Move to Start print in XYZ simultaniously

[ant0ny]

I tried to search for this but because I couldn't come up with a proper term for what I am after I come up with nothing. So forgive me if this already done and please point me to where I can find the info.

I have a few machines that I use and I always push the prints to the edges... doing this ends in tears when I hit the clamps. I always got around this my removing the clamp after auto level and putting it back once the print is on it's way.

I built a machine for a friend but he likes Cura... sigh... anyway after battling with it I discovered the LulzBot version has Z offset in the machine settings. yes a win!

Now while I was getting his machine setup with a Cura profile I noticed another thing... thus the title... when I hit Print the print head "descends like a beautiful angle till it kisses the bed" and prints away... I actually stopped the print and started it again as I thought I was dreaming.

How! or better... how can I make S3D do this?

Now forgive my lack of knowledge and "off the shelf" 3D printers probably do this... I have never used anything other than the 6 or 7 I have built myself.

Antony

[kabali16]

I am guessing the diff is probably in the starting script. Post both the scripts here and if possible a video that shows what it is currently doing. Skipping the binder clip is very easy to do. After Home all, you can raise the Z to a certain height skip ahead and then let it start the print.

[ant0ny]

The start script is not doing it, it will be something the LulzBot people worked into Cura to miss their huge washer clamps I think. I had already modded their script to get the print to print in the middle of the bed.

G21 ; metric values
G28 ; Home all axes
G29 ; bed level
G1 Z25.0 ; move nozzle to Z 25mm
G1 X35 Y0 ; move to print origin
G92 X0 Y0 Z25.0 ; set this coordinate to 0,0,25
G92 E0 ; zero the extruded length
G1 E10 F600 ; prime extruder 10mm
G92 E0 ; zero the extruded length again
G4 S10 ; wait give th nozzle a quick clean
M117 Printing...

For a while I was trying to just get the Z to move first but gave up I just use this sort of script and it starts just inside the clips at 0,0 so yeah, all good.

I was just interested in how they did it because it would stop 99% of issues people have when first setting up they printers and sorting start code etc to know that if the nozzle was going to descend in the 3 axis simultaneously it wouldn't matter if the bed was not physically in the right position.

[the_arrest]

If you download a program like Notepad++ you can read/edit the g-code file created by Cura and see the commands that are different from the S3D generated ones. I've used Cura for a while and I love the smooth glide through the XYZ to the start position. I've just got onto S3D finally and that was one of the first things I wanted to address. I got notepad++ and had a squiz. Here's what I found -

(I'm using a Creatbot DH+ that uses RepRap/Marlin)

The Cura line for the initial movement to the start position looks like this in an old gcode file I used to compare:
G0 F4200 X106.181 Y106.825 Z0.200
(with the X/Y obviously being dependent on the position on the bed in Cura)

The S3D movement is written as two separate movements that look like this:
G92 E0
G1 Z0.200 F3000
; layer 1, Z = 0.2
T1
; tool H0.200 W0.400
; skirt
G1 X68.938 Y64.912 F4200
G1 E0.0000 F540
G92 E0

So what you'll need to do is edit the g-code after it's been written by S3D.

Here's what I've done.

I've modded the startup script from the Cura based Creatware that primed the extruder to look like this:

G28 ; home all axes

G92 E0 ; zero the extruded length

G1 Z15.0 F2000 ; move the platform down 15mm

G1 F200 E20 ; extrude 20mm of feed stock

M117 Printing... ; display 'Printing...' on LCD screen


What follows is stock from S3D:

G92 E0
G1 E-6.0000 F1800
G1 Z0.200 F3000
; layer 1, Z = 0.2
T1
; tool H0.200 W0.400
; skirt
G1 X46.480 Y56.414 F4200
G1 E0.0000 F540
G92 E0


Which I edited to look like this:

G92 E0
G1 X46.480 Y56.414 Z0.200 E5 F4200
; layer 1, Z = 0.2
T1
; tool H0.200 W0.400
; skirt
G92 E0

I've combined the two movements and added an extrusion en route to the start of the print.

I got rid of the G1 E-6.0000 F1800 line which was retracting the filament just before starting the print, which meant that the skirt only kicked in on about the third lap (the E value was equal to the retraction amount set in the Extruder tab).

I also nuked the G1 E0.0000 F540 line as is was doing nothing beneficial as far as I could see.

Just open the file, make the changes then save. You'll be gliding into a glorious landing at the start point from then on.


I'm sure there's a bit of tweaking and refinement that can be done in different situations, and I'm definitely an amateur when it comes to g-code (this is actually my first crack at custom script) so there's room to experiment. I'll update you if I stumble across any other settings that'll help.

Hope that gets you started though mate.

[ant0ny]

wow thanks, I was trying to do exactly that today but ended up side tracked.

That is great that it is easy but most likely never do it unless the need is there to avoid a real life situation. For me I just print so much stuff time is not worth it but and again "for me" if this was to be implemented into S3D, it would be a bit of a nice little insurance that a user setting up a custom system is less likely to hit a clamp in the early sorting out sessions.

The second thing about the starting retract is also a thing that has bugged me from time to time and would also be a great feature if it could be turned on or off. I sometimes have to print right to the edge of the plate and forgo the skirt. This means I loose a little of my first perimeter and it annoys me.

I understand the idea that you are less likely to get a blob but not everyone has an old crappy leaky setup anymore... I think most systems, hotends and filament control is pretty good against this but hey if you have a 1.2mm nozzle with a volcano then hey it's probably needed so again as option it would be nice.

Now not knowing how hard it is to change these things in code... a idea for compromise might be to have a choice of a skirt or just a straight line on an edge like the makerbots have. This way at least the extruder is well primed and I have a chance to abort if the nozzle is to high or low or there is previous colour mixing.

Again thanks I'm going to do your little exercise on my next print to see it work.