Help with Big Rep Studio G2

[Izak Last]

I work in a 3D printing lab and am responsible for keeping the printers running. We have a nice German machine, the Big Rep Studio G2. It was great for a while but, recently, it has been failing over and over. Because of the industry I work in, we must have ESD safe material so we have been trying for some time to get 3DXtech ESD safe PETG to work. We also have some of Big Rep High Temp CF (PLA based material with chopped carbon). I can get a test print to run just fine. I print a low-poly skull in vase mode. Then, I throw a customer part on there, a simple rectangular frame with some vertical holes, maybe 1" tall, 12x14". It prints 1/3 of the part and then air prints. I pull the filament and check the tip. It's a little expanded and there is a half-moon carved out where the drive gear dug into the filament. The nozzle is NOT clogged and will extrude just fine with a new section of filament.  I have replaced the nozzle and the heat break. The fan shroud (downward fan) was broken and I though maybe the heat sink fan was not blowing directly on the heat sink because the shroud kind of contains the airflow (boxes it in on two sides) heat sink fan as well as the downward fan. Brand new shroud installed last week. I have switched back and forth between the materials, new spools (sealed in plastic with desiccant) each time.  I have changed the temperature from the lowest end of the range listed on the spool to the highest. I have reduced retraction and also disabled it. The Big Rep has a E3D V6 hotend and I have read through the assembly instructions. We are using Cura with a custom built machine profile and material profile derived from PETG. I have slowed the print speed way down and tried changing the extrusion multiplier by 1% on either side of 100. The part was printed solid if that makes any difference. I have had failures with low infill parts too. On the last fail, the filament had snapped off about 8 inches above the inlet to the extruder. I don't think it matters but it's a clue. I am using 3MM filament with a 0.8MM nozzle. We have a garolite sheet on a heated bed and I have it dialed to make perfect first layers. Somethin just happens a few hours into the print, usually when I have gone home for the night. 

I am out of ideas, I cannot figure this out. Why does the skull in vase mode print fine but a part we need will fail every time? 

[markni...@gmail.com]

Izak,

Just to try and understand, is this the printer that you're refering to: https://bigrep.com/bigrep-studio/?

Also, are you heating or cooling the enclosed build chamber in any way, like what temp is the build chamber at when you are printing?

You say you are printing on a garolite plate, but are you heating the build plate at all, and if so to what temp? 

If you are having the filament snap, it usually means the stiffer filament you're using has not been heated enough to make it properly flexible. There are various methods to pre-heat it slightly, before it enters the cold end of the extruder.

[Kurt The 3D Printer GUY!!]

I think I MAY have used the BIG Rep YEARS ago in San Diego at SD3D. I believe the machine has an Enclosure. If so - and you're printing PLA - you should print with Door Open!

Vase mode for Skull means it's probably printing Fast and done in a short period of time. But, you do the client part, it's printing Solid - and over a Much longer period of time - chamber is getting a bit Hotter - and you're getting Heat Creep - which seems to make sense in regards to what you're telling us. 

So - give it a shot and print with the door Wide Open!

Also - please give us a pic of the machine.

-K

[Izak Last]

Yes, that's the printer. It's the "G2" but looks identical to that picture. $80K machine with a $100 extruder. 

Chamber is not heated, it has vent fans that you can set the trigger temp for. 

Heated build plate set to 60deg C. 

No heated chamber for the filament, I can ask my lab lead about jury rigging some kind of heater. 

[Izak Last]

To Kurt, 

I can't take pictures on site, defense industry rules. I will try printing with the doors open, thanks for the suggestion. 

The skull is a print time of around 2 hours. The customer part is around 6 hours. This adds up!

Thanks again. 

[markni...@gmail.com]

Izak,

No need to jury rig a heater, any of the filament feeding driers heat the filament: https://www.microcenter.com/product/677196/creality-space-filament-dryer

I haven't used 3mm filament since back in the day, but I also found 3mm PETG very stiff and subject to snapping.

As far as I know there is no advantage to 3mm filament, it is much stiffer than common 1.75mm filament.

It doesn't allow you to print faster, it's just an artifact left over fro the early days of 3d printing, when 3mm was all there was.

[3D Printing Tips and Tricks]

The material is going soft too high up within the thermal break. Sometimes the reasons for that can be real subtle. the thermal tube has to be just right with the right amount of cooling. You stated it’s a V6. Did you assemble it or was it already assembled?  Where the top of the nozzle and the bottom of the thermal tube meet in relation to the hot block is kinda important. The further into the hot block the tube goes the higher up is the edge of the melt zone and the more likely the material goes soft too soon. IIRC… the nozzle goes all the way into the hot block, then you back it out one or two turns. Then you insert the thermal tube to meet the nozzle within the block.

[Izak Last]

I have taken the hot end apart and reassembled a dozen times, swapping heat breaks and nozzles. This is exactly how I assemble it. The confounding thing is tha tI can get a test print to work just fine, it's only customer parts it can't finish. I will disassemble to hot end and reassemble again just to be sure. I also plan on printing with the door open. 

[Jody Harris]

printing your test print in vase mode may be hiding the problem from you. With steady flow and no retractions, you're not testing the printer under the same conditions as your use case.

-j

Think carefully

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[markni...@gmail.com]

Izak,

A teflon lined thermal tube compensates for a multitude of sins.

If you only printing PLA and PETG, you are not likely to exceede the max temp with either filament.

[markni...@gmail.com]

Yes, check E3D dealers, some will have a 3mm thermal tube.

Measure your filament with a caliper, if it meaures 2.85mm get 3.10 I.D. teflon tube.

Worst case, P.M., I might be able to make you a tube on my metal lathe.

[Kurt]

Jody makes a good point. 

And - Yeah - if it's PLA - Heat Creep can occur - and that's why printing with  the door open may indeed solve your problem. No worries re: No Pics - I get it - we had military customers at Essentium.

-K

[Kurt A 3d]

So, in my case PETG this week has gone to hell.  In my house (not defense facility) I look at this as a result of season change 1) because it is slightly  warmer outside (above freezing now) it is conversely colder in my print room (partially above ground portion of my basement) because the houses heat is off more. Because It is slightly warmer outside, the humidity has now swapped from the winter situation where my room has lower humidity than my "dry" boxes to like over 30%.    So, if this is a less climate controlled facility than American defense industry - being my experience visiting Germany I believe this may be the case (not defense industry just general germans are hardier people who dont believe as much nor need as much climate control as in this US - then perhaps its the change of season effecting your results.   

But, you probably have to worry about heat creep as everyone else says :-)

Kurt-A

[Kurt The 3D Printer GUY!!]

Yeah Mr. Doppelgänger - I truly believe it's Heat Creep that is causing the problems for the OP. 

Ironically - I'm seeing a similar situation here in OH - and my co-worker with the new 3DPO - he has ALSO noticed a massive increase in humidity lately. It's OBVIOUS as to why. Due to temps rising fast lately - we have even had Several mornings of Heavy fog - so, all the snow is melting Fast - much of it vaporizing (although that is an extreme usage of the word and probably NOT proper) - but, this is causing a LOT of extra moisture in the air - which my co-worker brought to my attention. But, Honestly - it has NOT Affected my printing - I do NOT see issues in my ABS print - that might be due to moisture...

-K