TWI Knowledge Summary

Design for Manufacture (DFM)

What is DFM?

Followed during the design process, DFM is an approach which has the aim of improving manufacturing productivity. It brings major benefits when used during the design of new generations of products. It is a method of working which:

1. Helps the team focus on clear and common objectives
   
   
2. Encourages problem-ownership and prevents manufacturing problems being shifted from area to area (e.g. from direct to overhead costs)
   
   
3. Uses a top-down approach (preventing early and wasteful focus on detail) to product design

During DFM, the considerable background work required for the conceptual phases is compensated for by a shortening of later development phases.

Status

DFM is a well-established approach which involves -

1. Diagnosis
   Determination of the manufacturability of the present product and comparison with similar products on the market.
   
   
2. Setting objectives
   Set in terms of production costs, quality, flexibility, risk, lead-time, efficiency, environment.
   
   
3. Function definition
   Involves defining the main functions of the product and their interactions.
   
   
4. Clarifying the evaluation parameters and design ideas
   This is done for each of the main product functions.
   
   
5. Conceptual design
   This process is followed top-down in the sequence: corporate, family, structural and component levels.
   
   
6. Evaluation and selection
   Assess the manufacturability of the proposed concepts in terms of the DFM objectives. Select the best fit concept.
   
   
7. Translation to design
   Communicate the chosen concept to the development team, which then carries out the detailed design in parallel to marketing and production development.

Important issues

DFM implementation requires top management attention and support. A team approach is vital with, for example, the Product Development Manager being measured by an ability to contribute to more rational manufacturing and the Manufacturing Manager measured by the contribution to product design.

Application

Ideally, DFM begins with a pilot project aimed at producing a local success.

As most products have joints, TWI staff can make important contributions in DFM, either as members of the team or as experts providing vital data.

Benefits

Used correctly, DFM can lead to a 25-30% reduction in production cost without capital investment in new facilities.

Promoting the approach

DFM is not a miracle cure that will guarantee competitiveness, there will be a constant struggle against short-sighted and narrowly-focused views. Nor is DFM a commodity that can be bought. It is a way of thinking supported by a set of tools (the seven-step approach given above) for conceptual design, and the checks for assessing the design process supported by various specific process design tools (e.g. CAD, FEA).

The DFM process must be nurtured and promoted to create the appropriate mind-set. Practice and training will foster this method of working.

If you need additional information, please contact: manufacturing.support@twi.co.uk

References

The European Handbook of Management Consultancy, Oak Tree Press, Dublin, Ireland, 1995 (ISBN 1-86076-010-4)

Design for Manufacture DFM, National EUREKA Office (or 19H avenue des Arts, B-1040, Brussels, Belgium, tel. +32 2 229 22 40, fax. +32 2 218 7906)

Further information

If you have a query on this subject please email TWI's Manufacturing Support Department. manufacturing.support@twi.co.uk

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