Design Project Estimation Made Simple and Accurate

Estimating the time and cost of your engineering project can be verydifficult, yet it remains critical to your company’s success. If youconsistently underestimate, you will spend more than you make andeventually go bankrupt. If you consistently overestimate, you will loseall business to your competition and won’t make any money to beginwith. Neither result is acceptable.

The DPET was developed using our experience in the critical factorsrelated to CAD that determine modern design project schedules. The toolis detailed below:

The first section of the DPET (shown above) deals with variables that requirespecific consideration, such as (single) user skill level. Somejudgment is required here. For example, the skill level check box canbe interpreted as being relative to CAD tool use, experience in theindustry, familiarity with processes, or other critical factor ofinterest to the calculator user. In its entirety, the calculator isdesigned to account for the project work of a homogenous staff withskill set differences as accounted for in the first input section. Thecalculator can be run for each additional team member, combiningseparate totals for the aggregate project time.

The second input section (shown above), the project planning phase, asks for inputsrelating to the initial project work, with built-in factors for thecomplexity of the design’s Component Selection. These are off-the-shelfitems such as connectors and fasteners; items to be sourced andsubsequently integrated into the design once their suitability isestablished.

The third section of the calculator (shown above), part design and modeling,requiresestimates of the number of each part type to be designed and itscomplexity. Here, it is better to estimate high for the number of partsif an exact number is unavailable for two reasons. First, designengineering often takes longer than anticipated. Second, there may be arequirement for more parts than initially derived, or the integrationof fewer parts may take longer than anticipated.

Section four (shown above) has built-in factors to improve accuracy in computingthetime it will take for part and assembly drawing creation. DPET is wiredto account for electronic data transfer-type documents to fullydimensioned documents with tolerance analyses included.

Section five (above) and six (below), dealing withpart fabrication, prototyping andassembly, and de-bugging, simply asks for hours to be entered. Thoughthese tasks will not likely comprise a large portion of the project’stotal time expenditure, if the project task list includes fabricationand assembly, an accounting here will increase estimate accuracy. Ifthere is no requirement for assembly and de-bug, and other tasks areenvisioned that are not listed within the calculator, sections five andsix can be used to account for them instead.Once the sections are completed, thefinal section shows the totalcalculated project time in hours, days, and weeks. In just a fewminutes, and with a small amount of consideration as to project tasks,you get a reasonably accurate estimate of your project time.

Stephen Samuel is president of Design Visionaries. You can e-mail himwith suggestions, additions, or improvements to the DPET at [email protected].