Changed nozzle to .4mm to reflect my nozzle
.8mm retraction
.4 liftZ
30 mm/s speed <- i am suprised too... lowering speed actually works!
1mm extra length on restart
2mm minimum travel

in EEPROM
changed maximum acceleration E to 2000 mm/s2

Its possible that the hole is caused by z lift, with the nozzle not returning fast enough.  Maybe reduce z lift, speed it up by increasing max feed rate for z, or turn it off to see if it makes a difference.

I will try it again this weekend... if i have to set z lift to zero. i have to make sure my extrusion rate is correct (i think i might have the newer .4 nozzle) i doubt repetier is written for these new nozzles

It's not, in Repetier go to Config -> Firmware EEPROM Configuration.  You will get a window with fields for settings like Steps/MM, Maximum Feedrates, etc.  Just change the Max Feedrate for E (extruder) and click the Save to EEPROM button.

Thank you,
I tried the 150 limit and set E to 100 speed. however my retraction and re-extrusion still leaves visible hole. :-( I kinda give up on it. since extra extrusion setting doesn't do $hit.
I really wish i have strings instead having holes.

In the EEPROM Config window in Repetier, look for the Max Feedrates section.  Set the max feedrate for E to something like 150.  The default is more like 45, which means that even though the retract speed is set to 75, the firmware is limiting it to 45.  The rule of thumb I have heard is keep the speed high and the distance low, so try something like .8 retract distance, and 100 speed.

So... if we want retraction speed at 100(what's the unit?) we need to modify firmware? that sounds complicated...

BUT I still have trouble with first layer. especially the brim part of it... I am not sure if it's the slicer's issue(Repetier Host v0.82b) on brim (maybe retraction or extra extrusion wasn't used on brim) or first layer speed. since my first layer is at 50% of the regular speed.. and second layer seem to have good retraction and extra-extrusion ratio...

And be warned... extra retraction on thinner piece might left you with gap during re-extrusion, and since you need retraction one on wall(x layers). and once on infill... if the piece is too thin, it might be ruined b/c of these two gaps.

Also, I changed my retract lift on z... I set mine to .3 mm to avoid bumping... vibration loses object up, so its easier to curl.

If my experiance can be refined, please correct me. I am pretty new at this too.  thank you.

http://solidoodletips.wordpress.com/201 … libration/
http://solidoodletips.wordpress.com/201 … flow-rate/

Also, turning off "generate random start points" helps reduce that.

retract_before_travel = 2
retract_length = 1
retract_length_toolchange = 3
retract_lift = 0
retract_restart_extra = 0
retract_restart_extra_toolchange = 0
retract_speed = 75

Which one should I change and by how much?

I'm guessing "retract_before_travel = 2" and change it to maybe 3 or 4? Would that help you think?

Instead of following the circle all way round, it stops after 25% and moves over the empty space and starts at 75% of the circle, then stops moves to 50% of the circle... crossing empty space and leaving trails all the time.

1.) Adjust extrusion-multiplier
2.) Adjust retraction

When my printer is transporting from one end of the build platform to another it leaves trails of plastic. Please see attached picture.

I'm using Repetier Host v0.82b that is available on solidoodle.com. All my settings are default at .1mm print.

Any ideas on how to avoid this?

Thank you!