Wednesday, February 4, 2009

More Acrylic Bending - the Back of the Case

Moving on to bending up the back edges of the case now.

For this, I had to continue building out the wooden 'last' that was used for bending the front case curves. I attached a small piece of flat wood onto what would be the back face of the case.

This 'last' provided a fixed distance between the front and back faces of the case, and would help ensure that both sides of the case had the same length. I rounded off this edge with the wood plane.

Has a greatly reduced radius bend on it.

Now the plastic fits onto the last, with the front face of the case butted against one face of the 'last', ligning up the side ready for bending.

Applied the heat, got it soft, and did the bending.

Bent OK. I used some force once heated and bent to try and mould the sheet as close as possible to the 'last' shape...
Still not sure the best way to bend - is it best to try and get the material as hot and as pliable as possible ? Or is it best to heat just to the minimum amount necessary to get the bend ?
From the few bends done so far - I do think that it is probably better to try and limit the area that gets heated up - limit it just to the areas that should bend. Other wise you get some distortion in areas that are meant to remain flat.

After having bent the back two edges, it was now time to score and snap off the excess. The case mounted easily on an old stool, which was lucky. A bit of an unwieldy thing to work on once bent.

I also had to trim off the edges of the back plate. Note that next to the I/O ports on the back, there is now very little plastic left on the edge. I think in future it would be wise to leave more space on the sides of the case around the motherboard - would probably make a neater connection.

Fitting the case over the main box gives the following

Note that on the back edge next to the I/O ports I needed to trim an extra bit out of the curved edge of the case so that I didnt interfere with the ports...
I will probably also need to do some filing of the back plate, as the edges interfere slightly with the curves on the main case.

Next few steps are to try and fix this face plate in place - with some strategically glued pieces of perspex, and some screws.


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