coseng

Ha, thanks! Its actually about displacement per unit time. 😉 Chris

Thanks for the reply. I tried running outer wall first, but then had issues with the printed bead sometimes falling off the part and the show-through problem still happened. It seems that for the slight overhangs having the inner wall printed first gives the outer wall something more to adhere to and prevents the falling off. Switching to inner wall first eliminated the falling off problem and the show-through problem remained unchanged. Chris

@MariMakes Sorry about that, I dropped the wrong file in! Here is the 3mf file. Hope you had a nice New Year's. subframe-right-3mf.zip Chris

@MariMakes, thanks! Happy holidays and new year to you too! I can print lots of other thicker geometry without any problems, but these thin wall parts always seem to have these artifacts. The Cura preview window seesm to show full width wall paths, so not sure where these are coming from. The same part but thick with infill instead of thin with ribs prints fine. Those marks on the backside are where I cut off some ribs for printing stability. Here is the project file. subframe-chain-solid.zip Regards, Chris

I have a large (650x650x950) heated chamber CoreXY printer for printing ABS made with a Duet 6HC mainboard and E3D supervolcano hot end and 0.8mm diamond nozzle and am using Cura for slicing. I have generally very good results with thicker parts that have infill, but on thin wall parts have issues with the main outer surface showing remnants from ribs on the opposite side. The base of this part is about 400mm long. The g-code preview shows the printhead paths as smooth, but the resulting part is anything but smooth with the ribs on the opposite side clearly showing through. I've had this problem since finishing the printer and have been using Cura 4.13 since the early 5 releases with variable line widths were providing weird results. I thought the 5.2 release with a specific mention of mimicking injection molding could be an improvement, but so far it has not been. Is there a special mode to activate this feature or do I have some settings wrong? bad-outer-surface.curaprofile Any suggestions to improve any aspects of print quality are appreciated. Happy holidays to all.

I am a fan of KISS and any attempt to increase heat transfer should start with using a material that has much higher thermal conductivity (4x), like copper. I'd be interested to see if the 3 path brass nozzle is better than a normal bore copper one. But the 3 path one does look cool and has lots of marketing potential. Just to point out, that video is not really a comparison of only heat chamber geometry. The nickel coating of the CHT nozzle provides lower friction than a plain brass nozzle which will on its own increase the flow rate. From this testing it is impossible to attribute the increased flow rate to better heat transfer or less friction. A plain CHT or nickel plated brass nozzle would have been a better comparison. Copper seems to have a very positive effect, even when it is inserted as a pretty major obstruction in the flow path! Though I am not sure why he didn't just test an all-copper nozzle. I was already on my second nickel plated copper nozzle, having switched after about 15kg of ABS and 1 of PC. The bore itself was not wearing a lot (yet) but the exit chamfer was getting egged out and the nickel plating on the tip was about 50% worn off. So if the PCD tip prints well its wear resistance will be a cost saver in the long run, not even counting the reduced electricity for a shorter run time. The nickel plated copper nozzle was printing at 60mm3/sec with great results, and the PCD tip may let me increase that to 80 or so, at which point the stepper motor power is not up to the task of higher flow rates. At those rates I get absolutely no filament dust at the pinch drive mechanism after 12hr prints and the extrusion tests are very consistent and drop straight down.

I saw those, but to me a first step in better heat transfer to the filament is to switch from brass to copper. Branching the main filament passage to several smaller passages seems like adding a bunch of flow restriction. Maybe it is good for a 2.75mm filament, but one reason to stick with 1.75mm is it easier for heat to get to the center of the filament and melt it as plastic is a relatively poor heat conductor. The Diamondback nozzle tip is a big chunk of PCD that contains the entire transition from the 1.8mm or so filament passage to the 0.8mm nozzle hole. The copper part ends up being a 1.8mm thru hole, so easy to make with a really good surface finish. The PCD tip is a short and stubby part so easier to create smooth transitions for low friction flow than it is to machine smooth transitions at the bottom of a 50mm long, 1.8mm dia hole.

