Galileo 2 vs Orbiter 2 pushing force

[m00dawg]

I have G2's on both my 350mm 2.4 and 300mm Trident and generally they work really well. It's a fantastic extruder and I found it was easier to build than C2 and gives me better results. One thing I have noticed though is it seems to be easier to start skipping. I use Push Plastic's Black PLA for most of my prints (since opacity is very important and their black PLA is *super* opaque) but it's been a hard filament to nail down. On my Prusa MK3's (with Revos), I have to print around 235-240C. On the Vorons, which also have Revos, it's also 240C normally but I'm finding for some prints on the Triden I'm having to go up to *250C* to avoid clogs. That's getting awfully hot for PLA. By comparison on my XL, I'm printing around 215C for the same filament.

Trouble is if I lower the temp on the Vorons I start to get skipping.

So, my thought was to perhaps try out the LDO Orbiter just to compare and was curious if anyone has any opinions on the pushing force of it vs G2? And if it might work with Nitehawk for when I eventually (finally) start doing an umbilical.

To be clear also, I don't have these issues with the G2 for ABS or Atomic PLA. The G2 is a glorious so I don't want to come off as speaking ill of it. I'm just trying to solve for a potential special case.

 

[Dave32]

Is the extruder motor current set correctly?

And just so we are on the same page... you say "skipping", and you are referring to the stepper skipping, correct? (ie: not stripping the filament at the drive gear(s))?
Because the Orbiter and G2 might very well have different push force capabilities, because one is designed with dual drive gears to maximize grip, whereas the other uses a singular larger diameter gear with a smooth idler to obtain its grip without the alignment issues and VFA impacts of dual drive setups. I have no data for either, but they are definitely different.

 

[m00dawg]

Ah I somehow thought the Orbiter was a planetary gear system as well (hence "Orbit") but that's a good point. Indeed, it's the motor skipping due to being unable to push the plastic through. I did check alignment. It did take longer to align the this G2 vs the one in my 2.4 but it does seem well aligned and smooth. I recall reading not to put too much force onto the tensioner so try not to run that super right. I am able to see the filament getting chewed up some. This filament is known for not being quite as grippy / being easier to "eat" so that is certainly one factor there. Given the types of things I print on the Trident, better grip I think is something I would value higher than VFAs.

 

[Dave32]

You were correct - they do both use planetary gear systems. But that's for the gear reduction before the filament drive gear(s). On the Orbiter, the planetary gear reduction directly turns one filament drive gear, and the second filament drive gear is adjacent and gear driven from the first. On the G2, the planetary gear reduction powers a filament drive gear that is larger in diameter (so more teeth can bite the filament), and then the second drive gear is omitted in favor of a smooth idler.

 

[ChrisA]

I have G2's on both my 350mm 2.4 and 300mm Trident and generally they work really well. It's a fantastic extruder and I found it was easier to build than C2 and gives me better results. One thing I have noticed though is it seems to be easier to start skipping. I use Push Plastic's Black PLA for most of my prints (since opacity is very important and their black PLA is *super* opaque) but it's been a hard filament to nail down. On my Prusa MK3's (with Revos), I have to print around 235-240C. On the Vorons, which also have Revos, it's also 240C normally but I'm finding for some prints on the Triden I'm having to go up to *250C* to avoid clogs. That's getting awfully hot for PLA. By comparison on my XL, I'm printing around 215C for the same filament.

Trouble is if I lower the temp on the Vorons I start to get skipping.

So, my thought was to perhaps try out the LDO Orbiter just to compare and was curious if anyone has any opinions on the pushing force of it vs G2? And if it might work with Nitehawk for when I eventually (finally) start doing an umbilical.

To be clear also, I don't have these issues with the G2 for ABS or Atomic PLA. The G2 is a glorious so I don't want to come off as speaking ill of it. I'm just trying to solve for a potential special case.

it could be that you have some heat-creep. Because you are using such a high nozzle temperature, the heat is going up past the heat break. Melted plastic is harder to push than hard PLA. I guess you might try a bigger fan that pushes more air at a higher pressure.

Using more current, or tightening the spring may not be addressing the root cause which is printing PLA so hot that it is melting above the heat break.

 

[m00dawg]

it could be that you have some heat-creep. Because you are using such a high nozzle temperature, the heat is going up past the heat break. Melted plastic is harder to push than hard PLA. I guess you might try a bigger fan that pushes more air at a higher pressure.

Using more current, or tightening the spring may not be addressing the root cause which is printing PLA so hot that it is melting above the heat break.

Yep this has crossed my mind a lot though with more normal filaments, I don't print nearly as hot, typically around 215C. If I print the PP Black PLA around those temps on my Vorons, I get skips way earlier. In fact I have to print hot on my MK3s (Revos) also. The only one I can print cooler (215C seems to be working well) is the XL.

Secondarily I want to print hotter for a nicer top layer but the higher temps are largely because if I'm not up around 240C on the 2.4 or 240-250C on the Trident, I'll get skipping. Odd part is the "clogs" come out easily, I just unload the filament and it comes right out, clip off the plug at the end, load it back in, and off I go.

PP uses NatureWorks 4043D for this filament though I haven't been able to find information on print settings so easily when just searching by the virgin PLA.

I had thought maybe I'm outrunning the filament on the Vorons and XL I have the top speed set to 150mm/s (that's the solid infill).

