10 tooth Pullies?
Posted by schulz
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10 tooth Pullies? September 18, 2011 10:21PM |
Registered: 13 years ago Posts: 37 |
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Re: 10 tooth Pullies? September 18, 2011 10:30PM |
Admin Registered: 15 years ago Posts: 1,470 |
I use 10 tooth pulleys with XL belts, which are pretty close to the pitch of T5 belts. It works just fine.
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Re: 10 tooth Pullies? September 19, 2011 01:17AM |
Registered: 13 years ago Posts: 37 |
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Re: 10 tooth Pullies? September 19, 2011 02:27AM |
Registered: 13 years ago Posts: 91 |
NewPerfection, where did you get your 10 tooth XL pulleys? I have had trouble finding one for XL belts with a 5mm bore to fit on a stepper motor shaft.... all the XL belts seem to have SAE bores and not metric. Any suppliers in the US?
I'm currently using some PLA ones on my Prusa that i printed with my RepStrap, but they are just slightly off/not perfectly round (most likely from backlash in my repstrap), so I wanted to swap them out for some nice aluminum ones
I'm currently using some PLA ones on my Prusa that i printed with my RepStrap, but they are just slightly off/not perfectly round (most likely from backlash in my repstrap), so I wanted to swap them out for some nice aluminum ones
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Re: 10 tooth Pullies? September 19, 2011 07:57AM |
Admin Registered: 17 years ago Posts: 7,879 |
It has been suggested that if you print a new pulley with an inaccurate one the new can be more accurate. The reason being that the belt averages out a few teeth.
It would be an interesting experiment to iterate that a few times and see if you converge on an accurate result.
[www.hydraraptor.blogspot.com]
It would be an interesting experiment to iterate that a few times and see if you converge on an accurate result.
[www.hydraraptor.blogspot.com]
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Re: 10 tooth Pullies? September 19, 2011 05:02PM |
Registered: 13 years ago Posts: 485 |
Apart from Nophead's interesting idea for an experiment, I'd recommend going straight for a commercial pulley. My printed pulleys always had lash problems that tooth averaging wasn't able to overcome. The T5 belt never wrapped to the 8-tooth pulleys with any sane tension either. I think it was too tight a bend for the belt. It may be that my printed pulleys were not as good as they could have been, but I didn't want to fool with this key component anymore.
I just put on GT2 belts and pulleys from SDP/SI, with excellent results. The smallest GT2 pulley with a 5mm bore still has a smaller diameter than the normal Prusa pulley. (About 80% of the 8-tooth T5, IIRC). With more steps per mm, I get a little more theoretical position accuracy and acceleration in addition to proper belt fit.
I just put on GT2 belts and pulleys from SDP/SI, with excellent results. The smallest GT2 pulley with a 5mm bore still has a smaller diameter than the normal Prusa pulley. (About 80% of the 8-tooth T5, IIRC). With more steps per mm, I get a little more theoretical position accuracy and acceleration in addition to proper belt fit.
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Re: 10 tooth Pullies? September 19, 2011 05:39PM |
Admin Registered: 15 years ago Posts: 1,470 |
daufhammer Wrote:
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> NewPerfection, where did you get your 10 tooth XL
> pulleys? I have had trouble finding one for XL
> belts with a 5mm bore to fit on a stepper motor
> shaft.... all the XL belts seem to have SAE bores
> and not metric. Any suppliers in the US?
I just buy ones with 3/16 inch bores, which I then drill out with a 5mm drill bit since 3/16 inch is just under 5mm. You can get them from mcmaster-carr or from sdp-si.
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> NewPerfection, where did you get your 10 tooth XL
> pulleys? I have had trouble finding one for XL
> belts with a 5mm bore to fit on a stepper motor
> shaft.... all the XL belts seem to have SAE bores
> and not metric. Any suppliers in the US?
I just buy ones with 3/16 inch bores, which I then drill out with a 5mm drill bit since 3/16 inch is just under 5mm. You can get them from mcmaster-carr or from sdp-si.
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Help improve the RepRap wiki!
