Simultaneous engineering - a route to improved profit

TWI Bulletin, January/February 1994

Jim Foster graduated from Loughborough University with BTech(Hons) - production engineering. His experience in manufacturing engineering ranges from make-to-order high value electronic systems to high volume automotive brake and clutch system production.

Immediately before joining TWI he spent some years engaged in the introduction of new manufacturing technology and systems into a traditional (predominantly manual assembly) electronics company, to meet the demands of its new products. Since moving to TWI he has worked on a variety of projects related to the manufacturing industry, e.g. vision control systems, EMC, integrated manufacturing for the constructional steel industry and technical co-ordination of the Eureka EU462 Project.

In this short guide to enhanced product development efficiency Jim Foster summarises the concepts of Simultaneous Engineering and how these relate to Design For Manufacture and Quality Function Deployment. He considers the reasons why companies are now adopting these techniques, the experience of those who have, and how the whole product development cycle is likely to evolve.

Today's aggressive business climate demands that product life cycles shorten, enforcing reduced product development cycles and causing the manufacturing industry to reconsider its traditional product development route. Tradition required that the product marketing specification be available before design started, the design be well advanced before prototyping, a prototype be available before manufacturing planning, and that this plan be complete before manufacturing started. This cycle was further lengthened by 'brick walls' which impeded communication between the various departments involved.

Manufacturing organisations frequently seek to minimise the time a product is on the shop floor by performing manufacturing operations in parallel. This logic has been applied to the whole of the product development cycle where many stages can be carried out in parallel ( e.g. outline process planning can be done with minimal product design). Figure 1 illustrates this 'paralleling' of operations, which have traditionally been undertaken in series, in what has become known as Simultaneous (or Concurrent) Engineering (SE).

Products which are difficult/expensive to manufacture, or which do not meet the customer's requirements, frequently require changes; these changes considerably increase the product development cycle time and costs. This prompts the introduction of Design For Manufacture (DFM) and Quality Function Deployment (QFD) techniques. These techniques should not be confused with SE, though in many cases SE is the trigger for their introduction.

DFM seeks to minimise the cost of manufacturing by ensuring that products are readily manufacturable. This is achieved through designs which recognise the requirements of the manufacturing floor and explore alternative manufacturing technologies. It requires rigorous analysis of all items to ensure optimal manufacturing solutions; many of the analysis techniques used were developed for Value Analysis. There are commercial organisations offering complete systems comprising methodology and training (and in some cases software tools) for this purpose.

QFD aims to ensure that the product meets the customer's requirements. This is achieved by thorough market research, careful analysis of the customer's needs and effort to ensure that these are met by the design.

SE uses multi-disciplinary teams to undertake tasks in parallel and ensure that sound decisions are made as early as possible in the design process. It reduces the length of time taken to introduce (specify, design and develop) new products and ensures minimal product cost. Costs may be minimised through a combination of DFM, QFD and sound decisions. Several sources, ( e.g. Ref ^[1] and ^[2] ) have stated that decisions taken at an early stage of design have dramatic effects on the life cycle cost of the product, see Fig.2. Close links between the engineers designing the product and those designing its manufacturing process (as in a SE environment) are essential to achieve rapid feedback on the manufacturing cost implications of design decisions.

The combination of shorter development timescales and lower manufacturing costs, arising from a SE environment, provides the competitive edge and the potential to maximise profit which all manufacturers seek. SE requires a team work environment to succeed but it also enhances such an environment and provides scope for all team members to participate in areas outside their own speciality.

Determination of quantifiable savings arising from the introduction of SE is difficult; the reasons range from lack of knowledge of the starting point, to the desire to keep such information confidential. However, it is clear that whilst considerable savings can be made, the application of SE has been low. The IEE information pack ^[3] suggests that savings ( Table 1) in design, manufacturing and re-work costs by SE can be >30%, that by late 1991 only 14% of UK industry was familiar with the term and that the degree of application was even lower.

In addition to the savings indicated in Table 1, other important benefits arising from SE are:

• It is a starting point for cultural change within the organisation. Close knit teams drawn from different disciplines to concentrate on a particular product require old barriers to be broken down. Once these are removed other changes, such as the introduction of Company Wide Quality Improvement (CWQI), may follow.
• Adoption of DFM concepts leads to improved relationships with suppliers. To ensure the best possible design decisions suppliers' advice is considered and requirements are tailored to their facilities and skills.
• Improved product quality: simultaneously engineered products present fewer manufacturing problems and are therefore less likely to have inherent faults.
• Improved customer relations from the application of QFD techniques and improved product quality. Products produced through this route are more likely to match the customer's requirements, function correctly and give good service.
• Early identification of capital expenditure needs.

