DFM/DFA is ultimately about designing a part, assembly or process to be more cost effective, better quality, and meeting schedule requirements. Utilizing proven DFM practices will ensure quality, reduce delivery lead-times and provide a reduction in the product cost. In this day of overbearing global competition where cost, quality and speed to market are the key to a successful product and organization, we often fall victim to simple mistakes that are costly to our organization and our customers that could have been easily corrected during the design phase.
The following are the major cost drivers for new product development:
Product scope, intent and complexity (specifications)
Time to market requirements
Market costing requirements
Product competitive environment
Design, engineering and manufacturing tools
Staff experience and training
Quantity of end-item product (low, medium or high volume)
Organization Culture (To DFM/DFMA or not is the question!)
Design for Manufacturing (DFM):
Designing a component, part or a process utilizing practices that will improve fit, form, function and the ability to manufacture at cost and schedule. This becomes quite relevant when producing high volume or parts that require multiple and/or progressive manufacturing steps and associated tooling. In low volume environments DFM helps to reduce non-reoccurring engineering (NRE) and gets the product closer to the final deliverable version sooner and with less prototype, change notice documentation and manufacturing effort.Also, over-toleranced (tight) parts and complex or challenging to manufacture geometries can eliminated helping to reduce cost and schedule (read: people hours).
Design for Assembly (DFA):
Designing and managing a system of parts or end-item assembly where the processes and steps required are as cost effective and lean as possible. This could include designs that consider and integrate tooling, assembly methods, test-ability, procurement, maintainability and other critical items into the components, proccesses and product system/assembly. Other common definitions:
Designing for target capability or capacity
Designing for affordable rapid response
The DFA activity may also involve designing system components (sub assemblies) and manufacturing steps with an eye on reducing complexity and unnecessary steps to produce the end-item.
Management (program, project) for manufacturability
Design for machining
Design for sheetmetal
Design for moldability
Design for weldability
Notes about DFM/DFMA:
There is not a "one size for all" or one approach to DFM/DFMA within industry verticals or organizations. Volume, end-item costing, competitive business environment, industry, end-item complexity, product scope are just a few of the variables that may change the formulae for an organizations DFM/DFA utilization.
DFM/DFA is also about business culture and practices. Designing the perfect part and assembly is an ultimate goal, however a design through manufacturing business environment that fails to execute optimally can be much more costly.
DFA is generally more cost effective than DFM (individual parts) in high volume applications though low volume end-items can and do benefit.
All design activities should minimize or eliminate as many individual parts as possible.
An often overlooked issue during product design is the performance of the manufacturing system at all levels, from supply chain to production line. The performance of these systems is disregarded or not considered because it is considered hard to model and designers don't know much about the manufacturing system.
Design should be the "first" manufacturing step or consideration
Identify product concepts that are easier or less expensive to manufacture
Benefits of DFM/DFA
Lower end-product costs
Reduced development costs (NRE)
Smoother transition to production manufacturing
Reduced part count
Shorter design and development cycle
Greater product and process reliability
Lower service and maintenance costs
Reduction in manufacturing lead time - fewer schedules slips
Ability to use common parts - economies of scale
Faster prototype and/or first article
Reduced errors in fabrication and assembly resulting in fewer engineering change notices
More suppliers capable of producing outsourced components and assemblies
Improved vertical or industry competitiveness
Improved design-manufacturing communication (concurrent engineering)