Design for Manufacturing(面向制造的设计-外文资料)

Design for Manufacturing

Basic Principles of Designing for Economical Production

1. Simplicity

2. Standard Materials and Components

3. Standardized Design of the Product

4. Liberal Tolerances

5. Use Materials that are Easy to Process

6. Teamwork with Manufacturing Personnel

7. Avoidance of Secondary Operations

8. Design to Expected Level of Production

9. Utilize Special Process Characteristics

10. Avoid Process Restrictiveness

Think of these principles as design guidelines…not as hard

and fast rules.

Guidelines do not hold true for all situations. There will always exceptions

where doing something different than the rule will give a result that is better

or probably just as good. However, in most cases, if you stay consistent

with the rules as design goals, you are likely to have a more efficient, more

robust, and less costly production method.

产品开发流程的重要性

Rule 1: Simplicity

Description:

--minimize the number of parts

--use the least intricate shape

--require the bare minimum precision

--reduce the number of manufacturing operations

Motivation:

generally provides

-- reduced cost

-- improved reliability

-- ease of easier servicing

-- improved robustness

Example:

Dip stick swipe

Rule 2: Standard Materials and Components

Description:

--use standard off-the-shelf parts

--use widely available materials

--use materials from dependable suppliers

Motivation:

--generally

-- eases purchasing

-- simplifies inventory management

-- avoids tooling investments

-- speeds up the manufacturing cycle

Example

:

Standard shaft sizes, standard fasteners,

or standard commercial supply sizes

Rule 3: Standardized Design of the Product

Description:

For similar products specify

-- the same materials

-- the same parts

--

similar subassemblies …. if possible

Motivation:

-- provides economies of scale

-- promotes efficiency and familiarity in production

-- simplifies operations

-- simplifies inventory management

Example:

Common size hydraulic tanks used for lift vehicles

Rule 4: Liberal Tolerances

Description:

--make tolerances as forgiving as possible

Motivation:

--

tight tolerances are expensive … in a non

-linear fashion

-- tight tolerances require:

-- extra operations

-- higher tooling costs

-- longer production cycles

-- more scrap and higher rework costs

-- higher skilled labor and more training

-- higher quality material and respective cost

-- higher precision equipment

Example:

Figure 1.3.1 from Bralla's

Design for Manufacturing Handbook

.

Approximate relative cost %

Fig. 40.5 Relaltionship between relative manufacturing cost and dimensional tolerance.

from

Manufacturing Engineering and Technology

by Kalpakjian and Schmid

Table 1.3.1 Cost of producing Surface Finishes ( from Bralla's Handbook)

Surface symbol designation

Case, rough-machined

Standard machining

Fine machining, rough-ground

Very fine machining, ordinary grinding

Fine grinding, shaving, and honing

Very fine grinding, shaving, honing, and lapping

Lapping, burnishing, superhoning, and polishing

Surface

Roughness, μin

250

125

63

32

16

8

2

Approximate

relative cost %

100

200

440

720

1400

2400

4500

Rule 5: Use Materials that are Easy to Process

Description:

--take advantage of materials that have been developed

to be easy to process

some materials will result in different

-- cycle time

-- optimal cutting speed

-- flowability

-- generally soft material means easy to work

hard material means more difficult to work.

--

plastic is easy to work with…ceramics are not.

Motivation:

-- while easily processible material may cost more,

it will often provide lower overall cost since

the cost labor may be reduced

Example:

-- Carbon Steel vs.

Stainless steel.

-- Saturn exterior panels.

Rule 6: Teamwork with Manufacturing Personnel

Description:

--collaborate with the people that will be producing your

product … the earlier the better.

Motivation

:-- they provide a unique body of knowledge and useful insights

Example:

--Comments from managers at Eli Lily production plant tour

Rule 7: Avoidance of Secondary Operations

Description:

--minimize the need for secondary operations

secondary operations include

-- deburring

-- inspection

-- plating and painting

-- sanding

-- heat treating

-- material handling

Motivation:

--secondary operations sometimes can be as expensive

as the primary manufacturing operation

Example:

--prepainted steel or material that doesn't need painting.

-- use of turret lathe instead of single tool lathe.

Rule 8: Design to Expected Level of Production

Description:--

the number of parts you expect to produce affects which

method is the best to use for the production of a part.

Motivation:

--for a small number of parts, having high tooling costs can be

prohibitive

-- if there is a large volume of parts to make, the more

expensive equipment cost may provide a huge savings in

labor over the long term.

Example:

Sand casting vs. Die casting vs. Extrusion.