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MK3 Prusa Bear Calibration issues  

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Rayzerd
(@rayzerd)
New Member
MK3 Prusa Bear Calibration issues

Hello,

I would like to first apologize to Prusa3d.com for not buying parts or printers from them in the first place. I am a fool not to. I didn't know and still don't know much about 3D printer parts. I started off 3D printing with an i3 3D printer kit from ElectronicGeek.ca in 2016. They went out of business and the auto bed leveling kept failing on the printer and the extruder kept on crashing into the bed. I weighed my options to convert my current 3D printer vs getting a new one. I should have went with the ladder.

 

I'm in Canada and wanted to purchase parts on Prusa3d's website but it was during the pandemic and parts were limited. Idiotically I purchased from Aliexpress.ca. I did not buy a 3d printer kit instead I purchased part by part. I liked the look of the bear frame. Now I feel like I wasting hundreds of dollars. The only part from my original 3d printer are the x and y axis stepper motors. I tried to reuse the z-axis rod by cutting them down with a Dremel but the rods were warped.

I did recently purchase the Einsy board and pinda from Prusa3D recently to see if it would address my calibration issue but it hadn't.

 

What's happening is that the on the self test it detects an error X-Axis Length. There are no wires in the way and I even removed the zip ties on the back of the extruder. The next issue is that when I skip the self-test and test Auto Home the extruder crashes into the print bed like my original printer. The Pinda is detecting with 1 and 0 but the z axis just keeps going down.

Please forgive me and if you can please help me. I don't know what to do and clearly don't know what I'm doing. I've been doing this project for a year on and off again and tried googling/youtubing. 

If someone from this community can assist me I would be extremely grateful.

This topic was modified 1 year ago 2 times by Rayzerd
Posted : 11/12/2022 6:21 am
Netpackrat
(@netpackrat)
Reputable Member
RE: MK3 Prusa Bear Calibration issues

The Bear frame is awesome but the ones on AliExpress don't go together the same way as the actual Bear design FWIW.  The differences can make it more difficult to get the frame squared up although I doubt if that's your problem.  It's going to be difficult to troubleshoot a printer built from a dog's lunch of parts remotely given the number of possible variables involved.  As an example there was a guy on the Bear Discord yesterday who built a bear from scratch and had similar calibration issues.  His problem turned out to be the wrong size pulley in the X idler but there are lots of other possibilities, anywhere from improper belt tension to an incompatible stepper.

One suggestion I have is to go though both the Bear assembly guide and the Prusa assembly guide line by line and see if you can spot something you missed.  I'd look up what the correct mechanical parts are supposed to be, Google up some specifications for those parts, and measure to make sure you have the right ones.  Make sure your belt tensions are correct.  The Bear assembly guide has a section on adjusting it using an app on your phone to measure the frequency of the tone generated when you pluck the belt.  There's also a tension gauge that gets recommended here a lot, but it has to be printed  so without a working printer it's not going to do you much good.

Another thing to be aware of, is do you have the Bear X axis and extruder, or do you have the standard Prusa?  Sounds like your calibration is failing before you get to that point, but the Bear extruder needs the Bear firmware and the Prusa extruder needs the Prusa firmware in order to pass Z cal.

 

Posted : 11/12/2022 2:51 pm
Rayzerd
(@rayzerd)
New Member
Topic starter answered:
RE: MK3 Prusa Bear Calibration issues

There's a discord? Thanks I'll jump in there too. I didn't even know there was 2 separate firmware. I'm guessing it's my x axis 3D printed parts and my steppers. I'll gather details and post them in the discord.

Posted : 11/12/2022 4:09 pm
Netpackrat
(@netpackrat)
Reputable Member
RE: MK3 Prusa Bear Calibration issues

Looks like they are getting you squared away.

Posted : 12/12/2022 2:00 am
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