Design for manufacturing and assembly (DFMA) Presentation

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Design For Manufacturing and AssemblyTOASTER

MEHDI HOURMAND MM101120ALI KARANDISH MM121003

DFMA

DFMA stands on Design for Manufacture and Assembly. DFMA is the combination of two methodologies; Design For Manufacturing, which means the design for ease of manufacture of the parts that will form a product, and Design For Assembly, which means the design of the product for ease of assembly.

DFMA is used as the basis for concurrent engineering studies to provide guidance to the design team in simplifying the product structure, to reduce manufacturing and assembly costs, and to quantify improvements. The practice of applying DFMA is to identify, quantify and eliminate waste or inefficiency in a product design. DFMA is also used as a benchmarking tool to study competitors’ products, and as a should cost tool to assist in supplier negotiations.

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Introduction

The aim of this project is to identify unnecessary parts in an assembly and to Specify assembly time and costs.Reduction and redesign the parts is one task that is useful to decrease the costs and time of assembling . In this project, new design and old design have been compared and the results of development has been included.

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Objective-Numbering of parts in the original design- Redesign of the product (Description, Justification and Sketches)- Classification of each part for the new design- Estimated Assembly time for new design- Design efficiency of new product- Discussion/Comparison of new with the old design

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Product to be Studied

Toaster

The toaster is typically a small Mechanic-electric kitchen appliance designed to toast multiple types of Bread products. A typical modern two-slice toaster draws from 600 to 1200 Watts and makes toast in 1 to 3 minutes. There are also non-electrical toasters that can be used to toast bread products over an open fire or flame.

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Numbering of parts in the original designAccording to the Charts below the number of total parts in original design is : 82

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Name of assembly: TOASTER 1 2

The names of parts Part I.D. number

Number of times the

operation is carried out

consecutively

Front plate 1 1

Small L plate (nut) 2 1

rivet 3 5

L Plate A 4 1

Small Fire proof plate 5 7

Medium Fire proof plate 6 1

Holder of moving system guide 7 1

Guide 8 1

Spring 9 1

Main plate of moving system 10 1

Handling plate 11 1

Holder of U shape plate 12 1

U shape 13 1

Plastic part of U plate female 14 1

Plastic part of U plate male 15 1



Number of times the


consecutively



Number of times the


consecutively



Number of times the


consecutively

Heater board left 16 1

Heater board middle 17 1

Heater board right 18 1

Bread holder 19 2

Back plate 20 1

Upper cover 21 1

Wire connector 22 2

welding 23 4

Electrical kit 24 1

soldering 25 2

Timer regulator 26 1

Front cover 27 1

Snap fit 28 4

Stopper switch 29 1

Holder of stopper switch 30 1

Screw M3*6 31 5

Switch 32 1

Nut M3 33 1

Screw M3*20 34 1

connector plate 35 1

Washer 36 2

wire of plug 37 3

screw M3*6 small pitch 38 3

Holder of wire 39 1

Cover of wire 40 1

Screw M3*12 ,different shape 41 2

Back cover 42 1

Side cover 43 2

Screw M3*12 large pitch 44 4

Screw M3*12 small pitch 45 1

Bottom cover 46 1

Holder of bottom cover 47 1

Screw M4*6 48 1

Handling plastic part 49 1

0.179 82

Design Efficiency total part

Eliminated/Changed parts in the NEW design

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Name of assembly:

TOASTER

Must the part

move relative to all other parts?

Must the part be made of

a different materials

?

Must the part be

separate to allow access to

other parts it

encloses?

The names of parts

Name of assembly:

TOASTER

Must the part


Must the part be

made of a

different materials

?

Must the part be

separate to allow access to

other parts it

encloses?

The names of parts

Name of assembly:

TOASTER

Must the part


Must the part be

made of a

different materials

?

Must the part be

separate to allow

access to other parts

it encloses?

The names of parts

1 no yes yes Front plate0 no no no Small L plate (nut)0 no no no rivet0 no no no L Plate A

1 no yes no Small Fire proof plate

1 no yes no Medium Fire proof plate

0 no no no Holder of moving system guide

1 no yes yes Guide 1 yes no yes Spring

1 no no yes Main plate of moving system

0 no no no Handling plate

0 no no no Holder of U shape plate

1 no yes yes U shape

1 no yes yes Plastic part of U plate female

1 no yes no Plastic part of U plate male

1 no yes yes Heater board left1 no yes yes Heater board middle1 no yes no Heater board right

