I had some time today so I wanted to show you some tests I did on my printer. Of course one of the most interesting things to test is the extrusion: how fast can you go? I printed a bunch of test cylinders, both with the UM2 with Robert's feeder modification
, and with the Flex3Drive.
I got the tests from the Ultimaker forums: 3-10 mm³/s
and 8-15 mm³/s
. With the old setup, I only printed the 3-10 mm³/s test, because it would fail before reaching the end anyways.
MakerPoint Ultramarine PLA, printed at 230 °C.
Both were printed with the original feeder. Unfortunately I ran out of this filament, so I don't have any prints with the Flex3Drive. I printed this same test twice with exactly the same settings, because I wanted to see how repeatable the results were. As you can see, the results aren't bad at all. Up to 9 mm³/s the print came out very well, only at 10 mm³/s it started to fail. The second print is almost exactly identical to the first, so I'm quite confident that this is a reliable test.
MakerPoint Traffic Black PLA.
The left one was printed at 230 °C using the original feeder, the middle was printed at 210 °C and the right at 220°C using the Flex3Drive. I did have some trouble printing the large test. My first few attempts, I encountered a nozzle clog (see pic in previous post) and the print failed at 9 mm³/s. After I cleaned out the feeder, I decided to print it a little hotter, and it went without issues.
MakerPoint Signal White PLA.
Same story: left one printed with the original feeder at 230 °C, middle and right printed at 210 °C and 220 °C respectively using the Flex3Drive. The last one still shows some signs of under extrusion here and there, even though the last sections came out perfectly. Some time after I finished these prints I learned that the tension on the lever was probably too low.
MakerPoint Pearl Gold PLA.
With the original at 230 °C the print failed at 9 mm³/s. This filament displays under extrusion differently than the other ones, it seems to stick together more than the rest. With the F3D at 210 °C the test came out perfectly in one try.
MakerPoint Iron Grey PLA.
The upper three were printed at 210 °C, 220 °C and 230 °C respectively, using the original feeder. I printed it first at 230 °C, and was not satisfied with the way it turned out, the temperature was obviously too high for this filament. The surface finish was better at lower temperatures, but the test did not finish without under extrusion.
The bottom three were printed at 210 °C using the Flex3Drive. The leftmost cylinder was the first print I attempted after installing, and I was a bit dissappointed at first at how it turned out. It did look a bit weird to me though, the letters seemed a bit "fuzzy" compared to the other cylinders I printed. A while later I discovered I used a 0.6mm nozzle instead of a 0.4mm as intended....
The second print was done with the right nozzle, and it turned out fine. The surface quality isn't top notch, but there was definitely no under extrusion. The big cylinder came out well, probably could've been a bit better if I had tightened the lever a bit more.
MakerPoint White Aluminium PLA.
Printed with the F3D at 210 °C. This filament prints amazingly well. Definitely the best looking cylinder I've made so far, slightly better than the gold one even.
Comments on the tests
The small test runs very smoothly. It is very well made. On my old setup I used TinkerGnome, which allows you to monitor the flow as it is printing. I checked this test, and the output is exactly as indicated.
The big one has a few issues. The first section runs just fine, but from 9 mm³/s up the movement becomes very 'blocky' (can't think of the right word in English). You can actually see this if you look close, the surface is not smooth, it feels more like a 100 sided polygon or so. Also at most layers, some part of the circle prints faster than others, even if there's no text being printed. This is probably due to poor slicing, because every now and then there is a layer that does print perfectly smooth, so it definitely is possible.
Apparently there also exists a version that goes up to 20 mm³/s, but I haven't been able to find it. I've heard it was used at the Ultimaker HQ for testing purposes... Maybe @nallath could share it
Of course printing cylinders is nice, but how does it work when actually printing something useful at high speeds? For that purpose I made a test object. I chose for a gear, because it has some interesting outside geometry that might print differently at different speeds. I made it so that half of it would print with and the other without top layers, so I could inspect the infill.
I printed them at 210 °C, at .25mm layer height and a 0.4mm nozzle. The speeds used were 50 and 100 mm/s resp. for the top two, and 150 mm/s for the bottom three. This corresponds to 5, 10 and 15 mm³/s output of plastic.
As you can see, the results did not turn out quite perfect first try. The one I printed at 50 mm/s came out pretty much perfect. Infill is solid, top layer is nice and smooth, and not under extruded. Only thing I might change is the infill angle, to close the little gap in the top layer.
The print at 100 mm/s came out quite okay too for the first part. The infill printed great, and feels solid. The top layer had serious under extrusion issues though. My first attempt at printing at 150 mm/s (bottom left) didn't turn out so good. The bottom layers were a bit 'see through': there are small gaps between the lines. The infill was mostly okay, but still there was some under extrusion here and there, and it did not feel solid like the other two prints.
Of course this was a little bit disappointing, so I contacted Mutley3D for some advice. After some help I found the problems: I had not properly tightened the lever, which at low speeds is not such a problem, but a higher speeds it is. Also I made an error in the slicer, and I had set the temperature to 190 °C for the top solid layers... oops. So it wasn't very surprising that they failed at all.
The fourth and fifth prints I had made sure the lever was tightened properly, and I made sure the temperature was set correctly. The fourth one was still slightly under extruded for the solid layers, the infill came out perfectly though. The last print I increased the flow rate, and it came out a lot better. The top layer is not perfect, I used too few solid layers and the flow rate needs to be just a little bit higher. Other than that, the print turned out fine.
Concerning the outlines, they did look a little bit better on the slower prints.
Since then I have printed some actual prints at 100 mm/s, 0.2mm layer height so 8 mm³/s flow. For the outlines I reduce the speed to 40 mm/s or so. I use an extrusion multiplier of 1.10, and the prints turn out just fine. Especially for prints with large flat surfaces this can seriously reduce print time.
The Flex3Drive makes it possible to print much faster compared to the original feeder. However, this doesn't mean that you can just turn up the speed and expect miracles. You need to adjust your settings, and use the correct tension on the lever, both of which take some experience to get right.
Next time: prints with a lot of retractions