Why should engineers care about the business side of DfX? The answer is simple: management teams are often more interested in cost than they are in how innovative a product you’ve designed. An innovative product with a design that drives efficiency throughout product realization process is a true competitive advantage. So, let’s look at cost drivers and ways that they can be eliminated.
Key Cost Drivers
Materials
- Sole-sourced components
- Over-specified components
- Lack of component commonality
- End-of-life components
Production
- Over processing
- Designs that are difficult to manufacture, assemble or test.
In many ways, the materials side of the equation can carry the greatest cost. First, materials are often 70% or more of the total product cost. Developing a bill of materials and approved vendor list that includes multiple options for each component increases the ability of sourcing teams to shop for best combination of price, quality and availability. A wider range of options also helps in the event of allocation or supply base disruptions.
Over-specified components often limit options. For example, specifying painted screws or other specialized finishes on parts in areas of a product where cosmetics don’t matter increases costs and the risks of parts shortages, plus may increase the opportunities for cosmetic defects.
Lack of component commonality at the product family level increases working capital requirements, contributes to excess inventory risks and impacts schedule flexibility. In today’s highly variable demand economy, reduced schedule flexibility can translate to missed opportunities. Solutions in this area can be fairly simple. For example, EPIC Technologies’ engineering team routinely recommends its customers consolidate resistor and capacitor values on BOMs. BOMs with a large number of values for resistors and capacitors increase material transactions, inventory and the potential for manufacturing defects.
Sustainability can also be an issue. There are a number of product lifecycle management (PLM) analysis tools in the marketplace that enable component decisions to be sanity checked quickly during the design process. EPIC Technologies’ team usesSiliconExpert to check component lifecycle status, perform an engineering parametric analysis, monitor product change notifications, check RoHS/hazmat status and analyze market data. Analysis is performed both during design analysis and periodically over the life of the product to monitor sustainability issues.
From a production standpoint, designs that drive over processing can be costly. For example, hand insertion vs. automatic placement can triple the labor cost. Similarly, hand soldering vs. wave or reflow soldering results in triple the cost of automated soldering multiplied by the number of leads being soldered. For example, radial and axial components that are specified on the BOM with incorrect center-to-center spacing for automated assembly will drive manual assembly. Most components can be ordered with the correct lead bend and spacing for automated assembly, however, the PCB must also be designed accordingly. Designing a PCBA with limited spacing for automated soldering will drive the need for hand soldering and increase costs.
Manufacturability or testability issues that can increase processing time or costs include:
- Double-sided, mixed technology printed circuit board assemblies (PCBAs).
- PCBs with array designs that reduce fabrication utilization
- Improperly-sized through-hold pads and holes
- Designs requiring double-sided reflow
- Incorrect SMT land patterns causing added inspection in the process
- Insufficient in-circuit test access points that drive higher needs for in-process inspection and testing.
There is no question that tradeoffs must be made. Double-sided, mixed technology PCBAs are common. However, if a PCBA has only one or two through-hole components, redesigning it to be 100% SMT may be a better option.
From a business perspective, a strong design for manufacturability/design for testability focus (DFM/DFT) focus can support minimized production process variation which may reduce capital equipment requirements, floor space and production personnel. Additionally, minimized variation is the key to ensuring high quality.
Linking up the Teams
A strong design/manufacturing team focus can be achieved whether manufacturing is internal or outsourced. The key to success is leveraging the ability of design, materials and manufacturing personnel from day one of product development. When the process is entirely internal, teams should periodically meet to analyze ways the product development process can better align with materials and manufacturing objectives.
The same team alignment and working relationships can be established even when production is outsourced, if the supplier selection process includes auditing for product development support processes. For example, EPIC Technologies and its quick-turn prototyping alliance partner, RocketEMS, both have tools and processes in place to begin making DfX recommendations in customer early stage product development.
While product development teams aren’t typically the final decision makers on outsourcing partners beyond the prototype level, they may be part of the selection team and definitely should have some level of input into sourcing criteria.
Questions to ask when exploring EMS support capabilities for product development include:
- What design guidelines are in place?
- How are Lean principles integrated into DfX recommendations?
- Are there tools in place to perform PLM analysis?
- Are DFM/DFT recommendations clearly prioritized by the magnitude of potential cost or quality improvements they represent?
- What resources are in place to address sustainability issues later in the product lifecycle?
- Does the supplier arrange workshops, team with component manufacturers to develop technology roadmaps or provide other tools to help customer design teams work more efficiently?
When engineering teams understand both the technical and business sides of the equation, infinitely better choices can be made in terms of product design and supply chain. The end result is a more efficient product development team and products that are both technologically and cost competitive.