How can I adjust the times associated with our special fixtures for multiple fasteners?

To answer this, it is useful to realize that there can be more than one purpose for performing a DFA analysis. One purpose is to identify problem areas in a design with the goal of eliminating them through redesign. If this is the purpose of the DFA analysis, the times generated by the software should not be adjusted to account for special purpose fixtures, strategically placed drivers, etc. used in assembling the product. These special purpose fixtures are being used during assembly to overcome the problem areas of the design that DFA is identifying by increasing assembly times. Making adjustments to the assembly times generated by the software will decrease the usefulness of the software's output and suggestions for redesign.

A different purpose for a DFA analysis is to estimate the true cost of assembling a product. If this is the purpose of the DFA analysis, adjustments can be made to the assembly times generated by the DFA software. These adjustments are made on the Product Worksheet window. From the Structure Chart, click "Product Worksheet" in the "View" menu. A window will appear which presents an editable breakdown of all times estimated by DFA. For an operation which involves inserting multiple screws simultaneously, the repeat count of the screws should be set to the number of screws in order to get the correct part and fastener count in the analysis. The times displayed in the "Item handling time" and "Insertion/operation time" columns on the Product Worksheet should be changed to the average handling and insertion times per screw. If you have a videotape of the operation, use a stopwatch to time the handling and insertion portions of the operation. Divide those times by the number of screws being inserted during the operation, and enter these results in the columns on the Product Worksheet. The software will then multiply the entered times by the repeat count in order to generate the total time for the screw insertion operation.