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oftherocks
(@oftherocks)
Eminent Member
Should I cancel my conversion kit?

I have a conversion kit that will ship in the next few days. I have become increasingly concerned about both Prusa and the CoreONE over the last month. So my question is to those who have converted their printers to C1, do you have regrets?  Would you advise canceling a conversion kit at this time?

Posted : 09/07/2025 7:15 pm
SweetRide
(@sweetride)
Eminent Member
RE: Should I cancel my conversion kit?

I ordered the conversion kit day one. Months later I canceled when some of the VFA stuff started surfacing and coming to realize the timeline I was dealing with.

I suppose the FOMO wore off and I came to my senses.

Now, several months later, my enclosed MK4S chugs along just fine. 

Posted : 09/07/2025 7:48 pm
2 people liked
FoxRun3D
(@foxrun3d)
Illustrious Member
RE: Should I cancel my conversion kit?

Alas, the VFAs are very real. It's a fine machine for some small ASA objects I sell but for anything taller, the VFAs are brutal. I have both pre-assembled Core Ones and converted Mk4S. I will keep one Mk4S with an MMU because all the solutions I've seen for the Core Ones are hacks. 

Formerly known on this forum as @fuchsr -- https://foxrun3d.com/

Posted : 09/07/2025 10:50 pm
1 people liked
darkmattermaker
(@darkmattermaker)
Trusted Member
RE: Should I cancel my conversion kit?

I think you're the only person who can answer that question. I converted my MK4S and I'm quite happy with the machine. It's a brand new model so there's going to be growing pains associated with it. That's true for just about everything. I'm confident Prusa will provide an acceptable solution. If you're not willing to deal with potential issues then it might be better to just hold onto the MK4S for now. 

Posted : 09/07/2025 11:29 pm
4 people liked
RagingFury
(@ragingfury)
Eminent Member
RE: Should I cancel my conversion kit?

Unless 

Posted by: @oftherocks

I have a conversion kit that will ship in the next few days. I have become increasingly concerned about both Prusa and the CoreONE over the last month. So my question is to those who have converted their printers to C1, do you have regrets?  Would you advise canceling a conversion kit at this time?

unless you like putting your money on a long term deposit with a zero percent interest rate (as I have done with no relief in sight), I would keep your money and wait until they finally get their shipping under control.

Posted : 10/07/2025 1:14 pm
2 people liked
darksharpie
(@darksharpie)
Estimable Member
RE: Should I cancel my conversion kit?

Same.  Very happy with the converted machine (still have a MK4S for comparison) and impressed by the overall print quality. Certain materials and objects that print at certain angles I can see VFAs, but to me they're minor and don't overcome the overall results.  Like you, I expect they'll be solved eventually and it'll be an even better machine. 

Posted by: @darkmattermaker

I think you're the only person who can answer that question. I converted my MK4S and I'm quite happy with the machine. It's a brand new model so there's going to be growing pains associated with it. That's true for just about everything. I'm confident Prusa will provide an acceptable solution. If you're not willing to deal with potential issues then it might be better to just hold onto the MK4S for now. 

 

Posted : 10/07/2025 5:18 pm
1 people liked
nhand42
(@nhand42)
Estimable Member
RE: Should I cancel my conversion kit?
Posted by: @oftherocks

I have a conversion kit that will ship in the next few days. I have become increasingly concerned about both Prusa and the CoreONE over the last month. So my question is to those who have converted their printers to C1, do you have regrets?  Would you advise canceling a conversion kit at this time?

I just finished my conversion kit and I'm happy with the Core One - exceeds my expectations - and any lingering concerns I had about buying the conversion kit instead of the full kit have been put to rest.

My thoughts of getting the conversion kit was I wouldn't need both an MK4S and a Core One, and there's a decent cost saving for the conversion kit ($749) compared to the full kit ($1549). Financially it made more sense to buy the conversion kit than to sell the MK4S.

Prusa also did an outstanding job of reusing as much as they could. All the electronics, all the motors, the LCD, the PSU, the fans, the hotend, the Nextruder, the heated bed, the build plates, and about half the hardware (pulleys, bearings, rods, etc) got reused.

Timewise it added only 2 hours to my build time, so no complaints there either.

The only lingering doubt was whether I would miss the MK4S. And the answer is no. The Core One is superior in every way. It even takes up less bench space. No regrets would do the exact same again.

Posted : 13/07/2025 4:22 am
2 people liked
AvariCe
(@avarice)
Eminent Member
RE: Should I cancel my conversion kit?

I got the conversion kit, and for me it was the correct choice. 

If you like building/fixing stuff with your hands, then it is the correct choice.

I came across none of the problems that are reported here. The one issue I had was because I missed a step in the assembly guide and the gantry was wrong.

I loved the mk4s and will use the leftover stuff to build it again, but so far the mk4s inferior compared to the Core one. For now though only time will tell, because I haven't had the core one for a long period.