1 yes no yes Bread holder1 no yes yes Back plate1 no yes yes Upper cover1 no no yes Wire connector1 no yes yes Electrical kit1 no no yes brazing1 yes no yes Timer regulator1 no yes yes Front cover0 no no no Snap fit 1 no no yes Stopper switch

0 no no no Holder of stopper switch

0 no no no Screw M3*6 ,Large pitch

1 no yes yes Switch0 no no no Nut M30 no no no Screw M3*201 no yes no connector plate0 no no no Washer 1 no yes yes wire of plug

1 no no yes screw M3*6 small pitch

1 no no yes Holder of wire0 no no no Cover of wire

0 no no no Screw M3*12 , shape

0 no no no Back cover0 no no no Side cover

0 no no no Screw M3*12 large pitch

1 no no yes Screw M3*12 small pitch

1 no no yes Bottom cover

0 no no no Holder of bottom cover

0 no no no Screw M4*6

1 no yes yes Handling plastic part

Orange Color shows Eliminated parts

Green Color shows Changed parts

Introduction of Eliminated/Changed parts in the NEW design

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OLD (Original) Design NEW Design

Front Plate

Small L plate (nut)

Rivet

L Plate A

Holder of moving system guide

Large fire

proof

Small fire proof

Small fire proof

Description:New Front Plate has changed in the shown position. The Holder of moving system has been removed and replaced withthe folded part as you can see.The other change is about the fireproof hole, it has standardized with same size according to the other holes.Due to use just one shape of fire proof (Small size) .

NEW Front Plate

Eliminated Parts


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Main plate of moving system

Description:New moving system has produced with one sheet and using of folding the sheet instead of attaching the parts by rivet.

NEW Moving System

Eliminated Parts

Handling plate

Holder of U shape plate

Breads Holder

Rivet


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Upper Cover

Description:New Cover will cover all the parts easily . Also, the assembly time will reduce much. Stopper switch will assemble in the electrical kit such as regulator and there is no need to any holder or fastener.

NEW Main Cover

Eliminated Parts

Front Cover

Snap fit Stopper switch

Holder of stopper switch

Stopper holder

Fastener

Back Cover

Side Covers

NEW Stopper Switch


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Description:Fastening method for new switch has been changed from Nut and bolt to snap fit.

Switch

Eliminated Parts

Switch

Nut Bolt

Washer


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Description:The fastening method of Bottom Cover has been changed from old method to 4 screw and 4 snap fit which is fastened to the main body and the main cover will assemble via Screw M3X12 Large pitch.

Bottom Cover

Eliminated Parts

Bottom Cover

Screw M3*12 small pitch

Holder of bottom cover

Screw M4*6

Screw M3*12 large pitch


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Description:The previous design for connector needs 8 welding and 2 connector. However, in the new design it is reduced to 4 welding.

Connector s

Eliminated Parts

NEW Connectors

Welding

Description of each New Designed Parts of Toaster

Acc. To DFA Methods

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picture Name of partPart ID

NO.

No. of

part

α βTwo-digit

manual handling code

Manual

handling

time per part

Two-digit

manual insertion code

Manual insertion time per

part

Function

Front plate 1 1 360 360 30 1.95 00 1.5

Main role of front plate is Holding the heater

board and moving system

Small Fire proof plate 2 5 180 180 13 2.06 32 4 To avoid connection

between wire and body


Acc. To DFA Methods

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NO.

No. of

part

α βTwo-digit


Manual

handling

time per part

Two-digit



part

Function

Cylindrical Guide 3 1 360 0 11 1.5 32 4

To Control the sliding movement of moving

system.

Spring 4 1 360 180 20 1.8 34 6To Return the moving system in its position

(Returning The breads)

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NO.

No. of

part

α βTwo-digit


Manual

handling

time per part

Two-digit



part

Function

moving system 5 1 360 360 30 1.95 06 5.5

Holding the handling plate, Magnet, Bread’s

Holder. Also sliding movement to move the

breads down and return it up after toasting

Operation.

U shape 6 1 360 180 20 1.8 32 4

With Magnetic flux allow the moving system

to connect and hold down the breads.


Acc. To DFA Methods

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NO.

No. of

part

α βTwo-digit


Manual

handling

time per part

Two-digit



part

Function

Plastic part of U plate female 7 1 360 360 30 1.95 00 1.5

To avoid the connecting of magnetic flux to the

other parts

Plastic part of U plate male 8 1 360 360 30 1.95 00 1.5

To avoid the connecting of magnetic flux to the

other parts


Acc. To DFA Methods

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NO.

No. of

part

α βTwo-digit


Manual

handling

time per part

Two-digit



part

Function

Heater board left

(Standard Part)9 1 360 360 30 1.95 32 4 Toasting the breads

Heater board middle



Acc. To DFA Methods

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NO.

