RE: The 6.4.0-alpha firmware is awesome (so far)
I guess that is where my confusion was coming from.
RE:
The sharp peak change you are looking for happens as you turn the knob; not when you stand there looking at the belts with a stable frequency. If the belt is moving while the light is strobing, the frequencies do not match. The belt should appear stable and unmoving, or 'locked' with the strobe.
But I agree with you, the user information that comes with this alpha is, well, nearly useless. Not sure how Prusa expects people to really test the feature if it the usage is so obtuse.
RE:
The sharp peak change you are looking for happens as you turn the knob; not when you stand there looking at the belts with a stable frequency. If the belt is moving while the light is strobing, the frequencies do not match. The belt should appear stable and unmoving, or 'locked' with the strobe.
But I agree with you, the user information that comes with this alpha is, well, nearly useless. Not sure how Prusa expects people to really test the feature if it the usage is so obtuse.
No, that is not how it works in this case. The belt is not moving laterally, it’s vibrating. It needs to be tuned to the belts resonant frequency. I suggest you try it for yourself first before commenting.
RE: The 6.4.0-alpha firmware is awesome (so far)
The instructions say to look for slow movement.
To confirm. Was I doing it right in the video??
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The instructions say to look for slow movement.
To confirm. Was I doing it right in the video??
If you match with the web app and plucking the belt (with the head in the same position) then you did it correctly. Be careful with Prusa's instructions they tend to go through several iterations before they make sense. This is an alpha product so don't expect detailed (or correct) instructions at this point.
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The instructions say to look for slow movement.
To confirm. Was I doing it right in the video??
If you match with the web app and plucking the belt (with the head in the same position) then you did it correctly. Be careful with Prusa's instructions they tend to go through several iterations before they make sense. This is an alpha product so don't expect detailed (or correct) instructions at this point.
Yeah I've noticed this, but also willing to cut some slack because the instructions are written by people who probably dont use English as their primary language, often getting interpreted/misinterpreted by people who dont use English as their native language.
There's no reason why they cant release a simple, decent frame rate video (with subtitles for every language under the sun).
As the old saying goes, actions speak louder than words, and would clear up anything that is lost in translation.
Just to clear something up: have the target frequencies changed again ? last time I looked it was 98/92.
RE:
The sharp peak change you are looking for happens as you turn the knob; not when you stand there looking at the belts with a stable frequency. If the belt is moving while the light is strobing, the frequencies do not match. The belt should appear stable and unmoving, or 'locked' with the strobe.
But I agree with you, the user information that comes with this alpha is, well, nearly useless. Not sure how Prusa expects people to really test the feature if it the usage is so obtuse.
No, that is not how it works in this case. The belt is not moving laterally, it’s vibrating. It needs to be tuned to the belts resonant frequency. I suggest you try it for yourself first before commenting.
It really IS the way it works. Whether motion is horizontal left right or horizontal front to back or up to down, the goal is to stop the motion with the strobe. Movement, in this case capturing a resonance, is captured using a strobe to synchronize the light to the motion. Any deviation from a stopped image means the two frequencies are not aligned and synchronized. It really is very simple physics.
When the two are not sync'd, you get a beat frequency, that slow motion in the video. If that motion is once per second, it means the belt is 1Hz away from the light (or possible a harmonic of 1 Hz), but that'd probably be obvious.
ps: In case it isn't obvious @hyiger, the belt really is moving as it vibrates. Just as it moves when you pluck it. From Google:
To use a strobe light to measure resonance, set up an object to vibrate and apply a strobe light, then adjust the strobe frequency until the object appears to be stationary or to vibrate slowly. When the strobe frequency matches the object's natural frequency (its resonance frequency), the object appears frozen in time, revealing its modal shape.
RE: The 6.4.0-alpha firmware is awesome (so far)
The sharp peak change you are looking for happens as you turn the knob; not when you stand there looking at the belts with a stable frequency. If the belt is moving while the light is strobing, the frequencies do not match. The belt should appear stable and unmoving, or 'locked' with the strobe.
