I’m trying to print a bumper in PLA Flex for my glow in the dark print which is a bit brittle.
But my PLA Flex print is delaminating.
I print at 220C with layer height 0.2.
I think I need to increase the temp but on the label it says that i need to print with anything below 220C.
So what is your advice. And if i need to increase the temp by how much would you advice?
does it not print properly at lower temps? 205? Just wondering, because when you melt something, it’s properties change and once cool, might not have the properties you need, like adhesion to previous layer. If you’re printing at limit temperature, it may be just that, i.e. the material may have been designed to be used at spec temps.
You might also try a higher temperature. The reading on your thermistor may not be the same as the actual nozzle temperature. An offset of +/- 10C between the recommended temperature and your optimal thermistor setting wouldn’t be surprising.
Might also try disabling cooling - especially if you are printing rather slow. As Michael mentions - thermistors can be off a bit so 220C may be closer to 210C. I have some PLA that isn’t happy unless it is over 220C (don’t recall the exact temp.)
Why don;t people just use thermocouples? Thats what I don’t get…
@Daniel_Joyce because thermocouples aren’t very accurate, and unless the nozzle is actually part of the thermocouple they’d have the same problem: they’d report on their temperature, which may not be the same as that of the nozzle. If the nozzle was the thermocouple junction, then you’d be limited in what you can make the nozzle out of, you’d have to calibrate each and every hot end, and that calibration wouldn’t last very long because of aging or other changes to the junction. See http://en.wikipedia.org/wiki/Thermocouple#Accuracy
I now tried 225C with was better but I think i need to test more with the temp.
Thanks all for your tips.
And thanks Michael I did not realize that the temp in the hotend is probably lower than the temp at the thermometer.
I think that i need to make a little book with temps en settings per spool.
@Michael_Hohensee the thermocouples don’t see a high temp reducing atmosphere in the typical extruder. You can spot-weld a junction just about anywhere on a metal nozzle. Tolerance on a class 2 junction is ±2.5c. Better than many thermistors operating in our temp range. One poor crimp or bad solder joint will only add error unless your using a 4-wire (Kelvin) setup.
I’d thought that the spec for our thermistors (the ones in makergear or e3d hot ends) were better than 2.5 C, but I don’t have the spec sheet in front of me now… I’d understood that thermocouples were better at high temps, though.
Definitely, though you can get even better with circuits that have a reference cold junction, either in a known reference temperature bath or use a thermistor to measure the room-temp(ish) junction.
The other benefit is you don’t get ohmic heating of the thermocouple like you can with simple resistance measurement methods on thermistors.
It’d be fun to add welding to my printing hobby. Gotta get the wife’s welding kit from her parents garage back east. 
Yeah, my wife can run a better bead than me any day.
Did you marry an engineer too?
Guess so.
@Michael_Hohensee
Datasheet for the ATC Semitec 104GT2 as sold with our E3D hotends:
I do print with PLA Flex too, and found it to be very prone to delamination at every major x/y deviation.
Higher temp, reduced feed rate and layer height (to like 0.1 or 0.15) would certainly help you, but this would only reduce the problem.
The real problem here is the fillet on the top edge. Those never print well.
Try with a sharp edge (60°…90°) and most probably yor delamination problem will be gone.
