DFMA

PROCESS FLOW FOR THE RE-DESIGNED MODEL

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DFMA

RE-DESIGNED CAD MODEL

Re-design

Original

RE-DESIGN CHOICES

1. In our first redesign, we took out two support screws with part numbers 3&7 and figured out that if we made the bridge wide enough, we could actually get the plate to slide it so it could actually sit on the bridge. It reduced the number of parts in the toaster from 4 to 2.

2. In the second redesign, the on/off switch was removed because our team has decided that the timer knob could act as a reset button and also and on/off switch just in a scenario where the bread being toasted was burning. The on/off switch removal was a smart decision because technically, the toaster is always on because it is always plugged in into the wall socket, so it made no technical sense to add an on/off switch.

HANDLING AND INSERTION

3. The foot support with part number 11 was removed because we decided to make the wrap and the panel as a whole piece because we would be reducing cost by reducing the number of screws needed for the toaster as a whole. Therefore, the new designed toaster would have its own foot support that lifts the base off the ground just in case there was water leakage to avoid being shocked.

4. We removed the ground and changed the plug from a 2pointer plug to a 3 pointer plug to avoid the unnecessary ground part being added to the toaster

OPTIMAL DESIGN

PRACTICAL PART COUNT

COST BREAKDOWN TABLE

DFMA COMPLEXITY FACTOR

Two Factors

1.Np – Number of parts

2.Ni – Number of part-to-part interfaces

Multiply the two and take the square root of the total ：

√2(Np*Ni)

DFA complexity factor for the original design:

√2(Np*Ni) = √2(36*104) =61.19

DFA complexity factor for the theoretical design:

√2(Np*Ni) = √2(5*10) =7.07

DFA COMPLEXITY BASED ON NEW DESIGN

Two Factors

1.Np – Number of parts

2.Ni – Number of part-to-part interfaces

Multiply the two and take the square root of the total ：

√2(Np*Ni)

DFA complexity factor for the new design:

√2(Np*Ni) = √2(18*23) = 20.35

The Theoretical Part Count Efficiency

The theoretical Part count Efficiency of the original design = 13.89%

*But our goal is > 60%

By observing the value we can conclude that both of the DFA complexity factor for the original design and for the theoretical design are 43.68 and Hence we still hadn’t met the requirement for the optimal efficiency because of too many interfaces of each part.

INTRODUCTION

DFMA stands for Design for Manufacturing and Assembly techniques, which are used to lower the product cost via implementing various design and process improvement by the engineering team.

This helps the company to ease up the process of assembling a desired product by quantitative analysis of a design’s efficiency.

This technique focuses on using the minimum number of parts, less time to handle and the ease of putting the parts together in the assembly process.

EVALUATION OF ORIGINAL DESIGN

PROCESS FLOW DIAGRAM

WHAT IS DFMA?

PART STANDARDIZATION

THEROTICAL MINIMUM PARTS

By observing the table below, one can come to a concrete conclusion about the parts which plays vital role in the working of the toaster and has to be in the assembly in order for the working of the machine.

There are few parts which are needed to be standardized because of the change and replacement of many interfacial connected components of the particular part:

• Wrap: This part can be standardized by manufacturing the panels joined with the wrap and eliminating the work of joining, screwing and connecting the panels with the wrap.

• Wire: We joined the ground wire to the main electrical power plug.

They are as follow: