Z axis having problems lifting the set up

Hello! Probably some of you encountered this problem and probably it has already been discussed but i can’t find anything on the exact issue that I have. I’ve recently build the lowrider 2 and the Z axis just dosen’t have enough strenght to lift the setup, especialy when the router is on one of the sides. I’ve allready checked for the rollers and the lead screw to be cleaned and lubed. I’ve double checked for any wires that may constrain the movement but nothing is holding it down. I’m using a mini rambo with the firmware already installed by V1. Both engines run on one of the prots for the Z axis, but as far as I’ve seen online that is how they should work. I don’t know what to check next or what issues could cause this. Thanks for your help.

Do you have the motors wired in series? If you wired them in parallel, that would explain it.

How exactly is in series and how is in parallel? So on the rambo board are 2 slots for z axis. Bouth my motors are conectected to a single slot. There is a wire that has 3 conectors.One that goes to the board one that goes to my first z axis motor and one that goes to the second but on the second motor the conector needs to be reversed in order for it to spin the right way. Is this the correct way to connect them? Thank you for your time and help.

Oh good. That explains it. Series wires them so that two coils are on the same continuous loop, instead of having two loops to the same pins:


Wired in parallel, like you have, halves the current and halves the torque to the motors, which makes them too weak.

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So I’ve spent the last 6h trying to figure out what’s wrong with them. I’ve conected them in series but didn’t help much. they seem to have a smidge more power but still not enough to lift the thing effortless. Is there a way to measure the voltage or the amps that arrives to them? I conected one of the z axis motor to the x axis plug with direct connection still not much of a difference. I’m totally lost.

Take the steel angle off the top and see how it moves. That’s quite a bit of extra weight up there.

That, and th MC you are using for a drag chain. That stuff isn’t light either!

Hi guys. So I’ve removed evrything. Every single thing that could weight 10 grams. Still no improvment. I’m kind of sick of it. At this point I think i just wanna upgrade evrything so I can install some real cnc drivers and some big motors. The only issue is that i don’t know how to do that. Do i still have to keep nema 17 but the big ones the 625 , so it could work with the software or can i buy some nema 23 with a 1.8° turning angle? Will the nema 23 still work with the same software? I suppose I have to change the rambo to, right? So at this point I think it’s a complete Kit. So, any recomandations? Thanks again to all of you for your time and patience. Hope you’re having a nice day!

What voltage are your drivers set at and what is your z feed rate?

Also what are the specs of the steppers?

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It really should be pretty strong. Not as strong as you, but strong enough to reliably lift the router.

I’m assuming the motors are from v1, but if not, that could be the issue.

Check the grub screws. And the wiring. Intermittent wiring issues and loose grub screws trick us all the time.

You can boost the current in the firmware. M907. If it gets too high, the motors will warm up and the plastic will deform. Keep the motors under 50C and you should be fine. You may need a fan on the rambo. Test in 50mA steps or so.

If you really want new hardware, nema23s are probably the wrong choice. I would buy some 1 start leadscrews and a 24V power supply first. You will have to tune the max speed, but you won’t need any different plastic or mdf parts.

Hello. So this are the steper motors that i currently have on my setup (https://www.amazon.com/gp/product/B00QEYADRQ/ref=as_li_tl?ie=UTF8&tag=vicicn-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B00QEYADRQ&linkId=9bac1b13d6442c9999dfa43e785cec9b). What would be the strongest motors that i can buy that would be just plug and play? right now I’m feeding the motors 1000. They get kind of hot but nothing to serios. I just want something stronger that i dont have to worry about everytime I put it to work. There has to be a solution to get more power without friying the rambo, right? Thank you!

Something else is going wrong. I have the same motors, from steppersonline. They ought to be plenty.

Check that your PSU isn’t sagging. Use a voltmeter, put the negative lead on the PSU ground point and the positive on one of the ends of the 15A fuse (F4)

You should get your supply voltage. Keep checking the voltage as you try to lift the Z axis. If the voltage drops by more than about 0.2V, you’re getting some sag, meaning that your power supply is either faulty or just inadequate.

If voltage stays good, then it’s not a problem with supply current.

If there is a problem with the current to the motors, it can skip steps. This would be if the drivers aren’t set the way you think. Most of my drivers, current is set via a trimpot, generally current=2X Vref. so if I adjust the pot to 500mV, they are set to about 1A current, but I have one set of drivers where current=Vref. For those, they would need only be set to 500mA.

Check your crimps. I always have a terrible time with wire crimping. Some days I really just want to go back to soldering.