Successful introduction of SE requires:

• Application of appropriate tools;
• Provision of a system for gathering, storing, controlling and retrieving all product data.
• Commitment to change and staff involvement.

Tools

QFD ensures that quality is designed into the product. Most QFD applications start with an analysis of customer's needs which are then broken down to study their implications upon the product design and manufacturing processes. With complex products this analysis may go through a number of iterations requiring the options available to be systematically reviewed.

DFM has a number of well understood and defined analysis techniques. These range from complex computer based proprietary packages to the application of in-house developed systems comparing such measures as the number of piece parts, the number of design variations, the ability of a part to be multi-functional, handling requirements, etc. Whatever techniques are used they are aimed at minimising costs and the potential for errors in manufacturing.

Other techniques finding favour for improving the quality of decisions made at early stages of the product design are failure mode effect analysis (FMEA) ^[4] and manufacturing simulation. ^[5] A comparison of the benefits of various analytical techniques, based on the work of Miles ^[6] is given in Table 2.

Table 2 Comparison of benefits ^† of various analytical techniques

Data

Product development generates a large amount of information. In conventional systems much of this information remains internal to the department generating it; only 'issued' documents pass between departments. In a SE environment it is vital that all information, at all stages of development, is readily available to those who need it. Furthermore in the SE environment it is necessary to pass considerably more data (such as the manufacturing implications of product designs) between specialists to ensure sound decisions. Regardless of how this information is generated ( e.g. CAD system, Process Planning package, manually) it is important that all members of the SE team have rapid and easy access to it and that it is always up to date. This requires careful document control and/or dynamic databasing ( i.e. one which maintains updated records based on input from many sources).

Commitment

SE and its associated techniques, DFM and QFD, are established and provide positive benefits. Pressure to minimise product development lead time is growing and causing culture changes in manufacturing whereby SE becomes the norm. There are also a number of developments which will give further improvements, e.g.:

- decision support tools;

- on line databases;

- rapid prototyping;

- direct engineering.

Decision support tools

The strength of SE is that decisions made early in the product development life cycle are sound because they are based on inputs from all appropriate disciplines. However, some of the problems to be addressed ( e.g. manufacturing philosophy, shop floor layout) are so complex that they require decision support tools (simulation tools), such as WITNESS or the FactoryFLOW suite, to resolve. Manufacturing simulation techniques of this type have only recently been accepted by industrialists and are the subject of considerable work in TMC.

Databases/information technology

It is vital that all members of the SE team have rapid and easy access to all product information. CAD tools are common in design offices and the use of Computer Aided Process Planning (CAPP) tools is growing alongside established Material and Resource Planning (MRP) systems. The move towards 'open' computer systems, networked around manufacturing sites, is increasing the chances that the design and planning tools have the opportunity to communicate. These trends coupled with improved 'dynamic' database systems ( Fig.3) will allow direct data entry/retrieval through site wide networks ensuring that team members have the data they require, on demand.

Rapid prototyping

It is frequently necessary to 'see' a component, to be sure of its suitability and/or manufacturability. 3D CAD systems go some way towards providing this, however, in many cases a 'physical' part is necessary. Traditional prototyping methods are slow and expensive, therefore alternative techniques are being developed; these include high speed machining of 'soft' material and building up piece parts by deposition. Such techniques derive their base data from the CAD system in which the component was created and may have direct (DNC) links to such systems, thereby providing rapid prototypes to aid decision making and early product samples.

Direct engineering

As SE and dynamic databasing become commonplace it is believed ^[7] that it will be possible to make more use of existing product (and its associated manufacturing process) knowledge. It is argued that it will be possible to make greater use of 'parametric' ( i.e. based on existing) designs. This will require a new breed of engineers - Direct Engineers - who are as able to design and use databases as to design products and/or manufacturing systems. Most products consist of parts which either already exist ( e.g. standard fastening items) or for which 'something similar' exists. If the data on these 'existing' parts can be correctly accessed it should be possible to produce parametric designs of product and manufacturing process. Such a move would reduce development lead times and give a 'safer' design because much of it will have been field tested already.

In conclusion

For all design and manufacture organisations the benefits of SE are plain; namely reduced product development lead times and manufacturing costs leading to improved profits. SE can be used by large and small organisations alike and does not require large capital investments. However, some of the specialist analysis techniques ( e.g. VA and DFM) require expert assistance to establish the necessary skills within an organisation. Similarly, external assistance may be required to provide the decision support tools and to refocus members of a 'traditional' organisation when moving towards a SE environment. The Management Consultancy at TWI is able to provide the assistance required and, in association with The Management Consulting Group, appropriate training.

References