Yes, it's perfectly flat when in a cool room (2C) and in room temp (25C). For me, it looks like the heat distribution in PCB and in the borosilicate glass is poor and thus when the bed heats up in the center more than in the corners the heat is not distributed evenly. I thought of applying a thin sheet of aluminum (2mm) between the bed and the glass. This could help me at least to check if it isnby kjakobczyk - Prusa i3 and variants
Yes, of course - when the heatbed is warmed to 100C the blue line in the below picture is raised against the corners. For me it looks like the area around the blue line is heating more than the rest of the bed.by kjakobczyk - Prusa i3 and variants
Hi Guys! Again I've got a problem with my Prusa i3 with bigger heat bed (200x300mm, thus it's called XL). I have a 12V PCB heatbed with 3mm borosilicate glass on top. Even though the PCB is 12V I run it from 24V with 2/3 cycle setup in Marlin. I use it this way because the resistance of the bed on 12V pads is incorrect and with regular 12V PSU I wasn't able to reach 100C (even 24V need 30 mins tby kjakobczyk - Prusa i3 and variants
Hello, I had to replace J-Head in my home-made Prusa i3 XL. I've bought this one with an additional fan. The problem I'm facing right now is that rectangular chamber holding the 0,5mm nozzle is loosening when I head up the print head. Even if I tighten it up when the head is cold, when it reaches 220C it is loose what have negative effects on the leveling. During printout, the chamber may turn fby kjakobczyk - Prusa i3 and variants
Hello, I've faced an serious issue lately: my heated bed thermistor cable damaged, the heated bed stopped to heat the printout and because it was ABS it detached from the bed, but the print head was normally operating. I want to ask if you know a way in Marlin 1.0 firmware to stop the printout if such thing happens again.by kjakobczyk - Printing
Hello, Just a simple question concerning Prusa i3: I've got 3mm extruder handling 2,85mm filament. Can I use 1,75mm filament with this extruder? It seems that 2,85mm ABS is harder to get every month. Best regards, Chris.by kjakobczyk - Reprappers
Thanks for the replies Guys! @dc42: indeed in my whole research I forgot to verify the voltage that goes to the bed. I guess I assumed that since the voltage on the PSU is 24V (measured) and the only element between PSU and heatbed is FET transistor I can expect the voltage to be around 24V (the only voltage drop will occur between Drain and Source). Anyway the bed is rated for 140W, so I can'tby kjakobczyk - Prusa i3 and variants
Dear Community! Few days ago I was investigating together with you the issue where my Prusa i3 XL (large heatbed 200x300mm) was melting the prints directly on the heatbed (link). With your help I figured out that I soldered the heatbed incorrectly, so one part of the heatbed had 140C, while the second had only 40C. My heatbed is rated for 140W. It has 3 soldering pads with numbers 1, 2 and 3. Wby kjakobczyk - Prusa i3 and variants
ATMega is powered directly from the PSU and to be honest I've blown up 3 boards in the past and all of them (when they were working) caused the FET to heat dramatically. I'm using Marlin v1.0 firmware, so it's not capable of doing any PWM on the FET, just regular on-off cycle, so it would be strange that it's not fully opened. The regulator in the ATMega board works from much lower voltage than Iby kjakobczyk - Prusa i3 and variants
OK, but do you think that if the paths on the bed would be damaged I could visualy see it? I was inspecting the bed several times and didnt notice any problem. It of course may happen between inspections, but this I will verify today, because I need to dismount the bed and desolder from 12V, soldering it back to 24V. I remember that with stock FET on RAMPS and 12V/400W ATX power supply the FET hby kjakobczyk - Prusa i3 and variants
Hello again guys, I've got the updates. Following your advices I've made an experiment: I hooked up external temperature sensor with kapton tape directly to the bed and I placed 8 drops of water in the corners of the bed and in the middle. I let the heatbed to heat up, it took about 15 minutes from 5 degree Celsius and the results suprised me a lot! Take look at the photos: In the above photo yby kjakobczyk - Prusa i3 and variants
@o_lampe: I'll do the test as you suggest, this is easy. I have however notice that the bed heats up pretty evenly without much measurements, so I think it's not the case that coils are broken. Such metling occurs in every part of the bed, I've tried dozens of prints all around the bed with similar results. As for the borosilicate glass you told me something interesting: initially I had normal glby kjakobczyk - Prusa i3 and variants
Thank you for the answers guys! @Dust: I'll verify the temperature with external termometer tomorrow. I initially thought this may be the cause, but didn't check it out since there were some confusing information over the internet about bed leveling that may lead to the same effects. @MCcarman: The bed is connected to 12V leads unfortunatelly and this was my intended action. Initially the bed wby kjakobczyk - Prusa i3 and variants
Hello Dear Community, I'm new to the topic, but was struggling hard past times to get my ABS printout correct without any result, so I decided to ask for professional help. I've built Prusa i3 with larger heatbed (200x300), 24V power supply for the bed, 12V for the rest, hardened 4mm glass on the bed. I have no problem in reaching 110 degree on the heated bed even if the printer starts in an envby kjakobczyk - Prusa i3 and variants