DFM Introduction

DFM defines the concept of considering the product from the beginning of the design/planning stage to the finished assembly. Considering all of the aspects that go into the development of a prototype before you begin layout will aid you in developing better forecasts for development and production costs as 80% of all product cost is fixed at the time of design.

This concept is by no means a small aspect of product design and manufacturing. In fact two developers of DFM software have been awarded the National Medal of Technology by then U.S. President George Bush for having " dramatically reduced costs, improved product quality and enhanced the competitiveness of U.S. manufacturers."

Previously engineers were primarily concerned with the functionality of their design - the actual assembly and layout came later. Product engineering and circuit board layout are now rarely considered to be two separate entities - more and more engineers layout their own circuit boards and in doing so they are responsible for the entire design - mechanical, layout and electronics. Fabrication and manufacturing are no longer `post design' tasks. These issues must be addressed early in the design stage in order to facilitate the development of a manufacturable product. To achieve this goal the suggestion is to utilize rules-driven techniques in design, anyalsis and manufacturing.

Rules-driven design requires that any constants identified during system design are used to control physical layout. In a similar context, the layout process has to take into consideration the constraints that impact in the downstream process' - fabrication, assembly and testing.

The use of interactive analysis tools early in the design and development cycle can be used to replace some of the prototyping and preproduction runs. These tools can guide the initial board layout through the display of thermal maps or by alerting designers when critical net parameters exceed permitted values.

With automatic assembly, models can be created to simulate the board passing along the production line with components being added at each step. The information created from this can be used to adjust component placement in order to obtain maximum efficiency.