this is my start g code

echo:Marlin1.0.0
echo: Last Updated: Nov 26 2015 11:03:19 | Author: Zviper89, Migbot Stndrdauto lvl
Compiled: Nov 26 2015
echo: Free Memory: 3606  PlannerBufferBytes: 1232
echo:Hardcoded Default Settings Loaded
echo:Steps per unit:
echo:  M92 X80.00 Y80.00 Z398.27 E94.50
echo:Maximum feedrates (mm/s):
echo:  M203 X225.00 Y225.00 Z3.00 E25.00
echo:Maximum Acceleration (mm/s2):
echo:  M201 X2650 Y2650 Z100 E10000
echo:Acceleration: S=acceleration, T=retract acceleration
echo:  M204 S2650.00 T3000.00
echo:Advanced variables: S=Min feedrate (mm/s), T=Min travel feedrate (mm/s), B=minimum segment time (ms), X=maximum XY jerk (mm/s),  Z=maximum Z jerk (mm/s),  E=maximum E jerk (mm/s)
echo:  M205 S0.00 T0.00 B20000 X15.00 Z0.40 E5.00
echo:Home offset (mm):
echo:  M206 X0.00 Y0.00 Z0.00
echo:PID settings:
echo:   M301 P22.20 I1.08 D114.00
echo:SD card ok

(from Mac Pronterface)

here is my code for what it is worth.

G21; set mm units
G28 ;home all axis
G90; set absolute coordinates
G92 E0; reset extruder distance
M104 S205; set extruder temp and start heating
G1 Z5 F300 ;move platform down 5mm
G1 X195 Y195 F3000 ; move to back right corner
G1 Z0 F300 ;rest extruder on platform while heating to prevent oozing
M109 S205; wait for extruder temp to be reached
G1 Z[first_layer_height] F200 ;move platform close to nozzle
;G1 E7; extrude anchor
G1 F3000; center print head
G92 E0; reset extrusion distance

I am printing on a glass bed, so I dont think there are any real dangers of doing this, but I was curious if anyone is not doing this for a reason.

Any landmines I have not thought about?

Features:
1) Sets the bed temperature to 90C, and waits until it's there.
2) Sets the nozzle to 195C, then waits until it's there.
3) Puts the platform down 5mm in case the old job ended with the nozzle up to the platform (like an abort)
4) Goes to the X-axis and Y-axis end stop switches
5) Goes to the Z-axis stop switch, twice - once fast, once slow as in the Solidoodle original skeinforge start.gcode
6) Does NOT center, rather sets these coordinates as absolute X82 Y76 Z0 (this centers the coordinates)
7) Runs a thin line along the right edge.  As it starts (on the way from X82 to X75) it takes the dribble off the nozzle and discards it at the right side edge of the bed.
8) After the thin line is done, the normal G-codes of your slice take over.

The thin line works like the anchor concept, except it is laid out on the bed and not left on the nozzle.  It is very easily removed, and really consumes only about .3mm from your potential X-axis bed range.

Much thanks to  lawsy and the other contributors!  I've learned tremendously from the information provided here!  best regards - lewis
______________________________________________________________
Start Code:

G21
G91
M140 S90 ;then set bed to 90
M190 S90 ;set and wait for bed temp of 90 to be reached
M104 S195 ; set extruder temp and start heating
M109 S195; wait for extruder temp to be reached
G1 Z5 F500; make sure nozzle not on bed
G1 X200 F3000
G1 Y200 F3000
G1 Z-200 F500
G1 Z5 F500
G1 Z-10 F250
G90
G92 X82 Y76 Z0 E0
G90
G21
S1.0
S2.1
G1 X74.96 Y-64.74 Z0.35 F2400.0
G1 F600.0
G1 E0.65
G1 F2400.0
G92 E0
G1 X74.96 Y-64.79 Z0.35 F519.3344 E0.002
G1 X75.04 Y-64.79 Z0.35 F519.3344 E0.0053
G1 X75.04 Y64.79 Z0.35 F519.3344 E5.4472
G1 X74.96 Y64.79 Z0.35 F519.3344 E5.4505
G1 X74.96 Y64.74 Z0.35 F519.3344 E5.4525
G1 F600.0
G1 E4.8525
G1 F519.3344
M104 S190.0
S2.1
G1 F600.0
G1 E4.2525
G1 F519.3344
G92 E0

G21; set mm units
G28 ;home all axis
G90; set absolute coordinates
G92 E0; reset extruder distance
M104 S195; set extruder temp and start heating
G1 X145 Y145 F3000 ; move to back right corner
G1 Z0.05 F200 ;move platform close to nozzle
G1 E5 ;extrude anchor
G1 X10 F12000 ; move towards the back left as fast as firmware permits
G1 Z5 F300 ;move platform down 5mm
G92 E0; reset extruder distance
G1 Z[first_layer_height] F200 ;move platform close to nozzle

This pretty much successfully cleans the nozzle completely of any excess chaff, whipping it off with the rapid motion. It does result in a small gap in the skirt at the start though, but that is what the skirt is for.

lawsy wrote:

The new Slic3r 0.9.5 and Repetier-host 0.80 have fixed the issue with the slic3r variables. The start g-code will now work as stated in the first post.

