Upgraded 3018 Pro using MGN15H Linear Rails and a 500w Spindle

hehe, I do occasionally print things for ppl. Luckily I have no idea how much money I've spent on my 3D printers and CNC machine - so therefore neither does my wife.

 

I made a little more progress on my CNC machine today. First up I replaced the almost useless wifi antenna with a 6 dBi unit with works really well.



And I made myself an aluminum soldering jig so I don’t ruin anymore mini XLR jacks when soldering on the wires. These things are just so small and fiddly to work with that I think a jig is mandatory to wick away excess heat and get the pins from melting their way out of the plastic bung.

I do need to buy some more cable to finish the limit switches, but I’ll do that next year when I return from our regular Adelaide family vacation.

 

Btw, if anyone else wants to replace their wifi antenna on a DLC32. You just need an RP-SMA to PCI U.FL cable and antenna kit. They are cheap from Amazon. You just need to make sure you get the correct size. The “M2 U.FL” connectors are too small.

 

Since the rebuild, I’ve been struggling to calibrate my CNC motion to be accurate. It finally dawned on me that the leadscrews that came with the printer and extension kit are crap and have a thread pitch of 8mm.

So I’ve ordered some good quality X and Y leadscrews with a pitch of 2 mm and 4 starts. I’ve also ordered some anti backlash leadscrew nut blocks of the type that RatRig use on their lower spec CNC machine.

I also plan to install some retention collars and axial thrust bearings to keep the leadscrews from moving around. This will also allow me to switch from rigid stepper motor couplers to flexible couplers. I’m going to 3D print a pair of 40mm tall Nema 17 mounting blocks from ASA to accommodate the changes.

 

Hmm, these are listed as TR8x8 lead screws. Oh well, I wanted longer ones anyway for future mods.

8mm Metric Lead Screw / ACME - Maker Store PTY LTD

these nut blocks should at least provide LED backlash.

Anti-Backlash Nut Block Gantry Hardware Pack - Maker Store PTY LTD

 

I realised I have some old 2mm pitch lead screws in my spares box (from my 3D printer experiments), and comparing those to the ones on my CNC does show a noticeable difference. Admittedly I don't know the other specs of this 2mm pitch lead screw (top lead screw).

 

I finished the first prototype Nema 17 Mount design today, and I'm just in the process of printing one out for testing. The design integrates an Axial thrust bearing, and I'm hoping this will work well with a lock collar at the other end also supported by an AT bearing.

 

Testing looks good. I only needed to make a minor change to the holes for the M3 bolts as they were too snug. But everything else fit perfectly.



EDIT: Design is now available on Printables:

Printables

 

My ASA prints came out great - ignore the surface “zits”, I intentionally used random seams to avoid any concentricity issues.

 

My new lead screws and nuts arrived today - the ones that came in the cheap Chinese kits I started out with are definitely different. I don't know much about leadscrews, but the new ones look much better quality and the old one appears to have less "Starts" or "threads"? (top 2 = new ones)



Regarding the Anti backlash nuts - I bought the common twin brass nut + spring versions, and the Nylon block with adjustable AB grub screw. Anyhoo, Im curious as to what folks think are the best option here?

My only concern re the Nylon block, is how long it'll last?



edit: I stumbled across this design today, after some googling, I wonder if they are worth the cost? They’d certainly be easier for me to integrate with my current design.

ACME / TR8x8(P2) Anti-Backlash Nut (Type 2) - Maker Store PTY LTD

 

After getting some advice on anti-backlash nuts/blocks, I printed out some mounting blocks, I designed, for the AB Blocks to replace the spring types that came with my machine. I used ASA which is very strong and durable.



Install went smoothly, although, I am yet to reinstall my lead screws and stepper motors as Im waiting on some longer stepper motor mounting bolts to arrive. I did partially insert my lead screws to confirm everything aligned properly, and thankfully it all looked good.

