Massive rails for a small machine, my 2nd
I hardly finished my conversion of a proxxon mill when my dad called and said that he got four pieces of INA linear rails with trains for free (sh*t happens I guess ).
Now I've got 3 INA kwve 45H (4 row bearing) and one kwe 45H (2 row bearing).
I think I can build a better machine with them than the proxxon, wich is a round column mill with alluminium ways.
I also wanted to make a better anti-backlash mechanism for the leadscrews than I have in my current setup.
The rails are 280 mm long and the trains are 139 mm long so I will get around 140 x 140 x 140 mm of travel wich is about the same as the proxxon in x and y and almost double in the z.
I've decided to go with a moving gantry design. I know that's not common for a metal mill but since it's so small I think it will work.
I like the fact that the workpiece is stationary.
Another plus is that I can mount the steppers "inside" the structure and make a real compact machine.
I made a semi-rigid a/b nut design using two nuts, made from acetal (delrin) gears, wich are driven apart by a spring and then clamped between two alluminium plates. I installed one on the y-axis and it works realy well.
If there develops any play I just un-, and retighten 6 nuts to eliminate it.
The leadscrews themself are trapezodial 12x3 stainless.
Like any homebrew cnc builder does at a certain point in his life I made my own tap from a piece of rod and it worked better than I thought.
I will try to update weekly with pics if real life doesn't get in the way.
I welcome your thoughts/critism.
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Jeroen