Question

2. A prototype of a part is to be fabricated using stereolithography. The base of the part is shaped like a right triangle with dimensions 36 mm by 48 mm. The height of the part = 30 mm. Layer thickness = 0.15 mm, and laser spot diameter = 0.15 mm. The beam velocity across the surface of the photopolymer = 2200 mm/s. the minimum possible required to build the part, if 25 s are lost each layer to lower the height of the platform that holds the part. Ignore setup time and post processing.

Answer 1

`T_(m)` =1.53 hr

Explanation:

In your question 30mm should be the thickness. Also, the minimum possible time is required.

SOLUTION:

The part should be oriented on its side in stereo lithography, thus laser Area A is same for all layers.

A= 1/2 (b x h) =>0.5 (36 x 38)

A= 864 mm²

Time to complete one layer 'T' is same for all layers

T= [(A/spot size x velocity)+ last time]

T=[(864/ 0.15x2200) +25]

T=27.62 sec

Number of layers 'n' is given by:

n= t/ layer thickness =>30/0.15

n= 200 layers.

Next is to determine minimum possible time required,

`T_(m)` = n x T =>200 x 27.62

`T_(m)` =5524 s /60

`T_(m)` =92.06 min/60

`T_(m)` =1.53 hr