poor layer adhesion of anything less than 0.3 layer height

getting very poor quality from 2.5 layer height - anybody come across this?

width over ratio is 1.83

see poor webcam shot

Use Slic3r. It's much much easier than Skeinforge to decrease your layer height and get good results.

thanks but i have tried it, it doesn't have enough control to limit the z-speed and you need to do that on a sans Mendel

but if Slic3r can do it, does anybody have suggestions for Skeinforge ?

What size nozzle are you using?

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yeah, sorry 0.5 and printing with abs

@ 0.25mm layer and a 0.5mm nozzle I would suggest using 2.0 WOT or greater you want to print at least as wide as your nozzle and narrower than your die swell size. So if when you extrude into free air and it turns out 0.65 diameter I would set the WOT to 2.5 so you end up with a 0.625 width path. (2.6 WOT on the infill)

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Thanks sublime very useful info. Ill let you know how it goes.

Limiting your Z speed should be done in firmware, not software. All modern firmwares permit you to do this. I suggest Marlin!

I would bump up your e-step value a bit, or re-calibrate the extruder.

Are you using a heated bed. I assume you are, since there's not much point in rinting ABS without one.

With 0.1 layer height, on a 0.5, I find that I need to increase the perimeter count. Usually I do six, but it depends on the part countours, and what best works. Infill has to be high too, and bridging is pretty much a lost cause.

The adhesion problem may also indicate that you need to bump up the nozzle temp by 10 deg. or so.

Pointedstick, i did try marlin but didn't get it to work too well, just config problems but it is a very different beast from sprinters config, guess i didn't try too hard. Having excellent quality running at 0.32 with my current setup so I didn't find the motivation to really understand it.

jcabrer, you could be right but as above i get really nice prints with the current config, so not sure about the calibration being off. Yes heated bed, as you say can't run without it. Good tip on the perimeter count i only have two during build and three to open and close the object and infill is only 20%. I am already running at 250c so would not want to push that any-more.

Thanks again to all, will try all the suggestions they seem logical enough.

Try extruding at a higher temperature. Maybe your readings are higher than they actually are.

ABS only sticks superficially if the temp is too low. I extrude black ABS at 250º C and have not yet suffered from delamination.

If you are also using 250, maybe you should insulate your hot end or lower your feed/flowrate.

Maybe the quality of the ABS that you bought is sub-standard.

PS: Do you have a fan blowing all the time?

the problem only occurs when i try and print with very fine layers, but i think you are right about temp reporting, my thermistors have an unknown product number so i am using a general 100k table. the ABS is good quality, i pay over the top from Germany (via reprapcentral) to make sure.

Your parts are cooling off to quickly and probably not being extruded hot enough (possibly because you are printing too quickly and the extruded filament does not actually get up to the temp the head is at)

Use of a full eight skirt will help. Do NOT have any kind of fan blowing on the part.

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Maybe you should calibrate your thermistor using a thermocouple in the heater barrel. You can make a new temptable based on the values you record.

Nophead has done it before so I would check out his blog, and maybe PM him.

I do it before there is any plastic in the barrel.

I have a utility that reads the ADC value and calculates and prints the resistance.

I put a thermocouple inside and record the resistance and temperature at room temp. I then set the temperature to the target, record the actual temperature and resistance. From that I work out the beta.

It it easier for me because I use the thermistor equation in my host code and only send and receive ADC values to the firmware, so no table is required.

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