Question

1.What is working progress for Design for cost? 2.What is working progress for Design to cost?

Answer 1

Design for Cost

Designing for cost is the conscious use of engineering process technology to reduce life cycle cost. Design to cost is the iterative redesign of a project until the content of the project meets a given budget. Designing for cost seeks to increase system performance while reducing cost. Design to cost usually reduces performance until the budget is met. Designing for cost seeks to reduce cost as far as possible while meeting customer demands. Some of the significant cost contributors that can be attributed to design include:

1.) Material Specification : When a design engineer selects a “suitable” material, he/she has to be driven by performance, life expectancy, reliability goals and, intrinsically, the manufacturing process to be adopted. A material selected with lower endurance limits would require larger cross-sections and heavier designs to achieve desired life. The higher the endurance limit, the lower the failure rates.

2.) Tolerance Specification :While industries have perfected the art of communicating the tolerances for a part, the processes adopted for specifying the tolerance values is still a work in progress. Equal emphasis has to be there for tolerance specification. This is driven by Cost of Precision Vs. Cost of Poor Quality Analysis.

3.)  Number of Components in Assembly : Fewer number of components in assembly, lesser fitment issues and associated costs. It is common knowledge that fixtures are a part of the manufacturing and assembly process for any product. Part manufacturing fixtures, inspection fixtures, tooling fixture, assembly fixtures are common place in product engineering and manufacturing companies. Every one of them adds to the cost of the product.

4.)  Factor of Safety :FOS based designs have long been proven to be over-designed and costly. Life based designs are cost-effective and efficient. With changing customer priorities, it is all the more relevant that Design for Life takes the lead as a primary driver for cost-centric products. Giving design options for different life expectancy empowers sales to provide options to their customers in terms of price vis-a-vis warranty.

5.)  Knowledge of Manufacturing Processes : Process capability, processing sequence and stages have significant influence on product cost. If a design engineer provides for a location tolerance on a hole feature, that cannot be maintained, of what good is the tolerance specification? Product cost becomes higher due to design. Rejections add to the costs as well. Herein comes the answer by following a process – Cost of Precision or Cost of Poor Quality? Which one is higher?

6.)  Packaging & Transportation :Numerous instances of a product blemished during transportation are known. Product replacement, re-work at site / customer are cost indicators that need to be avoided at design stage. Upfront engineering, involving packaging considerations, handling and transportation requirements, ensures evaluation of reduced cost alternatives before product release

Design-To-Cost

Design-To-Cost (DTC) is one of the most important aspects of a product design. After all, in an average product, every dollar in cost equals five dollars in sales. Main components of DTC during the product design process are as follows :

1. Create an MBOM
Create the MBOM (Manufacturing Bill Of Materials) as soon as possible in the design process. The MBOM includes the non-engineering aspects (suppliers, prices, quantities, etc.). The sooner you have the MBOM data, the bigger the chances to update the design according to commercial parameters.

2. Know the product’s cost before it is too late for design changes
It doesn’t have to be a final or even accurate cost, but you must have a general idea of the product’s cost when you still have the option and the time to make design changes.

3. Calculate the cost yourself before sending RFQs
I find it is quite common for product managers to compare between different quotes, but much less common for them to compare quotes to their calculations. It’s difficult to negotiate without knowing the cost details. Doing your own calculations will teach you a lot about the cost parameters and will give you a much stronger negotiation position.

4. Make a Pareto graph of costs
This will lead you to effective cost reduction opportunities. Reducing product costs requires work and time. Make sure to spend your cost-reduction work in the right places.

5. Don’t miss the hidden costs
Hidden costs might have a great impact on the product’s total cost, and they tend to be skipped in cost calculations during the design stage. Hidden costs are the product’s indirect costs, such as by products, shipment, logistics, customs, taxes, funding, etc.

6. Time is money
In many cases, short timetables cost (much) more than the same work done over a longer period. You have two options: one is paying in time, and the other is paying in dollars. Both are fine – make a decision. Just do not be tempted to take shortcuts and think that you can win them both.