massive underextrusion problems

[milp]

Hi there,

for weeks now since i've started printing again i've been having massive problems with underextrusion on my rostock max v2

Things i have done:

- Replaced everything that was broken, new delta arms, new ptfe tube connectors, even replaced the nozzle just to be sure.

- Reset the entire printer, reuploaded the firmware and went through all the calibration steps again from scratch

- Reset my quality and materials presets in mattercontrol to default

- Bought high quality pla filament instead of cheap ones.

- Extruded 100mm of filament without the nozzle connected and measured the resulting piece of filament to make sure it is exactly 100mm long. And it was.

I have included three pictures where you can see some of the issues. Top layers, shells and infill all seem to be too thin.

Please help, i'm seriously out of ideas to try.

[stonewater]

1- did you measure your filament diameter and put it in your slicer?

2- is the hobbed gear doing any damage to the filament? if so your hotend temp may be too low or it is snagging in the Bowden tube. a bit of canola oil will help that.

3- is your hot end temp your actual hotend temp? need a multimeter with a thermocouple to make sure.

underextrusion is usually a setting in your slicer. you can modify your extrusion amount using the extrusion multiplier in your slicer...

Tom C

[milp]

Hi Tom,

- yes, i measured the diameter like 6 to 7 times at different positions around the spool, then removed the highest and lowest value from the list and proceeded to average out the rest of the values. I think i will repeat this step today just to make sure that the value is correct.

- i cleaned the extruder mechanics with a toothbrush yesterday to remove any filament residue and it works just like it should.

- i'll have to check the actual hotend temperature, the only digital thermometer i have around is a pyrometer though and it is not very accurate at lower temperatures (+/- 10 degrees celsius). So far i have been printing at 195 °C, that's the maximum temperature the filament manufacturer recommends.

Yesterday i've also retightened all the belts, just to be sure.

[Fiddler2070]

That doesn't look like an extruder or hotend problem to me. It looks like slicing setting problem. I get that double layer thing when I don't set the proper loops and skin thickness. Your insides look awfully hollow. I usually use 33% fill for parts that don't need strength and upto 80% for parts that require strength.

Also it looks like you haven't properly calibrated the bed flatness. I can't be sure because the pictures are fuzzy but it looks like the perimeter at the top of the picture is rounded while the perimeter below the part is squished. You need to print calibration items and measure and set the height and offsets until it is dead zero.

Mine didn't look as bad as yours starting out but the part looked like a dog had been chewing on it. It took me nearly a week to properly calibrate the thing. Rollie has a HTML app that will do the calculations for you, however you will need to jury rig a digital caliper or attach a dial indicator. It is very important that your bed is calibrated flat. Your horizontal radius is flat. Your height is set exactly otherwise you get really crappy prints.

[milp]

That doesn't look like an extruder or hotend problem to me. It looks like slicing setting problem. I get that double layer thing when I don't set the proper loops and skin thickness. Your insides look awfully hollow. I usually use 33% fill for parts that don't need strength and upto 80% for parts that require strength.

Also it looks like you haven't properly calibrated the bed flatness. I can't be sure because the pictures are fuzzy but it looks like the perimeter at the top of the picture is rounded while the perimeter below the part is squished. You need to print calibration items and measure and set the height and offsets until it is dead zero.

Mine didn't look as bad as yours starting out but the part looked like a dog had been chewing on it. It took me nearly a week to properly calibrate the thing. Rollie has a HTML app that will do the calculations for you, however you will need to jury rig a digital caliper or attach a dial indicator. It is very important that your bed is calibrated flat. Your horizontal radius is flat. Your height is set exactly otherwise you get really crappy prints.

I will get to that right away, i didn't think that would have anything to do with holes or thin lines in infill though. I think this print was done with 30% infill.

The manual mentions using a feeler gauge with some inch value, what value in millimeters would you recommend for using a feeler gauge? 0.1mm?

What is this html app you mentioned? Haven't found anything.

