Need help with some print issues

Hey guys im having a few issues with my printer and wondering if someone brighter than I am can help me figure out whats settings I need to adjust.

my printer is a prusa i2 using pronterface /slicer im using sprinter firmware on ramps 1.4

I have noticed when I get to larger areas of my prints my machine speeds up dramatically faster which would be great if my hot end could keep up with the speed of the filament its extruding is there a way I can turn this off?

Another issue I am having that is in mid print sometimes I will notice that my extruder has stopped extruding and I will pause it raise it by 10mm hit the extrude button until I get filament flowing again then when I lower it back 10 clean off the filament excess and resume print the extruder reverses however many times ive extruded kind of annoying and I want to stop it from doing this

Has anyone came across these 2 issues and know how to fix it?

Your printer is probably not speeding up for larger prints, it is probably slowing down for smaller prints. All of your speeds and all of the conditions governing then are set in slic3r. You can specify maximum speeds for a number of things, including first layer, perimeter versus infill, etc. In addition, you can tell it to slow down if the layer print time is too low in order to give the print time to cool. There is really no simple answer here. Study the options the slicer presents to you.

As far as your extruding issues are concerned, get your speed dialed in first. If your speed is too great for your hot end, back pressure can build up along the filament and it can start slipping in the extruder, Once things like this start happening, they tend to snowball. If you get the speeds right, this problem may go away, or at the very least be mitigated.

I don't fee this is accurately describing my problem?

I understand "most" of the settings in the printer speed area in pronterface I understand the default setting has the smaller perimeters set to slower than large perimeters I have the first layer set at 40% travel speed. So as my second layer prints it speeds up some and goes around the outer perimeter at the set speed then it does all the inner circles at a little slower speed then it starts the infill process

Now the problem im having is for example when its moving around a perimeter if its a long enough straight away for example no curve it will act as if its kicked into a second gear so to speak and picks up real quick and does that particular straight section fast.

It also does the same thing if I have large infill area basically so regardless of perimeter or infill with exception of first layer it does this I just changed all my settings to even slower than I usually print just to see if it still done it and it does.

current settings im using are

perimeters 50mms

small perimeter 30mms

external perimeters 100%

infill 50mms

solid infill 50mms

top solid infill 40mms

support material 60mms

bridges 60mms

gap fill 20 mms


travel 80mms

first layer speed 40%




I am printing at 245c with 618 taulman (starts oozing out the hot end at 220c and I have actually test extruded it at 210C and it will come out at a slow speed so I feel oozing at 220 I would think that the hot end staying around 235-239c average should be adequate enough but it keeps skipping

It sounds like what you are seeing is the printer accelerating up to your speed settings on long straight passes. You won't see this on short passes because there is not enough time for the machine to accelerate up to your speed settings.

What firmware are you using? Also, what is the acceleration setting?

Also, your nozzle will dictate how fast you can extrude. So, it's probable that your nozzle can't extrude plastic when the machine accelerates up to your speed settings.

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Try getting Cura as your slicer.

I typically run about 30 mm/s speed for prints that I want reasonable quality on,