But I agree with you, the user information that comes with this alpha is, well, nearly useless. Not sure how Prusa expects people to really test the feature if it the usage is so obtuse.
No, that is not how it works in this case. The belt is not moving laterally, it’s vibrating. It needs to be tuned to the belts resonant frequency. I suggest you try it for yourself first before commenting.
It really IS the way it works. Whether motion is horizontal left right or horizontal front to back or up to down, the goal is to stop the motion with the strobe. Movement, in this case capturing a resonance, is captured using a strobe to synchronize the light to the motion. Any deviation from a stopped image means the two frequencies are not aligned and synchronized. It really is very simple physics.
When the two are not sync'd, you get a beat frequency, that slow motion in the video. If that motion is once per second, it means the belt is 1Hz away from the light (or possible a harmonic of 1 Hz), but that'd probably be obvious.
ps: In case it isn't obvious @hyiger, the belt really is moving as it vibrates. Just as it moves when you pluck it. From Google:
To use a strobe light to measure resonance, set up an object to vibrate and apply a strobe light, then adjust the strobe frequency until the object appears to be stationary or to vibrate slowly. When the strobe frequency matches the object's natural frequency (its resonance frequency), the object appears frozen in time, revealing its modal shape.
Until you install the firmware and do this for yourself you are just spouting incorrect information
RE: The 6.4.0-alpha firmware is awesome (so far)
???
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ps: In case it isn't obvious @hyiger, the belt really is moving as it vibrates. Just as it moves when you pluck it. From Google:
What is obvious is that you are coming across to me and others in this forum as really rather arrogant.
The frequency resolution is 0.5hz you are most likely not going to be exactly on the resonant frequency so the belt for most is not going to stop in the strobe, slower yes but not stopped as you initially posted. As in Prusa's initial instruction and in their gif. Again, you should not comment on things you haven't tried for yourself.
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Interesting video about a handheld strobe and Core One belts...
And I realize this is NOT using the new FW tuning procedure. I found it interesting regarding the belt movement when the proper frequency is achieved.
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Hi,
so I was curious to see how the belt tuning actually works and what is going on with the strobe light and the vibration frequency. I have a small hand-held oscilloscope and a photoresistor lying around. I put together something very simply, a USB-C charger that "powers" the photoresistor and I measured the voltage in AC mode across the photoresistor. When I shine light onto the photoresistor, the voltage drops and I adjusted the measurement range on my oscilloscope to get some readings.
After installing the new firmware, I made a video with me trying the manual belt tuning and measuring the frequency of the strobe light. Turns out, that the strobe light is not at the frequency of the vibration (=the frequency that the head vibrates to excite the belts, so that they start to swing/vibrate as well), but it is a bit out of "tune" at 100/90Hz vibration, I measured 104/92Hz strobe light (see the two screenshots attached, sorry for the bad quality, I was holding my phone filming while taking the measurements).
So I believe it works this way: the vibration is exciting the belt and when it hits the resonance frequency of the belt (which is the roughly the frequency it swings when you strobe the belt) the belt swings with the largest amplitude (I think this is what they mean with "sharp regular peaks"). Since the movement is actually to fast for the eye, the out-of-tune strobe light will cause the eye to see the movement at the frequency of the beats (i.e. the difference between the vibration frequency and the strobe light frequency), so a few Hz, so that you can follow the "slow" movement/vibration of the belt.
I will try to upload the video, if you are interested. In end I also complete the belt tuning procedure, although the values that I measured are quite ok, so I did not do/had to do any adjustments of the belt tension.
RE: The 6.4.0-alpha firmware is awesome (so far)
The instructions of what you are supposed to be looking for are not very clear (a video would be good) but this is an Alpha release and it was stated that detailed instructions would be coming.
I have tuned my Core One using the new strobe method and I fell back on my training from my Engineering days, when the object is no longer moving in the strobe then the frequencies are matched.
