nick-foley

We're using a modified version of the mooncactus XY blocks. We changed some hole diameters to accept plastite screws instead of machine screws (and do away with the nuts!), as well as adding a lip around the bushing to hold it captive without excessive clamping force. There's been grumbling on this forum about the need to design a new XY block, and I agree. The mooncactus version is a huge step forward from stock, but it's still tedious to assemble and not that much easier to adjust. I've been sketching up some ideas but haven't had the time to execute them yet. (Edit - just modeled something up, will print tomorrow and start a new thread if they seem like a legitimate improvement.)

Woooo! We got our new machine with the latest E3D hotend and custom printhead up and running yesterday and we are really loving the results. It is definitely a more elegant solution than stock, as well as much easier to assemble and much lighter weight. I'm sure it will prove to be higher performance as well. Build volume doesn't seem to be compromised significantly - I believe Z is the same, X is around 210, and Y is around 200. We reused the Ultimaker heater (why not... it fits) but switched to the E3D thermistor instead of the thermocouple, because drilling out the provided aluminum block to accept the thermocouple didn't seem like a very functional solution (not located as close to the nozzle). Switching the firmware was easy enough, as was wiring the thing to the board. Instructions exist on these forums, but please ask if there are questions. Some photos: The head is printed in PLA as 3 separate parts (without support): The printhead body, the snap-mount fan duct, and the hotend clamp. The printhead body is an ambitious print without support - it is necessary to manually correct some curling during the print in order to complete it successfully. It's worth the handholding though - when you're done, you have an ultra lightweight, low-profile printhead for the E3D hotend, which uses a minimum of screws for assembly, has an optional (but tightly integrated) print cooling fan duct, and internal cable routing. Initial tests seem to indicate that there isn't significant waste heat moving up into the printhead during use, so without a heated build platform or chamber, PLA may be a fine material for the printhead. Going to try to reprint in nylon nonetheless, if we can get that going smoothly. Assembly requires: 2 #2 x 0.75" plastite screws 8 #2 x 0.5" plastite screws. Anyway, there are still many design improvements that could be made, so I'll put up the source files here: http://www.thingiverse.com/thing:121074 STEP and Solidworks so you can make edits and roll your own STLs. None of that low-poly mesh bs, right?

Joergen - Really great to see a summary. I wanted to be there but had a prior commitment. I'd love to hear more of your thoughts on that last point they make - that printers are good for prototyping, but not production. Did you end up doing production runs of your 360Rig on an Ultimaker? I'm gearing up to do some (relatively) large volume production on our Ultimakers, and am trying to figure out what pitfalls might lie ahead. We've had crazy good uptime and output so far, but I'm still holding my breath for things to go wrong.

Getting some awesome prints from this hotend. PLA looks great, haven't quite figure out nylon yet though. Going to share the printhead files shortly. There doesn't seem to be any heat getting up into the PLA printhead, which is promising. Another question though: Are there any DO's on the board which indicate that the machine is in the "printing" state? I would like to use something like that to control the active cooling fan on this hotend. We leave our machine turned on 24/7 since we print from the web using Botqueue, and so as a result, the active cooling fan will never be turned off. I'd like to wire it so that it is only on when the machine is printing.

Hmm, on my board there only seems to be the PCB fan connection, and it seems to be 19-20V (I think it's just passing on voltage from the wall power supply). It is the 1.5.7 version, but it looks very similar to this: (1.5.4 prototype from wiki)

Trying to set up this hotend on a new Ultimaker, using the E3D thermistor in place of the Ultimaker thermocouple. I also am trying to run a 12v rail for the E3D fan. I have a few questions: 1) Where is the 12v rail on the Ultimaker PCB? The only option I'm seeing is to solder something to the 12v regulator that's going to the stepper drivers? (Right next to where the 20V PCB fan connection is) Also, is there a schematic of the new Ultimaker PCB somewhere? Been searching with no results. 2) Do I need to reuse the amplifier PCB that's normally on the print head of the Ultimaker? Right now my thermistor is directly wired to the GND and SIG terminals of TEMP1 on the Ultimaker PCB (not through the amplifier PCB), with a 4.7K resistor soldered at R23. This setup isn't working right now (won't boot because it can't sense temperature) but it could be a variety of reasons. 3) Which TEMP_SENSOR do I need to set to match my thermistor in the Configuration.h file of the Marlin firmware? The PCB has TEMP 1, TEMP 2, TEMP 3 - but Marlin has: #define TEMP_SENSOR_0 1 #define TEMP_SENSOR_1 1 #define TEMP_SENSOR_2 0 #define TEMP_SENSOR_BED 0 (How do you do syntax highlighting on this forum, btw?) Which of these corresponds to TEMP 1 on the PCB? Is it TEMP_SENSOR_0? or 1? Edit: Thermistor seems to be working now - I had a faulty crimp. It now seems to be detecting temp correctly, though I'm still not sure if it's using TEMP SENSOR_0, or TEMP SENSOR_1, because I set them both to 1.