Posted : 14/07/2025 6:00 pm
2 people liked
JingleMePringles
(@jinglemepringles)
Eminent Member
RE:

I got the conversion kit and this was/is my very first 3d printer. If you have built PCs and such before or are used to building your own furniture (e.g. IKEA style), it's pretty straight forward. My goal was to build it myself so I can learn how it works and understand how to fix any [mechanical] problem that may arise. I was pretty satisfied with the kit!

The only thing I would warn you about is that the steel parts may come a bit rounded or slightly bent. Nothing too bad. Mine came like that, enough for some of the screw holes to be misaligned without me forcing it into place. I had to straighten then door handle for the door to shut completely which is very doable with pliers. It's primarily from tight packaging and Fedex handling all the way to the US from what I can tell. Oh, and maybe buy some additional M3 locking nuts with the nylon inserts--a handful of people (me included) were about 3 short.

If you decide to go the kit route, I would suggest ditching the adhesive as shown in the instructions and using two M3x8mm screws and two locking nuts to screw it onto the acrylic panel. I and quite a few others in the instruction comments found that the adhesive was so thick it actually prevented proper alignment of the handle to the panel.

This post was modified 2 months ago by JingleMePringles
Posted : 14/07/2025 8:12 pm
2 people liked
JingleMePringles
(@jinglemepringles)
Eminent Member
RE: Should I cancel my conversion kit?

I am not sure why I said conversion kit... I got the assembly kit. Sorry about any confusion.

Posted by: @jinglemepringles

I got the conversion kit...

 

Posted : 17/07/2025 7:29 pm
1 people liked
Artur5
(@artur5)
Honorable Member
RE: Should I cancel my conversion kit?

In all likelihood, I'm gonna be bashed by Prusa's die hard fans but IMHO I'd cancel the order right away. Look at the Core One forum, it's nothing else than an online replica of Jerusalem's Wailing Wall. 

Posted : 18/07/2025 6:03 pm
2 people liked
FoxRun3D
(@foxrun3d)
Illustrious Member
RE: Should I cancel my conversion kit?

else than an online replica of Jerusalem's Wailing Wall. 

Loving it!

Yeah, there are a lot of issues, and I see my fair share of them on my own Core One's (VFAs galore, random layer shifts, excessive homing....). My (naive?) hope is, history will follow the example of the XL. I got one of the earliest XL's, and it was nothing but misery. But truth be told, today it's arguably the most reliable (and fun) printer in my collection. Between some hardware improvements (I was able to retrofit) and many, many firmware improvements, my sentiments shifted from "why did I spent the money on this POS" to "love you, big fella". But at this time, the Core One is...rough

Formerly known on this forum as @fuchsr -- https://foxrun3d.com/

Posted : 18/07/2025 6:23 pm
2 people liked
zapta
(@zapta)
Estimable Member
RE: Should I cancel my conversion kit?

 

Posted by: @oftherocks

I have a conversion kit that will ship in the next few days. I have become increasingly concerned about both Prusa and the CoreONE over the last month. So my question is to those who have converted their printers to C1, do you have regrets?  Would you advise canceling a conversion kit at this time?

I just built a kit and am having server X/Y homing and other users reported here similar issues. The print head bangs the X/Y limit hundreds of times in some situations. This is still a pending issue, demonstrated in this video (not mine)

Prusa released the CORE One prematurely and is slow providing fixes.

Posted : 27/07/2025 6:05 pm
iftibashir
(@iftibashir)
Noble Member
RE: Should I cancel my conversion kit?

Only you can answer that question, but I went from the MK4s (which I sold) to the Core One and I have been quite happy with the move. I'm just a hobbyist, so do not sell prints etc, but for my odd use here and there its been great so far. Prusa will continue to refine and update firmware etc, as they do with all printers, so I expect teething issues to be ironed out - I do wish they would work on better communication however, although that's been outstanding for years without resolves, so most likely wishful thinking. Otherwise, the system itself is really good IMO. 

@zapta - I also had that head banging issue, but I've noticed since updating to the most recent firmware it seems to have resolved the issue for me. Just 2 calibration 'bangs' and it's done - pretty consistently now.....

Saying that, I have grown a little frustrated at the MMU solution. The MMU3 system seems like a bit of a tacked on afterthought for the Core One, and I grew impatient waiting for their next gen solution (which I feel should have been in development alongside the Core One itself), so I have just taken delivery of a competing model for multicolour prints, although will keep my Core One too!

Click here for VIDEO BUILD GUIDES + 3D Printing Tips!

--> Core One - MK4 - MK4S - MINI+ - MMU3 - Accelerometer Guide <--

Posted : 28/07/2025 10:53 am
1 people liked
Jürgen
(@jurgen-7)
Noble Member
RE: Should I cancel my conversion kit?
Posted by: @iftibashir

Just 2 calibration 'bangs' and it's done - pretty consistently now.....

