Set z=0 at a different point (printing on top of something else)

[cecilievf 0]

Hi everyone!

I have both a Ultimaker Original and a Ultimaker 2 available and I'd like to be able to set the z=0 at any point I want as I'm trying to print on top of an object lying on the printing bed (build plate). I'm pretty sure this can be done by editing the gcode in Cura but I can't seem to make it work.

If anyone has any advice or pointers for me to try I'll be very grateful.

Thank you.

 

[Titus 170]

Quick and dirty: You can press your endstop early, and finetune by turning the Z spindle by hand.

Slow and semi dirty: edit your Gcode so that every Z value is your desired height higher.

Perhaps possible and quite ok: pause print at the start, tune Z height and resume print(I believe this requires some different firmware, like the one with the babysteps)

Just three options that popped into my head

 

[cecilievf 0]

Thank you for your response.

Your first solution: Is that while leveling the build plate? I tried doing that and got it level to where I wanted it but then when I wanted to print it just ignored it and tried to go all the way up to its usual zero. This was on the Ultimaker 2. I haven't tried it yet on the Ultimaker Original.

How do I avoid my plate slamming into the nozzle when it starts printing?

 

[MartijnvG 16]

if you know the exact hight of the plate you can write some start code that will firstly move the head down then set that hight as the home position and then everything else will start from there. you can move the z-stage by using G1 Zxx.x and then using G92 Z0.0 to set that as zero.

please do keep your finger near the off switch. my G-code is a little rusty

you can check here: http://reprap.org/wiki/G-code

 

[cecilievf 0]

;Sliced at: {day} {date} {time}

;Basic settings: Layer height: {layer_height} Walls: {wall_thickness} Fill: {fill_density}

;Print time: {print_time}

;Filament used: {filament_amount}m {filament_weight}g

;Filament cost: {filament_cost}

;M190 S{print_bed_temperature} ;Uncomment to add your own bed temperature line

;M109 S{print_temperature} ;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 Z16

G92 Z0

 

G1 Z15.0 F{travel_speed} ;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 F{travel_speed}

M117 Printing... ;Put printing message on LCD screen

 

 

I had this as my start gcode because I wanted the platform 16 mm lower, but the printer started printing something like 8 cm above the platform.

Confuses me a lot..

 

[MartijnvG 16]

so i had a talk with David. it seems that in the Ultimaker 2 there is a bug that overrules G92, he thought he fixed it but that only seemed to be the case in the Ultimaker Original firmware.

so i'll ask him to fix it in the next firmware release for the UM2

 

[cecilievf 0]

So if i try the gcode I sent you on my Ultimaker Original i should be okay?

 

[MartijnvG 16]

it should be fine. according to david. Give me a heads up if it doesn't work. i'll try to get him to look at it.

 

[gr5 2,173]

I've used G92 for many things. Maybe I never did G92 on the UM2, but that's hard to believe. Possible though.

Anyway Martijn's solution is the better solution. You can play with it using pronterface, or just the Cura pronterface interface and send the commands manually.

For example:

G0 Z10

moves to 10mm off the bed

G92 Z0

Tells Marlin that this is the new Z=0

G0 Z1

Should go 1mm higher

G0 Z0

Should go back to the new z=0 location (10mm up).

G0 X100 Y100 Z0

Should go to center of platform at the new z=0 spot.

 

[gr5 2,173]

I know for sure I've used G92 E99 to set the extruder to think it is now at 99mm. I know for sure I've done this on the UM2.

 

[cecilievf 0]

I can't make it work on the Ultimaker 2 but it works just fine on the Original.

Thank you guys for all the help!

 

[Daid 306]

Which version of the UM2 firmware are you using?