I have this same problem on a second Ultimaker I'm building. Is it still the prevailing wisdom that some of this wiggle is actually a good thing?

The solution here is to use hollow tubes instead of solid 6mm axles - just use a larger diameter. Using a hollow aluminum or 4310 tube that's 12mm or 18mm OD is going to drastically increase your stiffness while keeping weight constant - maybe even lowering it (depending on your wall thickness). I ran some numbers for this a while ago when I was scoping out a large format 3D printer I'm working on and the stiffness/weight looks great for aluminum tubes. Apart from the easy availability, there isn't much going for solid drive axles. The only complication is finding tubes with a good enough surface tolerance, because purpose-built hollow drive axles are incredibly expensive. I suspect, however, that high quality aluminum extrusion or DOM 4130 aircraft tubing is going to be good enough. Carbon fiber tubing might also be an option because it can be had with a great surface finish, but unless you've got good connections, finding that cheap will probably be tough.

Yeah, I guess my thought regarding corrosion was that there might be some contaminant on or in the PLA that was dissolving the brass as it exited the nozzle and interacted with the air at high temps, the same way that materials with chlorine dissolve the internals of a laser cutter when you cut them. Seems pretty far fetched in this case though. It could also have just been some physical abuse that cause the nozzle to fracture... it looks like your tip had taken some hits. Anyway, cool stuff what you're printing. I'm working on a few printable lens adapters for my NEX camera. Is there some sort of optic being held in the screen cover you printed?

Great info. One thing I've noticed when turning things by hand is that higher speeds/volumes also greatly increase the turbulence of the flow in the nozzle, causing much more erratic behavior of the plastic as it exits. Notably, the Ultimaker Black PLA had this lovely tendency to hook to the right as soon as it left the nozzle when fed at higher speeds/volumes - and when immediately switching to Printbl PLA, the problem disappeared. This was something that was definitely affecting my higher speed prints, particularly on getting good first layer adhesion. Anyway, it seems like one of the most readily solvable problems in this equation is the extrusion system - have you experimented with any improved drives?

I've also fixed my stock setup with a Makergear nozzle+tube, and the near 200 trouble-free hours we've put on the machine over the past month are a good indicator of it's reliabililty. The only thing you may have to do is adjust your Z stops because of the longer tube. If you're doing prints at .25, you should probably also get a larger nozzle - I have the Makergear 0.5mm nozzle and have done some relatively fast (80mm/s) prints at .25mm layer height that came out extremely clean, despite using problematic (viscous) black PLA. The damage to your nozzle looks like corrosion, though... definitely strange. The prints in your new/old image look pretty matte, or maybe just somewhat underextruded. What brand of PLA are you using?

Try some Diamond Age PLA from Printbl. Switching from Ultimaker PLA to the Diamond Age PLA is like having a different machine - it prints smooth, with great adhesion, a clean surface finish, and way better detail. It's also far less brittle than the Ultimaker PLA, which makes it stronger and easier to modify after printing. It really makes a huge difference - switching back to Ultimaker PLA after using the Printbl stuff was depressing.

Wow, disappointing to hear that PVA is such a nightmare to print with. I've been having fantasies of setting up a nice dual extrusion head with PVA support that I could dissolve away and make my life easier... but now I'm second guessing that dream. A lot of what you describe sound like underextrusion problems... And they remind me of problems we encountered when using the ultra-miserable Ultimaker Black PLA. Have you tried upping Cura's default pre-extrusion so you don't have to do any hand cranking of the extruder? When we set that to pre-extrude 15mm, we got much more consistent starting results. Also, having it print a huge number of skirts/brim (10-20) would also prime the extruder pretty well. Another thing that would help with the first layer was doing micro-adjustments to the bed screws during the first layer of printing, essentially raising the bed up into the nozzle until the layers were forced to stick. I'd love to get a small amount of PVA to test out. Is there anywhere that you can purchase less than a full roll?

There's a lot of useful reference points here, and it's good to see that they generally follow the print profiles I've been developing as I do more prints. I wasn't aware that the volume limit was near that though - My most aggressive print so far has been 10mm^3/s (80mm/s speed * 0.25mm layers * 0.5mm nozzle) and it came out with great density and adhesion. (This was even using the tar-like Ultimaker Black PLA. ugh.) What is the max volume flow people are seeing?

