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Two posts, one day! Sounds like an internet meme..

So... My third attempt at a print larger than a 1cm ball. I'm printing ABS. Because, why not throw yourself into the deep end when you build your first printer, right?

I made a post this morning about def thermistors and other strange issues. Here's another one.

While printing this test print, I watched it carefully the whole time. The raft printed nicely and then the temp started plummeting. Here's my notes that I frantically typed down:

Bed heat plummeted to sub 60 after 2% of the print despite heat LED being on and set at 95. Approx 0.2 deg per second. I can hear snapping and popping of the raft - part must be cooling enough to allow relative motion of the coarse extrusions and delamination from the bed. Temperature at 54 after several minutes (3% printed). This print is at a similar location as the last time it failed (which was also the first time I tried it). A few mins later, bed at 52, still 3% printed on lcd.

Raft has delaminated on one edge of the ~4.5 inch diameter and both thermistors now read def. still 3% in.

Immediate reset using red LCD panel button reads temps fine immediately.

Bed can be set to 80 at the LCD and heats like normal.

What the what is going on!?

Thanks for the help...

Are the part cooling fans turning on? I have noticed that the part cooling fans provide enough cooling and airflow that they will drop the temperature of my bed and cause a heater error. I was able to fix this using the lower profile fans for the slim enclosure here or just closely monitoring the fans during printing and turning them off to let the bed warm back up.

Once the firmware detects that there is no temperature increase after about 5 minutes of pumping in current it will completely error out, throwing both thermistors as DEF and require a printer restart.

I'm printing ABS and I started with the standard ABS settings in matter control. By default it doesn't turn the three-fan-array on for ABS. It only runs the one PCBA fan.

That's great info about the timeout. It seems strange to me that the head thermistor would also def and it would totally cut out power, but I can see how someone would decide to do that programmatically just to cut off all power in case of a major fault.

Maybe my bed setting is too high for it to achieve while also laying down plastic. I'm going to insulate the bottom of the bed as I've seen in other posts and try again.

Thanks for the response!

Check your hotend, Thermistor connections. From your other post and this one, it sounds like you may have a bad solder joint. If one thermistor faults, the display will show both as def.

Are you sure about that? When I was missing a print head thermistor and I had finished the rest of the build I plugged in my printer with no print head attached and turned it on to see if everything else was working properly and the bed heat would read out but the head heat wouldn't display.

Never mind.

i assume that was before you flashed the firmware on the rambo board, after you flash the firmware it will error out both regardless if its only one.

Yes, I believe that is correct. I love the knowledge and collaboration here!

aodhan wrote:I'm printing ABS and I started with the standard ABS settings in matter control. By default it doesn't turn the three-fan-array on for ABS. It only runs the one PCBA fan.

UPDATE!! Matter control turns the fans on by default with ABS but it isn't obvious!! It doesn't have them on when it prints the extruder priming loops and doesn't have them on when it prints the part, but it DOES turn them on when it is printing the raft. Quite possibly the WORST time to turn the fan on! I'll be testing another print tomorrow with the GCODE changed to not turn on the fans at all. I'm very excited for my first successful print larger than 1cc volume!

Friends don't let friends slice with matterslicer

Truthfully, to get dimensionally accurate prints I switched over to KISSlicer and my stuff is much better.

Thanks for the recommendation. Once I get a print I'm going to start looking to refine things - changing slicers, different print surfaces, increased speeds, etc etc. I actually slowed down the speed to 75% of the standard values in Matter Control and it's looking all warbly. If I can just get a successful print, though... Optimization isn't possible until then!

i'd ditch matter control asap. i have no idea why seemecnc partnered with such a shit slicer, but it's time to move on.


the acceration default values in mattercontrol are also way too high.