Solved No extrusion during print, but can manually extrude ("cold extrusion prevented?")

Hello again forum. You've helped in the past and I've been having another problem with the r1+. I'm currently only trying to print with PLA, which I've printed with in the past very successfully, but now it isn't extruding during the print. I can still manually extrude. I've set my z-offset using the paper trick--it is currently -.62. My printer has the standard hexagon all-metal extruder. I'm printing at 183 degrees. It's pretty oozy and drippy but I want as much flow as possible right now while I'm troubleshooting, I'd think? My bed is glass and heated to 55 degrees, currently without any sticky agents on it, though I don't think that will be relevant.

I unscrewed my old brass nozzle nib, cleaned out the inside of the extruder tube (could see through it very clearly), and replaced the nib with a brand new one. I then seasoned it following these directions.

When I'm holding open the latch on the filament feed area, I can push the filament straight down into the nozzle and it will gush out the tip. (Same thing happens when I have the boot unlatched and the extruder is free.) When I turn the big gear to manually push filament down, that works fine as well--no clogs at all. I've turned the tension screws until they felt very tight. The hobbed bolt doesn't appear to have any blockages or bits of filament in it.

I let a print get 7 layers in, with no extrusion. I then turned the big gear to manually extrude a little bit and it worked. I undid the boot latch to free the extruder and turned the gear so that the extruder would drop down. I wanted to check for spots of wear where the hobbed bolt was chewing the filament but found no "bites" or anything, but it felt slightly rough.

I let a print go all the way through. It looks like maybe a TINY amount was extruded and just kinda collected around the nozzle (probably just ooze?). Even when the extruder was up in the air a few mm at that point, there was still nothing coming out so I don't think the nozzle was ever too close to the bed. I then undid the boot latch again and did the same as above, dropping the extruder down to look for wear, and found nothing new. I then grabbed the hexagon and the filament, and it felt like there was a small gap (couple mm) between the nozzle and the tip of the filament--likely due to oozing?

Any words of wisdom? Sorry that I don't know the proper terminology for a lot of this stuff. I also have no idea what information is relevant so I apologize if this is excessively word. I appreciate any advice.

(Oh, I should add: before I replaced the nozzle, I was having similar problems. It would under-extrude and at random just stop extruding, resulting in bands of empty space on the first layer. But when I pushed the filament through, it seemed to flow alright. During this process I leveled out the bed and tightened the tension screws considerably, so maybe that was part of the problem, though it certainly isn't helping now.)

 

Interesting update ... I watched the gcode terminal during a print and it was constantly saying "cold extrusion prevented." So, I suppose that the software (or the firmware?) doesn't think that the hot end is hot, even though it is. However, the "extruder temperature" display is correct--it's showing that the extruder and bed are ~183 and ~55 degrees respectively.

By the way, I'm using MatterControl.

 

Under the Configuration.h tab of the firmware you can find the following line with some value. You can adjust that down to a lower level if you need.

#define EXTRUDE_MINTEMP 185

 

Whaaaaaaat. 190 seems like a crazy "lower limit." Thanks a ton, guys. I'm not at home right now but when I get back I'll go poking around in the firmware and see what happens. Do you know off the top of your head where I can find those files?

 

http://guide.robo3d.com/Wiki/ROBO_3D_Firmware_Release_Notes

All the stock Robo firmwares are found there, but you'll need to make sure to pick the correct one for the version of Robo you have.

 

Well, a test print at 192 degrees works, so that was the problem! I'm still working on changing the value in the firmware. I've never altered any firmware before but I'm trying this method (or is this the ONLY method?). It's giving me some grief, but that's a topic for another thread, so I'm marking this resolved. Thanks guys!

 

@Heimdall if you need any help let me know. There is a known compile error that I documented in the comments section of the download page.

 

Yeah, it was the compile error. I rolled it back to the 1.6.9 version and it worked, but if it just comes down to changing the name of a structure, maybe I'll do that in the future. Thanks man!