DFA IS USED TO ENHANCE VALUE ENGINEERING/VALUE ANALYSIS WORKSHOP OUTCOMES
26 September 2006 - Boothroyd Dewhurst

Faced with these pricing constraints and continuing cost pressures, the suppliers and OEM's alike have resorted to a multitude of formalized techniques designed to meet the challenge. These include GFD, TQM, VE, VA, and DFM, DFA. Some of these techniques have met with success while others have been tried briefly and dropped. At the Magna Interior Systems Seating Group, we have found the most powerful combination by a wide margin has been the melding of the disciplines of DFA and VE/VA.

This paper describes the means by which the Magna Seating Group VE/VA team has employed the Boothroyd Dewhurst DFA method to enhance the outcomes of our Value Engineering Workshops, resulting in significant savings in materials, design costs, tooling, and processing of parts and assemblies.

Value Engineering/Analysis as a Full-Time Activity
Because of the continuing requirements for maintaining downward pressures on all costs, it has been found productive to establish and maintain a small department within Engineering whose only purpose is to concentrate on the broadest areas of cost reduction through the Value Engineering/Value Analysis approach. This department is made up of experts in each of the disciplines required to develop and manufacture the products of the supplier company. Personnel were selected for their demonstrated skills in the areas of product development, manufacturing, tooling, and processing as well as their overall industry experience. In many organizations, it would be difficult to take people with these skills out of the mainstream of product development for an extended period of time for this effort; however, the fact that some of the best and most experienced personnel have been assigned exclusively to this program at Magna speaks to the level of commitment required to achieve success.

Once the commitment is made, we have found that the payoffs can be several times the cost of supporting the group. Further, properly equipped with the latest computer equipment and software, and trained to use every available means to spot cost reduction targets, it is easily demonstrated that a full time VE/VA group can have a major impact on the bottom line.

At Magna Seating, we have used the DFA technique to strongly enhance our cost reduction efforts, not only in the area of metal parts, but also in the analysis of cut & sew products such as seat and armrest covers. We believe this second application of DFA is an industry first. We have developed our own formulas for each sewing operation and have verified the accuracy of the outcomes by comparing them with actual observations during visits to the various facilities. DFA is now the standard tool used to target our VE/VA efforts.

Correlating Product Design with the Manufacturing Process:
Effective design for lowest cost and fewest components can only be accomplished by a product design and engineering staff that understands the manufacturing capabilities of the plant(s) in which the assembly will be made. Unfortunately, in today's working environment, the design team is often not conversant with the processes and procedures of the manufacturing facility. Further, program time constraints frequently seem to force the design to be initiated without thought of how the final product will be made. Time for analysis is usually not scheduled into the program, and the design proceeds to a point of no return before a realization is made that tooling and processing of the parts, subassemblies and assemblies have not been considered adequately in light of plant conditions.

In order to minimize this problem, the training of product engineers and their design counterparts must include continuing exposure to the plants charged with manufacture of the products for which they have technical responsibility. Visits to plants for orientation and training should be for a minimum one week period with as much floor exposure as can be practically included. In some cases 3 to 6 month plant assignments may be considered for newer members of the product design and engineering staff.

The payoff for this type of training is the ability of the engineers and designers to visualize the manufacturing process during the preliminary design stages of new products, including direct knowledge of process layout when conducting the initial baseline DFA analysis. This procedure minimizes false starts, redesigns, issuance of Design Change Notices and the accompanying cost of tool changes later in the program.

When conducting the baseline DFA it is important to include inputs from the entire product team. Insights into potential production and assembly problems by those who live with the plant environment on a daily basis is invaluable in assuring the accuracy of the DFA outcome. Minor design changes which may vastly improve the processing of the assembly and its components can produce a major cost impact on the final product.

Purchasing, Sales, and Quality Assurance personnel will enhance the knowledge base of the team and bring independent ideas to the DFE, VE/VA process which could easily be missed by the technical staff because of their close contact with the product being considered.

Targets For Change, DFA, A Tool for Focus:
The usual way to attack a high cost part or assembly is to wait until after the design is released, tooled and in production and suddenly discover that the expected margins are not being generated. Obviously, by this time a lot of engineering and design cost is already burdening the product; often it is discovered (usually by the CEO) that "we're shipping this thing with dollar bills wrapped around it." This is usually not too good for the long term career prospects of the design or product manager. Clearly, early analysis of new designs using the DFA technique is crucial to the commercial success of each and every product. A strict regimen needs to be imposed providing for DFA analysis as soon as the first concept layouts and illustrations are sufficient to define the product in all its functions.

The early review at concept stage will reduce parts count and processing steps by highlighting possibilities for combining parts, reducing extra screws, bolts, and washers, and reduce or eliminate extra or superfluous reinforcement achieved by parts layering (common in the automotive seating industry). Major development, tooling and gauging costs are saved by the lowering of parts count, and all are familiar with the high cost associated with making changes later in the product development cycle.

A review of operations will reveal other opportunities for cost savings in the processing area. A good example is in automotive seating systems where many parts are covered with foam or fabric, or are otherwise not visible. For many years, certain customers required that all steel parts be painted or otherwise coated to prevent rust; however in the JIT environment, parts are not stored for long periods of time prior to final assembly, and, once assembled, are no longer exposed to atmospheric conditions which cause corrosion. Given these new conditions, it is no longer required that the steel parts which are covered be coated. In many cases even exposed parts which are not visible can be left without surface protection.

Wire welding is another process which often can be minimized or eliminated.
When reviewing the DFA and the preliminary design, an examination of weldments usually will expose relatively small parts (gussets, trim tabs, etc.) which could easily be made integral with the basic part to which it is welded. Very often these parts are so small that time penalties must be attached because of handling problems. If manually welded, the welder must pick up these parts using bulky gloves, place the parts in a fixture and perform the welding operation. Observation of this process in the plants has indicated that the elimination of the small parts can save 30 seconds to a minute in the assembly sequence.

Very often a change in the approach to the method of accomplishing a desired function can reduce parts count by 1/3 to 1/2. This is especially apparent in the guiding of moving parts, such as folding seats, latches, etc. Forming special guides and welding them to brackets requires extra parts sand processing to achieve a motion or function that can just as well be done by piercing a slot in the main base bracket to act as guides.

Anyone visiting a mechanisms assembly plant will observe manual lubrication of mating parts by using a brush or rag. Automation of this process can eliminate as many as three people from the assembly team and almost always results in significantly reduced material use. Equipment cost can be paid back in a very short time and exposure of personnel to a potentially hazardous environment is eliminated.

Designers and engineers are fond of creating assemblies with lots of screws, rivets and small parts. Unfortunately, these parts are difficult to handle and process, even with automated equipment. On the other hand, if caught soon enough, it is possible to find alternate constructions that will provide the same function with fewer components. At Magna we have been able to minimize the quantity of these small parts and automate the assembly of those absolutely required, using the "Suggestions for redesign" function of the DFA software to target opportunities.

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