Beginner help - home offset

MandalorynOranj

Hey guys, just got my JGAurora Magic set up and I seem to have a home offset of X -16 mm that I can't change, leaving the home position hanging off the edge of the build plate. I can't quite figure out what's going on in the menu of this thing, can anyone help out please?

MrKrafty

picture would be good.  the home position will have the nozzle head below the print surface and mine shows a -16 value as well.  it will retract before it prints.  it makes it harder to level the plate because you cannot level the print surface from the "auto home" position". 

Samuel Pinches

Welcome @MandalorynOranj and @MrKrafty

I understand that this is correct, but what is the issue? The nozzle should move onto the bed area correctly for x = 0.

You can disable steppers in the menu to help free the head for levelling.

MandalorynOranj

Thanks guys. I had just been nervous that it would spit filament right on the table and hadn't tried a print.

However, when I did (the print pre-loaded on the SD card), I got a strange issue. It would deposit one small line of filament (using the filament that was included with the printer for this) and then pull up the extruder, eject the filament, and have me reload the filament. I humored it a couple of times to see if it would fix itself but it did not and continued doing this. Anyone ever see this before?

Video here: https://drive.google.com/file/d/1MdpCSbfNef9BCx3Xj_4kyG3k2ER-Hwv-/view?usp=sharing

Samuel Pinches

Are you using Cura 4.1? Make sure you set the Max Z speed, it's a nasty bug. Otherwise, can you please upload your gcode file here and we'll check it?

MandalorynOranj

I'm just using what was preloaded on the included SD card. I haven't edited or touched that at all.

Samuel Pinches

Can you please upload that file here? It could be corrupted or something else strange. Try copy it all off the SD card, format the SD card (FAT32) and then try again - or even try another memory card.

MandalorynOranj

Here it is

Samuel Pinches

Looks all fine there! I suggest formatting the SD card, or trying another.

Samuel Pinches

When you do, please just copy that file back, nothing else.

MandalorynOranj

I figured out what it was... I hadn't watched the video on the SD card before starting and I didn't realize which piece was actually the filament detector. I had the filament feed mounted the wrong way and the filament wasn't passing through the detector. Thanks for bearing with my dumb self!

Samuel Pinches

Ah... doh! Glad you got it sorted!

MandalorynOranj

Is there a way to change the home Z offset? I bought a glass bad to replace the plastic one so I could use acetone to clean it and it's 2mm thicker than the bed that came with it, which is more than I can retract the base using the level screws. The new bed doesn't fit under the nozzle as is, but there has to be a way around this, right?

Samuel Pinches

You can raise up the z endstop switch, which is mounted near the z axis motor.

MandalorynOranj

Ah cool, thanks. Now to figure out why my print isn't sticking. Might not have re-levelled it as well as I thought, or I've seen some suggestions of using hairspray on the glass.

MandalorynOranj

After messing around a little more, it seems like it starts extruding while the build head is moving to the start position. This leads to a few strands that don't stick while subsequent ones do, but then the head is pushing around this loose strand of filament all through the rest of the build.

Spark

What is your gcode start? 
Mine is:

G28 ; Home all axis

G1 Z15.0 F6000 ; Move up 15mm at 6000mm/min (note: more than the max speed set in the printer firmware)

G92 E0 ; Reset extruder length to zero

G1 X0.0 Y0.0 F1000.0 ; go to edge of print area

G1 Z0.200 F1000.0 ; Go to Start Z position

G1 X60.0 E9.0 F1000.0 ; intro line

G1 X100.0 E21.5 F1000.0 ; intro line

G92 E0.0 ; reset extruder distance position

MandalorynOranj

M190 S60.000000

M109 S200.000000

;Sliced at: Tue 06-08-2019 21:42:50

;Basic settings: Layer height: 0.1 Walls: 1.2 Fill: 20

;Print time: 3 hours 40 minutes

;Filament used: 6.609m 19.0g

;Filament cost: None

;M190 S60 ;Uncomment to add your own bed temperature line

;M109 S200 ;Uncomment to add your own temperature line

G21        ;metric values

G90        ;absolute positioning

M82        ;set extruder to absolute mode

M107       ;start with the fan off

G28 X0 Y0  ;move X/Y to min endstops

G28 Z0     ;move Z to min endstops

G1 Z15.0 F9000 ;move the platform down 15mm

G92 E0                  ;zero the extruded length

G1 F200 E3              ;extrude 3mm of feed stock

G92 E0                  ;zero the extruded length again

G1 F9000

;Put printing message on LCD screen

M117 Printing...

;Layer count: 30

;LAYER:0

M107

G0 F9000 X74.776 Y58.016 Z0.300

G0 X74.482 Y58.406

;TYPE:SKIRT

G1 F1200 X74.776 Y58.016 E0.02437

Brushie

I managed to mess up the z axis home.  I accidentally raised the z axis higher than the max and now the z axis homes about 2 - 3 mm below the build bed.  Is there some way to reset the z axis home preferably using the menu items on the touch screen (I have the latest Marlin firmware installed)?  If not, is there a setting I can change in the firmware?  I'd prefer not to have to change the hardware.

Samuel Pinches

The z should stop when the z axis endstop is triggered?? Maybe your z endstop has slipped? You'll have to explain a bit more about your setup. Are you using mesh bed leveling etc.

Brushie

The problem was with the z axis endstop switch.  I was able to resolve the problem and re-leveled the bed.  It is now working properly.  Thanks.