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Hi guys. It was the power supply that was faulty. I’ve changed it with some laptop one and it seems to do a much better job. I’ve tested the limits of the motors with high speed and big feed rate. I’m not entirely pleased. I will still rather swap them for something stronger. Especially that I’ve decided to do some upgrades on the machine for better rigidity and that will make it heavy. I will like some suggestions on what kind of motors/drivers are better suited for me. Can I just buy some stronger motors and just plug them in? Can i buy some drivers and plug them into the rambo board and atach stronger motors to that? Or i need to change everything from the power supply, the main board buy some specific drivers and motors? Whatever the case is i will really appreciate some suggestions. thank you !

This is how nasty rumors get started.

So glad you found the issue.

First, I have firmware limited the max speed of all the steppers in the firmware. Second, have you maxed out speeds while actually cutting or just running it around the table. “Travel moves” could be faster but you will sacrifice multi-hour job reliability.

Stronger is not faster unless you gear them differently. 20% faster, needs 20% stronger. Bigger motors = larger moving mass=more rigidity needed. It is a balance. (although there is room to change the gearing now https://youtu.be/ex_8JbaqT9Q).

Maybe one more thing to note. The faster you turn the steppers the weaker they get. So if for some reason you actually need to go faster, get larger pulleys or a steeper leadscsrew. I can tell you this is built for routing wood, and geared/powered and speed limnited accordingly. Slapping a 5hp router on here with 300oz/in steppers will not make the fame any stronger and the machine will actually perform worse.

This is a ~$500 router capable of full sheet routing. At some fairly insane speeds if you really dial it in, Barry almost beat me and my small MPCNC with his full sized LR. https://youtu.be/VGoFSxNS8bk

I highly suggest you stick to the suggested hardware dial in your feeds and speeds we recently found 1/4" bits seem to actually perform almost 3x faster than the 1/8" ones. There is a lot to learn, start where you are at and don’t worry about free air speed tests.

Nothing is better suited for this machine. You would need a different frame if you like the idea of larger steppers. If you do not like this answer the next option is use this machine, as is, to learn about CNC, see how to grow and expand your business then determine if investing $(X)XX,XXX in a faster machine is actually worth it to you. No point in having a fast machine if it sits idle 95% of the time. The LR can help you determine all of this very cheaply.

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If you need to change all that… You got the wrong CNC.

The board you have can do much better without needing to change much else. I run my CNC on a 24V power supply (Though I don’t need to, I just happen to have several extras, as well as things like 24V fans.)

When you run stepper motors faster, they generate their own voltage opposing your power supply. The faster you move the motors, the more they generate backwards. The easiest way to get back to “full power” is bump up the supply voltage, if everything else can deal with it. A basic Arduino Mega and RAMPS 1.4 can’t deal with more than 12V easily, but almost all integrated boards (RAMBo, SKR, etc) can deal with at least 24V. This allows you to turn the motors faster. that is all that it allows and it does not otherwise increase the power, but it can be nice if you want things to move fast. For your rapid moves, maybe all you need is to bump up to a 24V supply, leaving everything else including your driver current alone. This will allow faster rapids.

24V is my go-to for my 3D printer, which I’d actually like to move faster than it presently is possible. That is the reason (And the only reason) that I’m running 24V on my MPCNC, which I’m otherwise running much slower than many other people are with 12V, because it’s larger.

Now, i you’ve tested your motors with the router ripping through the wood, and you think the router could do better… More power to ya. I figure the only thing that I might want to run faster would be a laser, and even then, unless I’m going to bolt a 40W CO2 laser on, I think it’ll do fine.

Those 84oz-in motors that you have are about the most that you’re going to be able to effectively use, IMO. Anything bigger is going to be pure placebo, as you’ll start running into other limitations of the machine quickly.

I think that Ryan’s machines are really amazingly good for what they are, which is hobbyist level CNC. They’re not going to have the <0.001" accuracy of a machinist’s mill, nor the speed you’ll likely find in a professional sign making shop. They also aren’t even in the same price category.

There are DIY plans put there for pro quality CNC machines, many of which assume that you have a starter machine (Like your LR) in order to get the process bootstrapped. You’ll probably spend close to your whole LR machine budget on controllers, stepper drivers and motors, maybe with a couple of ballscrews if you’re frugal and get some good deals. They you’ll need the rest of the mechanics, and to build a gantry. Be prepared to spend a couple grand, because that’s what they’ll cost, but you’ll very probably end up with a beefier machine.

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