 

Mainly I’m not quite at the stage where I can justify the costs of upgrading to Nema 23 motors + appropriate drivers.

My existing Nema 17’s are beefy 48mm tall, 2.5 amp rated LDO 42STH48-2504AH units. I’m sending the full 2 amps per phase my drivers can supply - for such a small machine (300x300mm actual work area) 55N-cm Holding Torque seems to be more than enough. Plus these motors are rated for high temp’s so aren’t going to fail on me anytime soon.

If I ever get around to finishing my flying gantry design, I’ll allow for both Nema 17 and 23’s to be installed so I have an upgrade path.

 

I found some time to work on my CNC machine today. I’m still waiting on 60mm bolts to install the steppers, but in the mean time, I’ve changed the wiring on them to use my shielded cables for most of the run.

I also added some gel style glue to the wires to absorb vibrations and improve durability.

And I finally got around to making my emergency stop switch.


I also discovered that one of my limit switches was broken and I didn't have a spare ... so I decided to buy some 5v optical limit switches from Maker Store. As my control board doesn't support the 12-24v inductive limit switches I bought a while back, this saves me the hassle of designing and building a PCB with optocouplers to get around the voltage issue. Hopefully optical limit switches be just as reliable, if not more so.

 

Hmmm, that's a good point - my garage gets quite dusty so I think I might cancel that order and stick to switches.

On a positive note, my longer bolts arrived, and I was able to install my Stepper motors - I also attempted to install my lead screws, but found my anti-backlash block mounts were too tall / short by 1mm respectively. luckily, that is an easy fix.



EDIT: Thankfully, Maker Store have awesome service, and I was able to change out my order of Optical end-stops to Switch end-stops of the type I’m already using.

 

The 1mm height change worked perfectly! I did a quick test fit of both axes and have now properly installed the Y axis with bearings and lock collar.



I was about to install the X axis when my lovely wife requested an audience to discuss the latest developments from the dreaded mother in-law (her mum is a PITA).

 

Cool! Welcome to the CNC club, it’s a fun hobby!

I’d be 99% sure that they can’t support 2 amps. I had to buy high end LDO Nema 17’s (same ones I use on my 3D printer). Id have preferred to go straight to Nema 23’s, but my chassis doesn’t support them.

 

That all looks pretty good, except I think you are short 2 MGN15H Blocks, the X axis needs 2 and the Y axis needs 4.

the only item I don’t recognise is the “GX80 Double Line Rail Ball Screw”?

 

I’m using an anti backlash block on both the X and Y axis. My Z axis doesn’t need one as I’m using a ball screw system for that axis.

for the cable chains, it’s best to use stranded wire inside silicone sheathing. I found the best option was 4 core, shielded microphone cable. It’s really affordable and very durable. It’s also really nice to work with.

This is were I got mine in Australia (modern equivalent of Radio Shack):
https://www.jaycar.com.au/4-core-sc...-cable-sold-per-metre-sold-per-metre/p/WB1540

No worries, I’m glad you’ve found it helpful. I’ve documented my journey for a few reasons, A/ it’s fun, B/ other might want to try similar upgrades, and C/ so I can recall what I’ve done.

My various models and designs are stored here in printables. I do try to keep them up to date and mostly succeed.

Printables

 

Nice, that should work well. That should work perfectly with the “new” mounts a designed for mine.

 

FYI: I took a closer look at that and the only thing you’ll need to change is the stepper motor coupler. It comes with a cheap rigid coupler, but you’ll need a good flexible coupler or you’ll have binding issues which will damage the motor and guide bearings.

just avoid the simple looking spring type like this, they will introduce backlash.

Flexible Coupling 5x8x25mm - 3D Print Creativity

 

I finally finished putting the X axis back together - the lead screw was way too long, so I cut it to size with my angle grinder and the re-ground the end back to
spec on my bench grinder.



Now I just need to finish the X and Y limit switch wiring.