New product design is crucial to the survival of most companies. Although there are some firms that experience very little change in their products, most companies should review them continuously.
In rapidly changing industries, introducing new products is a way of life, and very sophisticated approaches to introducing new products have been developed.
Manufacturing costs, as well as warranty and repair costs, are greatly affected by product design.
Thus, it was found that in General Electric 75% of its manufacturing costs were determined by the design, detecting similar proportions in other companies.
For example, at Rolls Royce design determines 80% of final production costs and at General Motors design affects 70% of its production costs for truck transmissions.
Now, what is the implication of the above? These statistics clearly show that significant reductions in manufacturing costs are feasible if more attention is paid to design.
Decisions made during design constitute the dominant influence on product costs, the ability to meet specifications, and the time required to bring a new product to market.
Once these decisions are made, the cost of design changes can be enormous.
Significant improvements are registered in terms of costs and quality, as a result of the simplification of the design, since it makes manufacturing and assembly tasks easier.
By reducing the number of parts, material costs are reduced, while reducing stocks, the number of suppliers, and shortening production time.
Another direct effect is the reduction in the costs of managing purchases, suppliers and warehouses.
Various research and studies carried out show that the time and cost of assembly are proportional to the number of parts that are assembled.
IBM made many important benefits by designing a new dot matrix printer called Proprinter.
Until then, IBM was sourcing printers manufactured by the Seiko Epson Corporation, considered a low-cost global provider. What did IBM do? I design a printer with 65% fewer parts.
They were designed in such a way that the parts and subassemblies could be assembled under pressure without using screws. This generated a reduction in assembly time of the order of 90%, and a notable decrease in terms of costs.
Design must be coordinated with manufacturing to produce consistent quality items with minimal waste. For example, it is normal for a company to replace parts that are damaged during the testing of a product, with more complicated equivalents.
This action only increases manufacturing costs. The option is to redesign the product based on the least expensive parts. Thus a watchmaker in Japan found that with a cheap capacitor variations in less expensive crystals were compensated for, and still highly accurate.
Many aspects of product design can negatively affect ease of manufacture, in addition to the corresponding quality.
Disregarding the consequences generated by design decisions is quite common in traditional companies, considering as such those attached to paradigms no longer consistent with new realities in scientific, technological, social and economic matters. In these organizations there is a lack of good sense when designing the products, which brings with it as a consequence a series of problems to the production area.
The components are given tolerances without reference to the capacity of the processes available.
Too many components intended for a single assembly, and these lack a suitable design to take advantage of the forces generated by the process; giving rise to failures in the efforts of mechanization, assembly and different types of fastening.
Simple design details can superlatively alter the investment levels required for manufacturing. The effects of design on production costs are as shown below, the same being the results of various studies carried out in companies in the United States and Europe.
World-class design is achieved through integrated product development, which combines the needs and experience of all involved.
The cost of the final product is a matter that must be accepted by the department, or those responsible for the design, as a factor as important as any other.
New product development has a major impact on the operations function, because any new product that is designed must be produced by operations. The existing operations may limit the development of new products.
Product decisions are a prerequisite for production. Product specifications must be given to operations before production can start and before operations can make some important decisions.
Operational decisions such as process design should not wait until product specifications are finalized, as they must be made at the same time the product is designed.
Design simplification
Systems such as group technology, value analysis, cause-effect analysis, Taguchi methods, simultaneous engineering, design for production, design for assembly and automation, all converge in a single great objective, which is design for simplicity.
This simplified product design has two characteristics that are unique to it:
- The reduction in the number of component parts of a product; and The use of standard parts.
When these two characteristics are achieved, it is achieved:
- Reduce production costs. Reduce delivery times.Reduce levels of uncertainty. A better balance in operations. Reduce inventories. Reduction of the physical space destined to inventories of supplies and components. Ostensibly improve quality levels. Increase reliability. Simplify maintenance. Increase adaptability. Automate activities and processes. Simplify the flow of inputs and components. Better monitoring and control of materials.
