Hey, Recently I got a heated bed and I've been trying to print ABS and my extruder skips on speeds higher than 35-40mm/s. This results in a temporarily under extrusion which shows like a missing layer on the prints. I'm able to print PLA at 75-80mm/s with ease and good quality, so I'm wondering why I can't do the same with ABS or PETG? I'm using this extruder: http://www.thingiverse.com/thing:275593/ I tried a range of temps from 215 to 242 for ABS and the extruder always skips on higher speeds like 50-60 etc... I can print ok at about 35mm/s, but even then it sometimes skips but it is VERY rare at that speed. My filament is measured and set at 1.8mm in the settings. My nozzle is 0.4mm. Edit: btw I'm not sure if skipping is the right term so I'm just gonna explain what happens exactly. What I mean by "extruder skipping" is that the extruder jumps back and forth for a few seconds and the filament doesn't move. It looks like filament doesn't have any room to go forward, which makes all this happen. Thought a photo might help: This was done at 40mm/s and I even reduced the speed by 15% half way through and it still didn't help. It wasn't this bad yesterday, I was able to print fine at 40mm/s.
I've used that same extruder for a while. Even made an alteration from it. The problem with this extruderdesign is that when using an non-geared steppermotor the force needed to push the filament through the nossle is more then the motor can deliver. Since then I went back to the 'standard' Wades extruder and everything prints as it should
Interesting! I gotta get a hobbed bolt and try that, thanks man! So you can print ABS at 50-60mm/s then, right?
Strange, I'm printing Colorfabb XT (PETG) at 245C and 50mm/s with a stock direct drive on my Bigbox (1.0). Is the hobbed bolt grinding the filament? Or is it not moving? I think direct drive (>40Ncm NEMA17) should work on 1.75mm filament. What happens if you push by hand?
I checked the gear, no grinded filament. Also it uses a MK8 gear, not hobbed bolt. My motor is rated for 3.5Ncm, so perhaps that's why it can't push fast enough? Do you mean if I manually push the filament into the hotend? or pushing it when the motor is also working? I'm gonna buy some m8 screws etc... today to try and make a Hobbed bolt for a wade extruder, hopefully that'll solve the problem. Thanks
Woha! 3.5Ncm does not make sense. Is it a regular size nema 17? My guess its 35Ncm and you or someone got the units wrong. Nm, Ncm foot feet, inches and pounds. Sorry, I was thinking of "hobbed" gear or whatever is the correct term