Observation while cutting some more sleds, Plunge or Drilling cuts are painfully slow with the z-axis motor, its the only place where I’ve experienced any ‘browning’ or obvious high friction. It’s not enough to be dangerous, but it’s clear that the Z axis, and the 1-3mm slop associated with using the default Router height adjustment and really any other movement/alignment will add to this.
edit: forgot to mention that i’m using a down-spiral bit, with 2 plunges but it doesnt seem to matter as much as the slow speed of the vertical movement, more pecks would just leave more time in the hole…
any tips to getting more out of the Z-axis motor speed wise? maybe some additional gearing?
Yes, drilling is painfully slow and I can smell the bit burning the wood as it’s going.
That was my first thought as well. If you could introduce either a gear or a timing belt into the system then you could increase the travel speed of the z-axis. I’ve been planning a new Z-axis that uses both timing pulleys and a higher pitch lead-screw to speed it up, but I haven’t had a chance to cut a prototype yet. The stock setup moves around 40mm/min at top speed. I was able to (theoretically) increase that to 120mm/min on my prototype. Check our Fusion360 project, it should be in one of the folders.
The other option would be to use a higher rpm motor. I know some people have experimented with this a little, so maybe they can weigh in on what works and what pin configurations they run. I know @bar selected the motor he did so that it would have enough torque to move even the heavier routers.
yeah, now that i’ve got the machine workin, i’m ready to dig in, I’ve really been spending some time in Fusion360, to the point of attempting to model the entire machine, its not there yet, but I think it’ll pay off in the long run for jigs and other machine wide setups.
I’ll share once it’s further along, many thanks for your pantograph models! I’m using the vertical linkage in my model. I’ll be throwing things into the shared folder soon, I’ve been focused on getting both my Fusion360 skills up and the Maslow tuned to be useful and will be increasing my contributions back soon…
I have a 100mm travel ball gear on the way, and recommend checking out ( First Cuts, metal pantograph linkage ) to see the upgrade I put on the metal pantograph mount. ~$12.50 worth of aluminum extrusions and another ~$25 of mounting hardware and I can adjust the mounting points to the mm. .
I think it will be useful to continue investigating speeding up and shimming the slop out of the Default router (not jumping ship to custom-Z until its the only option).
I’m building 2 more sleds today and a ‘sled stand’ to more easily handle making adjustments to them while on the machine.
That was my first thought as well. If you could introduce either a gear or a
timing belt into the system then you could increase the travel speed of the
z-axis. I’ve been planning a new Z-axis that uses both timing pulleys and a
higher pitch lead-screw to speed it up, but I haven’t had a chance to cut a
prototype yet. The stock setup moves around 40mm/min at top speed. I was able
to (theoretically) increase that to 120mm/min on my prototype. Check our
Fusion360 project, it should be in one of the folders.
The other option would be to use a higher rpm motor. I know some people have
experimented with this a little, so maybe they can weigh in on what works and
what pin configurations they run.
picking a different RPM motor or gearing the stock motor would end up with
similar results, so just get a different motor
I know @bar selected the motor he did so that it would have enough torque to
move even the heavier routers.
He did not do any testing of different motors, he just picked one with lots of
torque, so it’s very possible that he picked one more powerful (and slower) than
it needs to be. We really need someone to test a bunch of the motors and see how
fast we can go (before stepping up to a more powerful motor)
That could definitely come in handy. Are you modeling your unistrut build? If you made some drawings with it we could put together a Unistrut frame assembly guide of sorts. I’ve modeled my version up to the hardware being used, but I haven’t attempted to do the chains and stretchy string tensioner. In my head, I should be able to use joints to have a fully articulated chain, but haven’t really spent enough time to figure out how to do it yet.
No problem. That’s part of the reason I took the time to get the assembly all together. To be honest, though, I just used David’s OnShape models for the metal linkages and just imported them. All I did was the joints
That is pretty slick. I like the idea of having adjustment to the assembly, that could really help if something is just slightly off.
Totally read that as “Dewalt” first… I might be watching too many AvE videos…
I’m just about at the point that I’m annoyed enough at the Rigid’s base that I’m really ready to move on to a more accurate Z-Axis. I’ve had quite a few dadoes that I’ve had to clean up with a chisel.
Are you also going to have the sled wall above the machine? xD I have quite a few iterations myself now, and I keep a little museum of them above my machine. Or at least, I will, once I can get at it again.
Yeah, I’ve been thinking the same about the motor. I have yet to start looking into it, but I would like to get a faster motor myself. I’d be willing to bet, though, that someone will beat me to testing different motors. If not, I’ll be more than happy to try it out myself when I get the chance.
lets make sure we’re using 100% of the existing motor, and have made all best attempts to wrest out the slop from the router base before moving into additional z-motors.
there are plenty of 3d-printer ppl here (though I am not one ) to get a higher tolerance model of the screw-router block put together. that and the connection at the bottom of the screw (outside the housing) are the sources of most of the slop I’m seeing.
Aren’t these two different issues? As in, the feed rate of the base is related to the motor speed/lead screw pitch, and the slop is related to the build quality of the depth adjustment assembly?
While I do have a 3D printer myself, it’s not a terribly good one and building a Prusa I3 to replace it is on my to do list. I wouldn’t (yet) describe myself as one of the 3D printer crew.
