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Given the "hackfest" nature of this build, I went ahead and ordered this for the twin-screw axis:
https://www.ebay.com/itm/US-Ship-1ax...72.m2749.l2649
Says 1090 in-oz. (I get 7.7 Nm) and 4.1mH inductance. My intention is to mount it underneath and between the 2 ballscrews and come up with a timing belt arrangement to drive both from one motor. If I can get the Y-axis moving under power, it will give me encouragement to drive forward.
Thanks,
Wallace
Not as easy as I thought to find timing belt pulleys and belts. What width belt would I need to drive this? I see XL, L, HTD, etc. - what do you guys typically use?
Thanks,
Wallace
I use HTD belt and pulleysQuote:
Originally Posted by wallyblackburn
Htd is supposed to have much lower backlash then the other profiles (backlash free?)
Go with 5mm pitch.. seems a popular choice. I got 3mm pitch delivered and Im hoping thats fine.
15mm width belt is a good choice.
Saw a spreadsheet that demonstrated that 10mm width is fine for routers but it seemed close so I chose 15mm :)
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Thanks guys. Well, I find a ton of them on eBay - of course they are all from China and seller is away until 02/20. Oh well, I guess our friends in Asia need time off too :)
I am just looking for 1:1 I think. I just want to drive both screws from one motor. Given that I was going to pick 3 20 tooth pulleys and 2 idlers. Any reason to use more or less teeth?
Thanks,
Wallace
How about belting online? I think they are uk based?Quote:
Originally Posted by wallyblackburn
20tooth pulleys are generally recommended here.
Good size to strength to tooth engagement.
Larger pulleys have higher inertia
Smaller pulleys have smaller boss for setscrews
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Well, here is what I ended up with:
Attachment 23895
Attachment 23894
Sorry the 2nd pic is rotated (again) - but I think I figured it out now that I have one that is and one that isn't...
Anyway, I am thinking of an adjustable tensioner. Seems like a long span there on top - you guys think that'll be a problem? I really have no experience with timing belts like this.
Thanks,
Wallace
Hey Wally!Quote:
Originally Posted by wallyblackburn
I have no experience with such long belts, but I can imagine that the top part will flap if going fast?
A tensioner on top might be a good stabilizer ;)
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More importantly is that a Mustang in the rear of the photo? Camaro and Firebird man myself but could slum it with a mustang whilst I wait for a 67SS to drop from the sky or a 77 Trans Am ;)
The commercial printers we scrap always have tensioners on and the belt lengths are measured in inches (Short), if you can get tensioners easily enough than I'd fit them. They're sprung to apply constant tension and are adjustable.
It is actually a '65 T-Bird. I went to an auction with the intention of buying a '63 Impala SS, and somehow came home with that over-engineered POS. Auction fever, I guess!Quote:
Originally Posted by Desertboy
I think I will try to fab up a tensioner for the top span.
Regards,
Wallace
I'd try the setup as is. The worst case scenario is the belt flaps far too much and causes resonance problems, and you then have to add some idler pulleys.
If it does need a couple idlers added, I would probably add a couple rollers to the top, to drop the belt down in the middle and increase wrap on the ballscrew pulleys.
Rigged up a tensioner using stuff on hand - including a Subaru timing belt idler bearing:
Attachment 23897
First movement!!!
https://youtu.be/HMjVgd4S_KA
I don't think it will cut anything without a Z axis:applause:Quote:
First movement!!!
Be careful not to over tension because will deflect the ball screws causing whip when at opposite end of travel. It would have actually been ok without a tensioner thou it's better down out of the way.Quote:
Originally Posted by wallyblackburn
Thats not movement that's a twitch.!. . . . Let it have it's head to shake the gremlins out.:smiley_simmons:Quote:
Originally Posted by wallyblackburn
Interesting. I’ll back off the spring pressure and adjust as needed when it’s actually working.Quote:
Originally Posted by JAZZCNC
Thanks!
Sent from my iPhone using Tapatalk
Yes, that long run of belt, I would have probably around 10mm of easy deflection in it - you really do not want to "twang" timing belts like guitar strings ;)Quote:
Originally Posted by wallyblackburn
As long as they are not flapping in the breeze, the tension does not affect accuracy as much as you might think, but it will wear things out, cause resonance and generally not be good.
