39-245
Rapid Design through Virtual and Physical Prototyping

Carnegie Mellon University
Spring 1997

It is useful to keep your part within certain dimensions so that you have a reasonable number or slices per sheet and so that the number of sheets is not too great. Under 40 sheets: Height =< 1.8", Width =< 2.2", Depth =< 2.2" Under 30 sheets: Height =< 2.0", Width =< 1.8", Depth =< 1.8"

These figures are not absolute. You will have to experiment to determine the number of sheets with which you are comfortable working. I have found that reducing the width as much as possible, and thus increasing the number of slices per page, is the key to reducing the number of sheets that comprise the prototype.

The limits on the part size are:

• Maximum width of the prototype = 7.5"
• Maximum length of the prototype = 5"
• Minimum width (with minimal amount of flexibility) = 0.25"
• Minimum length = 0.25"
• Maximum height (to prevent from having to manually line up sections)= 5.5"
• Minimum height (to have relative amount of rigidity) =0.25"
• Minimum diameter of inner circle = 0.1"
• Minimum distance between outer edge and inner edge of a part = 0.2"

These maximum measurements will cover the entire sheet. The minimum measurements are from experimentation. It may be possible to make a part smalle; however, this would require a lot more effort (use of X-acto knives, manual placement of slices, etc). Also, accuracy would be greatly reduced. It is also possible to make the part taller. The only problem is that the registration posts do not go any higher. You can create subparts of the model and put the subparts together manually. This may limit the accuracy of your model.

sfinger@ri.cmu.edu