[milp]

I have just done the calibration and noticed that when i was working with the feeler gauge (used 0.2mm) there is so much play in the nozzle carriage, that the measurement would change between too tight and too loose on every given position if i only so much as touched the carriage. Is it normal that it has that much play? Or is that some kind of the delta arm blues?

[Fiddler2070]

I have just done the calibration and noticed that when i was working with the feeler gauge (used 0.2mm) there is so much play in the nozzle carriage, that the measurement would change between too tight and too loose on every given position if i only so much as touched the carriage. Is it normal that it has that much play? Or is that some kind of the delta arm blues?

Did you tighten the carriages? you use the eccentric cams to make sure that the carriages are properly set against the 3 towers.

I don't know what you mean by play in nozzle carriage. The nozzle actually moves back and forth? That should not happen. It should be rock steady.

I use the smallest feeler gauge. I don't know what it is but is is thinner than paper. I found out that using paper is fine. Don't bother unless you have a dial gauge and is using Rollies bed leveler.

http://forum.seemecnc.com/viewtopic.php?f=36&t=8698" onclick="window.open(this.href);return false;

There you go. When you calibrate manually, you have to go through many cycles until the bed measures the same offset at each tower. This includes horizontal radius each time. Like I said, it took me days to do this properly. If you don't it will print like its drunk.

What settings are you using?

look in my posts. I have one where I'm trying to figure out how to print threads. I have pictures of what a proper print looks like. Just printing threads didn't work.

[milp]

It slightly moves when you touch it, mostly up and down. Yes i tightened the carriages so the rollers have no free play but aren't overly tight.

I'm using all default settings for quality and material except for the filament diameter. Yesterday i calibrated it so that both in the middle and at each tower base the 0.2mm feeler gauge goes through with slight drag.

I'll try that calibration tool later today, thank you.

[milp]

Ok, i retightened the X/Y/Z carriages a little, noticed the hotend carriage still moves a lot in every direction when you touch it and started to put cable ties around the ends of the rods to fight this. It seemed that the play came from differences between the rod end holes and the little white plastic holders.

Now it barely moves when you touch it. Keep in mind, the rods are brand new. I had 2 of the old ones snap while printing without supervising the printer some months ago.

I have now tried to print a 25.7~cm wide 1 layer circle thing after manually doing the calibration again with a .1mm feeler gauge. It seems like it's printing completely uneven, at the base of the Y tower it will go onto the glass to the point where it won't even extrude anymore, just next to it in the middle between Y and X tower it moves away from the glass like .5cm.

If only i could figure that tool out, i tried to utilize it but with no luck:
http://forum.seemecnc.com/viewtopic.php ... 868#p75868" onclick="window.open(this.href);return false;

[Fiddler2070]

I haven't use the tool myself. You can't do one calibration cycle and say it is even. After you change the figures you lower the hotend and check. There is no way that your machine is calibrated if you are getting uneven prints.

I have all kinds of layers attached to my bed and it took me days to get it calibrated properly. I even gave up for a few days.

In any case, a test print is the easiest way to tell if it is calibrated properly or not. You can easily see the results. I don't have that much experience so I will just say that you need to go over the manual carefully regarding the machine calibration procedure and also make sure your towers are 90 degrees straight up. My Y is 2.5 degrees off vertical.

It can incredibly frustrating. Keep reading and calibrating.

[milp]

Ok so i noticed that my towers aren't in a 90 degree angle to the bed anymore. Is there any way to fix this without having to disassemble half the printer?

Other than that, could there be mechanical damage from when i had the arms snap? Like a bent axle or someting? What is most likely to break?

[Fiddler2070]

I can't answer those question because I don't know. I haven't taken my machine apart to straighten the towers out. Someone with more experience will have to answer those questions.

[milp]

I can't answer those question because I don't know. I haven't taken my machine apart to straighten the towers out. Someone with more experience will have to answer those questions.

Well i have now measured it again and just pushed the top side towards the right direction to fix it, and it seems to have worked. The towers are pretty much in a 90 degree angle now. It's not like it changed anything though, might have to try some 20 iterations with that delta calibration script and see if it helps.

I really wonder where there could be a mechanical defect in my machine, causing it to be so uneven.