September 19, 2020

Tr2W

Technical support

Hi folks, I am a newbie in CNC stuff. I have started desginign a CNC...

Hi folks,

I am a newbie in CNC stuff. I have started desginign a CNC router out of my need. I am a hobbyist and I own a small lathe, A drill press, Spot welder, sheet rolling machine, dremel etc. Its a small hobby workshop that I have built out of passion. I use to mill small stuff occasionally on my lathe using a milling attachment. But this is painful and also very limited to what I can mill on it. So finally decided to go CNC router route.

Commercially available router are very costly for my requirement. for the last 1 week I read about CNC router on this forum and have come up with a design. I appreciate everyones input here to direct me and help me avoid any pitfall.

Objective: Mostly light aluminium work and some wood carving for RC aeroplane work.

I first studied some CNC routers and came up with my design. This is like 3rd iteration and I expect it to change here and there. As I will be milling aluminium, I tried making it rigid by having dual linear shaft rod on both side of X axis with four mounting support to avoid any twist/moment.
Most of the parts are aluminium/aluminum either flat rectangle or extrusion. I have depicted the proposed dimensions on the rough sketch (Little old school).

Estimated rough weight of the load on each axis: (I calculated it based on metal and part weights)

Gantry: 32Kg (All vertical load like. Y+Z+vertical support plate)
X axis: 18Kg (bed+lead screw)
Y axis: 16Kg (load of Z axis component and its own weight)
Z axis: 6Kg (including router)

Below is my spec. I have tried to get what I can get in my country and within my budget. My req. is hobby purpose so it won’t be running 5 hours a day.

3 Nema 23 = (26kg-cm)(368 oz-in) holding torque
3 DM542 driver
1 Power supply 40V, 7.4Amp
Mach 3 breakout board
Router makita 700W (1HP, I know this is low for aluminium but I could not find any other powerful router here, spindle with VFD are very costly like 4 times)
Ball screw= Two option available 20X5 or 16X16(this is relatively cheap) I was looking for 16by5 but its not available here.
Guide linear shaft =16mm on X and Y and 12 mm for Z axis

Router dimension:
X end-to-end =1meter
Y end-to-end =1meter
Z end-to-end = 0.4meter

I will work on CAD after I finalize the drawing to get all the parts right and fit well. I have no access to big mill and due to Covid shops are shut mostly. So I will do it all by hand with whatever I have. Could you please help me if I am going right.

I have not purchased anything yet. I am sizing all parts and cost for it. This whole setup translate to 1200 USD so far. It could have been cheaper but china is not shipping to India. So I am buying locally which is little costlier but quality is certain.

Open to hear from you guys.

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