 

[Dave32]

Have you tried calibrating your max volumetric flow?
It could be that the majority of your printing is doing just fine (staying within reasonable flow rates), but some part of your print is printing faster, or with a higher layer height, and is exceeding the physically possible limits.

Note that supports are a common gotcha for this. You do a bunch of work to get your profiles tuned - set reasonable speeds, etc - and then the slicer generates variable layer height supports at a thicker layer height than you are using, and that "reasonable speed" you set is actually exceeding the volumetric maximum your nozzle can flow. That's why tuning the max volumetric limit is important, even if you normally print slow enough that it doesn't matter.

 

[m00dawg]

Have you tried calibrating your max volumetric flow?
It could be that the majority of your printing is doing just fine (staying within reasonable flow rates), but some part of your print is printing faster, or with a higher layer height, and is exceeding the physically possible limits.

Note that supports are a common gotcha for this. You do a bunch of work to get your profiles tuned - set reasonable speeds, etc - and then the slicer generates variable layer height supports at a thicker layer height than you are using, and that "reasonable speed" you set is actually exceeding the volumetric maximum your nozzle can flow. That's why tuning the max volumetric limit is important, even if you normally print slow enough that it doesn't matter.

Oooh that's actually an excellent point! Pretty sure I haven't. I've done extrusion calibration but not the actual volumetric flow. I think that would be well worth the exercise, thanks for the insight!

 

[Dave32]

Sure thing! If you are using OrcaSlicer, there is a built in tool that generates a test pattern that is super easy to use.

 

[m00dawg]

Aha so there is! Yep I use Orca for the Vorons. Yep that should make that super easy. I'll hopefully run through that tomorrow and report back for folks. Would be good to document my results just in case anyone else is using PushPlastic Black PLA (and I assume at least some of the other colors would have similar behaviors too).

 

[m00dawg]

Alrighty! So ran the flow rate test at 240C. The flat side along the Y shows some artifacts that I think are unrelated but I might need to look at those (I don't see them on the Y side curves).

Along the X straight bits, looks like I am run at 10mm/s as a conservative max. Reality is it doesn't start actually skipping until around 16mm/s but I start seeing some lines which I think relate to the thermal expansion of the plastic past 10. I looked at the flow rate of the models I was having issues with and it was around a max flow-rate of 12 (but most of the time seems to be around 10.7).

I'm going to try 9mm/s at 240C and see how things go. 240C at 12mm/s was giving me good results for one model but oddly bad results using a different but rather similar model.

I'm also going to ask Push Plastic if they had any recommendations on VFR.

EDIT: Quick update, looking at the print settings PDF from Push Plastic (avail here: https://www.pushplastic.com/pages/print-settings), the print speed they seem to recommend is 45-55mm/s. That puts the flow rate at around 3.5-4mm/s or so if I did my math right based on my tests though this is at 215C. Noting Revo's seem to require higher temps (due to where the thermister is at) so could be indicating I'm outrunning the filament and am just getting luckier with the MK3 extruders.

 

[Dave32]

Stefan at CNC Kitchen had an interesting take on the thermal characteristics of the Revo... namely that the ring heater puts the thermistor very close to the heating element, making it possible to have a thermal gradient where the nozzle itself is colder than the thermistor reports. (As opposed to the V6 design, where the heater cartridge and thermistor are on opposite sides of the heat block, making the nozzle be typically warmer than the thermistor reading.) He also noted that the Revo was more susceptible to temperature differences due to part cooling blowing over the nozzle. So that could also be part of it?

E3D RapidChange REVO Review — CNC Kitchen

RapidChange Revo is E3D’s new hotend eco system. As the name RapidChange already suggests – one of the main advertised features of Revo is the ease and convenience of nozzle changes because no tools are needed, and it can and should be done, while the hotend is cold. But E3D did more than this becau

www.cnckitchen.com

There is some "normal nozzle" data in his Revo High Flow review as well:

E3D Revo High Flow Review — CNC Kitchen

High-flow 3D printer nozzles are in my opinion one of the most important additions to 3D printing of the last years because they are able to melt material way more quickly at the same size as a standard nozzle. No more long, unstable hotends and custom fan shrouds. E3D released their REVO hotend sys

www.cnckitchen.com

 

[Dave32]

One other thing - pressure advance could also play a factor, as that varies the flow rate at the printer firmware level (past what your slicing software knows about).

So for example, if my printer could print say 20mm3/s before skipping, and I sliced a model to print with a maximum of 20mm3/s, the *actual* flow the printer tried to push through the nozzle could still exceed that 20mm3/s during model features where pressure advance is doing its magic.

 

[m00dawg]

PA is a great point yep.

As is the thermistor of the Revo. Interesting point there is my MK3s all run Revo's and do not have any skipping issues for the same models even at the same speeds and similar temps. I don't use the cooling fan by default on these models either. However I am using a different slicer (Orca vs PS) and the PA values I got on my Trident are different than my 2.4 so I think there might be something to look at there, that's a good point. Why I got different values I'm not sure though. There are small differences between the two. Perhaps because I'm running a faster heatbreak fan on the 2.4 it's decreasing the melt zone and changing how PA may be working there? *shrug*

PA in my Trident is 0.062 and on my 2.4 is 0.02. I calcuated PA on my 2.4 using a Ellis' PA generation tool though used Orca's built-in for the Trident. Means I should perhaps retest the 2.4 for apples to apples (it's out of commision at present while I wait on parts alas).