Kossel + Duet3D + titan + volcano = quick printing?
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I agree with @Danal ,I have a Bondtech QR pushing plastic through a Bowden fed volcano and it has no issues with running a 1.2mm tip at 50mm/s. My biggest worry is my extruder motor overheating so I put a heat sink on it.
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As you say you are "hitting the melting limit for the hotends" that sounds like you've done the temperature-filament calibration work (e.g. described in step 9 of this post - poorly written but useful math) and know some maximum speed you can accurately lay down a commanded volume of melted plastic with your current setup before the extruder starts missing steps or grinding. If not, this procedure will help you to know the answer for your system without spending any money.
Pushing melted filament out is the rate limiting part of how fast you can print, the rest of the story is all about smoothly and accurately positioning the melted plastic without motion artifacts (quality).
The Volcano's longer melt path will reduce the backpressure by melting the filament faster so the Titan can push more through without skipping steps, until you reach the speed limit for your Titan stepper motor and electronics (24V faster than 12V). If you search around the E3D website, Sanjay has some comments about not being able to use small nozzles with the Volcano because the flow rate is still slower and the plastic gets overcooked (look for "why not always use Volcano") so there are trade-offs.
Sounds like the Bondtech or other dual drive extruder may be able to force more through a given hotend as well. Depending on the failure mode (skipping steps or grinding) this may help (Deckingman has some interesting comments on the Bondtech in this blog post).
If you are staying with the 0.2mm layer height then the 0.5mm nozzle will only lay down a wider strip of plastic. This will give you thicker/stronger walls, but does not seem like this part will necessarily speed things up - though depending on the part design and slicer settings there will of course be cases where that added 0.1mm will help.
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Thank you all for your replies. You have given me lots to think about. I will start out with a standard E3D v6. Might change into a volcano later.
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Hi if i may wade in here i currently run a volcano hotend with a titan extruder with absolutly no issues, but it does take a fair amount of tinkering to get it dialled in correctly, and i found simplify 3d helped greatly with this mainly because of the print preview. If you wanted to use the e3d v6 hotend you can use the 3dsolex matchless v3 nozzles ( http://3dsolex.com ) they go from 0.25 up 2.0mm. I ordered from here https://www.3djake.uk/3d-solex/matchless-v3-nozzle. I hope this helps.
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This video gives a good breakdown of what is involved in the trade offs of increasing nozzle size in relation to melt rate and print speed.
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I ended up typing a lot more than I expected to...
I have a Tevo Little Monster I've converted to Duet/RRF, with a Volcano nozzle & Bondtech extruder. I've used every nozzle on it from .4 to 1.2mm. I've always gone by the rule of thumb that a standard hotblock can output a volume of plastic about 10cubic mm/sec , while the volcano can do around 30cubic mm/sec (the flowrate). And like mentioned above, it's the volume of plastic you're pushing that makes the print go fast, not how fast the toolhead moves. I've done testing to push those limits, and they seem to be a pretty good rule of thumb: Even if your extruder is strong enough to push more plastic in there (and the Bondtech is good at that), at a certain point the heater can't keep up (more cold pastic is moving in than it can heat up in time), and you get temp drop, and a filament jam. You can compensate by running even higher temps (say, print your PLA at 250c), but it's a dangerous game, I've tried for testing purposes, not recommended.
So with a 1.2mm nozzle (with a 1.2mm extrusion width), you can print 900 micron layers at 27mm/sec (.9 * 23 * 1.2 = 29.16), or you could print 300 micron layers at 83mm/sec and still hit the 30mm3/sec (.3 * 83 * 1.2 = 29.88) flowrate, and technically (based on your acceleration & jerk values) the'd both have the same overall print time.
I've found thin\thick layers both have some advantages\disadvantages compared to each other:
- The lower your layer height, the better you can do overhangs, since you have more 'steps' to print on below each layer. And the layers cool faster which can matter.
- But since the big fat layers have to be printed at a slower speed, it really mitigates out any speed related artifact like XY ringing, and technically you're getting a stronger bond simply because you have fewer layers being glued together : On my core-xy (RADDS/RRF), I have a crazy powerful ducted fan specifically designed to cool down big layers, since that residual heat is very easy to build up.
