Question

There is a requirement to make a hollow and fully closed cuboid of dimensions 70mmX50mmX50mm. The raw material available is a sheet of width 175mm and length 300mm. Create a Laser Cutting and Bending Drawing for the sheet metal so that minimum raw material is used and also weld length is minimised. Calculate the weld length to manufacture the cuboid.

Note:

● Usable raw material post laser cutting is defined as the maximum area rectangle that can be fit in the remaining raw material.

● Between two laser cuts a minimum of 2mm gap has to be maintained to keep a clean and dimensionally accurate cut.

● Hand drawings with all dimensions mentioned are sufficient for the answer.

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Answer 1

Given:

Dimensions of the cuboid to be made :  $70mm\times50mm\times50mm$

Dimensions of the sheet given to construct the box : $300mm\times175mm$

To find:

The laser cutting and bending sheet-metal diagram for the cuboid to be constructed.

Solution:

1. First we will calculate the total markings to be made. With respect to exploded view of a cuboid.
2. On the length of the metal sheet we will mark the length and height of the cuboid i.e we will mark 4 segments of the cuboid. Whose combined length will be $50+50+70+70=240mm$ .
3. But the sheet has a length of $300mm$, therefore the excess length is $300-240=60mm$ . We can divide this excess length in half and mark on top and bottom.
4. Therefore, on the edge of length $300mm$ of the cuboid sheet we have to first mark $30mm$ from the top and bottom. Then starting from the $30mm$ mark on the top, we will mark points at a distance of $50mm$.
5. Taking that as the base mark a point further below at $70mm$ and and then the same way at $50mm$. (The remaining $70mm$ segment mark is the 30 mm mark we created at the bottom in the starting.)
6. Repeat steps 4-5 on the opposite edge of the metal sheet.
7. Now join the points opposite to each other.
8. We will mark the breadth of the cuboid on the breadth of the metal sheet. The total length of these mark segments will be $50+50+50=150mm$. And the excess length will be $175mm-150mm=25mm$  which can be halved and marked at top and bottom.  
9. For marking the breadth of the cuboid, we will mark points at a distance of $14mm$, $50mm$, $50mm$ and $50mm$ from the starting of the edge in similar pattern as before and repeat on the opposite side.
10. Join the points apposite to each other and mark as shown in the figure.

The shaded portion is the layout of the cuboid to be laser cut and folded as per markings. Open ends can be sealed by welding. However if you wish to make the box by only folding, you can keep the hems that are marked.  

Note: Hems can be kept of any length from $5mm$ to $10mm$.