Documenting a Product for Production — A Key to Quality

If a product fails to meet customer expectations (the definition of quality), then there are three possibility causes:

1. The manufacturer failed to maintain drawing compliance.
2. The drawings failed to produce a product that meets the requirements.
3. The product was used outside the product requirements.

Production can only make a product as good as the documentation. Even if the product is perfect, if it is not documented correctly, quality will suffer.

Engineering has completed its mission when the product will meet the requirements if the drawings are followed — that is, production is in “drawing compliance”. The drawings should leave nothing unsaid. Tribal knowledge should be reduced to written instructions. Workmanship compliance should be specified. All parts should be on the BOM — including consumables. Approved vendors should be called out where they are important.

Anything short of perfect documentation will result in a less-than-perfect product.

Here are some tips in your quest for the perfect documentations:

Make Sure the Requirements are Correct: Our research, as well as others, show that the number one reason for a lack of ROI on product development is a failure of “product market fit”.

Documenting your product for manufacturing will take time and money. It’s important to make sure you still believe that the product will fit the market — that is, enough people will buy it for enough money to create a profit that exceeds the investment.

We have a great Requirements Document template here.

If you want a refresher on how to determine product market fit, have a look at our white paper here.

Do a Design Verification Test (DVT): You don’t want to document a product that does not meet the requirements. Conducting a DVT will prove that the product does meet the requirements. A good DVT should validate all the requirements with a test, analysis, or inspections. At a minimum, your should verify:

1. Functional Requirements
2. Performance
3. Unit Cost/COGS
4. Compliance: UL, FCC, RoHS, etc
5. Reliability
6. Life Span

Create a Drawing Tree: If you have not already done so, create a drawing tree and review it with the team — engineering and production (or your CM and vendors if you outsource manufacturing). Often this review will reveal missing drawings that need to be made or drawings that are incomplete.

Use Checklist to Review the Drawings: Each drawing should be reviewed by at least two engineers using a checklist specific to the type of drawing: detail, PCB Layout, assembly, etc.

We have a set of drawing review checklists here.

Get Production Involved Early: It’s never too early to get production involved — including your CM and any key vendors. Often that can help with parts choice and methods.

Have a Drawing Control System: Drawings are only as good as the system that controls them. Using the wrong drawing is one of the leading causes of poor quality and high parts scrappage costs.

Manage Work Instructions/POs: Creating good work instructions and POs is an important part of controlling the supply chain. Now is a good time to review your procedures.