EP6 - CNC3018 Rebuild - Assembly Process

In this video, we get to put the CNC3018 back together into a recognisable form, and it's one big leap towards having an operational CNC again. (Yay!!)
This is the sixth episode in a series where I upgrade my cheap 3018 CNC in an effort to improve its precision, performance and work area size.

[@incubatork]

Great upgrade overall, I have a Genmitsu 3020 pro max and am debating weather or not to upgrade to a 3040 with an extension kit, not cheap but my main problem is time. Measuring up for what I need it would be half the price getting things rom china but with the delays involved sending to Europe. I'm still on the fence as to which way to go, your videos have been a great help to see what exactly is involved, thanks for sharing.

[@ForOurGood]

Thanks for the comment! I am glad to hear the video might be of some help. Good luck with your rebuild!

[@Cybernetic_Systems]

Nice work, your build went really well! I’m curious as to how the spiral flexible couplers work for you? I find they introduced a small amount backlash and replaced them with dual helical slit couplers which have been perfect. The only issue is I can’t find where I bought them from to buy more! 😢
Edit: you covered the couplers at the end. Honestly I’d throw away those rigid couplers ASAP, they’ll wreck your stepper motor bearings.

[@Cybernetic_Systems]

Ps, the couplers I’m referring to are sometimes called beam couplers too.

[@ForOurGood]

Yep, the flexible ones are garbage as far as I can tell, at least for my application. They actually caused a weird harmonic that would cause the lead scew to sing, so as soon as I heard that I dumped them. I do know that rigid couplers are not great for the steppers, but for now I will leave it be until I get motivated to look for some decent replacements. Thanks for the info however, at least that is a better starting point than me just randomly buying something on Ali-Express.

[@Cybernetic_Systems]

@@ForOurGood no worries. I dug through my emails and found that I got them from amazon (shipped from china) and they just called them flexible couplers. The photos show the dual helical slits and a pair of grub screws per shaft-end. They were quite cheap but much better than the other half dozen different couplers I've played with, and weren''t expensive at all.

[@AndyJenkins999]

Very neat indeed I like it a lot. Yes those couplers are garbage I had similar issues on mine and went back to the solid ones which work fine. Have you noticed any backlash on the leadscrews I found those spring loaded nuts a bit hit and miss? Great build really professional looking.

[@ForOurGood]

So keeping on using those leadscrews was a bit like putting lipstick on a pig in the end. But I felt constrained by budget, and the fact it is no longer a cheap 3018 once you go to that level. Using the laser alone, for now I am optimistically measuring about +/-0.0125mm of backlash in the X and Y axis, which is not as good as I hoped for, but better than it was. I think before I was seeing closer to +/-0.03mm when using the laser. Obviously any improvement is unlikely due to do with the leadscrews or backlash spring nuts, because they are the same. So it ultimately comes down to the improvements in the rigidity and motion of the axis, which are pretty obviously improved. I would say the outcome with regards to just the accuracy is this. For the laser operation, it's only a moderate improvement. However, for the spindle, it looks like it is going to be easily an order of magnitude improvement. So some of my unfounded hopes were ultimately dashed, but others look like they might far exceed my expectations. I guess only once I get to doing some serious work with the CNC will the full picture be known. Thanks for the comment!

[@AndyJenkins999]

@@ForOurGood useful Info thanks I know what you mean about budget where domyou.stop and to be honest that's a very very good tolerance for what is still essentially a 3018 albeit massively improved. In addition the PCBs you made.in the last of the PCB series looked really good so improving your accuracy should give you even better quality. Great series very enjoyable thanks