5.5 Fusion 360: Mounting Mechanism - axolstudio-ca/Introductory-Guide GitHub Wiki
From here we will work on the mounting system of this macropad. The mounting system of choice here is top mount as it is simpler to design. To do this we will hide the bottom piece and start a new sketch on the bottom surface of the plate.
We will be using M2 screws that are 4mm long to hold the plate into the top piece. The specs on this screw can be found here: (https://www.mcmaster.com/92000A011/)
Since the screw head is 4mm, we want to have the wings of the plate that attach to the top piece to be wider than 4mm across. To do this, we will be using the space between each key cutout. The cutouts here are 5.05mm across, which is perfect for our application. To do this we will be drawing a rectangle in the sketch with the x value of 5.05mm, with the y value of 10mm.
We will repeat this process 3 more times in the following locations:
From here we will round out the corners of the wings. We will use the fillet tool under modify to round out these edges.
Repeat this for all the following edges:
After this process we will add the cutouts for the top piece for the plate to rest in. To do this we need to create another offset of each of the wings with an offset of 0.5mm. Select the 4 cutouts and use the offset tool to create the offset cutout required.
After this offset is done we will then finish the sketch and start with extruding the wings to join with the plate. We are now going to hide the top piece and work with the plate only.
Select the inner shapes for the wings and extrude them to the same height as the plate. From the top orientation, select the wings and extrude it -1.5mm. Make sure that on the right-hand side the operation type is join.
Your plate should now look like this:
While we are working on the plate, we are going to fillet the 4 main corners. We will fillet this with a radius of 2mm. The result should look like this:
Now that the cutouts for the plate are done we are going to add the cutouts for the top piece for where the plate will nestle in. Hide the plate and make the top piece visible again. From here, select the outer cutouts for the wings and extrude them -1.5mm. Make sure that the operation for this is set to cut.
The result should look like this
Now that we have the cutouts and the wings in place, we can now add the screw holes for the plate. To do this make the plate visible again and use the hole tool to add in the holes. We will again use references and this time the value of the reference will be 2.525, with the depth of the cut being 1.5mm. Repeat this step for all 4 wings.
The result should look like this
We will now add holes to the top piece of the case. Toggle the plate visibility and make sure in your workspace only the top piece is visable. We will now use the hole tool to add the screw holes. We will again use references, however this time the values is 3.025. We are using this value since the offset from the exterior edge of the plate is 0.5mm, we must add this value to the reference values used on the plate. The depth of this hole will be 4mm.
Repeat this step for all the other wings. The result should look like this:
After this step we need to add in the clearance for the screw heads on the bottom of the case. The screw heads have a height of 1.7mm, so we will be required to cut out 2.5mm from the top of the bottom case where the heads go. To do this we will reuse the cutouts from the wings of the plate however this time cut downwards into the top of the bottom case. This will only be required for the side of the case without the extra space for the PCB.
The result should look like this:
To complete the case we will need to add the USB cutout however we will leave this for after the PCB design is finished. One other step before moving on to the PCB is that we will need to export the sketches for the plate. If you right click the sketches, select Export to DXF and save the files as Sketch1 and Sketch2. We will need these files when we get to designing the PCB.