6. Large format CNC (computer controlled Machining)¶
During this week we tested the CNC machine and tuned in the ideal settings Group Assignment - Large format CNC (computer controlled Machining)
Design¶
I wanted to design a small coffee table, and have finger joins to connect the top and bottom, and a cross lap to create a unique and stable support in the middle.
Let’s Sketch the first part of the center and extrude it to the same thickness of our material (12mm plywood)
The top is a simple “Slot” Shape, with a thickness of 12mm to match our material
Here are the fingers, that will go through the slots
Added the 2nd middle support, and had it at a 90 degree angle
Next I added the top and bottom of the table
The top part will connect with finger joints, but I also wanted to double up the thickness with another top that will be glued on. It will also have a 3mm engrave so that we can add some acrylic in the middle
Here are all the parts laid out!
DXF View
DXF File (after all changes listed below) Coffee Table DXF
Cutting¶
Now comes the time for cutting! Plywood was the selected material, and it creates very messy edges. Unlike MDF which has a very clean, ready to paint finish.
Whops! The Cross Lap doesn’t exactly fit.
So we need to adjust and re-cut, the new design added 2cm to each slot in the Cross Lap.
This time around it fit flush, and so did the top and bottom. We can now see our initial coffee table.
I added some glue to add the 2nd top.
Added clamps, but made the mistake to use thin cardboard rather than thicker material, and the wood ended up having clamp marks on them sadly.
Laser cutting the acrylic, white 3mm was selected
Finishing¶
Loads and loads of sanding was needed. 220 Grit sandpaper and makeshift Sanding block using a square object found in the workshop.
Looking great! But lets do one more thing.
I got a Gel Stain that would give a nice finish to the plain plywood
I put on the clamps again, as the glue didn’t dry, next time I would first wait for the glue to fully dry.
And here is the final result!
Matched perfectly with my garden chairs.
