Mini 2 questions

A forum dedicated to the stock LulzBot Mini 3D Printer
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Traiger
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Joined: Thu Jun 23, 2016 8:51 am

Mini 2 questions

Post by Traiger » Tue Jan 08, 2019 11:59 am

We just got two Mini 2's and I'm testing them out before unleashing them to the public and I have a few questions. The Minis will be replacing a couple of Taz 5's, so I have experience with replacing parts and working on somethings but the Mini is quite a bit different.

Homing: When homing one of the Minis it fails while homing X. The toolhead will travel to the left and shudder a bit and sometimes home successfully and sometimes fail. I didn't realize there wasn't an endstop so I assume it's done in the firmware. Is there a way to adjust how X homes? I can get it to home successfully if I help push it a bit while it's struggling to home X.

Modular bed: We only print in PLA but parts are sticking too well to the PEI bed. Does the modular bed PEI require some preparation to allow prints to release easier? I've never had to use glue stick on our Taz 5's PEI bed but I'm willing to try if it will allow prints to release easier.

Replacement parts/improvements: Are there any parts I should print out now for backups? Any parts that I should keep on hand when they fail? -I'm debating just buying a toolhead to keep for emergencies. The Mini 2 is pretty new but are there any improvements I could make to make printing easier/faster? We had a .8 ruby tip nozzle on the Taz 5 I wanted to use and then remembered ruby won't conduct electricity...

Thanks for any feedback you might have!

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Orias
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Re: Mini 2 questions

Post by Orias » Wed Jan 09, 2019 1:54 pm

Traiger wrote:
Tue Jan 08, 2019 11:59 am

Homing: When homing one of the Minis it fails while homing X. The toolhead will travel to the left and shudder a bit and sometimes home successfully and sometimes fail. I didn't realize there wasn't an endstop so I assume it's done in the firmware. Is there a way to adjust how X homes? I can get it to home successfully if I help push it a bit while it's struggling to home X.
Reach out to the support team with a video if you can. They'll be able to help make sure it's homing smoothly.
Traiger wrote:
Tue Jan 08, 2019 11:59 am
Modular bed: We only print in PLA but parts are sticking too well to the PEI bed. Does the modular bed PEI require some preparation to allow prints to release easier? I've never had to use glue stick on our Taz 5's PEI bed but I'm willing to try if it will allow prints to release easier.
Use this tutorial to adjust your Z-axis offset. If you reduce the offset just a bit, the nozzle will start printing a little higher off the bed, lessening your printed part adhesion: https://ohai.lulzbot.com/project/z-axis ... zBot-Mini/
Traiger wrote:
Tue Jan 08, 2019 11:59 am
Replacement parts/improvements: Are there any parts I should print out now for backups? Any parts that I should keep on hand when they fail? -I'm debating just buying a toolhead to keep for emergencies. The Mini 2 is pretty new but are there any improvements I could make to make printing easier/faster? We had a .8 ruby tip nozzle on the Taz 5 I wanted to use and then remembered ruby won't conduct electricity...

Thanks for any feedback you might have!
Look into the new tool heads that are compatible with your Mini 2: https://www.lulzbot.com/store/tool-heads?combine=|

Happy printing!

Traiger
Posts: 6
Joined: Thu Jun 23, 2016 8:51 am

Re: Mini 2 questions

Post by Traiger » Wed Jan 09, 2019 3:24 pm

I reached out to the support team about the X-axis issue and they recommended trying "X-axis leveling". I'll try it once the machine is done printing. It still doesn't answer my question though on how the X-axis homes and if there is a way to adjust it.

On adjusting the Z offset you're saying reducing from the 1.04 or whatever to 1.02 would increase the distance of the nozzle from the bed? Seems counterintuitive, wouldn't you increase the offset to have the nozzle higher?

I know I could spend $300-750 on a new toolhead but that's not in my budget at the moment, unfortunately :( . Is swapping in a .8mm E3D brass nozzle not an option for higher speed printing? I assume it would void the warranty for the hotend?

Thanks!

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Orias
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Re: Mini 2 questions

Post by Orias » Thu Jan 10, 2019 10:24 am

Here's an image of the bump stop that's used to gently stop that axis from moving any further during the X-axis homing process. Once the tool head hits that bump stop, the motor current changes. Once the Einsy RAMBo sees that it knows it stops moving and establishes that point as X0.

The flexible bumper is located here on the left hand side of the X-axis:
Mini2_RightFace_FullRes_WhiteBG.png
1480493.jpeg
As for Z-axis offsets, the top of the metal bed probing disks establishes a 0 point, so the Z-offset's negative. The bigger the negative value, say -2.00, the deeper it goes past the top of the bed probing disks towards the print surface. Your Z-axis offset can be adjusted on the fly during the first layer, and the graphic should show how you're moving that axis up and down.

Due to the specific torque required to ensure a trouble-free seal between the nozzle and the rest of the hot end, any nozzle changes are not covered if issues arise. Reach out to the support team for specifics on what would & would not be covered.

A larger nozzle diameter will certainly speed up the printing process, ideally it's pared with a larger heater block with a greater thermal mass to further support the speeds you can achieve with larger nozzles.
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1480493.jpeg

Traiger
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Re: Mini 2 questions

Post by Traiger » Mon Jan 14, 2019 2:38 pm

Thanks for the clarification on the offset. I adjusted it slightly and now parts release a bit easier.

After x-axis leveling and re-homing several times the printer did shudder less and less when homing x. I wish I understood better how the x-axis is homing so I could troubleshoot it but I'm happy it has worked itself out.

Thanks for all the help!

Brent.I
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Re: Mini 2 questions

Post by Brent.I » Mon Jan 14, 2019 3:02 pm

Traiger wrote:
Mon Jan 14, 2019 2:38 pm
I wish I understood better how the x-axis is homing so I could troubleshoot it but I'm happy it has worked itself out.
The Mini 2 uses Trinamic 2130 drivers on the Einsy Retro electronics board. These drivers are "smart" and can sense how much current is being sent to them in order to move the print head. Once the current gets above a set level, it will trigger an endstop essentially. (This occurs when moving the tool head, and it hits and object like your rubber bumper.) This rubber bumper is meant to prevent ABS on ABS contact, giving the sound of a "smoother" X axis home.

But adjusting out your endstop further out, you are preventing the ABS on ABS contact which will make a louder homing sounds.

Traiger
Posts: 6
Joined: Thu Jun 23, 2016 8:51 am

Re: Mini 2 questions

Post by Traiger » Mon Jan 14, 2019 6:53 pm

Brent.I wrote:
Mon Jan 14, 2019 3:02 pm
Traiger wrote:
Mon Jan 14, 2019 2:38 pm
I wish I understood better how the x-axis is homing so I could troubleshoot it but I'm happy it has worked itself out.
The Mini 2 uses Trinamic 2130 drivers on the Einsy Retro electronics board. These drivers are "smart" and can sense how much current is being sent to them in order to move the print head. Once the current gets above a set level, it will trigger an endstop essentially.
I found in Marlin where you can adjust the endstop sensitivity. http://marlinfw.org/docs/gcode/M914.htm
I hope I don't ever have to do it but I feel better knowing I can. ;)

Brent.I
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Re: Mini 2 questions

Post by Brent.I » Tue Jan 15, 2019 9:42 am

Traiger wrote:
Mon Jan 14, 2019 6:53 pm
I feel better knowing I can. ;)
Open source, for the win!

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