Kraken sounds very cool, I love what you're trying to do. Just finishing up the design of my new printhead to use the V5 E3D hotend, really looking forward to getting this going. Will post pictures and files as soon as I get it assembled. Can anyone comment on how well this hotend withstands clogging when using Cura-standard retraction?

I was referring to aquarium air pumps, which certainly don't require liquid or submersion, but regardless, this isn't something I've looked into doing very deeply. My main reason for not pursuing high-velocity targeted cooling is that I don't feel I have a good understanding of what the most desirable cooling result would be, ie: how instantaneously do we want to cool the plastic once it's extruded? ...should it be allowed to slump for a while, or cooled immediately? Is the larger region of cooling provided by a fan more useful in that it cools the whole part, not just the print zone? or if you are cooling the print zone perfectly, does the rest of the part stay cool on its own? Will you need to decrease airflow on the first few layers so that the build platform doesn't redirect too much air back up towards the nozzle, cooling it and reducing extrusion? I can imagine a pretty sexy air nozzle that surrounded the print head in concentric jets of air, but I don't think I'll be pursuing anything like that because a decent amount of testing would be required to get it right and I've already got my hands full with too many other projects... Looking forward to seeing other's results though!

How is the noise with this mod? I really like the idea of this, but it seems like several people have stated that this makes the machine louder.

I've been thinking about this setup for a while as well - our laser cutter uses a similar arrangement. I'm not positive it's the perfect setup, but it's something I'd like to try. I'd think the power necessary would be way beyond the fan circuit capacity though. I think an appropriate air source would be a airbrush compressor or maybe a powerful aquarium pump. You could then easily use the fan power on a relay which controlled the AC compressor. Finding a quiet enough compressor for a reasonable price becomes another project then though.

Yeah, unfortunately the source cad is a bit of a mess. I'm traveling for the next few days but I'll try to find time to clean it up and post the stock UM version as soon as I can.

Interesting. I had been wondering how it calculated time. Nonetheless, it is definitely very inaccurate. for short prints (<30 min in Cura) it's usually off by 2-3X, but for longer prints it's still off by 1.3-2x, which is pretty significant.

Couldn't it also work just as well to have a short melt zone, powerful heating capability, and intelligent software with a very rapid response to temperature fluctuations and flow rate? Thermal mass as a melt buffer is surely a good solution, but for absolute max performance it seems like a more responsive system could be beneficial. Not saying that this solution provides that, but it could possibly get close by using a higher than normal temp. I guess in the situation you're describing, though, the biggest problem is the thermal mass of the heater block creates a lag time between the filament chamber being cooled, the thermocouple detecting that temperature drop, and the heater counteracting it. Short of intelligent software that predicted that temperature drop before it happened based on anticipated extrusion rates, maybe the solution here is more immediate temperature sensing of the filament? Though if max throughput is the goal, maybe thinner filament is a simpler solution that would have a more powerful effect than any of this.

I like autoslicing.

It's clear when you get to the fan duct assembly step of building an Ultimaker that although the duct is an origami marvel, it isn't exactly a great design. It's tedious to assemble, challenging to install (and keep installed), and not highly optimized for airflow. After several revisions, we've arrived at an improved fan shroud which allows the printing of significant overhangs with drastically reduced curling issues and much simpler installation. The shape is probably far from aerodynamically optimized, but nonetheless it results in major improvement in print capability. See test example below of printing a 2mm thick, 75mm dia sphere section. (220C, 0.2 Layer Height, 0.5 Nozzle, 100% fill, Diamond Age Banana Yellow PLA. Prints were flipped over after printing to show overhang quality.) The one on the left is the most recent version of the shroud design, which produces better prints than the middle one, which was an earlier custom shroud design. The one on the right is the original UM shroud, which could not even complete the print due to horrible curling which knocked the print off the bed. The design could certainly be tweaked further. Right now the height is set up for use with a Makergear brass tube instead of the UM brass tube, so use with a stock Ultimaker may require trimming off a few mm from the top or bottom of the shroud. The fan mounts to the shroud using #2 x 0.5" plastite screws. The one irony with the design is that it may not be printable without support using the original UM fan duct due to the overhangs... http://www.thingiverse.com/thing:107413

Also noticing the same thing regarding no support material on hook-shaped objects. Quite a pain. Removability of the support material has been a mixed bag - sometimes it is challenging, but generally speaking it comes off easier and leaves a finer surface underneath in 13.06.2

I noticed this as well, but once I set the infill to something like 20-30%, I get similar infill to a 70% setting in 13.04, but easier to remove. Definitely some significant changes were made with infill, but I think with properly adjusted settings the results are better.