PETG Help

[massnerder]

OK, so I am suddenly having some very odd issues specific to PETG. The symptoms sound like some more common issues, but I have been working on this for a while and it definitely is not a simple clog/ jam/ etc.

Some backstory: I was 100% noob to 3d printing when I got my Da Vinci 1.0a, and I immediately flashed Repetier to it and all was well. I experimented with different projects and materials like nylon, PLA, ABS, etc with success before I settled on PETG for my MPCNC project. At this point my printer has about 30 days of run time on it and I have learned a thing or two, but I am still a bit noob-ish.

So a few weeks ago I began printing to parts for my MPCNC and again all was well. Suddenly more than halfway through the parts list I am now having major print issues. Clicking, under extruding, if the print does finish its extremely weak and I can flex it by hand. Funny part is I have the exact same piece (among many others) printed on the exact same printer with the exact same settings that have all came out perfect. I am not sure why I am suddenly having this issue as the only thing that changed was the filament roll. Same exact filament, and I have even tried a different brand PETG filament and am seeing the same results. After making perfect prints through 3 other rolls I am reasonably sure that the filament is good, or at least that I didn't get 2 batches of lemon filament

I have taken it all apart and made sure that there were no clogs, feed gears are clean, connections are solid, etc. It seems to come and go, IE I can print a tall part and some random layers of it will be perfect and some are bubbly/cloudy/weak. I have dried the filament just to be sure that wasn't an issue. What really kills me is that if I turn off my heated bed and change no other settings, then I can make perfect PLA prints all day long... So it's hard to believe that something is wrong, but something is definitely wrong lol.... Any ideas why my printer is suddenly so anti PETG??

[airscapes]

Only a few months ahead of you but I have been printing with PETG for a while. Started with eSun White and recently bought MakerGeek Crystal Red Blue and Clear. I have printed with all 4 rolls with no issues.

From your descriptions, sounds like a hot end or power supply issue. You mentioned PLA prints fine with the heated bed off, what happens when you print PLA with a heated bed, as that is the only way I have ever printed PLA. Do you have issues with the heat one? If so, sounds like a weak power supply or something. PETG prints much hotter than PLA and with the heated bed on that would require your power supply to output the highest amount of current. Could also be a bad thermistor in the hot end. With the hot end at room temperature does the software report the same temperature as your room air temperature? With the statement of clicking noise which I assume is coming from the filament drive it stands to reason the hot end it not holding a constant temperature. Also examine all wiring that would move during normal operation, you may have a loose connection or broken wire that only intermittently conducts power. There should be no resistance though the wiring harness to the hot end, but a loose or damaged connection will cause the resistance to rise and possibly pass sufficient current to print at PLA temp but not at PETG temp. Good luck tracking it down!

[massnerder]

thanks, but I have checked all of that. PLA prints fine with the heated bed on, but the PETG requires a hotter bed. I have never really used the heated bed for PLA, only ABS, nylon, and PETG as its easier to just switch it off than lower the temp. Temp reading on the hot end stays consistent when the issue occurs and when not printing. Printing NovaMaker PETG and I can't remember what PLA both at 240, have previously gone as low as 230 for PLA and NovaMaker says 230-260 on their PETG.

I suppose it could be a power supply issue or a thermistor issue, but I have watched it go and the temp reading is consistent within about 2 or 3 degrees when it happens, or at least the printer and software seem to think so.

Honestly this is a relatively new (less than 1 year) printer and if I am going to end up dumping more time and money into fixing a faulty hardware issue then I might just replace it, since that Ender 3 is so cheap lol

[airscapes]

Well, as a tool guy, I can say with authority, when buying machines and tools, you almost always get what you pay for.
Also, this is not the last hardware problem you will have, you need to isolate it and find root cause as replacing a machine when a part on it fails makes no sense.
My M2 has had the wire on the heater fail and it was new in Feb. The wire broke off at the heating element. It was covered under warranty but was only a few bucks if it had not been.. Keep looking you will figure it out!

[massnerder]

Well, my other goal was to do this whole thing again and make a bigger/better 3d printer on the MPCNC platform, after the CNC is done... I know I can only do so much with the stock davinci hardware and my real issue is that the thing is just a pain to work on. Being able to access those parts more easily would be a lot nicer for when these things happen.

But I hear ya, for just $60 and a little print time (assuming it prints lol) I could just upgrade the whole assembly to an E3d/bowden extruder, save almost $150 over the Ender and still have the enclosed print area... it'll just still be a pain to work on