Unwanted Pause After First Layer?

[JATMN]

I have noticed something that is driving me nuts now.

When slicing with S3D for my Ultimaker 2 I get a unwanted "pause" effect at the end of the first layer.. The reason this becomes an issue, where the head pauses it continues to extrude (or maybe ooze?) filament.. The pause only lasts about a second or two but its just long enough to make a nice little blob of filament that causes print defects in that area of the print (sometimes it even induces print failure later). The nozzle will continue to *hit* this blob for the next 2-4 layers until its smoothed it out.

Anyone know how to control this? It happens exactly at the end of the first layer, EVERY time. I do not see the pause issue on any other layers except the first one.

Printing from SD card.

I have looked around the FFF tabs and not seen anything that appears to effect this.
Does anyone know?

[CompoundCarl]

Perhaps it is heating and waiting for one of the temperatures to reach a certain level?

[JATMN]

That could make sense.. but it does it even with only single print temp set..

[zemlin]

I don't think it's a pause for a temp change, as I messed around with an extruder temp change after the first layer and printing would not pause. I had hoped it would wait for the new target temp to be reached, but that was not the case.

[SimpleScott]

The start of your cooling fan, and the "blip fan to full power" option, can cause this type of delay.

The "blip fan to full power" option starts the fan at full speed, PAUSES 500ms, then sets it to the desired speed. For example, here is the S3D-generated GCode where the fan is set to 0% for layers 1-2, then 40% at layer 3, with the "blip fan to full power" option enabled:

Code: Select all

; layer 3, Z = 0.87535
M106 S255
G4 P500
M106 S102
; inner perimeter

S3D hits the fan with full power (the S255 "blip"), PAUSES FOR 500ms for fan spin up, then sets the fan at S102 (40%).

If your fan will start at your desired speed without the "blip", then you can avoid the pause by disabling the "blip fan to full power" option. That will remove the "M106 255, G4 P500" sequence and therefore eliminates the delay. Most fans will probably start ok without the "blip" at ~35% or higher, but you'll need to test your fan.

If your fan needs the "blip" to start spinning at your desired speed, then the pause is probably unavoidable. The "Force retraction between layers" on the Other tab might help with the oozing there, but I haven't tested that solution.

[JATMN]

Interesting.. I will have to try that later.

But not sure that's related.. because lots of my prints.. the fan is either left off completely. 0% or runs same speed at layer 0 as the rest of the layers..
Wonder if the slicer is still pausing for a blip even if its not doing it.. Now I have some investigating to do