The technique called "design for manufacturability" is focused on simplifying design to make it workable.
The emphasis is on reducing the total number of parts, the number of different parts, and the total number of manufacturing operations. To do this, software is used to analyze a design and identify opportunities to simplify product assembly.
This type of software separates the assembly step by step, asks questions about the parts and sub-assemblies and provides a summary of the number of parts, the assembly time and the minimum theoretical number of parts and sub-assemblies.
Using the software enables designers to learn simple manufacturing principles analogously to reliability, maintainability and safety analyzes.
In one example, the proposed design of a new electronic cash register was analyzed with design software for manufacturability (DPM). The result was that the number of parts was reduced by 65%. A person without using screws or nuts can assemble the register in approximately one minute and thirty seconds.
This simplified terminal was put on the market in just 24 months. This simplification of design reduces assembly errors and other sources of quality problems during manufacturing.
Thus, a simplification in product design allows a company to become more competitive. The reduction of the number of parts and their standardization are fundamental characteristics to be able to compete in globalized markets.
The stages of a design project and its importance
Every design project must consist of five stages, these being the following:
- Conception. Consisting of preparing the preliminary draft specifications. Acceptance. It shows that the specifications are reached by means of mathematical calculations, sketches, experimental models, models or laboratory tests. Execution. Consisting in the preparation of several models from the work of the previous stage, building pilot plants as a continuation of laboratory experiments. Adequacy. Stage in which the project acquires a form that allows it to be integrated into the organization and adjusted to the final specifications. Preproduction. When sufficient quantities are produced to verify design, tools, and specifications.
Regarding the relationship of each stage listed above with costs, the following aspects to be taken into account are especially noteworthy:
- The estimated cost of the design must be one of the figures that are submitted to consideration in the design acceptance stage. Regarding the conception, among the minimum and fundamental components to be taken into account are: the technical or performance requirements, including explicit statements about quality and reliability; the intended sale price or the production price; the probable quantity that will be needed, affecting it substantially to the design, and consequently, to the initial cost; and the maximum acceptable design cost. Regarding the adaptation stage, the following questions must be asked at all times: “This piece should not cost more than….. Can it be manufactured with that amount? If not, how can it be redesigned? ”
Consideration should be given to the "decreasing performance law on design effort," according to which the longer the time spent on a design, the less the increase in design value, unless a significant technological advance.
Design work is expensive: A qualified engineer or scientist not only has a high base salary, but draws considerable auxiliary personnel and sometimes large amounts of industrial equipment. Frequently it is possible to avoid the heavy fixed costs of a permanent technical team by purchasing the design effort.
The most common mistakes
There are many aspects of product design that can adversely affect the ease in the manufacturing process, and consequently its level of quality. Some parts are designed with features that are difficult to manufacture repetitively, or with tolerances that are unnecessarily tight.
Some parts may lack details to align themselves, or features that prevent insertion in the wrong position.
In other cases, parts may be so brittle or susceptible to corrosion or contamination that part of them may be damaged in shipment or by internal handling.
Sometimes, due to lack of care, a design simply has more parts than necessary to carry out the desired functions, and then there will be a greater probability of errors in its assembly and subsequent operation.
Therefore, poor design issues can arise in the form of errors, poor performance, damage, or malfunction during manufacturing, assembly, testing, shipping, and end use.
Design and quality
The design of a product affects quality in two main aspects: at the supplier's plant and at the manufacturer's own. A frequent cause of inconvenience with the supplier is the incomplete and inaccurate specifications related to the item that they must provide.
This often happens with bespoke components, and it occurs both at weak points in the design process by engineers, or at weaknesses in purchasing and order management.
Thus, the greater the number of distinct parties, and the greater the number of suppliers, the more likely it is that a supplier will receive an incomplete and inaccurate specification.