Just click "Edit" in the top-right corner of the page and start typing. Anyone can edit the wiki! |
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Re: 10 tooth Pullies? September 19, 2011 09:13PM |
Registered: 12 years ago Posts: 1,611 |
I did what nophead was suggesting; I iteratively improved my pulleys on my 1X2 repstrap build; from printing using a smooth belt (which needed to be homed each layer), to a rough pulley with gcode from repsnapper, and on through two more iterations using skeinforge, until I managed to produce a really neat pulley. And this when I was on the steep part of the reprap learning curve. It was a fun experiment, but I suppose if people want to get printing, the aluminium ones are the quickest solution, and do provide very good results.
To shamelessly self-promote, here is a thing I designed: [www.thingiverse.com]
It can make any T5 or XL pulley you might want, and the 10-tooth is a really nice size. I have two waiting to be included in my Prusa build.
To shamelessly self-promote, here is a thing I designed: [www.thingiverse.com]
It can make any T5 or XL pulley you might want, and the 10-tooth is a really nice size. I have two waiting to be included in my Prusa build.
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Re: 10 tooth Pullies? September 19, 2011 10:44PM |
Registered: 13 years ago Posts: 91 |
NewPerfection Wrote:
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> I just buy ones with 3/16 inch bores, which I then
> drill out with a 5mm drill bit since 3/16 inch is
> just under 5mm. You can get them from
> mcmaster-carr or from sdp-si.
So is it safe to assume then that an XL pully with a 5mm bore doesn't actually exist normally (without drilling it out to 5mm myself... I don't have any metric drill bits)
droftarts Wrote:
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> I did what nophead was suggesting; I iteratively
> improved my pulleys on my 1X2 repstrap build;
Good to know that it can be done Droftarts, maybe i will have to try that before I buy a metric drill set and some Aluminum XL pullys
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> I just buy ones with 3/16 inch bores, which I then
> drill out with a 5mm drill bit since 3/16 inch is
> just under 5mm. You can get them from
> mcmaster-carr or from sdp-si.
So is it safe to assume then that an XL pully with a 5mm bore doesn't actually exist normally (without drilling it out to 5mm myself... I don't have any metric drill bits)
droftarts Wrote:
-------------------------------------------------------
> I did what nophead was suggesting; I iteratively
> improved my pulleys on my 1X2 repstrap build;
Good to know that it can be done Droftarts, maybe i will have to try that before I buy a metric drill set and some Aluminum XL pullys
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Re: 10 tooth Pullies? September 19, 2011 11:03PM |
Registered: 13 years ago Posts: 37 |
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Re: 10 tooth Pullies? September 19, 2011 11:27PM |
Registered: 13 years ago Posts: 1,352 |
schulz Wrote:
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> So is it right, in saying that you do not need to
> change/configure anything if you have 10 tooth
> pullies as opposed to 8 tooth pullies?
>
> thanks,
> Schulz
Dunno about others, but i would say that one will constantly need to change / configure the firmware on the printer, and pulleys arent the big part of it. For example you would update the firmware to the new version, or change to other firmware, so on so forth. So you cant really skip the configuration process entirely - its not something you can "ditch" or dodge, and you need to be able to do it anyways. Technically might be needed just once, but i bet in practice it will turn out to be lots of times more. But the good news is that is as easy as writing a post here on the forum and press "post message" button, in our case would be editing in arduino window and pressing upload button.
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> So is it right, in saying that you do not need to
> change/configure anything if you have 10 tooth
> pullies as opposed to 8 tooth pullies?
>
> thanks,
> Schulz
Dunno about others, but i would say that one will constantly need to change / configure the firmware on the printer, and pulleys arent the big part of it. For example you would update the firmware to the new version, or change to other firmware, so on so forth. So you cant really skip the configuration process entirely - its not something you can "ditch" or dodge, and you need to be able to do it anyways. Technically might be needed just once, but i bet in practice it will turn out to be lots of times more. But the good news is that is as easy as writing a post here on the forum and press "post message" button, in our case would be editing in arduino window and pressing upload button.
