CNC Project Started

Hi guys, thought i would share my project. After researching for days on the internet i decided to put a kit together for a fixed gantry CNC machine. Just thought i would share it with you guys as a work in progress. Overall size is 550mm long by 350mm wide

I started with the frame, and although I love working with wood, I wanted to work with something a little more durable. I decided on aluminium channel as the machines I had seen on the internet made from the same medium appealled to me. I made the linear rail from the 25x25mm square tube and screwed a length of 10x10mm U channel on top. Then placed 16mm stainless rod on top. This worked well with the bearings and gave me the height to have the table move over the motor at the front to gain a bit more cutting area.

The gantry are connected with plastic corner connecters. ( I will later countersink small screws in to each side into the connectors but i can tell you, once they are together, they are a bugger to get apart ) I found some aluminium square that also had a profile that had a rib running along it ( as seen in the photo below) i used these pieces to line up the U channel for the linear bearings, and the sides of the gantry. A tucked in a piece of 18mm MDF board that sits perfecty flush, but now thinking of turning them around so that the rib can be seen from the outside of the gantry to make it look a little more tidy and paint the mdf. I am still working on cost effect z-axis design which I am coming close to putting together so hopefully in a week or two (in between other projects) I can post them up.

Well after dwelling over it for a couple of days, i have decided to go with the mdf solution :)Attachment 219044

As well as that I have been looking at how i could make a cheap backlash flange. Not sure if anyone else has done this, but I was thinking about spark plug sockets. They are cheap at Kmart at only a few dollars, the rod holders are only about $4.00 on line. The hole at the end of the socket fits M8 thread perfectly (could aways be drilled out for larger dia thread). I had 1/2 inch sockets in my toolbox, one was 20mm overall diameter and the other was 18m (suppose the end could be lathed down to 16mm to suit a 16mm rod holder.
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Anyway, after alot of time reworking my plan, I have revamped my machine. With nema23 motors, i am setting up dual actuators to run the gantry (x axis). Have to attach braces on the back of the gantry, and still waiting for some parts for setting up the y axis. Still deciding whether to attach the motor behind the z-axis and have the motor and bearing set up running along the belt with the belt attached at both ends of the gantry or have the motor on one end of the gantry and run a similar actuator type setup??
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Ok, so i have the dual belts set up. Just need to replace the 6mm alum shaft with the 6.35 steel one before hooking it up to the motor with a coupler and then line the belts up nicely. Seems to work smooth when i turn the shaft by hand.
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Clever. Looks like it's developing into a nice little machine. Is that little stepper going to be able to drive the gantry directly?Looks like you're going to get maybe 30-40mm movement per rotation of the shaft.

Thanks tahustvedt!. One rotation is about 35mm with a 18t pulley. Originally I was going to run the gantry with one belt (on the right hand side) as I was confident that it would run the the gantry (once i finished bracing the gantry) comfortably without any drag. The gantry is 400mm wide. While i have seen other small belt driven CNC's run duel motors on either side of the gantry (to evenly run the gantry depending on its width), I thought a second motor was a bit of an over kill and for this setup and this was a much cheaper option.
I am running a single Nema23 motor (holding torque of 12.6kg.cm) driving a shaft with 2 x 18t pulleys. I have just recently purchased a 400w er11 spindle (only for the fact that they are quiet and i want to run this CNC in an enclosure in my office), but the trade off is that the weight of these spindles are approx .9kg opposed to the light weight dremels. Anyway time will tell, if it doesn't work, I can always easily attach another motor on the left handside for a dual motor x axis running each belt, or attach the lighter weight Dremel if all else fails.

I am currently purchasing slotted rail, bearings, wheels etc for a larger 2nd project 1500mm X-Axis and 1000mm Y-Axis (belt driven), running a palm router, which will defiantly have a dual motor X-Axis.

Hi...havn't posted in a while but tought I would start posting pics of final design. X and Y running GT2 belts, with Y motor mounted under the bed . Z is tr8x2 leadscrew All working well. I am running the 3 axis TB6560 board and Mach 3. I have set the switches to 1/16 step for the Nema 23 and have calculated the steps by mm through Mach 3 (and a online calculator) which both worked out spot on. However, on my G-code , I have to set the feed rate at approx 1000 to get reasonable speeds on the machine for cutting. Dont know if that sounds right. To move the head as fast as I can manually jog, I have to set the G-Code feed rate to 5000 ??? (not that I would cut that fast with this type of router) These photos are a couple of weeks old, but will post up the final product up tonight.

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This is the second CNC I am working on using the Openbuild V-Slot system and CNC sheild v3. Will be running 4 nema17 and a 400w spindle.

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