No. of

part

α βTwo-digit


Manual

handling

time per part

Two-digit



part

Function

Heater board right


Back plate 12 1 360 360 30 1.95 33 5 Holding the heater boards


Acc. To DFA Methods

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NO.

No. of

part

α βTwo-digit


Manual

handling

time per part

Two-digit



part

Function

connector 13 2 180 180 10 1.5 96 12Connecting the

electricity between heater boards.

Electrical kit(Standard Part) 14 1 360 360 30 1.95 92 5

Distribute the electricity between heater boards,

Magnet system andSetting the time of

toasting.


Acc. To DFA Methods

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NO.

No. of

part

α βTwo-digit


Manual

handling

time per part

Two-digit



part

Function

Timer regulator 15 1 360 360 30 1.95 30 2 To Change the time of toasting

Stopper switch 16 1 360 0 11 1.8 30 2 To Disconnect the electricity


Acc. To DFA Methods

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NO.

No. of

part

α βTwo-digit


Manual

handling

time per part

Two-digit



part

Function

Screw M3*6 17 2 360 0 11 1.8 38 6 Fastening the electrical board

Switch(Standard part) 18 1 360 360 30 1.95 30 2 Electricity Connector


Acc. To DFA Methods

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NO.

No. of

part

α βTwo-digit


Manual

handling

time per part

Two-digit



part

Function

wire of plug 19 3 180 360 20 1.13 92 5 Transfer the electricity

screw M3*6 small pitch 20 3 360 0 11 1.8 38 6 Fastening the wire of

plug


Acc. To DFA Methods

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NO.

No. of

part

α βTwo-digit


Manual

handling

time per part

Two-digit



part

Function

Screw M3*12 large pitch 21 4 360 0 11 1.8 38 6

Fastening the Main Cover to the Bottom

cover

Bottom cover 22 1 360 180 20 1.8 30 2To cover and maintain all assembled parts and the

main cover.


Acc. To DFA Methods

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NO.

No. of

part

α βTwo-digit


Manual

handling

time per part

Two-digit



part

Function

Top Cover 23 1 360 360 30 1.95 00 1.5 Covering all Sub assembly parts.

Handling plastic part 24 1 360 360 30 1.95 01 2.5 To ease of moving down

the breads by users


Acc. To DFA Methods

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NO.

No. of

part

α βTwo-digit


Manual

handling

time per part

Two-digit



part

Function

Holder of wire 25 1 360 360 31 2.25 00 1.5 Holding the wire


Acc. To DFA Methods

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Product tree structure for new design

Toaster

1-Main Body 2-Top Cover 3- Bottom Cover 4- Handling Plastic Part

3- Holder of wire1-Electrical kit

2-Time Regulator 3- Stopper switch

2- SwitchSub assembly is in

the next page

1- Screw M3*6

1- Screw M3*12 large pitch

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Product tree structure for new design

Toaster

1-Main Body

2- Cylindrical Guide 1- Front plate 3- Spring 4- moving system 5- Heater board left 6- Heater board middle 7- Heater board right 8-Back plate

9- connector10- wire of plug

1- Small Fire proof plate

1- U shapePlate

2- Plastic part of U plate female

3- Plastic part of U plate male

1- screw M3*6 small pitch

2-Top Cover 3- Bottom Cover 4- Handling Plastic Part

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Assembly

1

2

5

4 6

3

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Assembly

AssemblySketches

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Classification and analysis for each part of the new design

Name of assembly: TOASTER 1 2 3 4 5 6 7 8 9


Number of times the


consecutively

Two-digit manual

handling code

Manual handling time

per part

Two-digit manual

insertion code

Manual insertion time

per part

Operation time (sec) 2*[4+6]

Operation cost (RM)

Figures for theoretical

minimum parts estimation

Front plate 1 1 30 1.95 0 0 1.5 3.45 0.004485 1

Small Fire proof plate 2 5 13 2.06 32 4 30.3 0.03939 5

Guide 3 1 11 1.5 32 4 5.5 0.00715 1

Spring 4 1 20 1.8 34 6 7.8 0.01014 1

Moving System 5 1 30 1.95 0 6 5.5 7.45 0.009685 1

U shape 6 1 20 1.8 32 4 5.8 0.00754 1

Plastic part of U plate female 7 1 30 1.95 0 0 1.5 3.45 0.004485 1

Plastic part of U plate male 8 1 30 1.95 0 0 1.5 3.45 0.004485 1

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Number of times the


consecutively

Two-digit manual

handling code


per part

Two-digit manual

insertion code


per part


Operation cost (RM)