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Re: 10 tooth Pullies? September 20, 2011 01:45AM |
Admin Registered: 15 years ago Posts: 1,470 |
daufhammer Wrote:
> So is it safe to assume then that an XL pully with
> a 5mm bore doesn't actually exist normally
> (without drilling it out to 5mm myself... I don't
> have any metric drill bits)
I think so. But if you order from McMaster, you can get a 5mm drill bit for less than $2.
> So is it safe to assume then that an XL pully with
> a 5mm bore doesn't actually exist normally
> (without drilling it out to 5mm myself... I don't
> have any metric drill bits)
I think so. But if you order from McMaster, you can get a 5mm drill bit for less than $2.
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Help improve the RepRap wiki!
Just click "Edit" in the top-right corner of the page and start typing. Anyone can edit the wiki! |
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Re: 10 tooth Pullies? September 20, 2011 06:39AM |
Registered: 12 years ago Posts: 33 |
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Re: 10 tooth Pullies? September 20, 2011 02:48PM |
Admin Registered: 17 years ago Posts: 7,879 |
I think those are pinions to mesh with a gear, not belt pulleys.
Are helicopter drive belts timing belts? I.e. do they contain steel or kevlar wires to stop them stretching?
[www.hydraraptor.blogspot.com]
Are helicopter drive belts timing belts? I.e. do they contain steel or kevlar wires to stop them stretching?
[www.hydraraptor.blogspot.com]
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Re: 10 tooth Pullies? September 21, 2011 02:46AM |
Registered: 13 years ago Posts: 91 |
NewPerfection Wrote:
-------------------------------------------------------
> I think so. But if you order from McMaster, you
> can get a 5mm drill bit for less than $2.
Thanks NewPerfection! Im not sure why i didn't think to order a 5mm drill bit from McMaster at the same time as the pully! Im actually only about 30 min away from McMaster in Los Angeles so i can pick stuff up for free at Will Call rather than pay for shipping! That's where i got all my hardware for my Prusa! I appreciate the tips!
Edited 1 time(s). Last edit at 09/21/2011 02:47AM by daufhammer.
-------------------------------------------------------
> I think so. But if you order from McMaster, you
> can get a 5mm drill bit for less than $2.
Thanks NewPerfection! Im not sure why i didn't think to order a 5mm drill bit from McMaster at the same time as the pully! Im actually only about 30 min away from McMaster in Los Angeles so i can pick stuff up for free at Will Call rather than pay for shipping! That's where i got all my hardware for my Prusa! I appreciate the tips!
Edited 1 time(s). Last edit at 09/21/2011 02:47AM by daufhammer.
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Re: 10 tooth Pullies? September 24, 2011 03:04AM |
Registered: 13 years ago Posts: 91 |
Actually, wouldn't these be perfect.... "A 6Z 3M10DF09505" [sdp-si.com]
It's a 10 tooth XL pulley with a 5mm bore, so no modification necessary (and they are cheeper than the McMaster ones too).
Has anyone tried these?
It's a 10 tooth XL pulley with a 5mm bore, so no modification necessary (and they are cheeper than the McMaster ones too).
Has anyone tried these?
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Re: 10 tooth Pullies? January 31, 2012 08:50PM |
Registered: 12 years ago Posts: 9 |
I made a set of 12 tooth pulleys (based on [www.thingiverse.com]) for my X and Y drives on a standard Prusa because I felt that the diameter of the 8 tooth pulleys is too small for the T5 belt... Although they are not perfect because of the backlash on the 8 tooth ones I had to print them on, they practically eliminate the terrible problems I had of the belt jumping a tooth, causing wrecked prints.
On a standard setup, only 4 teeth are actually going to engage at any one moment and any inaccuracies in centering or tooth evenness are really obvious. More teeth on a pulley (as long as they are the right pitch for the belt!) mean that more will be engaging at any one time... Less chance of slipping and any inconsistencies tend to average out.