My TLM shipped with a knockoff Titan. I use a Bondtech on my other core-xy : I very quickly bought another Bondtech for the TLM. Bondtech is great, especially when you're trying to squeeze large amounts of filament into the nozzle: The dual hobbed-gears in there are the clear winner compared to a spring pressing against an idler.
Also, there are 3 main differences between the volcano and standard e3d v6 hotend:
- Bigger nozzle orifices (although you can run any size you want, I'm currently running a .4 on my corexy volcano)
- Bigger hotblock: Physically more metal.
- Higher wattage heater cartridge: When I bought my first volcano, they accidentally sent me the heater cartridge for a standard hotend, and I couldn't figure out why I couldn't print at the flowrates described above: After checking the resistance on it, I realized it was under-powered: I got the correct wattage cartridge, and everything started to work as it should...
So if you go with a 'normal' v6 and decide to upgrade to a volcano, you need to replace all 3 of the above.
The only main downside I've seen is they have a larger melt-zone, and thus are more prone to stringing/oozing/blobbing, and you need to be a lot more aggressive with your retractions.
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The Volcano and the standard heater blocks come with 30W heater cartridges. E3D also sells a 40W cartridge, either 12 or 24V.
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As @mrehorstdmd has pointed out 30W is probably enough for most "standard" filaments. As far as I can see the issue is not how hot the heater block has the potential to get (e.g. a 30W cartridge vs a 40W, 400C vs 550C or whatever) rather its the amount of time the filament is in contact with the hot area (melt zone). with a 30W cartridge, the potential max temp is way above the "normal" printing temps for PLA/PETG so other than an slightly quicker heatup time and quicker recovery from very large changes in flow rate, the 30W cartridge is fine (and its safer).
The Volcano (and now supervolcano) primarily increase the melt zone, so more energy can be transferred into the filament, increasing the max melt rate an thus extrusion speed. Yes you can set the desired temperature to significantly higher than the print temperature to increase the heat flow gradient - i.e print PLA at 250C to make it melt quicker - but that only works when you are printing super quick. A few seconds of slow down due to printing small areas etc and you end up with horrible blobs and possibly a blocked nozzle due to charred filament.
@deckingman is an expert at this as he has characterised the 3 and 5 input diamond hotends. they necessarily have a large meltzone (big block of metal!) but a 40W heater cartridge is still more than adequate. His blog is a great reference for a detailed analysis of all this. (see https://somei3deas.wordpress.com/2017/06/22/exploration-of-print-speeds-with-a-diamond-hot-end/ as a start point).
What is important is to determine what the true limiting factor in the system is (it changes!). For example with a insufficient heat flow rate into the filament, due to a short melt zone, it is possible to get better performance through using a more powerful extruder (as you can shove part melted filament out the nozzle faster) however you are not truly solving the problem and are likely to end up with layer adhesion problems as the not hot enough filament fails to stick to the layer below properly.
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@t3p3tony you should check out 3dsolex.com there nozzles are really quite clever
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@mrehorstdmd : The issue was, after removal and checking the resistance, the heater mine came with was 20w. I ordered a 40w one for replacement, and checked it upon arrival: Actually came in more around 35w. But regardless, it got me the flowrates I needed.
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On the e3d forums they've said that the theoretical maximum on the volcano is 40 cubic mm/s and the v6 is 15 cubic mm/s.
I have managed to get close to that maximum flow rate on my volcano with a nimble extruder.
1mm nozzle: 1.2mm extrusion width x 0.75mm layers at 30mm/s = 27 cubic mm/s
I attempted printing at 50mm/s but was stalling out the extruder on fast print moves as the volume extruded was 45 cubic mm/s at those speeds. I didn't spend much more time finding the absolute maximum but could possibly do so. (44 mm/s would put it just below 40 cubic mm/s)
I am using a 24v 30w heater in my volcano, using typical temperatures for pla (200°c), same as on my v6, volcano nozzle temperatures remained consistent even though the extruder was stalling, so I don't believe a higher wattage heater cartridge will improve volumetric output. As Tony said wattage is more a function of maximum temperature.
I have not yet attempted to test if increasing the nozzle temperature impacts the maximum volumetric output as I assumed it would have a negative impact on areas where the speeds are low enough that the volumetric output is within the limit of the volcano.
