Long router for ski building

[mholling]

After seeking some design advice on this forum last year, I'm posting a build thread now that my machine is starting to come together. My long-term goal for this CNC router is to be able to cut parts for ski building, so the design is long and skinny to accommodate skis up to 210cm in length. The cutting dimensions are about 220cm x 50cm.

I made a detailed Sketchup design before starting any physical work. I've really enjoyed this method, and being able to measure clearances and so on with great precision. My machining skills and tools are minimal, so I've used aluminium extrusion for the bulk of the design. I had a shop cut my mounting plates from 6mm aluminium using a waterjet cutter.

My gantry is now mostly assembled. I'll be getting ballscrews made up for the Y and Z axes soon, and they will hopefully slot right in. The Y axes uses a 2010 ballscrew and 15mm guide rails.







My Z axis uses a 1204 ballscrew, 15mm rails and has about 140cm of travel. I'm using a 1590 extruded plate for my spindle mount.





I'm building the table frame from 8080 aluminium, which is cut, machined an ready to assemble. I have a rack on each long edge, to be driven by planetary gearboxes mounted on the bottom of the gantry.

Lots more work to do of course, but it's nice to see some structure taking shape. The Y and Z movements feel really nice and solid.

My electronics are also underway. I'm planning to use a Beaglebone Black and a 4-axis driver (Leadshine MX4660) to drive the steppers. Couldn't find any suitable Beaglebone interface boards so I'm building one my self (luckily I have some PCB design experience).

More to come, very slowly, as I progress. My current sketchup model is here:

https://3dwarehouse.sketchup.com/emb...0-d2740e2c3c4b

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[mholling]

Progress on the gantry, which is nearly complete with motors, ball screws, cable chains and limit sensors all installed. I ordered 10mm lead for the y-axis ballscrew but received 5mm; I'll leave it for now to see how it performs.







Quite a lot of thought went into cabling, and how to keep it neat.



The frame is complete after a lot of screw tightening:



I picked up some very nice levelling casters on eBay. Really nice to have the frame up off the ground and mobile:

[mholling]

While waiting for some fasteners to arrive, I've soldered the PCB for a Beaglebone cape I designed. I'm hoping to use it with Machinekit on the Beaglebone to control the CNC. A ribbon cable will connect directly from my board to a Leadshine MX4660, which I bought to run the steppers.

Soldering surface-mount components on a hotplate:



Surface-mount components done and through-hole connectors installed:



Mounted onto the Beaglebone:



Figuring out how to set up Machinekit will be next

[mholling]

Next up, the electronics enclosure, which I have embedded in the frame at one end (beyond reach of the spindle). Power supply and stepper driver mounted on an aluminium base plate:





Drilled front panel:



Front panel is the mount for an e-stop button, a pair of 60mm fans, a couple of 12V and 5V regulators, USB and HDMI connectors and Beaglebone, power button for Beaglebone, and output power and control connectors for a VFD for the spindle. (VFD will be located elsewhere.)





Final enclosure with components all installed. Cabling a job for another day.

[mholling]

A long hiatus due to my garage being too cold to work in over winter! Then other things took priority during spring, but after a shed cleanup I was able to mount the gantry and complete the cabling.

Gantry mounted on the frame:



All the electronics are on-board, except the VFD which I will mount somewhere separately.



Details of interior wiring:





Ends of the gantry, showing mounted motor and connectors:





The x-axis gearboxes drives the gear racks directly. (If there's any part of my design which will cause trouble, I expect it to be this, but hopefully not.)



Cabling breakout on the gantry:



The y-axis cable chain:



Detail of the z-axis and spindle mount. Inductive proximity sensors are mounted on the moving part of the x-axis.



With the exception of a few connectors, construction of my CNC is complete. The spindle is heavier than I was expecting, so I'm looking at adding a gas spring to support it. I omitted this in my original design but it looks like I will be able to squeeze it in.

Next main task is to set up my Beaglebone Black with MachineKit. It looks like a steep learning curve ahead!