Of course, the downside is that to drive the belt a given distance takes fewer steps of the stepper motor, so you theoretically get lower resolution. I changed the 80 steps per mm down to 53.333 steps per mm in the firmware to compensate for the larger diameter pulleys - the theoretical resolution is therefore reduced from 0.0125 mm to 0.01875 mm - way finer than I think is going to be possible on any Prusa anyway. In theory, the more teeth you have, the better as far as I can see - up to the point where either (1) the pulley gets too big for the place it has to go, or (2) the torque of the motor isn't enough to drive it around...
Any thoughts?
On a standard setup, only 4 teeth are actually going to engage at any one moment and any inaccuracies in centering or tooth evenness are really obvious. More teeth on a pulley (as long as they are the right pitch for the belt!) mean that more will be engaging at any one time... Less chance of slipping and any inconsistencies tend to average out.
Of course, the downside is that to drive the belt a given distance takes fewer steps of the stepper motor, so you theoretically get lower resolution. I changed the 80 steps per mm down to 53.333 steps per mm in the firmware to compensate for the larger diameter pulleys - the theoretical resolution is therefore reduced from 0.0125 mm to 0.01875 mm - way finer than I think is going to be possible on any Prusa anyway. In theory, the more teeth you have, the better as far as I can see - up to the point where either (1) the pulley gets too big for the place it has to go, or (2) the torque of the motor isn't enough to drive it around...
Any thoughts?
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Re: 10 tooth Pullies? February 04, 2012 05:39AM |
Registered: 12 years ago Posts: 1,611 |
Try my new pulley openscad file [www.thingiverse.com]. It can make any number of toothed pulley you want, but accurately. You'll get rid of the backlash. I use 10-tooth pulleys on my reprap, with 32 steps per mm as opposed to the normal 40 steps per mm. The larger you go, the less positional accuracy you will achieve unless you use a solution like Madkite's resolution doubling technique [forums.reprap.org]
However, the problem really is why was your belt jumping on a 8 tooth pulley? Not tight enough? Axes have too much resistance? You can usually tune out these problems.
If you were using 80 steps per mm with a 8-tooth pulley, I guess you are using 16x microstepping. Anything above 10x microstepping cannot be considered accurate, as there is a +/-5% inaccuracy on motors at FULL microstepping. By 16x microstepping, you can be a full microstep out. This, from [www.geckodrive.com]
However, the problem really is why was your belt jumping on a 8 tooth pulley? Not tight enough? Axes have too much resistance? You can usually tune out these problems.
If you were using 80 steps per mm with a 8-tooth pulley, I guess you are using 16x microstepping. Anything above 10x microstepping cannot be considered accurate, as there is a +/-5% inaccuracy on motors at FULL microstepping. By 16x microstepping, you can be a full microstep out. This, from [www.geckodrive.com]
Quote
Why are all Geckodrive stepper products ten microsteps by default?
All stepper drives manufactured by Geckodrive have a default resolution of ten microsteps because of motor linearity. A step motor is a mechanical device that is manufactured to a certain tolerance. Typically a standard motor has a tolerance of +/- 5% non accumulative error regarding the location of any given step. This means that any step on a typical 200 step per revolution motor will be within a 0.18-degree error range. Stated otherwise, the motor can accurately resolve 2000 radial locations. Coincidentally this is the resolution of a 10 microstep drive.
Any microstep resolution beyond 10, such as 125, yields no additional accuracy, only empty resolution. By analogy, a voltmeter having a 6 digit display while having 1% accuracy would have meaningful information only in the first two digits. There are two exceptions justifying higher resolutions: The step motor is being run in a closed-loop application with a high-resolution encoder or the application requires smooth operation at very low speeds (below 5 full steps per second).
The secondary reason behind the ten microstep number is step pulse timing. If you have a motor control such as the G203V that requires 2kHz to move one full step in one second, you can get 1500RPM from a 50kHz signal. If you have the exact same signal speed at 256 microsteps your motor will drop off to 58RPM with the exact same accuracy of +/- 5% of one full step. The net result is a drop in speed with no clear improvement in accuracy on the mechanism.
