NSF/ASEE WORKSHOP ON CREATIVE AND STRUCTURED DESIGN METHODS

 

Exercise 3: Evaluation - ELECTRIC DRILLS

An electric drill is to be selected for domestic use. Data for three candidate drills are given in the table below.

(a) Use this table to prepare a set of approximately ten assessment criteria and rank these requirements in order of importance by preparing an Objectives Tree.

(b) Make a quantitative evaluation of the three drills using an Evaluation Chart.

(c) Discuss the strengths and weaknesses of the evaluation procedure used in part (b). Make any suggestions you can for overcoming these weaknesses.

  DRILL A DRILL B DRILL C
       
Price, $ 50 160 120
Weight, kg 1.5 2.1 2.2
Output power, W 240 315 365
Max speed, rpm 3100 2600 2600
Variable speed control No Yes Yes
Feedback on speed control No Yes Yes
Chuck capacity, mm 1-10 2.5-15 1.5-13
Flex length, m 1.3 2.5 1.4
Depth Stop No Yes No
Widest hole in wood, mm 19 25 30
Widest hole in steel. mm 7 10 13
Performance, drilling steel Average Very Good Good
Hammer drilling Poor Average Good
Screwdriving No Yes Yes
Endurance Average Very good Good
Ease of handling Poor Good Average

 

 

 

Note: All three drills meet all electrical safety standards.

Papers due to Paul Clayton on 10/9/99