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AutoHome 0,0,0, location  

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peter.c
(@peter-c)
Active Member
AutoHome 0,0,0, location

I'm very new to 3D printing so I've searched around before posting this but couldn't find an answer.
I just purchased this printer March 2016 and it looks like it has the up to date Firmware 2.2.4
What is the correct position for Auto Home 0,0,0, the origin? Is it supposed to be on the glass?
Here is a video clip of what happens when I activate the Auto Home function.

The X and Y end stops seem work fine, I think, but the Z end stop seems too low to me.
The extruder head goes all the way down to the heat bed (missing the glass) and then backs off just a bit (I've learned it's normal for it to back off 0.23mm).
The heat bed is as low as it can go. The Z adjuster knobs are as high up the heat bed screws as they will go. I filed out the holes in the Y carriage so the screws go all the way in, and the Z adjuster knobs are resting on the carriage.
So where do I go from here?
I cannot lower the heat bed any more to get the extruder head above the glass.
Do I manually move the extruder head to the glass at each corner and use the "Calibrate Z" function and the card to level the bed as described here?
http://prusa3d.dozuki.com/Guide/Calibrate+i3+Plus+LCD-SD/4
I will have to raise the Z-axis up to get the extruder head over the glass, but then the Z-end stop will no longer engage, stopping the head from crushing the glass.
Should I raise the Z-end stop to accommodate the thickness of the glass?

Thanks

Pete

Postato : 07/04/2016 5:04 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: AutoHome 0,0,0, location

Hi Pete

I believe that the intention is to position the nozzle just on the edge of the glass sheet with regards to the X axis, which means moving the X end stop slightly to the right.

However, I do like to position the nozzle just off the glass and when printing starts, any ooze is cleaned off when the nozzle moves onto the glass.

With regards to the Z position; something is wrong here. There should be 2 to 3 mm adjustment available when the Z axis is homed. This is most likely an error in the build.

Can you post some photos of the extruder and from slightly under the heated bed - both from the side so we can have a look to see if there is anything obvious?

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…

Postato : 07/04/2016 5:14 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: AutoHome 0,0,0, location

Pete

With regards to calibration, there is a menu option "Calibrate Z" which homes the Z axis and turns off the motors, which sets the nozzle at 0.23mm (Z axis) and allows the movement of X and Y by hand to move the nozzle to each corner for calibration.

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…

Postato : 07/04/2016 5:16 pm
peter.c
(@peter-c)
Active Member
Topic starter answered:
Re: AutoHome 0,0,0, location

Pete

With regards to calibration, there is a menu option "Calibrate Z" which homes the Z axis and turns off the motors, which sets the nozzle at 0.23mm (Z axis) and allows the movement of X and Y by hand to move the nozzle to each corner for calibration.

Peter

Hi Peter,
Thank you for your quick response.
I will try the Calibrate Z when I can figure out the correct position.
I'm just worried that starting from the Auto Home position I get now, the extruder will smack right into the glass.
I will take some photos when I get home tonight, and then post them here, to see if I missed something in the construction.
What is a likely mistake I could have made? I'll double check it.
I will adjust the X end stop. I like your idea for wiping the nozzle clean. 😀

Pete

Postato : 07/04/2016 5:38 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: AutoHome 0,0,0, location

Pete

Looking at your video, the extruder seems to be OK, so I do think the issue is in the Y chassis. There are a few things to look at:

1. Ensure the glass is not sitting on the heater solder pads
2. Ensure the corner screws are able to move through the chassis hols properly (warning - do not drill out/enlarge the chassis holes)
3. Ensure bearings are fitted properly
4. Ensure the threaded chassis rods are seated as low as possible into the Z frame and that the nuts are tight.

It is possible to overcome this issue by simply raising the Z end stop holder, but there is then the possibility of that moving at some point in the future and then damage to the hot end.

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…

Postato : 07/04/2016 5:48 pm
peter.c
(@peter-c)
Active Member
Topic starter answered:
Re: AutoHome 0,0,0, location

Pete

Looking at your video, the extruder seems to be OK, so I do think the issue is in the Y chassis. There are a few things to look at:

1. Ensure the glass is not sitting on the heater solder pads
2. Ensure the corner screws are able to move through the chassis hols properly (warning - do not drill out/enlarge the chassis holes)
3. Ensure bearings are fitted properly
4. Ensure the threaded chassis rods are seated as low as possible into the Z frame and that the nuts are tight.

It is possible to overcome this issue by simply raising the Z end stop holder, but there is then the possibility of that moving at some point in the future and then damage to the hot end.

Peter

Hi Peter,
1. I checked the glass, it is not on the solder pads.
2. Corner screws are able to move through the holes. Why the Warning about drilling out the holes? I don't understand.
3. Bearings seem to be seated fine
4. The Y chassis rods? They could probably sit lower if I raised the frame. The Z frame sits on the bench surface along with the Y frame feet.

Here are some photos I took, hopefully they will help you figure out my issue




Postato : 08/04/2016 12:00 am
RCNet
(@rcnet)
Trusted Member
Re: AutoHome 0,0,0, location

Hi Pete,

It looks like your problem is related to item 4.

The Z axis frame should be up off the table. Fully seat the Y axis frame threaded rods as far as they will go in the slots of the Z axis frame before tightening the nuts. This should effectively raise your extruder above the print bed. You can then raise and level the bed with the corner screws to get the proper 0.23mm gap as normal.

For a reference, I have about an 8mm gap between the bottom of the Z axis frame and the table surface on my i3 with the anti vibration feet.

Roger

Postato : 08/04/2016 5:38 am
RCNet
(@rcnet)
Trusted Member
Re: AutoHome 0,0,0, location

Oh, also you don't want to drill out the corner screw holes because that could create sloppiness in the X and y directions which would affect the quality of your prints.

Postato : 08/04/2016 5:56 am
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: AutoHome 0,0,0, location

Pete

Just to add to Roger's last comment; some people have drilled out the holes as the screws were tight due to a small excess of paint during manufacture.

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…

Postato : 08/04/2016 9:54 am
peter.c
(@peter-c)
Active Member
Topic starter answered:
Re: AutoHome 0,0,0, location

Hi Pete,

It looks like your problem is related to item 4.

The Z axis frame should be up off the table. Fully seat the Y axis frame threaded rods as far as they will go in the slots of the Z axis frame before tightening the nuts. This should effectively raise your extruder above the print bed. You can then raise and level the bed with the corner screws to get the proper 0.23mm gap as normal.

For a reference, I have about an 8mm gap between the bottom of the Z axis frame and the table surface on my i3 with the anti vibration feet.

Roger

Looks like that solved the problem. I have plenty of space to level the bed now.
That should be interesting. 😕
Thank you all for your advice. I'm sure I'll be back with more questions.

-Pete

Postato : 08/04/2016 1:48 pm
peter.c
(@peter-c)
Active Member
Topic starter answered:
Re: AutoHome 0,0,0, location

Very first print. PLA, models from the included SD card.

And shortly after I started this

Spot anything I need to address?
I think they look pretty good.

-Pete

Postato : 09/04/2016 12:58 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: AutoHome 0,0,0, location

Hi Pete

That's great. Looking good. There are a couple of things which you will need to look at in future (filament calibration), but for now, just enjoy the printing.

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…

Postato : 09/04/2016 1:26 pm
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