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Re: 10 tooth Pullies? October 12, 2013 12:04PM |
Registered: 10 years ago Posts: 41 |
Sorry for bringing back an old post but I'm new. I bought some nice T5 12t aluminum pulleys for my I3X but have no way (nor no how) to change the firmware. I checked the travel on my printer and with an indicator on it when I jog the 1 on the machine my x and y axis travel about .042" and my z (stock) only moves .023". so obviously my parts will not be scaled correctly.
Those plastic 8 tooth POS gears are worthless. I'm not sure what to do. I have the Sagni@#$#$ control board. But no way to change the setting
My big question is: if I move .042 when I click the 1 on the pronterface theoretically im only about .003" off. Am I correct? But why is my Z moving only .023" when I move 1 on pronterface?
Sorry for English measurements but my indicators are English.
Edited 3 time(s). Last edit at 10/12/2013 12:18PM by makovai.
Those plastic 8 tooth POS gears are worthless. I'm not sure what to do. I have the Sagni@#$#$ control board. But no way to change the setting
My big question is: if I move .042 when I click the 1 on the pronterface theoretically im only about .003" off. Am I correct? But why is my Z moving only .023" when I move 1 on pronterface?
Sorry for English measurements but my indicators are English.
Edited 3 time(s). Last edit at 10/12/2013 12:18PM by makovai.
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Re: 10 tooth Pullies? October 12, 2013 12:22PM |
Registered: 13 years ago Posts: 118 |
[calculator.josefprusa.cz] assuming 16x microstepping and 1.8degree steppers 53.33 is the steps per mm.
You will have to update your configuration.h file, recompile and upload the updated firmware. Or, if your FW supports it, use the command G92 X53.33 Y53.33 to temporarily set the steps per mm.
As for the Z, again assuming 1.8degree 16x microstepping and the recommended 5mm leadscrew you would use 4000.00. Again G92 Z4000.00 would allow you to test. If your microstepping is different, use the calculator.
-Jay
makovai Wrote:
-------------------------------------------------------
> Sorry for bringing back an old post but I'm new. I
> bought some nice T5 12t aluminum pulleys for my
> I3X but have no way (nor no how) to change the
> firmware. I checked the travel on my printer and
> with an indicator on it when I jog the 1 on the
> machine my x and y axis travel about .042" and my
> z (stock) only moves .023". so obviously my parts
> will not be scaled correctly.
>
> Those plastic 8 tooth POS gears are worthless. I'm
> not sure what to do. I have the Sagni@#$#$ control
> board. But no way to change the setting
>
>
> My big question is: if I move .042 when I click
> the 1 on the pronterface theoretically im only
> about .003" off. Am I correct? By why is my Z
> moving only .023" when I move 1 on pronterface?
>
> Sorry for English measurements but my indicators
> are English.
You will have to update your configuration.h file, recompile and upload the updated firmware. Or, if your FW supports it, use the command G92 X53.33 Y53.33 to temporarily set the steps per mm.
As for the Z, again assuming 1.8degree 16x microstepping and the recommended 5mm leadscrew you would use 4000.00. Again G92 Z4000.00 would allow you to test. If your microstepping is different, use the calculator.
-Jay
makovai Wrote:
-------------------------------------------------------
> Sorry for bringing back an old post but I'm new. I
> bought some nice T5 12t aluminum pulleys for my
> I3X but have no way (nor no how) to change the
> firmware. I checked the travel on my printer and
> with an indicator on it when I jog the 1 on the
> machine my x and y axis travel about .042" and my
> z (stock) only moves .023". so obviously my parts
> will not be scaled correctly.
>
> Those plastic 8 tooth POS gears are worthless. I'm
> not sure what to do. I have the Sagni@#$#$ control
> board. But no way to change the setting
>
>
> My big question is: if I move .042 when I click
> the 1 on the pronterface theoretically im only
> about .003" off. Am I correct? By why is my Z
> moving only .023" when I move 1 on pronterface?
>
> Sorry for English measurements but my indicators
> are English.
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