These drawbacks can be reduced by designing products with fewer parts, a high level of standardization, and selection from few reliable suppliers.
In manufacturing and assembly processes, there are numerous problems and drawbacks.
For example, in designs with many parts there could be a mixture of parts, a lack of components and a greater number of failures or errors in the tests carried out.
If some parts are similar, but not identical, the chances that a shipowner will use the wrong part increase. Parts or components that lack detail to prevent insertion in place or in the wrong orientation will lead to misplacement or reassembly.
Complicated assembly steps, or joining processes where tricks are used, can cause incorrect, incomplete, unreliable, or otherwise failed assemblies.
Finally, by not taking due account of the design, the conditions to which the parts must be subjected during their assembly, such as humidity, temperature, vibration levels, static electricity and dust, can generate failures during their subsequent tests and utilization.
Design to facilitate manufacturing is the process of designing a product in such a way that it can be produced with the minimum of work, money and waste, and with the highest level of quality.
The primary goals are to improve product quality, increase productivity, reduce product ready time, and maintain flexibility to adapt to future market conditions.
The purpose of this process is to avoid product designs that only simplify assembly operations, but that require more complicated and expensive components, or that simplify the manufacture of components, but complicate the assembly process, as well as simple and cheap designs of product that is difficult or expensive to support and service.
Fundamental design practices
Making room for the following practices results in more effective and efficient designs, which are conducive to new management practices.
- Analysis of design requirements, with special emphasis on statistical studies. Determination of the real possibilities of the process to manufacture the designed components, within the established specifications and tolerances. Identification and evaluation of potential quality problems. Process selection productive processes that reduce technical risks to a minimum. Systematic evaluation of selected processes under real manufacturing conditions.
Design guidelines for quality improvement
- Minimize the number of parts or components. Minimize the number of part numbers. Design for efficiency achievement. Taguchi method. Elimination of adjustments. Facilitate the assembly and proof of failures and errors. Use of repeatable and clearly understood procedures. Selection of components that can survive the operations of the process. Design of effective and adequate tests. Parts distribution to finish the process reliably. Avoid engineering changes in products in the market.
The lever effect
Doubling the amount of time, resources and effort in the design work, making it clear is, in a consistent and systematic way, it will significantly reduce the total manufacturing costs.
We are therefore facing a fundamental strategic cost. This is a type of cost whose increase allows via: training, planning, teamwork, benchmarking, value analysis, retroengineering, product reengineering, and simultaneous engineering; Reduce the time between the start of the design process and the time of the products being released to the market, consistently reduce costs by making the target cost feasible, and improve the profitability of assets, while achieving a higher level of satisfaction in customers, consumers and users.
Training and education, within what is called the management of knowledge and intellectual assets, is critical and fundamental, when it comes to creatively improving product designs.
Design for reliability, maintainability, safety, and other parameters should be done with the simultaneous goal of minimizing cost. Formal techniques for achieving an optimal balance between performance and cost include both quantitative and qualitative approaches.
The quantitative approach uses a ratio that relates performance and cost. This ratio tells what is obtained for each monetary unit spent. This ratio is very useful especially for comparing alternative design approaches to achieve the desired function.
Various approaches have been developed to strike a balance between performance and cost.
Value engineering is a technique for evaluating the design of a product to ensure that it provides essential functions at a minimum overall cost to the manufacturer or user.
A complementary technique is the "design for cost" approach. This begins with a definition of the target cost for the product and the desired function, continuing with the development and evaluation of alternative designs.
Engineering defines the performance standards required for products and parts, processes, materials, tools, and finishing, based on verifiable characteristics and economic degrees of uniformity.
You have to design the product and the manufacturing procedure. All knowable factors are desired to function exactly as projected, excluding all other possible factors.
But technical projects, operations and measures are not infallible. The designs and specifications of production factors are complex and rarely complete.
The same factors are often unstable, designs are sometimes evolutionary in nature, and demands often advance to current results.