Are you sure about the "just 2 bangs"? I have never seen less than "right, right, front, front -- right, front, right, front, right, front, right, front", neither on my own Core One nor in any videos. 

Posted : 28/07/2025 12:13 pm
iftibashir
(@iftibashir)
Noble Member
RE: Should I cancel my conversion kit?

Sorry I was referring two two sets of bangs, but yeh I think its a bit more like how you suggested below, but I'll keep count next time I print (currently playing with a different printer so devoting time to that 'new toy'!).

I just felt it strange how as soon as I applied the new firmware it just kinda fixed itself - I haven't bothered pretensioning belts etc at all and it's nothing thats even noted in the firmware release notes....

Posted by: @jurgen-7
Posted by: @iftibashir

Just 2 calibration 'bangs' and it's done - pretty consistently now.....

Are you sure about the "just 2 bangs"? I have never seen less than "right, right, front, front -- right, front, right, front, right, front, right, front", neither on my own Core One nor in any videos. 

 

Click here for VIDEO BUILD GUIDES + 3D Printing Tips!

--> Core One - MK4 - MK4S - MINI+ - MMU3 - Accelerometer Guide <--

Posted : 28/07/2025 1:46 pm
zapta
(@zapta)
Estimable Member
RE:

 

Posted by: @jurgen-7
Posted by: @iftibashir

Just 2 calibration 'bangs' and it's done - pretty consistently now.....

Are you sure about the "just 2 bangs"? I have never seen less than "right, right, front, front -- right, front, right, front, right, front, right, front", neither on my own Core One nor in any videos. 

Same here, the minimum I could get from a single X/Y homing is 12 head bangs, the maximum is 286. On my last non Prusa  sensorless printer I always got exactly 2.

Video (not mine): https://www.youtube.com/shorts/HtYJ19jUuC8

Prusa could fix it with a single line change in the firmware. The culprit is a faulty algorithm that they added to the Marlin firmware to 'refine' the X/Y homing that they insist on keeping. 

https://github.com/prusa3d/Prusa-Firmware-Buddy/blob/818d812f954802903ea0ff39bf44376fb0b35dd2/lib/Marlin/Marlin/src/module/prusa/homing_corexy.cpp#L820

EDIT: Another reason for this flaky behavior is cost cutting by Prusa of not having proper X/Y limit sensors. Homing by stall detection has limited accuracy because it provides resolution of a full stepper step, ignoring the micro-steps fraction (aka 'phase'). 

 

This post was modified 2 months ago by zapta
Posted : 28/07/2025 5:04 pm
Jürgen
(@jurgen-7)
Noble Member
RE: Should I cancel my conversion kit?
Posted by: @zapta

Another reason for this flaky behavior is cost cutting by Prusa of not having proper X/Y limit sensors. Homing by stall detection has limited accuracy because it provides resolution of a full stepper step, ignoring the micro-steps fraction (aka 'phase').  

In principle I like the Stallguard sensing approach instead of a dedicated limit switch. It is always perfectly aligned with the physical end stop, does not break or drift out of alignment, and can be quite accurate.

I am not sure why  Prusa is struggling with accurate homing in the Core One. It might be a combination of the long, slightly flexible belts and the dual mechanical end stops (left & right), both of which can smear out the stall pulse?

I am wondering whether Prusa might be better off if the left and right end stops were deliberately displaced against each other by design. I.e. make one end stop block a bit longer, such that it is always the one which stops the travel. That would ensure that there is always just a single "stall event", rather than two of them which might coincide if the gantry is perfectly squares, but will cause a double step in motor current otherwise. It would probably be a softer ramp, but should have a reproducible shape independent of finicky gantry squaring.  

Posted : 28/07/2025 6:08 pm
zapta
(@zapta)
Estimable Member
RE:

 

Posted by: @jurgen-7

I am not sure why  Prusa is struggling with accurate homing in the Core One.

Assuming the hardware is given and can't be changed, the culprit is the over engineering and complexity of the firmware, as in "perfect is the enemy of good".  A single bang on X and a single bang on Y would improve the overall user satisfaction with this product.

 

 

Posted : 28/07/2025 10:46 pm
Jürgen
(@jurgen-7)
Noble Member
RE: Should I cancel my conversion kit?
Posted by: @zapta

 Assuming the hardware is given and can't be changed, the culprit is the over engineering and complexity of the firmware, as in "perfect is the enemy of good".  A single bang on X and a single bang on Y would improve the overall user satisfaction with this product.

As a workaround, I agree. As discussed months ago, it seems that the "precise homing" is only required to enable an accurate resume after power loss -- which most users do not care about. 

For some users, who live in regions with an unstable power grid and often  run large prints, the "power panic" cabability might be important. So I see where Prusa are coming from. But indeed, if they can't achieve a smoother implementation than what we currently get, they should offer an option to disable "precise homing", or even disable it by default.

Posted : 29/07/2025 5:26 am
2 people liked
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