In electronics design, many elements can directly impact the cost of manufacturing a product. DfM aimed to move the tradeoff analysis for decisions affecting manufacturing as early as possible in a design phase. I'll attempt to move this into the software architecture realm in a future article, but for now I want to explain how this worked in Electronic Product design.

What design decision matter in Electronics?

In electronic product design, here are a few to start your thought process -

Component Selection - Choosing components from an approved supplier and components that meet requirements but don't exceed specification (giving latitude to safety margins) directly impact cost of an item. Assisting engineers choose preferred part, parts already purchased and in inventory, and offering alternatives can really decrease costs and improve turnaround time.

Printed Circuit Board Size and Shape - Small PCB's aren't made one at a time. They are panelized onto larger sheets, fabricated and even assembled (components positioned and soldered into place) in that form before being broken apart and put into their cases. The more individual boards you can fit to a panel, the less waste and fewer panels need to be moved through auto-assembly equipment.

Printed Circuit Board Technology - If you make the board smaller to fit a certain device, you often need to add 'layers' for interconnecting components. This adds cost; If you make individual features smaller to fit more interconnects onto fewer layers, the manufacturing yield decreases due to mis-registrations. Its a real trade-off and highly dependent on your partners capabilities.

Printed Circuit Board Hole Count and Sizes - For some PCB technologies, drilling holes can be time consuming. Smaller holes needs to be positioned more accurately and these drill bits break more often. Normally, fewer holes of larger sizes is the cheapest way to go; However, some PCB technologies don't incur a cost per hole - which one will you specify?

Component Placement - Where is it safe to put large components? Where will the battery connect? Where are the pushbuttons? All of these decisions need to be considered when the PCB is being designed - BUT they seriously impact the final case design. How can the electronics designers and the mechanical (and brand) designers collaborate to agree on an acceptable design? For extremely high volume designs, placing similar components in the same orientation can reduce the number of machine rotations and component reel changes which reduces the total time of assembly. Saving 1 minute for 1 million pieces is substantial!

Early Focus and Scoring Matrix Definition

Design for Manufacture initiatives aimed to bring focus on the types of decisions made above and allow engineers and designers to perform trade-off analysis as early as possible in the process. The product might have to be smaller than a competitors and that forces a smaller PCB size and shape, which then causes a specific choice of technology - However, the key aim was to understand that early and make informed choices about which remaining options fulfill the global good.

To build a Report Card or Scoring Matrix, the basic process is -

1. Get together with all of your partners, suppliers, fabricators and designers and brainstorm a set of issues that impact cost. Similar to the list provided above, the idea is to get the 'issues list' on the table.
2. Group these issues into a sub-set that can actually be measured and scored. E.g. "Number of boards per panel", "Number of holes smaller than 0.5mm", "Number of different components types", etc.
3. Determine relative weighting for each measurement. Some requirements cannot be broken, other just incur a cost. I'll propose a process for determining this weighting in a future article; for now, just understand they won't all have the same weighting factor.
4. Build the scoring scale for each factor. This step tries to normalize the different scales of measurements into a smaller linear set (i.e. 1 to 5, rather than 1 to 1 million for one factor, and 1 to 10 for another)
5. Calibrate the scorecard by testing on existing systems. Agree and alter the specific factor "Weightings" until you gain confidence in the scorecard
6. Use the scorecard on future design discussions.

Summary

Is it just as simple as substituting "IT Operations" for "Fabricators"; "Usability/Interactive Designers" for "Packaging Designers"; "External Hosting Partners" for "Suppliers"? 

In future articles i'll look deeper into -

• How to build a weighted score card based on issues relevant to software
• Propose some software specific issues and attempt to weight those appropriately
• Test our new scorecard and determine if it is achieving the goal we intended.

Be interested in comments as to whether other people agree there might by parity between DfM in Electronics to DfM in Software.

Troy.