Design for Manufacture Design for Manufacture and Assembly (DFMA)and Assembly (DFMA)

BMF 4723BMF 4723Engr. Wan Sharuzi Hj Wan Harun

sharuzi@ump.edu.my0197799152

Introduction

• Is a combination between DFM & DFA

DFM Design for ManufactureManufacture

Manufacturing of individual component parts of a product or assembly

DFA Design for AssemblyAssembly

Addition or joining of parts to form a complete product

DFM?

• The design for ease of manufacture of the collection of parts that will form the product after assembly.

DFA?

• The design of the product for ease of assembly.

Where to apply?

1. To the design team in simplifying the product structure, to reduce manufacturing and assembly costs, and to quantify the improvements by using concurrent engineering approaches.

2. As a tool for benchmarking to study competitor’s products.

3. As a should-cost tool to help negotiate suppliers contracts.

DFMA

• Intended to increase the awareness of engineering design team to the need for concurrent product and process development.

• Design process is where about 80% of product’s total costs are determined.

• The cost of making changes to a product as it progresses through the product development process increases by orders of magnitude at various stages.

If the cost of making a change to a product during its conceptual design phase is RM1K,

Then the cost of making the same change after the drawings are released and the initial prototype are

fabricated is approximately RM10K,If this same change is not applied until the production run has started, the cost impact will be approximately

RM100K,If the need for the design change is not recognized after the product has been purchased, the total cost will be

approx. 1000 times more than during conceptual design review.

The Six Basic Considerations

The Ten Commandments

The Ten Commandments

1.1. SimplicitySimplicity

How to keep part count minimum?

• Key principles revolve around THREE questions:

If all answers is NO

The part’s function The part’s function can be combined can be combined

with another existing with another existing partpart

The part’s function The part’s function can be combined can be combined

with another existing with another existing partpart

The effects of reduced part counts?

Why do we need fastener?

Why fasteners should be minimized?

PROTOTYPE DESIGNS MAY PROTOTYPE DESIGNS MAY REQUIRE ADDITTIONAL REQUIRE ADDITTIONAL

FASTENERS AND INTERFACES TO FASTENERS AND INTERFACES TO TEST VARIOUS DESIGN OR TEST VARIOUS DESIGN OR

COMPONENT OPTIONSCOMPONENT OPTIONS

PRODUCTION DESIGN SHOULD BE PRODUCTION DESIGN SHOULD BE STRIPPED OF ANY EXCESSIVE STRIPPED OF ANY EXCESSIVE

FASTENERSFASTENERS

Minimum Orientations

• Guiding principle are: – To create a design that can be easily assembled

with minimum use of special tooling.– To always use gravity to aid you in assembly.

• Minimizing number of fasteners will obviously headed for minimizing number of orientations needed.

Multifunctional Parts

• Is a primary method of reducing the total parts count.

• Thus, enhancing design simplicity.

Modular Subassemblies• Good design method to predesigned for

continuous product improvement through block upgrades.

• Promote similar product line enhancements over time.

• As new technology moves into practice and becomes cost effective, modular subassemblies can be easily replaced to provide expanded capabilities, higher processing speeds, market competitiveness or more economical substitutions.

However, • It may increase the total part count of the

original product.• Positive trade-off could yet be achieved by the

added ease and speed of implementing improvements for many products or product families.

However, • It may increase the total part count of the

original product.• Positive trade-off could yet be achieved by the

added ease and speed of implementing improvements for many products or product families.

2.2. Use Standard Materials Use Standard Materials Components and DesignsComponents and Designs

• Its describe the sixth commandment – STANDARDIZE

• Design reuse – Most cost-effective method• By defining company-or product family-

related standard materials, standard parts, specific design process standards. – Reduce cost and TTM, while reliability will be maximized.

• The key element of standardization; – Establish the discipline within the organization to

keep the standards current and readily available to the PD team.

– Enforcing their effective and consistent use.

3.3. Specify TolerancesSpecify Tolerances

• Embodied in seventh commandment – Avoid Difficult component.

• It is based on process capability not from design engineer’s affinity.

• CE approaches in PD team is the most effective way to achieve. – Design Engr.@Manu. Engr.

4.4. Use of Common MaterialsUse of Common Materials

• The fifth design consideration – use of the materials most processed.

• Materials that are commonly machined or processed should be the first choice for various components.

• Exotic or state-of-the-art processes or materials should be avoided.

• To preclude extended process activities – C↑,TTM↑, Quality↓, & Reliability↓

5.5. CE CollaborationCE Collaboration

• The sixth design consideration.• Its essential for the design team to include

cross-functional personnel such as;– Manufacturing engineers– Quality engineers– Procurement specialists

• To ensure all the appropriate design trade-offs are properly analyzed and selected.

• The traditional ‘Over-the-wall’ approach is guaranteed to produce product attributes that contribute to Higher production cost & Longer TTM.

The Final Three Design Commandment

True learning is based on discovery by mentoring rather than the transmission

of knowledge (John Dewey)