Tool Design - What is DFMA (Design for manufacturing and assembly)...

                                       Design for manufacturing and assembly (also called DFM, DFA, or together DFMA) refers to the set of tools, methods and processes for analyzing the manufacturing consequences of design decisions and improving a design in order to reduce manufacturing cost and complexity.


                                   DFMA guidelines and checklists when followed, it tend to reduce complexity and cost of production. The general idea is that if the designer has guidelines in mind during conceptual design and detailed design, they can make better decisions from a manufacturing perspective. Guidelines and checklists are only rules-of-thumb, and in some cases rules may contradict one another. Using checklists is generally helpful but is not a substitute for involving a manufacturing engineer in the design process.

DFM Guidelines

1. Minimize Part Count: Eliminate fasteners, part consolidation
2. Standardize Components: Take advantage of economies of scale & known component properties
3. Commonize Product Line: Economies of scale and minimum training and equipment
4. Standardize Design Features: Common dimensions for fewer tools and setups
5. Keep Designs Simple: Simplest way to achieve needed functionality
6. Multifunctional Parts: e.g.: fingernail clipper
7. Ease of Fabrication: Choose materials easy to work with
8. Avoid Tight Tolerances: Causes exponential cost increases
9. Minimize Secondary & Finishing Operations: Only where needed
10. Take Advantage of Special Process Properties: e.g.: color in injection molding

DFA Guidelines

1. Minimize Part Count: Eliminate unnecessary parts
2. Minimize Assembly Surfaces: and sequence them
3. Use Subassemblies: can be assembled and tested separately, can be outsource
4. Mistake-Proof: unambiguous, unique assembly orientation
5. Minimize Fasteners: snap fits and part consolidation
6. Minimize Handling: position for insertion or joining is easy to achieve
7. Minimize Assembly Direction: ideal is to add each component from top to base
8. Provide Unobstructed Access: consider assembly path (e.g.: oil filter)
9. Maximize Assembly Compliance: chamfers and radii help assemble parts with variance 

so  analyse all and then start the tool design..