Task: Produce a press fit kit (accounting for kerf) using the laser cutter
Making the Design
The main aim is to use parametric design software to ‘simplify the process’. Being able to edit the sketch automatically by adding parameters and using these to dimension the sketch instead of manually changing them.
First step was to create the rough design on Fusion 360 and then dimension it to ensure that it would fit together.
As you can see above the dimension with fx: 2.5 are the parameter dimensions. These are controlled by the parameter menu and are what you use to account for the kerf using these identities below: See my post about how to use parameters
+ addition
– subtraction
* multiplication
/ division
^ power
( following BIDMAS
) following BIDMAS
; delimiter for multi argument functions
Laser power settings were already determined my John and Gary on the saved power settings
Working out the kerf of the laser cutter is different for every material, due to the taper that it puts on when cutting. I worked out that the kerf was 0.125mm for 4mm Acrylic which is what I chose to make my model from. I decided to skip the card model as I felt it wouldn’t work very well with the clip mechanism that I was going to use and time would be better spent making it with either acrylic or MDF.
Overall 18 different versions were made on Fusion 360 to get the fit just right, and by doing several cuts using the laser cutter i worked out the correct tolerance as well as the correct dimension for the clip ‘nubs’. I do however have a graveyard of broken acrylic parts to show for it! The clips works by having a ‘nub’ which sticks out and slots into a cut out hole on the other piece. This allows the model to go together but it won’t came apart once assembled.
Assembling the completed part in Fusion was also relatively easy, although not as intuitive as Solidworks – much prefer Solidworks as it gives more control and the interface is more technical.
Pre-assembly
Post-assembly
Material thickness – Acrylic – 3.91mm