With momentum of mass operations and complete insensitivity of operational controls all too prevalent, unclear deviations from standards lead to piles of scrap metal and disguised costs that are overlappingly claimed by faulty management to be regarded as normal and unavoidable loads.
In a company with net annual production of $ 10,000,000, the generally accepted 20% decrease in a precision product represents such a loss in direct manufacturing cost that analytical control was implemented.
Thus, each monetary unit spent for this concept reduced losses in the form of waste by $ 15 during the first year. Here again we see the effect of properly focusing attention on strategic activities and costs.
Method Engineering versus Product Engineering
While method engineering aims to create the best workstation design for a given product design and with the equipment and tools available, the goal of product engineering is to generate the most fabricable product design; by using existing or purchased equipment and tools or making new ones if needed, and then providing the best workstation design.
Based on this, we can list the approaches of both systems as follows:
- Method engineering approach
- Product design is given (i.e. relatively frozen). Manufacturing and method engineering follow product design. Equipment and tools are selected and arranged to best fit the manufacturing process for the design of the given product. The equipment is generally selected from what is currently available. The tools are purchased or designed to suit the selected equipment.
- Product engineering approach
- Product design can be changed to fit the desired end function of the product at the lowest cost. The producibility engineer is a member of the product design team, and advises the product designer on the available manufacturing alternatives and their relative effects and costs. Product design and process design are simultaneous and dependent activities. The product can be modified to meet machining requirements to reduce manufacturing costs. The producibility engineer optimizes the lowest cost of product design relative to the desired function, regarding the determination of design characteristics that affect equipment capabilities / limitations, tolerances, material selection, and process controls.The design team may specify modifications to existing or purchased equipment or tools, or provide design criteria for the acquisition or development of new equipment or tools.
Concurrent engineering
Also called concurrent engineering, it is the process of designing a product using all inputs and evaluations simultaneously and initially during design, to ensure that the needs of internal and external customers are met.
The objective is to reduce the time between the conception of the product and its placing on the market, prevent quality and reliability problems and reduce costs.
Traditional companies during product development are managed sequentially, not concurrently.
Thus the marketing department identifies a product idea; later, the design engineer creates it and builds some prototypes; the purchasing department requests quotes from suppliers; then the manufacturing department produces the units, etc.
In each step, the exit of a department "goes to the other side of the wall" to the next department, that is, there is very little information, during the design of the impact or effect that is generated or produced in the remaining stages of the process. It generally causes continuous revisions until a plausible design is achieved.
Concurrent engineering provides significant benefits, such as 75% fewer engineering changes and a reduction of the order of 55% in the time from product conception to market placement.
Conclusions
Optimal product design management significantly reduces costs due to:
1. Facilitate manufacturing processes.
2. Reducing the level of inventories and the physical space to the destined one.
3. Reducing costs related to warehouse management.
4. Reduction of financial costs corresponding to excess inventories.
5. Remarkably decreasing the level of failures or flaws.
6. Thanks to the previous point, avoiding the need for reprocessing and adjustments.
7. Facilitating inventory control and order requests.
8. Achieve greater and better control of the components, as a result of fewer components.
9. Effects of standardization on the experience curve of the producer and its suppliers.
10. Decrease in the amount and times corresponding to the processes and activities of preparation and tool changes.
11. Increase in scale in the production of components or parts by using them by other competitors, strategic alliances in between.
Among the final aspects to consider it is of fundamental importance to underline the importance of modular production.
It consists of an approach used to generate a greater variety of products from a limited number of components for them. Such an approach is used to control the proliferation of products by limiting the number of components or modules available.
Bibliography
Calitividad - John York - Editorial Marcombo - 1994
Successful Production - James Tompkins - McGraw Hill Publishing - 1992
Production Manual - Alford, Bangs and Hagemann - Noriega Editores - 1997
Industrial Engineering and Administration - Philip Hicks - CECSA - 1999
Product and service development - Mauricio Lefcovich - 2004
