2. Design for X
X = MANUFACTURING
X = ASSEMBLY
X = RELIABILITY
X = MAINTAINABILITY
X = ENVIRONMENT
X = SERVICEABILITY
X = LIFE CYCLE COST
3. DIFFERENCES:
• DESIGN FOR ASSEMBLY
Concerned only with reducing the product assembly cost.
Minimizes the number of assembly operations.
Individual parts tend to be more complex in design
• DESIGN FOR MANUFACTURING
Concerned with reducing overall part production cost.
Minimizes complexity of the manufacturing process
6. What is DFMA?
• A set of guidelines developed to ensure that a product is designed so
that it can be easily and efficiently manufactured and assembled with a
minimum of effort, time, and cost.
• Products designed using DFMA principles should have higher quality
and reliability than others.
• This ensures that the transition from the design phase to the production
phase is as smooth and rapid as possible.
• The best results occur when DFMA is used at product conceptual stage
12. 1) MINIMIZE PARTS COUNT
The final cost of the product is
directly proportional to the no of
parts
Reducing no of parts is the best way
to reduce the manufacturing costs
Less parts implies fewer purchases,
inventory, handling, assembly
difficulty etc.
13. 2) USE MODULAR DESIGNS
Modularize multiple parts into single sub multiple parts into single
sub-assemblies.
14. 3) MAKE PARTS MULTIFUNCTIONAL
Some parts can be designed to
serve more than one purpose at a
time
This reduces the complexity of the
parts
15. 4) USE OF STANDARD PARTS
Design time and effort is reduced
Design of custom-engineered
components is reduced
There are fewer part numbers
inventory control is facilitated
Quantity discounts may be possible
16. 5) DESIGN PARTS TO BE SELF ALIGNING AND LOCATING
Self aligning parts can be placed into an
exact location with no adjustment required.
This makes assembly easier and faster for
the assembly workers.
Examples of self-locating features include
projections, indentations, chamfers,
molded keyways, etc.
17. 6) ELIMINATE INTERFACES
Interfaces increase the cost of an
assembly.
Each interface doubles the amount of
information required and increases overall
assembly time.
Eg : 2 sets of dimensions, 2 sets of
tolerances, 2 sets of interface features,
assembly labour, assembly materials, etc.
18. 7) DESIGN PARTS THAT CANNOT BE INSTALLED
CORRECTLY
Use physical obstructions to stop
components being fitted in the wrong
place, or the wrong way round.
This is known as Mistake-proofing
19. 8) MAXIMIZE PART SYMMETRY OR EMPHASIZE ASYMMETRY
Make components fit either way round
whenever you can.
Ideally, parts will have rotational and end-
to-end symmetry.
If the part cannot be made symmetric, then
emphasized asymmetry allows us to reach
the correct orientation faster.
20. 9) MINIMIZE THE USE OF FASTENERS
Fasteners increase the cost of manufacturing due to their handling and
feeding operations.
Unnecessary use of fasteners can be avoided by using tabs and snap
fits.
21. 10) MINIMIZE ASSEMBLY DIRECTIONS
If possible all parts should be assembled in one direction.
The best way to add parts is from above, in a vertical direction so
gravity can take its effects
Also make provisions for easy insertion of parts
22. 11) ENSURE EASE OF HANDLING OF ITEMS FROM
BULK
Eliminate tangling/ Nesting
Handling Difficulties
23. ADVANTAGES OF APPLYING DFMA
• Speed: Significantly reduced programme on-site through the use of
prefabricated elements.
• Lower assembly cost: Fewer parts, decreasing the amount of labour
required.
• Higher quality and sustainability: A highly automated approach can
enhance quality and efficiency at each stage.
• Shorter assembly time:DFMA shortens assembly time by utilizing
standard assembly practices such as vertical assembly and self-
aligning parts.
• Increased reliability: DFMA increases reliability by lowering the
number of parts, thereby decreasing the chance of failure.
24. REASONS FOR NOT APPLYING DFMA
• No time
• Not invented here
• Low assembly cost
• Low volume
• Prefer design rules
25. DFMA Software
• Boothroyd Dewhurst, Inc. has developed a software package to
implement DFMA techniques.
• Calculates the costs involved for different materials and manufacturing
processes as well as identify areas where the number of parts can be
reduced.
• Easily considers the impact of using alternative materials and
manufacturing processes
