Week 2 : Press-fit Laser cut kit


1. Automate the slot depth / width: I achieved this by creating a block in rhino and placing this block manually wherever needed. When using rhino blocks you always have to be very careful of the location of your block's base point (I just draw an actual point so that I never forget the location).



2. Find the right slot width: In order to find the right width I cut a piece with several sample slot widths, ranging from 2.5 to 3 mm (my material thickness was aprox 2.6mm ). I then tried every slot width and found the 2.8mm one to be the best fit, I went back to the rhino model and changed the slot block, I only had one slot type so by changing one block the whole model was updated.



3. Laser cutter settings: I made several test cuts in order to find the right settings, I started with 80% power and 5% peed and kept increasing the power and decreasing the speed. My material (1/8 in Acrylic) is fairly difficult to cut through so I settled on 100% power and 4% speed (on the Universal laser).



4. Cut pieces / Material treatment: I cut all the pieces leaving the plastic / paper film on the acrylic in order to avoid getting smoke marks, this way the smoke / burn marks stay on the film and comes off once you peel it from the final pieces.



5. Assembly: I found this to be the most challenging part of the process, the slot width is fairly effective well once all the ribs are in place but the slot with is not tight enough to hold the structure when there is only one rib so locationg the second one is very tricky, the whole thing fell appart several times when I was attempting to place the second rib. It would be much easier if I had made some kind of rig to hold the pieces together while I locate the ribs.



6. Final Product: I am quite pleased with the final product, however, I think more care should have been paid to the slot widths, because of the laser cutter variability (It cuts differently depending on which area of the bed it is cutting) it is difficult to predict with precission how big the slots are going to be, this would not be too much of a problem with a more flexible material but As professor Gershenfeld said, Acrylic is not a good material for press fit assemblies, it is much too rigid.