I'm look forward to the detailed instructions coming.
RE: The 6.4.0-alpha firmware is awesome (so far)
I started getting inexplicable layer shifts in large prints in the Y direction. I checked the belt tension and made a slight adjustment. Then I ran the Y-axis calibration test and it failed a few times. Gantry is perfectly square, there are no gaps. Ran X axis then afterwards Y axis passed. Turned everything off, slackened the belts completely, checked squareness, everything was fine. Retensioned the belts, checked squareness again and it was perfect (within reason). Ran Y calibration and after running homing procedure and then doing the Y axis test it failed. So I downgraded the firmware to 6.3.4 and did this process again. Now the Y calibration passes each time. Also the layer shifts are gone. My thoughts? Maybe, it my extra massive copper heat block and the new homing procedure? Or perhaps it's just a general bug. Anyway, I'm back to 6.3.4 and things seem better.
To downgrade the firmware, remove 6.4.0-alpha from the USB stick, copy 6.3.4 onto it. Press the reset button, as soon as the Prusa logo appears press the knob in once. This will force a firmware flash with 6.3.4.
RE: The 6.4.0-alpha firmware is awesome (so far)
Also wanted to add that the printhead moves freely in both X and Y in all 4 corners. There are no snags or obstructions. IDK, again my guess is maybe an issue with the new homing procedure. I might try again with a lighter heat block. Maybe the extra mass is causing problems.
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They need to get a handle on this layer shift thing, I wasted a fair bit of filament on a big print, tried it a second time and that layer shifted within 2 layers of the first failure…about 75 % through the print.
Reading the GitHub bug comments it seems related to G3 arcs, but I tried it with g3 commands disabled, and with both gyroid and grid infill…same result.
I won’t be printing anything big again until this is resolved, which is bordering unacceptable when you think about it.
RE:
Also wanted to add that the printhead moves freely in both X and Y in all 4 corners. There are no snags or obstructions. IDK, again my guess is maybe an issue with the new homing procedure. I might try again with a lighter heat block. Maybe the extra mass is causing problems.
Nah mine did it a few weeks back on the stable firmware also…Ive only seen it 3 times, all on tall, long prints.
my understanding was this alpha implemented several fixes for layer shifting, that’s why I tried it to see if it resolved the issue I had a few weeks back.
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After my belt tuning experiments I did a couple of tunings (input shaper etc.), but I started to notice some other bugs, like missing sensor information in the "sensor" screen (door, board temp etc. there is already a bug report on github).
I finally reverted to the stable firmware before I was able to start any prints. For me also the Y-axis test failed over and over again. The movement of the gantry was unobstructed and I using the stock print head/heat sink. I only tuned my belt by 1/8 turns at some point during the belt tuning tests. X- and Z-axis tests were ok, also the door sensor was fine despite the missing door sensor information.
After I went back to the stable firmware everything was working fine again, so I tend to agree that there is something wrong with the new homing procedure, but I could not test more.
I think the new firmware is a good step ahead, I hope they will shake the remaining bugs.
RE:
Also wanted to add that the printhead moves freely in both X and Y in all 4 corners. There are no snags or obstructions. IDK, again my guess is maybe an issue with the new homing procedure. I might try again with a lighter heat block. Maybe the extra mass is causing problems.
Nah mine did it a few weeks back on the stable firmware also…Ive only seen it 3 times, all on tall, long prints.
my understanding was this alpha implemented several fixes for layer shifting, that’s why I tried it to see if it resolved the issue I had a few weeks back.
In my case, I'm coming to (a) conclusion that maybe it's due to the much heavier copper heat blocks I was using. The heater calibration tests failed which makes sense given that it takes longer for the copper blocks to reach temp and it's probably running a timer. Also, I do think maybe the extra mass is messing with homing and Y calibration. I've switched to an aluminum heat block and things seem a bit more stable. What was nice about the copper heat block was a rock solid nozzle temp. I'll give the alpha firmware another try later.