Heater board left 9 1 30 1.95 32 4 3.56 0.004628 1

Heater board middle 10 1 30 1.95 32 4 3.56 0.004628 1

Heater board right 11 1 30 1.95 32 4 3.56 0.004628 1

Back plate 12 1 30 1.95 33 5 6.95 0.009035 1

Wire connector 13 2 10 1.5 96 12 27 0.0351 2

Electrical kit 14 1 30 1.95 92 5 6.95 0.009035 1

Timer regulator 15 1 30 1.95 0 1 2.5 4.45 0.005785 1

Stopper switch 16 1 11 1.8 30 2 3.8 0.00494 1

Screw M3X6 17 2 11 1.8 38 6 15.6 0.02028 2

Switch 18 1 30 1.95 30 2 3.95 0.005135 1

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Number of times the


consecutively

Two-digit manual

handling code


per part

Two-digit manual

insertion code


per part


Operation cost (RM)



wire of plug 19 3 20 1.13 92 5 18.39 0.023907 3

screw M3*6 small pitch 20 3 11 1.8 38 6 23.4 0.03042 3

Holder of wire 21 1 31 2.25 0 0 1.5 3.75 0.004875 1

Screw M3*12 long pitch 22 4 11 1.8 38 6 7.8 0.01014 4

Bottom cover 23 1 20 1.8 30 2 3.8 0.00494 1

Top Cover 24 1 30 1.95 0 0 1.5 3.45 0.004485 1

Handling plastic part 25 1 30 1.95 0 1 2.5 4.45 0.005785 1

25Total

different part

0.4851

Design Efficiency

38

Total part

235.02 0.305526 38

TM CM NM

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Discussion – Comparison between New design and Old design

New Design

The formula to calculate the design efficiency :Design efficiency =(3*NM)/TM

* NM = Theoretical minimum number of parts According to DFA worksheet, NM= 38

*TM = Total manual assembly time According to DFA worksheet, TM= 235.02

*CM = Total Cost of Manual assembly According to DFA worksheet, CM= 0.305

Design Efficiency = (3*38)/235.02 = 0.485

Old Design

The formula to calculate the design efficiency :Design efficiency =(3*NM)/TM

* NM = Theoretical minimum number of parts According to DFA worksheet, NM= 38

*TM = Total manual assembly time According to DFA worksheet, TM= 641.24

*CM = Total Cost of Manual assembly According to DFA worksheet, CM= 0.833

Design Efficiency = (3*38)/641.24 = 0.178

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Discussion – Comparison between New design and Old design

No. Criteria Old Design New Design Improvement Percentage

1 Design Efficiency (%) 17.8 % 48.5 % 30.7 % 30.7%

2 Assembly Time (sec) 641.24 sec 235.02 sec 249.62 sec 36.65%

3 Total Assembly Cost (RM) 0.833 RM 0.305 RM 0.528 RM 36.6%

4 Total Number Of Different Parts 49 25 24 51%

5 Fasteners 32 12 20 37.5%

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Conclusion

Based On Design For Assembly (DFA) Guideline, The aims of this method have been satisfied by:

- Simplifying the assembly sequences, component handling and insertion.- Standardize the materials , components and subassemblies to increase economics of scale and reduce tooling costs.- Reduction of mass production of many parts.- Taking the advantage of process capability to reduce unnecessary components of additional processing.

In addition, the new design outcome is available in below.* Design efficiency has been improved 30.7 %* Assembly time has been reduced 249.62 sec* Manual assembly cost has been reduced 0.528 RM* Total Eliminated different part is 24

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Appendix B1

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Appendix B2

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References

1- Boothroyd, G., Dewhurst, P. & Knight, W. (1994), “Production Design for Manufacturing and Assembly”, New York: Marcel Dekker, Inc.2- http://www.investinpahang.gov.my/index.php?rp=comptetitive_wages.pdf3- Norcross, Eric (2006). "The Cyber Toaster Museum". Toaster.org. The Toaster Museum Foundation. pp. section "1900–1920". http://www.toaster.org/museum.html. Retrieved 2008-08-16.

4- http://en.wikipedia.org/wiki/Toaster5- http://www.dfma.com/software/index.html

http://canada.esat.kuleuven.be/docarch/smart/EU_seminar_Engelen.pdf






http://www.toaster.org/museum.html


http://www.toaster.org/museum.html




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Thank You

Design for manufacturing and assembly (DFMA) Presentation

Engineering

Transcript of Design for manufacturing and assembly (DFMA) Presentation