ENME 414 Computer Aided Design

Homework Assignment 4 - Dimensions, Tolerances and Surfaces

Due 9:00 am, Monday, March 3, 1997

Statement: The performance of a component or a part is determined by the material the part is made from. The performance is also related to the dimensions, tolerances, and surfaces of the part. During the design stage, dimensions, tolerances, and surfaces are three attributes that are specified by the product designer. The physical realization of these specifications has a dominant influence on the production cost. Design for manufacturability and design for assembly call for careful consideration on specifying these three attributes.

Problem 1 Tolerances can be specified in three formats, depending on their natures. They are unilateral format, bilateral format, and limit format. For each of the tolerances listed below, write the other two formats if these formats exist.

Problem 2 Use the tables provided on pages 52-67 to identify

1. the maximum and minimum dimensions of the hole and/or shaft;

2. the tolerances for the hole and the shaft, respectively; and

3. the maximum clearance and the minimum clearance.

(1) basic diameter: 5 inches, Basic-Hole System, Clearance Fit = LC2.

(2) basic diameter: 5 inches, Basic-Hole System, Interference Fit = LN3.

(3) basic diameter: 5 inches, Basic-Hole System, Transition Fit = LT3.

(4) Draw a comparison diagram which includes the above three cases.

Problem 3 Use the tables provided on pages 52-67 to identify

1. the maximum and minimum dimensions of the hole and/or shaft;

2. the tolerances for the hole and the shaft, respectively; and

3. the maximum clearance and the minimum clearance.

(1) basic diameter: 5 inches, Basic-Shaft System, Clearance Fit = SLIDING.

(2) basic diameter: 5 inches, Basic-Shaft System, Interference Fit = FORCE.

(3) basic diameter: 5 inches, Basic-Shaft System, Transition Fit = LOCAT. TRANS.

(4) Draw a comparison diagram which includes the above three cases.

Problem 4 The following figure is the measurement of a surface profile. Calculate the roughness average value, root mean square value, and peak-to-valley value (four sections are assumed)


place the figure here