What do you guys typically use for steps per revolution on your drivers?
Thanks,
Wallace
Totally dependant on the mechanical setup - pulley sizes etcQuote:
Originally Posted by wallyblackburn
Step per rev isn't a setting you can pick or choose. It's an absolute calculation that is derived from several factors. The pitch of the ballscrew, Microsteps set on drives and any mechanical ratio.Quote:
Originally Posted by wallyblackburn
If your unsure mach3 can do this for you. Go to settings tab and just above Reset you'll see Set Steps per button. Click this and select the axis want to set. It will then ask for distance to move. Enter a value, make it small to start with, then measure how far it actually moved and enter the amount. Mach3 will then calc and set the steps per for you.
Do this for each axis using a small value to start then repeat and set over a longer distance. Very important you measure accurately.
I think I asked wrong question. From this reply, I think I meant to ask what you typically use for microsteps? On my DM560B clone from Long's, you set dip switched for pulse/rev - that's what I mean. Oh, and I'm not using Mach3 - I'm using Centroid Acorn.
I have it at 400 and empirically determined a setting (turns/in. I think it was) in the Acorn config wizard to get 0.100" movement for 0.100" called for (oh yeah, I'm using Imperial measurements too...lol). But, when I ask for 0.100", it will sometimes go to 0.1004" - I assume because of resolution limitations.
<steps away>
So, I just went and set the dip switches on the DM560B to 2000 pulse/rev and updated it in Acorn controller too. I set up a dial indicator and am getting pretty damn good accuracy for an initial setup. After 5 moves of 0.100" my DTI reads about a needles width off - maybe couple tenths. If I go back, it is dead on zero again. AND, now I get a readout on Centroid of 0.1000" for a move instead of 0.1004" or something.
But, what am I sacrificing with the tiny microsteps? I seem to remember you lose torque - but is there a rule of thumb as to what we can get away with? I know it would depend on material and such, I was really wondering what most folks used for microstep.
Long way around there! And also, the irony of a Yank asking Brits about how to get good Imperial movement from metric leadscrews?! You folks put the Empire in Imperial! LOL.
Thanks,
Wallace
ok makes more sense now. When it comes to MS then speed of controller comes into play because the higher the MS the more pulses are required. So some lesser controllers cannot provide enough pulses to allow high feed rates a router requires. In which case you'd use a lower Ms amount.
In your case you have more than enough pulses so can afford to go higher on the MS. However going much above 2000 is wasted because steppers cannot resolve to much more than this.
The main advantage of higher MS is smoother motor action. Yes you'll lose little torque with high MS but not enough to worry about or even notice.
Typical MS for router is 1600 or 2000.
However the drives/motors and how they are affected by resonance can come into play when selecting MS. Some motor/drives combo's don't perform very well with certain MS settings because of resonance. This is esp true of some Analog drives which I think the Long's DM560B are, they are basicly Leadshine DM copies. So in cases like these you some times have to select different Ms setting to try move out of the resonance range.
Resonance will and does cripple performance so if you start getting stalling motors or struggle to get good velocity then chances are resonance is affecting the drives/motors.
Digital drives handle resonance much better so are not affected as much, if at all, it's also big reason why they perform so much better than Analog drives.
Thanks for the info, Jazz. I am fiddling with it. At this point, I have it at 2000. So far, I am at 200 IPM with no apparent problems. Obviously, this is very preliminary, but I'm pretty happy:
https://youtu.be/M6a3rZEUpZo
Regards,
Wallace
Got X-Axis moving today!
https://youtu.be/K5v0Z2IYLTQ
I have to back off a little and clean up. Shop is a disaster area. Then on to Z!
Has anyone tried the prefab Z-axis units from Fred at BST? I'm getting anxious (and lazy) and that might be a way to speed things along. Something like this:
https://www.aliexpress.com/store/pro...47196cadq6FoR8
Regards,
Wallace
Nicely done :D
How fast are you going in that YouTube vid?
