Question

Explain what is wrong with the poor designs in the figure below?

To be machined No Yes No Yes To be machined Fillet radius Sharp T TA No Yes No Yes o No Yes No Yes

Answer 1

Starting from top left to right and going to downward rows.

1. In this one initial design is poor because if it is cast out, it would not be having better properties as it increases in size going upwards. Also, there would be imperfections in the corners due to casting. A better approach would be to cast it with a better base size and then machine it to finalize the dimesion. this would ensure better mechanical properties throughout hte job.

2.Direct casting such a hollow rod with section cutout is not suited because edges may not be perfect due to casting. Better design is to cast the hollow tod and machine the section a shown

3.Left side design is a poor one because internal grooves are preferred. And also in first design the cross sectional area at joint is decrased which would make it prone to breaking. On the other hand design on the right is having a better area at the joint.

4. In this one the right hand side design is preferred because giving a fillet radius in such situation is preferred to decrease stress concentration.

5. In this one the left hand side design is having too many edges which are not suited ergonomically as well as they cause stress concentration. An alternate design which is provided to the right is more suited.

6. In this case straight lines would provide a better grip than knurling hene second one is preferred.