documents associated with the product in a defined structural relationship organized under each product. This idea of organizing all information by product (rather than by type) is relatively new. The concept is called Product Data Management or PDM. PDM is a new paradigm, and under the new paradigm the DMR includes document types such as clinical studies, hazards analysis, FMEA, policies (quality manual), product development plans, product submissions to the FDA, marketing materials and so on. We do mean every document.

The FDA also created a new requirement, the Design History File, or DHF. From a PDM point of view, the DHF is simply a subset of the DMR, and should be managed as such.

Traditionally the contents of the DMR are found in several departments around the company. Drawings are controlled and maintained by Engineering. Marketing controls labeling. R&D controls and maintains design reviews, engineering studies, and development plans. Quality controls the quality documents and Manufacturing controls work instructions. The content of the DMR is determined by different departments and maintained at different levels of control. Combining all product related documents into the DMR and setting up a system specifically designed to control the DMR insures all product related documents are identified and controlled consistently.

The second aspect of managing the DMR is how documents are linked or related to each other. The following example using BOM and assembly drawings illustrates how this linking of information can affect overall performance.

There are three ways in which BOMs and assembly drawings can be organized or structured.

Option 1: BOM and drawing: one document and document number

Option 2: BOM and drawing: two documents with the same number

Option 3: BOM and drawing: two different documents, two different numbers

All three options work; however, we found keeping drawing changes to a minimum significantly reduces the time needed to process changes. Drawings are the most expensive and time consuming documents to create, change, reproduce, distribute, file, and retrieve. So anything you can do to reduce drawing changes will reduce cost and speed-up change processing.

Using Option 1, the traditional model, works well for manual drawings, but on a CAD system the plotting time alone makes this option inefficient. We found that the graphic part of the assembly drawing usually does not change when part numbers on the BOM change. CAD also requires highly trained and well-paid operators.

Using Option 2 does not entirely eliminate the CAD function from the change process. The revision on the assembly drawing must still be changed to keep the BOM and assembly drawing in sync. Most companies using this option are creating the BOMs from the MRP system. BOMs can also be created on word processors, or ideally in a CM/PDM database system.

We feel Option 3 is the most efficient method overall. Requiring additional pieces of paper on the production floor is the main objection to this option and option2. We have found having one or two documents on the production floor is more of a personal preference than a question of efficiency. While not having the part list on the drawing is perceived as "extra work" the reality is that many organizations do have two pages and have made it work effectively.

There are lots of other examples of how document relationships affect document system efficiency: labeling and art work, tabulated drawings, software and firmware, to mention a few. Document organization can be done many ways, but we have found that only a very few "options" really work effectively over the long run. When a company is small or young with only a few documents, almost any option will work. Inefficiencies begin to show up as the company's product line grows and the document system gets larger.

The biggest problem with Option 1 leads us to the next aspect of the DMR. Ultimately, this is the most serious limitation of Option 1 thinking in a modern day information-based operation. We refer to this aspect of DMR management as document content.

Anytime a part number (document number) is put into the text of a document (or on a drawing), the only way of associating the part number with the document is to read the document. One has to read each document to determine "where used". Before computers and MRP, doing a "where used" effectively was next to impossible. Parts were put on assembly drawings to make an association to help humans navigate in the system. Other tools such as "intelligent" part numbers and complex classification schemes were also used. None of these tools, however, could guarantee one would find everything. Success depended more on the individual's knowledge of the system, and knowing the content of each document, rather than the system itself.

Today we make these associations in a structured database. We do not look at a document's content to run a "where used", but go to the computer. Creating and printing out a "where used" is a simple and efficient task for MRP.

MRP has done a good job with the "where used" for parts, but many document systems are still relying on content as a primary means of finding documents. For example, one may have to go to the assembly instructions to find which QA inspection procedure to use. There is no "where used" capability on the QA inspection procedure unlessthe procedure is listed on the BOM. (Note: MRP can handle this using work stations and routers to tell production what to use. Work stations and routers are not part of the product structure as required by PDM. In other words, procedures would not show up in a fully exploded top-level BOM, or DMR)

To effectively manage the DMR, each document must have its own unique number and must be structured under each product with which it is associated. CMDC created a concept we call the Controlled Document List, or CDL, for doing just this.

A CDL is like a BOM in that it contains all the parts and subassemblies in an indented structure, but, unlike the traditional BOM, the CDL also includes all product related documents associated with an assembly. CDL structures are inherently more complex and typically contain more than twice the number of items found in a BOM. For example, a BOM structure typically goes just to the part level. In the CDL you will find under the part the inspection procedure, any qualifications, supplier ID numbers, and material ID (if applicable). Supplier qualification, record of audit, waiver of audit and qualification record, and so on are found under the supplier ID number(s).

CDLs can also be set up as indexes. SOPs and policies associated with manufacturing can be placed in an index under the product. Regulatory documentation, such as 510(k) or PMA submissions and releases, can have its own index under the product. Design History File (DHF) documents can also be indexed under the product. This type of organization will keep track of all product related documents, which will make it much easier to know if a change might affect or be affected by some earlier product development work.

Again, the objective of PDM is to organize all documentation under the product in a structure much the same way MRP structures assemblies and parts. It's an excellent way to effectively manage the DMR.


We recommend that each company have a written policy that addresses the content and structure of the DMR, and work toward a fully structured DMR on their next product. The fully structured DMR contains all of the documentation in a structured (indented) relationship.

Establishing a policy does several things for you. Products will be structured consistently. The agreed-upon product structure will provide project management with an excellent tool for determining what documents (tasks) are required at the beginning of the project. The system works equally well in automated or manual mode, and meshes particularly well with typical project management systems. Any document can be found by starting with a Device Master Record Index. All documents (i.e. the DMR) are centrally organized and consistently controlled. The DMR is no longer being maintained in several systems by different departments at varying levels of control.

Getting used to using product structure rather than document content to find documents is not difficult. If fact, many people find searching for documents much easier once they have abandoned traditional classification schemes and numbering systems, techniques developed during World War II.

We do not recommend that you try using a fully structured DMR in MRP systems. MRP is designed for controlling parts, labor, and cost. Your DMR system controls documents (paper). Documents are not purchased, stocked, or consumed. Adding document information will more than double the MRP item master with information the system was never designed to control. Our system (and the data model we provide in the book) is designed to manage documents outside the MRP system and coordinate where necessary.

We provide an example of a fully structured DMR in our book. This structure can be easily extracted into a corporate policy, and can be applied to any product. We also discuss "options" that you have in structuring the DMR and recommend those that will cause you the least trouble in the long run. It's not that other options won't work; these options will maximize the overall system efficiency.

PDM (fully structured DMR) is truly a new paradigm. For more information on PDM we suggest you visit the PDM web site .

We would like to hear from you. Please feel free to contact us with any comments or questions concerning the Advisor via e-mail. There is no obligation.

Return to CMDC Home Page  Image

Return to Advisor index

Copyright 2003, CMDC systems, inc. All rights reserved.