Urbs New Build

After much thought and procrastination onto my 3rd and hopefully best build. It'll be hobby grade in aluminum extrusion. I chose aluminum extrusion for ease of assemble while meeting my accuracy and rigidity requirements. I ordered the extrusion from a Canadian supplier MakerParts and the rails from aliexpress. Hardware from all the different sources to whatever is convenient at the time. The work area will be around 50"x30"x8" with the X axis being the longest so I can use the table as a desk when not in use. I found the longer 1500mm cbeam extrusions flex quite a bit so I mated 3 of them together which seemed to provide adequate stiffness. Still have to tie the back of the beam together. The last thing I did was to mount the 20mm rails on the gantry beam. Some work with the dial indicator up next. The drive system will be R&P from avidcnc. I originally wanted ballscrew but R&P is accurate enough and the easiest to for me to mount. I'll use the electronics, motors, and vhd/spindle from my 2nd cnc, a joes2006. All the plates will be mocked up in 3/4" plywood then likely 1/2" aluminum plate when I finalize the design. I've designed the gantry sides but need to hit the hardware store for some ply.

Maybe an update in a few months as I plan to take this slow. Very slow. Posts are always better with pictures.....


https://lh3.googleusercontent.com/op...-no?authuser=0 https://lh3.googleusercontent.com/l-...-no?authuser=0

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Opps. I guess google photo's requires permission to access saved files. Here are the pictures.

Small update. Cut the top brackets for the gantry. Although my joes2006 may not be very good it's a whole lot better at accuracy than I am. Makes a huge difference with the many precise holes. You can see where the two sided tape let go luckily at the end of the cut so only superficial damage. A good reminder to myself to ensure the workpiece is securely fastened down. Screws next time. Not sure the 8020 is suffice for the gantry wall. I know it's use on the openbuilds lead machine so I'll just have to see how that goes. If there is too much deflection I'll get some 8040 or cbeam like the avidcnc stuff. Same with the plywood plates. Still intending on going with 1/2" 6061 plate but that might end up 3/4".

Got around to making the bottom gantry plates. Learned my lesson and screwed down the workpiece this time. I tried climb cutting for the first time. Interesting. I think the tearout means my bit is no longer sharp. I should really stop being so cheap and use a new one. The two plates allow me to experiment with the amount of clearance. Once finalized the height of the gantry sides will be cut as one plate. I love peteeng's suggestion of laminating an aluminum skin to the plywood. May try that instead of the 1/2" aluminum plate but that's to be decided later after I see how it runs on the ply plates. I've decided to try ballscrew on the X so I ordered a pair of 1616's from bstmotion. I'll be taking a cue from v0dka's plan and running the ballscrew under the xrails using a plate screwed to the bottom of the extrusion. Tapped the extrusion while the plates were being cut. Found a m5 tapping guide on thinguniverse which works very well. https://www.thingiverse.com/thing:2105706

Next step is to mount the gantry to the X so I can finalize the 4020 crossmembers. Maybe make a stand but I haven't decided if I'll buy some steel and relearn how to weld. Been a while. How hard could it be? Famous last words...

Small update - Mounted the gantry to the base. Was a bit wobbly with just blocks to hold up the beam so I threw some tie straps around the ceiling. As mocked up I have about 5" of z height to work with. I'll probably go with 7" for the final design. Cut and added the cross members. Starting to look like something. The base and end plates will be next. That and ordering more screws. So many screws.

A little here and a little there throughout the week. Placed some ply on the table surface which added rigidity throughout the whole frame. Ballscrews came in and I instantly learned how to reball the nut. Yeah spun it a bit too far in the wrong direction while testing with a drill. One is perfect, the other is usable. For the price I am not complaining. I finalized the gantry walls which I cut using baltic birch. At this point I don't see a need to buy aluminum plate but that may change when I do actual cutting whenever that may be. This weekend I plan to make some brackets out of 3" x 1" x 3/16" aluminum angle for the ballscrew and cut some end caps so the bearing don't fall off the table. I just don't feel like packing any more ball bearings right now.

Cut the rear end plates that support the steppers. The cavity is for grease nipple clearance. Wouldn't be the first time I have crashed the gandry into the end plates. The ball screw bearing block mounts are 3/16" aluminum angle. The pictures clearly show why I need a cnc. My precision and accuracy with hand tools is awful. The "bad" ballscrew seems to work much better mounted in machine. Just a little vibration at 1000rpm which is faster than I will run with my motors. At this point I think I'll just buy steel channel workstation legs. Getting going on welding would be my first choice but time and budget are limited. Waiting on screws and motivation to do more.

I haven't actually done anything in a few weeks but did make some progress before then.

1. Printed off some motor mounts that hold aluminum standoffs. Not sure if this is adequate so we'll see.
2. Printed a wiring harness/extender for the G540.
3. Bought a multi purpose welder so steel tube base it will be. After comparing stiffness I would've just gone steel tube for the entire build from the start. Maybe for the next one....

Apologies for the grainy pictures. I need to get better lighting down in the basement.

