MachiningA systems approach

Ref: Chen, Joseph (2001). Educational Factory - From Design to Manufacturing Overview. Iowa State University

Manufacturing System

Manufacturing Cost

DFMA basic understanding of Design for

Manufacturability, DFM, makes you a more

effective manager (ITEC) and/or teacher

(TechEd) by understanding the interaction

of [a] machining operation(s) within the

context of material processing with respect

to COST, QUALITY, and PRODUCTIVITY!

3 mechanisms toward DFM

1. Design-manufacturing Teams

2. Common CAD systems for design &

tooling

3. Understanding the value concepts

Training Needs

Comparison of Industry and Academic Perspectives on the Training Needs of the

U.S. Manufacturing Workforce (Prziembel, 1995).

Value Engineering

THE VALUE OF A PRODUCT IS THE RATIO OF ITS PERFORMANCE TO ITS COST

Obtaining the maximum performance per unit cost is the basic objective of value engineering (Gage, 1967; Mudge, 1971)

Economic Perspective

The “Economic” Perspective on Value CreationFor any product, a “value equation” can be defined...

Non-reoccurring Cost allocation

Indirect labor costs

Direct labor costs

Direct material cost

Profit per unit - $$

PRICE orVALUE

Determined by Customer

Value Analysis

• Value analysis (VA) programs, as generally conducted today (Bradyhouse, 1984), first challenge the design of the product - searching for simpler designs that will reduce cost while maintaining function.

A simple example

2 parts 1 part

Screw – $ 0.02

Washer - $ 0.01

100 units = $ .03 * 100 = $ 3.00

5 seconds/screw = 5 * 100 = 500 seconds (8.33 min)

2 seconds/washer = 2 * 100 = 200 seconds (3.33 min)

(8.33 + 3.33)*($0.25) = $ 2.92

($ 3.00) + ($ 2.92) = $ 5.92

Screw – $ 0.02

100 units = $ .02 * 100 = $ 2.00

5 seconds/screw = 5 * 100 = 500 seconds (8.33 min)

(8.33)*($0.25)= $ 2.08

($ 2.00) + ($ 2.08) = $ 4.08

Material Cost

LaborCost

Material Cost

Material + Labor = Cost Material + Labor = Cost

LaborCost

Cost Comparison

$5.92$4.08 = .69 ~ 30% cost

reduction with new design

OLD2 part Design

NEW1 part Design

The other side

• Manufacturing Engineering– Concerned with assuring that parts can be

manufactured and assemblies made and tested to meet specifications with available or potentially available techniques, tooling, and test equipment at cost compatible with the product’s selling price (Howell, 1982).

– The emphasis in manufacturing engineering is to protect the interests of the manufacturing function

VA/Mfg. Engr. Relationship - Before

Product Development-Review

Traditional: Sequential Product Development

Aka: “Throw it over the wall”

MARKETING RESEARCH &DEVELOPMENT

ENGINEERING MANUFACTURING

Voice of the Customer/

Market OpportunitySatisfaction of Customer’s Needs

Concurrent Product Design

Satisfaction of Customer’s Needs

Design for Manufacturing (DFM)Needed

• Concept decisions, product design, and testing are performed prior to:– Manufacturing system design– Process planning and production

• TEAM approach is the KEY for success

2 Main streams of DFM

• Design for Machining (DFM)Design for Machining (DFM) is designing products with machining in mind.

• Design for Assembly (DFA)Design for Assembly (DFA) is designing products with minimum assembly cost in mind

Design For Machining

Goals of Design For Machining

1. Reduce machining time

2. Reduce material costs

3. Reduce tooling costs

4. Reduce setup cost

Eventually increase VALUEVALUE of a product

Examples of design concepts using Design For Machining

Limit Tooling

Bad Design – 2 different techniques required

Better Design – profiles similar

Radius Corners of Pockets

Extremely difficult, if not impossible to

machine

Better Design

Chucking Surface

Better Design:Area for clamping

Poor Design:No place for clamping

Restricted Surfaces

Better Design:Both areas now

accessible

Poor Design:No access

Single Plane Clamping Surfaces

Better Design:3 surfaces for

clamping

Poor Design:Awkward and time-

consuming for clamping

Design For Assembly

Texas Instrument Example

Design For Assembly

Comparison - DFA

Original

Design

Redesign

DFA

Improvement

(%)

Assembly Time (h) 2.15 .33 84.7

Num. of Different Parts 24 8 66.7

Total Num. of Parts 47 12 74.5

Total Num. of Operations 58 13 77.6

Metal Fabrication Time (h) 12.63 3.65 71.1

Total Weight (lb.) .48 .26 45.8

vs.

Comparison - DFA

TEAMWORK

Concurrent Product Design: Include ALL members

Team Makeup

• Basic understanding of teamwork in work force environment

• Decision making techniques, ie. Brainstorming, etc

• Project management skills

• Communication skills

• Problem resolution technique

Flowcharting

Gantt Charting

Communication Skills in Teams

1. Listening skills: hearing and comprehending what is said as opposed to waiting for one team member to stop talking

2. Dialoguing skills: interacting for the purpose of increasing mutual discussion

3. Consensus building: synergizing, building new understanding as opposed to compromise which is “both team members giving something up” to arrive at a solution

Characteristics of effective teams

• They produce results

• Purpose of the team is clear and takes priority over personal agendas

• Members feel invested in success and accountable for the outcome

• People are clear on their roles and assignments

• Nothing is under the table

• Team members are not afraid to surface a problem

• Trust, collaboration, and candid discussion are evident

• The team does not lose sight of its goal

Attributes of good team members

• They have strong, shared values• They overcome obstacles and handicaps• They incorporate and represent diverse

backgrounds• They are protective and supportive of one

another• There is a submission of self for the good of

the team

CAD Systems

Spatial Skills

REVIEW

Who casts the biggest shadow in terms of cost % in manufacturing?

Product Design

Explain how Design For Manufacturing is an integral part of the product design cycle?

Review

• How can we add value to a product?

Reduce: Machine Time, material costs, tooling costs, & setup costs

• Of the 3 communications skills, which do you feel you can work on to improve ? Why?

Listening, dialoguing, consensus