Startup Script for Lulzbot Taz5

[Mikes]

Hi all,

I'm learning a lot about 3d printers having just gotten my first one: a Taz 5.

I was using Cura initially, but after reading the reviews for Simplify3d I figured I would make the purchase early on so I could use it throughout the learning process instead of switching down the road.

I'm very happy with Simplify 3d, but Cura did one thing that Simplify3d is not. When you started a print with a Cura G-Code the Extruder went to the corner of the bed, lowered and extruded a little, picked up off the bed, lowered again, and then started the printing process. I never had a problem with extra filament being dragged into the print.

Simplify3d goes to the corner of the bed, lowers, and then goes to print. It drags some oozed out filament into the print causing all kinds of trouble. My searches indicate I need to create a startup script.

I looked at my Cura Gcode and it has:

Code: Select all

;Sliced at: Wed 30-12-2015 21:09:05
;Basic settings: Layer height: 0.1 Walls: 1 Fill: 20
;Print time: 1 hour 6 minutes
;Filament used: 1.128m 3.0g
;Filament cost: None
;M190 S0 ;Uncomment to add your own bed temperature line
;M109 S0 ;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 F10500;move the platform down 15mm
G92 E0                  ; zero the extruded length
G1 F200 E0              ; extrude 3mm of feed stock
G92 E0                  ; zero the extruded length again
G1 F10500      ; set travel speed
M203 X192 Y208 Z3       ; speed limits
M117 Printing...        ; send message to LCD

Simplify3d currently only has:

Code: Select all

G28 ; home all axes

There is a lot of stuff going on in the Cura startup script and I am tempted to just copy paste it into the startup script area of Simplify 3d, but I am afraid I might add something to it that will mess Simplify3d up. I'm not really sure what absolute positioning would do and it seems those speed limits would slow me down. Also if I start with the fan off, will it still come on later?

I'm guessing I would modify it into:

Code: Select all

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 F10500;move the platform down 15mm
G92 E0                  ; zero the extruded length
G1 F200 E0              ; extrude 3mm of feed stock
G92 E0                  ; zero the extruded length again

Does that seem correct?

Thank you for taking a look!

-Mike

[CompoundCarl]

You're close! I would use the following:

Code: Select all

G28 X0 Y0 ; home XY
G28 Z0 ; home Z
G1 Z15 F10500 ; lower the bed
G92 E0
G1 E3 F200 ; extrude 3mm of filament

Note: it looked like the extrusion command at the end was wrong, but I think what I posted will work. A lot of those other commands are already taken care of by the software.

[Mikes]

Thank you, CompoundCarl! I started a print this morning using your startup script and it worked great!

Thanks again.

-Mike

[CompoundCarl]

Great, happy to help!

[Mikes]

Well, I thought we had it! I had a couple of sucessful prints, but now I'm back to having issues.

I think what happened was conditions were right and it just so happened that no excess filament was extruded prior to the print starting and the nozzle was clean at the start. When the nozzle is clean at the beginning I get great prints.

Most of the time though, it seems instead of the excess filament sticking to the bed, it sticks to the head and gets dragged into the print area. It also prevents the very beginning of the print from sticking to the bed as the head is blocked temporarily with this "junk" filament. After it gets pulled off by the strings it seems to print with no issue.

Here is a video of what happens. I really think if I can get it to consistantly not have junk on the nozzle at the beginning of the print I'll be good. I do not believe this is a bed leveling or heat issue as if I baby sit the printer at the beginning and manually remove the filament just prior to it reaching the bed it prints perfectly.

Here is a video of my printer when the junk gets stuck:

https://youtu.be/CrczC0ZpTO0

Do you think there's some way we could modify the startup script to prevent this? I tried taking out the very last line "G1 E3 F200 ; extrude 3mm of filament" to see if having less filament would work and that is what you'll see in the video.

I think the difference between Cura and Simplify3d here is that Cura would raise the head and then do X & Y movements to get over to the print area after doing this procedure and then lower the Z axis. Simplify 3d lowers the Z axis back down into the "junk" first and then moves X & Y over to the print area.

Thanks for any help!

-Mike

[dkightley]

What I see in the video is the nozzle squirting some filament ON the corner of the bed, lifting and dropping back INTO the squidged plastic...and then dragging it across the bed to start printing.

My start up script (the S3D default script) moves the nozzle to just off the bed at printing height, squirts filament tp prime the nozzle, then wipes the nozzle onto the bed, scraping the extruded plastic off...then runs across to start printing. You get a tiny bit of oozing, but that wipes off before the nozzle reaches the starting point.

[Mikes]

Thanks, Doug!

Your description is exactly what is happening.

Do you have a Taz 5? The defualt script for mine just planted the nozzle in the home position and then went straight to printing which is what made me start tinkering with the script to begin with.

Could you post your startup script so I can try to adapt it to my printer, please?

Thank you!

-Mike

[CompoundCarl]

At this point, you might want to learn some basic gcode. These are extremely easy changes that you are asking for. Just go learn how to write a simple G1 command and then you can easily make the changes yourself. I recommend this guide: http://reprap.org/wiki/G-code#G0_.26_G1:_Move

[Mikes]

Awesome resource. Thank you, I will give it a shot. One quick question - as I understand 0 is the home point, will my printer allow me to go negative on the X axis do you think? It has a end stop switch - would that prevent me from going past home?

Thanks a lot!
-Mike

[dkightley]

Do you have a Taz 5?

No, I don't. In fact when I watched the video, it looked quite strange seeing the bed move back to front and the nozzle up and down!!

I have two Makerbot Replicator 2s. One I've had for nearly three years...and its been hammered quite heavily, but seems as good as new. The other I got on Xmas Eve at a bargain price..its about two years old..and hadn't even been out of the box!