How well does the MK2 calibration work? What happens if a print fails?
Hello! I'm hoping to get some feedback from people who have gotten the MK2.
I bought and assembled an original i3 a few years ago and I'm now thinking of buying the "i3 upgrade package so I can rebuild my i3 to an MK2. But I have some concerns.
Background
Sometimes, my prints have failed due to missalignment (I have noticed that some models are "harder" to print than others). What happens (very rarely) is that the extruder can sometimes collide with the already printed plastic. When this happens, the force exherted by the extruder on the printed model will push the glass off (or partly off) the heatbed (since the plastic is stuck on the glass, the force transfers to the glass). This is of course not fun, as you have to start over with the print, but on the other hand: The glass (held down by clips on the heatbed) will, in a way, act as sort of a "failsafe mechanism". If the extruded pushes on the plastic, atleast the extruder won't be damaged(?).
Question
My question is, on the MK2, where there are no glass on the heatbed. What will happen if the extruder bumps into the already printed plastic and push against it? Since the plastic is stuck to the heatbed with no movable glass I would assume that the motor will keep pushing into the plastic? Could this damage the extruder nozzle? Is this something that has been thought of in the design of the MK2? Are there some feedback mechanism that will abort printing if this happens? Or are the calibration so good that this won't happen?
Re: How well does the MK2 calibration work? What happens if a print fails?
It happens from time to time. The result is - either the printed object is kicked off the bed or stepper motor skips steps resulting to shifted layer. The print is ruined in both cases. There is no feedback mechanism.
Re: How well does the MK2 calibration work? What happens if a print fails?
I bought and assembled an original i3 a few years ago
Marcus The i3 "original" that is upgradeable has been around only for a couple of years and the early models will have a mini RAMBo 1.0 board and 3mm extruder. Those will both require upgrading before you can upgrade to the Mk2.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: How well does the MK2 calibration work? What happens if a print fails?
It happens from time to time. The result is - either the printed object is kicked off the bed or stepper motor skips steps resulting to shifted layer. The print is ruined in both cases. There is no feedback mechanism.
Do you have personal experience with this? Do you know if there is any chance the extruder could be damaged when this happens? Do you know if the auto calibration will reduce this problem?
Re: How well does the MK2 calibration work? What happens if a print fails?
Marcus
Unless you have an "original" Mk1 bought direct from Prusa Research, it will be extremely hard to upgrade to a Mk2.
That being said, with a properly set up printer and properly sliced model, it is very rare that nozzle contacts the print. The Mk2 includes an E3D V6 hot end which has a stainless steel heat break; that is very difficult to damage by nozzle/part contact.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: How well does the MK2 calibration work? What happens if a print fails?
Marcus
Unless you have an "original" Mk1 bought direct from Prusa Research, it will be extremely hard to upgrade to a Mk2.
That being said, with a properly set up printer and properly sliced model, it is very rare that nozzle contacts the print. The Mk2 includes an E3D V6 hot end which has a stainless steel heat break; that is very difficult to damage by nozzle/part contact.
Peter
Ok, there seems to be some confusion here. Maybe I wasn't clear enough in my original post, so I'll clarify:
Yes, I bought an Original Prusa i3 "Mk1" from Prusa Research and are thinking of buying the upgrade kit to "Mk2". This is Not the issue.
The question is only regarding those (very rare) instances when the nozzle of the extruder will collide with a print:
Re: How well does the MK2 calibration work? What happens if a print fails?
Marcus
You did say "a few years ago"; considering the Mk1 1.75mm has only been available for 15 months or so I was just wanting to clarify the situation.
As I mentioned previously, the S/S heat break is fairly strong. I cannot remember the nozzle hitting a printed part so if it does happen, it is a ver rare occurrence. I have both the Mk1 and Mk2 and with the Mk1, I never experienced the glass coming away due to a collision.
The only reason I have had to change the nozzle on both printers is simply wear or serious blockage when changing is quicker than cleaning.
Regarding calibration, I don't see how that could assist in avoiding a collision.
I think the most important aspect is to ensure your model is properly sliced for the printer and with suitable settings.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: How well does the MK2 calibration work? What happens if a print fails?
Marcus
You did say "a few years ago"; considering the Mk1 1.75mm has only been available for 15 months or so I was just wanting to clarify the situation.
As I mentioned previously, the S/S heat break is fairly strong. I cannot remember the nozzle hitting a printed part so if it does happen, it is a ver rare occurrence. I have both the Mk1 and Mk2 and with the Mk1, I never experienced the glass coming away due to a collision.
The only reason I have had to change the nozzle on both printers is simply wear or serious blockage when changing is quicker than cleaning.
Regarding calibration, I don't see how that could assist in avoiding a collision.
I think the most important aspect is to ensure your model is properly sliced for the printer and with suitable settings.
Peter
Ok, thank you for the information
Re: How well does the MK2 calibration work? What happens if a print fails?
As a piece of additional information, if your using the new Prusa version of Slic3r along with Mk2, i noticed it has Z-hop enabled by default (it moves the extruder up slightly durning moves) So this should help reduce this from happening.
its usually the settings and or bed adhesion that causes the issue you describe, no the printer itself. (i.e. not enough adhesion and corner of the print curls up causing the collision.)
The stepper motors themselves are not strong enough to cause any damage to the nozzle or extruder if they collide with a print, you will simply end up with a ruined print (either due to it getting dislodged , or the motor skipping causing a laywer shift) so no worries, on that front.
The added bonus of the PEI surface should help with bed adhesion and have less curled corners and chances of a collision.
Re: How well does the MK2 calibration work? What happens if a print fails?
As a piece of additional information, if your using the new Prusa version of Slic3r along with Mk2, i noticed it has Z-hop enabled by default (it moves the extruder up slightly durning moves) So this should help reduce this from happening.
its usually the settings and or bed adhesion that causes the issue you describe, no the printer itself. (i.e. not enough adhesion and corner of the print curls up causing the collision.)
The stepper motors themselves are not strong enough to cause any damage to the nozzle or extruder if they collide with a print, you will simply end up with a ruined print (either due to it getting dislodged , or the motor skipping causing a laywer shift) so no worries, on that front.
The added bonus of the PEI surface should help with bed adhesion and have less curled corners and chances of a collision.
That's a great setting! Thanks for the info. Will see if this option is available for my current model as well
Re: How well does the MK2 calibration work? What happens if a print fails?
Marcus
The original Mk1 doesn't handle Z-Lift particularly well due to backlash issues. It can be made to work to an extent, but not as well as the Mk2.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…