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I think that is 200IPM...Quote:
Originally Posted by Nr1madman
Cool :DQuote:
Originally Posted by wallyblackburn
Have not played with my speeds yet. Think mine is set to 2000mm/min. Yours seemed FAST in comparison :)
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Working on my control cabinet. Not the neatest ever by far, but latest power up did not release any smoke :).
Attachment 24033
Had to bag these 4-pin microphone connectors. Got the female side hooked up OK, but no way in hell these old eyes and fingers are going to get the wires soldered on those tiny little tabs on the male connector side.
Attachment 24034
For now, I'll just hardwire them. What do you guys use to connect steppers to control side?
Got my spindle and VFD from BST (actually came from Huan Yang directly.
Getting there!
Wallace
Had to bag these 4-pin microphone connectors. Got the female side hooked up OK, but no way in hell these old eyes and fingers are going to get the wires soldered on those tiny little tabs on the male connector side.
Attachment 24034
For now, I'll just hardwire them. What do you guys use to connect steppers to control side?
Wallace[/QUOTE]
Sigh, just looked at the connector for the spindle motor. This old-style microphone connector seems like a really poor choice for power to a 2.2KW motor - anybody tried to replace these?
Thanks,
Wallace
I use those litle 4-way connectors for signal connections (limit switches, etc) - they are fiddly to wire, aren't they?
For stepper connections, I personally use 4-way XLR latching connectors, which are a bit chunkier to handle! Not sure what other people use but XLR are readily available and not too expensive compared to some of the more exotic connector types.
A little more modern to boot. I just took another look at the spindle connector - it is actually a larger version of the 4-pin mike connector. Doesn't look too bad to solder to and seems a bit heftier.
Decided to affix the spindle to my surface plate and check it out while I was messing with it. The inner contact surface of the spindle is nuts on - I get under a tenth of runout - very nice! The included collet, not so much. More than 2 thou (once the needle on my tenths indicator starts moving that much, I don't bother to get an exact measurement). Probably worrying too much for a primarily wood machine, but that collet goes in the trash. I'll order a Lyndex or Royal...
This is getting fun!
Wallace
First cut! The requisite circle :)
https://youtu.be/OvcXHagAsHY
Attachment 24051
Still so much to do, but that is definitely encouraging!
Regards,
Wallace
Wally!
Good work and well done :D
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More test cuts. Doing calibration.
https://youtu.be/LhO3nABnEpA
Thanks,
Wallace
Nice, looking good.
Is that a Fusion tool path??
It is. I have to say, of all the hurdles so far Fusion 360 has been the biggest. But, I am finally starting to get the hang of it.Quote:
Originally Posted by Davek0974
Makes sense, I suppose. I have lots of experience with building stuff and electronics. But, CAD is new to me.
Thanks,
Wallace
Its a steep curve but once you get over the top, the fun really starts - there is great satisfaction in designing a part in 3D then converting to tool paths and watching your machine turn it out. :)
Yes it is!!! I made a dust shoe top! Getting ready to try the bottom here in a few.Quote:
Originally Posted by Davek0974
https://www.youtube.com/watch?v=Mw_H8ifVLu4
Thanks,
Wallace
Well, I'm at the point of cutting real stuff:
https://youtu.be/ILxyh3d0wrA
Attachment 24202
And - of course - thinking about what I want to do to make this one better AND what I'll be doing for the next one! :)
I am leaning towards a 4x8+ made out of extrusions. Wood-only, so I think extrusions will be fast and adequate. Want to be able to put a whole sheet of plywood on at once. But, just thinking/dreaming at this point.
For this one, I am planning the following:
- 1/2" steel table with a 3/8"-16 hole pattern for bolting down MDF wasteboard, Aluminum pieces, etc.
- 3 or 4:1 belt drive on X- and Y-axis. The X and Z are direct connected. The Y is belt, but 1:1
- More rigid gantry with 1/4" steel end plates and 2040 Rexroth crossbars. With a slanted design to allow more real estate to be accessible
- Maybe filling some of the frame members with something - mortar maybe? Sand?
Thanks to all for the advice gotten here,
Wallace