I saw a thread a little while back where someone managed to shim the slop out of the lead screw. If I’m remembering correctly, they used a retaining clip and some washers until it didn’t have any appreciable backlash in it. I’m going to have to do some digging to find the thread though.
I’m planning on transitioning to a more traditional Z-axis for my machine for more reasons than just slop and feed rate, but they’re the big ones and the most frequent reasons I cite.
yes, there are 2 issues z-Axis speed and drive gear sloppiness. I should be able to compensate for it in Fusion but not quite in today’s cuts.
The main reason I wanted to keep focus on the Default Setup is to make sure we’re exhausting what can be done with it before moving on to bigger possibilities. I encourage everyone focused on MaslowCNC improvements to try the same. It’s only as I type this that I realize I’ve completely abandoned the wood frame, so… heh.
Anyway, I’ll take a look through the old posts, I think i remember that too from months back.
The problem with the Z axis moving slowly isn’t anything to do with tolerances,
it’s just a matter that the very high gear ratio of the motor is going to move
slowly, even at max power.
the only way to fix that is to have different gearing (or change the voltage),
and it’s far easier to switch to a different motor with the same physical size,
but different gears.
If we then find that the faster motor isn’t powerful enough, we can switch to a
bigger motor, but we should test different gearsets first
There’s nothing that can be done with the default setup to speed up the Z axis,
but if we can test different motors, the next batch may be able to go out with
different motors (but we need to test early, as it takes a long time to order
motors, and we don’t want Bar to have a pallet of the wrong motors on hand.
That’s pretty sound reasoning. From my initial sketches I went with a welded steel frame, so I’ve never really thought of myself as being anywhere near the “stock” setup. As a result, I feel the need to constantly improve and innovate, even if it deviates from the original design. Maybe this means that some of the lessons that I learn from experimenting could be applied to the stock design?
If I could do this again, that would be a pretty good mindset to follow.
Would it make sense, then, to play with a couple of pulleys first and try to get the motor to stall to get a good approximation of just how much torque is needed from the motor? A couple different size pulleys sounds cheaper to me than a set of different rpm motors. Maybe it wouldn’t give us as controlled results, though, for the stock setup…
I wish I could get this testing done myself so I’m not simply a backseat driver… Really need to get some time off from all this moving to play with the Maslow again. Unfortunately, that might not be for awhile.
If I’ve read the forum correctly, the present 12V motor gives 11kg.cm of torque on ~.5A doing in the neighborhood of 12rpm at the shaft.
I’m thinking of this one, which lists 72kg.cm of torque and ~50rpm. It is thirstier, though - a smoking 6.5A stall current instead of the 2.4A of the stock motor. That would fry a stock Maslow board in an instant… It needs the connector signals re-arranged.
available in 12v or 24v and in many different gear ratios resulting in
6,10,15,18,30,38,55,88,`50,165,265,500 rpm
although double check that all gear ratios have the same dimensions
$24 each
the one you link to lists a stall current of 6A, which will fry the system
(unfortunantly the one I link to doesn’t say it’s stall current, but it’s no
load current is only 45ma compared to 250ma for the CQRobot one)
I disagree that ‘nothing can be done’ about speeding up the Z-axis motor, at least until we know we’re burning motors or shields. So far, we’re (I’m) just a little frustrated that its working so well, and could be working faster. =)
Today’s progress aside from Z-axis slop and speed constraints:
I was able to get some excellent ‘constant loading’ on long cuts with continual z-axis movement, apologies for misidentifying it as an issue, it was entirely my Fusion360 settings.
I was able to get my head around Fusion’s ramping features, mostly loosening up everything away from presumably metallic milling settings.
Similarly with tabs, and other Z-critical things given the slop in that axis, i ended up making much larger tabs and over-cutting some more into the wasteboard. Excellent entry and exit cuts with very little tear-out. (again on 3/4" home depot cabinet ply (the best looking pre-sanded ply in homedepot, sic)
The torque rating on that motor is 9kg.cm at 24V, so probably half that at 12V. That’s less than half the stock z-axis motor. Higher speed and lower torque doesn’t seem desirable. Still, if someone tries it, we will know.
we try to fit a small gear on the router base screw and consecutively larger gears until we can’t turn the screw any more with the motor, start losing motors, or blowing shields.
which leads naturally to the possibility that more power will be needed (could be utilized) in the future.
I doubt much work been done to see where the next appropriate level of ‘upsizing’ would be on a future Shield board, but perhaps that might be worth beginning to investigate…
or a ‘power agnostic’ shield, that doesn’t require a motor’s direct current into the shield?
or some sort of stacked ‘shield per axis’ setup?
I’m thinking about that kinda current (per @blurfl 's link) per axis and you’re talking real amperage… not that X-Y needs more power, but thats a whole other thread…
My point is to begin the discussion of how best to prepare for the possibility. .
That’s certainly the post I was thinking of. Thanks for finding it, I spent most of last night working through designing built-in’s for the new home with the wife. I clearly mis-remembered how the fix was done, though >.> Not sure where I got the idea of washers/retaining clip.
Also, super cool to see @blurfl approaching more powerful motor drivers in this thread! It’s really cool to see the progress happening!
