Underextrusion/Missing layers

Hey guys, im running a robo3d r1 plus with and e3dv6 hotend and dual cooling fans.
so i was printing some parts and then some started coming out worse and looking like this i have tried multiple solutions like cleaning and oiling all the rods, changing my nozzle, adn using another slicer but have had no improvment, if anyone knows what the problem is and can help that would be awesome, thanks.

https://gyazo.com/07524221e389aab7d325b43f60ec2a3a
https://gyazo.com/0dcb716ed9245a847a14a872bbba8e90
https://gyazo.com/49c6d2b9f5da94e2133cc619d5f8f131

Hi

How tall *should* those parts be? Put another way, are they 2X taller than they should be?

What do you see as you print? Is the extruder simply running up in mid air?

Either way, one very real problem could be that your slicer / firmware is very confused about how many esteps there are on the Z axis to make up 1 mm. What have you changed recently?

Bob

Those missing layers are often signs of temporary clogs or hydration in PLA filament. If the extruder clogs during a print, it will sometime manage to push the clog out and start printing again, but there will be sections of the print that didn't extrude. If the filament is PLA and has absorbed water, there may be moments where you have bursts of steam during extrusion that cause clogs or just generally get in the way of printing. Poor quality filament I've heard can cause clogs too.

Under-extrusion in general can be caused by many things, such as: incorrect Esteps, incorrect value for the nozzle width in the slicer, incorrect value for the filament width in the slicer, and some other things. Esteps calibration is a good starting point for under-extrusion troubleshooting. If your slicer has an extrusion multiplier (assuming the nozzle and filament widths are correct) tweaking the extrusion multiplier is a good way of compensating for extruding too much or too little material.

The first image is of special note, though. The way the layers split is likely due to one or both of these reasons: the layers are being printed too cold and are de-laminating; or the Zsteps are off and the layers are not printing at the correct height. If you measure one of these prints and it's printing at the height you want, then your layers are likely de-laminating and splitting from each other. It probably overall doesn't help that the prints are under-extruding meaning that there isn't that much material in each layer to stick to the next anyways.

EDIT: could you possibly post a picture of how the end of the filament in the extruder looks after one of these prints if you took it out?

Hi,

I suggest these solutions:
- Calibrate your print bed
- Print at lower layer heights for better adhesion
- Adjust the pressure your extruder exerts on the filament and/or increase flow rate. What kind of filament are you using?
- Turn off or lower the amount of cooling. I expect cooling to be the problem here causing the warpage and poor layer adhesion.