Belt Tension Frequency
What frequency should the belts be when fully tightened for X and Y axis belts per your specifications on the MK3? For example when using a gates 507C or 508C Sonic tension meter.
The build guide says a low note on the X axis but what specific frequency.
Update: A friend of mine happened to ask support and he was told to look at belt status. How is this derived? What range should they be in and why isn't this mentioned in the build guide?
Re: Belt Tension Frequency
its measured during calibration, I assume using some sort of calculation with stepper current/position.
the belt status is discussed in your handbook, i believe its 240 +- 40. thats a pretty big gap but you're almost certainly in the ball park if twangs like a low guitar string. where you fall in that range is not super important certainly not down to 1hz, but there was a thread where someone did exactly this (can't find it now)
Re: Belt Tension Frequency
I am requesting someone at Prusa with perfectly tuned belts to please measure the frequency of sound of belts when plucked. This can be measured using various free phone app such as 'n-track'. The inbuilt measuring of belt tension on my MK3 does not appear to function correctly. For example, after noting X tension was 290, I released the belt one notch (I LOOSENED the belt) but the X tension reading actually went up to 300, yet the belt is clearly too easy to pinch together.
Re: Belt Tension Frequency
I am requesting someone at Prusa with perfectly tuned belts to please measure the frequency of sound of belts when plucked. This can be measured using various free phone app such as 'n-track'. The inbuilt measuring of belt tension on my MK3 does not appear to function correctly. For example, after noting X tension was 290, I released the belt one notch (I LOOSENED the belt) but the X tension reading actually went up to 300, yet the belt is clearly too easy to pinch together.
This is an excellent idea and better even than telling someone to go for a low sound or even the sound of A220 an octave below A440 with out the tip about the smart phone tuner apps it won't help most non musical folks. any sort of quantification helps in the construction of a high quality 3D printer like the MK3.
I am very lucky to have a 50 kilo granite surface plate in the Metrology corner of my home machine shop and I will of course use it to be sure I have built my frame square and true tomorrow (if DHL come through with their delivery projection 😉 but very few will have that chance. but most folks have access to a smart phone.
They added torque values to the frame construction of the manual (4 1/2 Newton/Meters or 40 inch/pounds) so I think you should leave this good idea in the comments to this stage in the instructions. I wish they had torque values for fastening in various kinds of well printed plastic (such as PRUSA prints) both as a bolt and nut or 3mm through fastening to self tapping into plastic. but this is so connected to the quality of the printing I understand its absence
Re: Belt Tension Frequency
I am requesting someone at Prusa with perfectly tuned belts to please measure the frequency of sound of belts when plucked. This can be measured using various free phone app such as 'n-track'. The inbuilt measuring of belt tension on my MK3 does not appear to function correctly. For example, after noting X tension was 290, I released the belt one notch (I LOOSENED the belt) but the X tension reading actually went up to 300, yet the belt is clearly too easy to pinch together.
Higher numbers indicate a looser belt.
You need to tighten it to get to a reading of ~240.
I can totally understand why PR would not want to rely on random measurement devices for troubleshooting printers around the globe. Ambient noise, first time assemblers, cheap phone microphones, etc.
Re: Belt Tension Frequency
Higher numbers indicate a looser belt.
You need to tighten it to get to a reading of ~240.
I can totally understand why PR would not want to rely on random measurement devices for troubleshooting printers around the globe. Ambient noise, first time assemblers, cheap phone microphones, etc.
Ahh higher number means lower tension, gee how could that have possibly been confusing. Thanks Peter!
btw regarding plucking the belt to get a sound to measure, this just requires a spectrum analyzer, ancient tech, you would have to actually intentionaly want false results to get them. EDIT: and I've just tested my great idea and it turns out the sound from a plucked MK3 belt is actually so full of harmonics its difficult to discern a particular frequency, also the frequency is based not just on belt tension but also unfortunately other things like belt material density/wear/temperature etc etc etc etc . Basically I could not get a meaningful result. Stick around peter, for such few posts you already have contributed a lot I see!
Re: Belt Tension Frequency
Higher numbers indicate a looser belt.
You need to tighten it to get to a reading of ~240.
I can totally understand why PR would not want to rely on random measurement devices for troubleshooting printers around the globe. Ambient noise, first time assemblers, cheap phone microphones, etc.
btw regarding plucking the belt to get a sound to measure, this just requires a spectrum analyzer, ancient tech, you would have to actually intentionaly want false results to get them. EDIT: and I've just tested my great idea and it turns out the sound from a plucked MK3 belt is actually so full of harmonics its difficult to discern a particular frequency, also the frequency is based not just on belt tension but also unfortunately other things like belt material density/wear/temperature etc etc etc etc . Basically I could not get a meaningful result. Stick around peter, for such few posts you already have contributed a lot I see!
Thanks for the compliment.
I'm no bobstro, pjr or Joan, but I try not to lead folks down a path I've never been on. I try not to guess.
Now, if I could just manage to keep a tab logged into the forums that would allow me to reply...
Every time I would like to answer, I get a requirement to login again. But the same login credentials for the eShop do not work. I have to close the tab and click the Forum tab in the eShop again.
I'm using Android chrome if that makes a bit of difference.
Re: Belt Tension Frequency
Now, if I could just manage to keep a tab logged into the forums that would allow me to reply...
Every time I would like to answer, I get a requirement to login again. But the same login credentials for the eShop do not work. I have to close the tab and click the Forum tab in the eShop again.
Hmm, well I also was not able to even log into the forum despite having made an account. I asked support and they did explain what I needed to do to fix the issue. Something about logging into the shop then clicking a specific link to get to the forum from there. Perhaps related?
RE: Belt Tension Frequency
Prusa launched a belt sound frequency checker:
https://belt.connect.prusa3d.com/
And a video on how to use it :