Hi Lawzy,
where you referring to the extruder temperature triplet being fixed ?
if so .. what am I doing wrong with the start gcode then..

using rep host 0.82b and M190 S[temperature] is returning the M190 S195,195,195 for me..
repetier is set for a single extruder in printer settings.

ah well .. I might just drop the temps out entirely and use manual control top set them pre print and save reslicing ..

You can edit the start gcode before printing to be correct.  I don't know if there's a clear cut way to stop this.

The new Slic3r 0.9.5 and Repetier-host 0.80 have fixed the issue with the slic3r variables. The start g-code will now work as stated in the first post.

Hi Lawzy,
where you referring to the extruder temperature triplet being fixed ?
if so .. what am I doing wrong with the start gcode then..

using rep host 0.82b and M190 S[temperature] is returning the M190 S195,195,195 for me..
repetier is set for a single extruder in printer settings.

ah well .. I might just drop the temps out entirely and use manual control top set them pre print and save reslicing ..

I'm not exactly sure if it was anything I might have changed accidentally but it seemed like it wouldn't even do the extrude anchor and would then start print in front left where extrude anchor was to take place.  Repeatedly slamming off the non endstop side of x and y.

Also is there a setting of some sort I could fix in slicer 097 with regards to the extruder hear line of code that puts it like multiple extruders are present?

Slic3r puts in its own extruder temperature instructions at the start of the g-code.

M104 S190 ; set temperature

This causes the extruder to remain heated for a long time before the bed temperature is reached, which isn't that good for PLA. I fixed this by overriding the temperature at the beginning of the start g-code with a relatively low temperature.

M104 S50            ; override slic3r extruder temp

The extruder temperature variable still didn't work so I had to put it in directly in the g-code.

M104 S185         ; start heating extruder

This instruction crashes the platform right down into the floor, so I removed it.

G1 Z150 F300 ; lower platform to bottom

When using PLA the anchor sometimes didn't stick to the platform, causing it to be dragged into the print and ruining the first layer. Instead I made the extruder lift from the platform after extruding the anchor, move to the side, go down again and scrape off the remaining plastic on its way to the print area.

start code:

M104 S50                    ; override slic3r extruder temp
G21                        ; set mm units
G28                         ; home all axes
M190 S60                 ; set and wait for bed temp to be reached
M104 S185                 ; start heating extruder
G90                        ; set absolute coordinates
G1 Z5 F300                ; move platform down 5mm
G1 X10 Y10 F3000             ; move to front left corner
M109 S185                ; wait for extruder temp to be reached
G1 Z[first_layer_height] F200    ; move platform to the first layer
G92 E0                    ; reset extrusion distance
G1 E10                    ; extrude anchor
G1 Z5 F300                ; move platform down 5mm
G1 Y20 F3000                 ; move away from the anchor
G1 Z[first_layer_height] F200    ; move platform to the first layer again
M140 S50                    ; lower bed temperature

end code:

G28 X0 Y0                ; home X axis and y axis
; G1 Z150 F300 crash the platform into the floor
M104 S0                    ; kill extruder temperature
M140 S0                    ; kill bed temperature
M84                        ; disable motors

The new Slic3r 0.9.5 and Repetier-host 0.80 have fixed the issue with the slic3r variables. The start g-code will now work as stated in the first post.

Exciting stuff! Good to see good software getting better.

I've not been happy with the default start and end g-code, so have been developing a better version based on the versions Ian posted on his blog.

I'm not sure about others, but I was particularly sick of the nozzle scraping across the platform in the back right corner as it left the home position to start printing. I was also sick of the first extrusions not working as plastic had oozed out of the hot tip.

My g-code rectifies both of these problems.

For Slic3r
Slic3r will let you use variables in your start and end g-code, which I have done. This g-code works best if you set the first layer extruder temp to 0 in Slic3r. Don't worry, it will still be heated appropriately for the first layer using this code.

Start:

G21; set mm units
G28 ;home all axis
M190 S[first_layer_bed_temperature] ; set and wait for bed temp to be reached
M104 S[temperature] ; set extruder temp and start heating
G90; set absolute coordinates
G1 Z5 F300 ;move platform down 5mm
G1 X10 Y10 F3000 ;move to front left corner
M109 S[temperature]; wait for extruder temp to be reached
G1 Z[first_layer_height] F200 ;move platform close to nozzle
G92 E0; reset extrusion distance
G1 E7 ;extrude anchor

EDIT:
Repetier-Host 0.74 kills the above code due to support for multiple extruders. Instead of [temperature] in those two lines, subtitute in your actual temp number you are seeking. EG:

M104 S200 ; set extruder temp and start heating

End:

G28 X0 Y0  ; home X axis and y axis
G1 Z150 F300 ; lower platform to bottom
M104 S0 ; kill extruder temperature
M140 S0 ; kill bed temperature
M84 ; disable motors

For Skeinforge
Manual values must be substituted whereever Slic3r variables were inside [square brackets].

Example:

G1 Z[first_layer_height] F200 ;move platform close to nozzle

becomes

G1 Z0.25 F200 ;move platform close to nozzle

or whatever your layer height is set to.

Here is a video of the new g-code in action:

I hope this has been added to the wiki. Good work, once again!