Looking good jack - keep at it - Peter

After a long break focusing on additive manufacturing I've started working on the router again with some design changes. At the loss of about 2" travel on the X axis I mounted the ball screw end block to the outside of the frame to save 6" on rear footprint. I purchased two motor mounts with integrated bearing blocks for the X axis resolving issues I had with alignment. Made a new electronics box although it too is a wip. Originally I had planned rack and pinion for the Y axis but the 1616 ballscrews is running 1000IPM rapids with ease which is plenty speed for me. So 1616 for the Y axis, intergated bearing block motor mount, and a sturdy stand are the next planned purchases. Progress is bittersweet though as the parts are coming off the joes2006. Sad to see that go.

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I have a bit of free time these days and have been working more on the router table. I do plan on going 1616 ballscrew for the Y axis but in the meantime while I wait for the parts to arrive I decided to make use of the drive system from the joes2006. The Y axis leadscrew is 10-1/2 5 start acme with about 34" of travel. That's a loss of around 26" of travel on the current table. I do have the X axis leadscrew which is the same spec but the 72" is too long and would require cutting which I am avoiding for now. This setup yields 400 ipm rapids which is slow compared to the ballscrew on the X axis but it was suffice on the joes2006 and will do for now. I've reduced the X travel speeds to 600 ipm. I tested up to 1200 ipm which was not issue for the components but that was just inviting a bad gantry crash on such short travels. It has a bit of the printnc feel to it. I'm a bit suprised how rigid the printed plastic is and it is much more accurate than anything I could fabricate by hand. Not sure how long those components will last but should be ok for limited use. I'm definitely not going to push speeds and rates. Mounted the old Z axis but that too will be replaced with a more rigid solution. Likely 15mm profiled rail mounted on aluminum plate. All that can be worked out later.

Plan today is to mount the leadscrew nut. I'll make this out of wood and see how that goes.Speaking of, while researching leadscrew replacement parts I learned DumpsterCNC had retired. Such a great resource for us DIYers. Enjoy that retirement, well earned.

The joes2006 is no more. Completely disassembled and ready for the bin. I would donate the frame but it was awefully made. I did not take the require time and care during fabrication and with my limited knowledge created an impossible to fix mess. Just the like JGRO I'll salvage what I can.

I need better basement lighting.

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Finally made a stand. Originally I planned to buy some hot rolled 2x1 steel tube but the price would've been around $350 CDN before tax. Everything is just so expensive so instead I repurposed the steel tube, threaded rod, and timber from the joes2006. Fabrication took a lot longer than anticipated. The welder had no skill (me). Good thing a grinder fixed most of the cosmetics. Over all I'm very pleased with how it turned out. No more worry about the table falling over. I'll need to add leveling feet and a vertical panel on one of the sides to mount the electronics.

I slowed the rapids down to 600 ipm. I could've easily gone with 1610 ballscrew for more resolution and still achieved faster speeds. Live and learn.

Still a long way to go but if needed I could run some cuts.

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The motor cables were from my first table and assembled poorly with electrical tape and no understanding of grounding the shielding. Remade but those too will need to be replaced for adequate length and silcon sheathed for ease of routing. Attached some plwood to one side and bolted the control box and VFD to it. Also moved the table to it's final location. Leveling, squaring, and motor tuning will be next. Waiting for some heat sink and a fan for the electronics.


Short video of some sample code (cam clamps for the hold down system). "Cutting" at 120 ipm, travel at 800 ipm.


https://www.youtube.com/watch?v=lrMI0dmgk9k

Some pictures of recent progress.

Added a grounding bar from spare aluminum angle. Really crooked drilling there. Still have to change out some wire for the shielded equivilent. Mounted the e-stop to the front and wired a potentiometer to the vfd. I tried to get speed control from mach 3 but no success. I'll need to get my hands on a occiliscope to check if the pins on the g540 are functioning. Leveled the table and trammed the spindle using a simple jig with a dial indicator. Added a picture of the hold down that I used on the joes2006 and is the code that was running in the previous video. Credit to Marius Hornberger for the design. The first cut I will make is a grill cover for the eletronics. Speaking of, added some heat sinks and a 60mm fan to cool things down. Was getting hot before but now barely gets warm.

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Some actual cutting. A simple pocket cutout. 1/4" 2 flute upward spiral bit at 100 ipm, 0.125 doc, and around 18000 rpm on the spindle. I'll need to add another second or so to give the spindle time to fully spin up. Not absolutely perfect but I'm happy with the result and it's a big improvement over the joes2006.

To do: dust shoe

Actually the to do is a very long list but progress is being made.

https://www.youtube.com/watch?v=o9pf5-GVBbg

After many tries at each component the dust shoe is done. Using Fusion 360 was particularly trying. Hopefully over time I'll get a better handle of how to model objects. Happy with the result and the cnc in general. As the pictures show I'm over compensating on the depth of cut. I did add more lighting to that area of the basement. Next I'm likely ordering the 1616 ball screw for the X axis and perhaps some 3/4" aluminum plate for the gantry walls. Cutting aluminum is going to be interesting.

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I just noticed there is no good view of the rail system for the dust shoe. The rail is standard t-slot with a standard t-lot bolt and knob. The rail bearing is plastic that holds the plwood arm in alignment. I'm going revise the shoe to optimise the air flow. The inner structure to screw the pipe down is not required and should be removed.

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I really like your dust shoe design.

Do you have easy access to the collet for tool change?

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Originally Posted by Biggs427

I really like your dust shoe design.

Do you have easy access to the collet for tool change?

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Hey, thanks. Yes. There is plenty of room for a manual tool change.