In the search for a little more print speed (I'm a racer for a reason.....) I did a little beta testing for the people making the print nozzle with a PCD insert tip, ChampionX. https://www.championx.com/products-and-solutions/drilling-technologies/diamondback-nozzles/ It is not a coating, but a little chunk of industrial PCD that is inserted in the tip. It is hard as a natural diamond, but black. It also has a very high thermal conductivity, so will keep the filament as hot as possible right up to the nozzle exit. That is secondary though, as diamond's low friction properties for me are the main point of interest to reduce the effort needed to push melted filament out of the orifice. Less friction leaves more stepper torque available to put to use pushing filament out, which results in higher print speeds. The company advertises the nozzle as resistant to abrasion with CF or glass filled or otherwise abrasive filaments. I did not test any of that, but considering it is diamond, would think it would last for a printer's life. They also mirror polish the flat tip so that the tops of prints come out really smooth. The visible parts of my prints are mostly the sides of the extrusion, so also did not test this aspect. They have products for a bunch of nozzles and are coming out with a Volcano version, but not yet for a Supervolcano, so a bit of lathe work was needed to do a retrofit. The brass nozzle on the right was used to verify the modifications before doing it to the more expensive copper nozzle on the left. I tested at 240C printhead temp, which is my current ABS print temp. I lowered the bed to the bottom of travel and just ran the extruder using a G1 E200 FXXXX command. Using the existing E3D copper/nickel plate supervolcano 0.8mm nozzle I normally run prints with a max extruder speed of 1200mm/min (150mm/sec print speed) which gives very consistent results with no filament dust on the hobbed drive wheel after 12hr prints. At 1500mm/min I start to get sporadic filament slippage but it still extrudes successfully. At 1800mm/min it will not start to extrude and just slips at the hobbed drive wheel. With the Diamondback 0.8mm tip inserted in a copper nozzle I was able to get consistent extrusion with no filament grinding up to 1800mm/min. At 2000mm/min it would not start to extrude at all and sometimes got stepper stuttering, but at that speed it may also be bumping up against the stepper’s speed limits. So the quick takeaway is that there is definitely a significant reduction in the force needed to extrude. Combined with essentially no wear, I think it is a no-brainer upgrade. I have no financial interest in this product. I’ll keep the nozzle in there for the next series of prints and see if I can bump the print speed from 150mm/sec to 180-200mm/sec. Possibly faster for the support printing, as a little loss in quality there is a non-issue. Even a 10% or so speed increase would be great, and considering that the printer is essentially a 6000W heater, the PCD nozzle is also an energy/cost saver.

YES!!!!!!! I love the light weight and simplicity. Well, the last bike was a lot simpler....... I raced a RS125 GP 2 stroke for a bunch of years and that is what got me hooked on lightweight bikes.

The parts are in ABS. That style error happened a lot initially, but now only happens on thin corners of unsupported downward facing surfaces, so think I am just asking too much from the print technique.

Thanks! >>What engine will you be racing with? The engine is a semi-custom 600cc single cylinder engine using a Ducati Panigale 1199R cylinder head and piston with custom billet crankshaft, counterbalancer, and crankcases. The frame is also unique in not using telescopic forks but a linkage system.

Happy 4th of July everybody. Those laydown prints of the front upper sides worked well. Here's a pic of the nearly finished product. All the red, white, and blue body panels were printed out. And the black seat 'pads'. I'm going to keep refining the slicer settings and printing more parts as I make updates to the design, but for now can consider this a completely successful printer build project. Thanks to the forum for all the suggestions.

Win a few, lose a few. I tried running a thinnish part standing up with minimal slicer supports but thought decent CAD bracing and got an area with a failure similar to the initial thin part print failures where the end got all wiggly. I also had an issue with the one of the chamber heaters blowing on the part and causing some sagging and warping. I tried to heat and bend it back, but it was not working good enough to make it a usable part, so back to the printer. I had run this part previously laying down and got a bunch of bad finish areas on the inside under the support structure, but the other areas ran fine. With this print I made a CAD error on the wall thickness so some of the part has one pass for each wall and a small hollow space in between. The result is quite flimsy, otherwise I would have used it. I could imagine 130mph wind blowing a hole through it. For the next print I will go back to the laydown orientation and tweak the support roof settings a little.

They don't let me wear my cape on the racetrack. 😞

Round 2 was a success! Or mostly a success. Definitely a usable part for initial track testing but the print does have some blemish areas. I added Z hopping at 1mm so there was a ton of z motion going on but it did not affect the print time that much. The Z motor was a lot hotter. I may have to tune the retraction settings now as at some points it seemed to be depositing a tiny drop of material, z hopping to a couple mm away, and repeating for 30-50 times in a row. I am not getting any blobbing or stringing issues, so likely have some margin to reduce retractions. The added z motion did accentuate the instability of really tall (500mm+) and slender support structures, as you could see them swaying back and forth a bit. Once the printhead was printing on them the motion was quickly damped, but it has a noticeable effect on surface print quality. I think the fast accelerations of the printer are causing problems when the center of mass of the printed plastic for an island is not over its center of support, so when I create these new CAD supports will try to either prevent that situation or try to give the added bracing some torsional stability. I found that adding 1 perimeter wall option to the support generation adds a lot of stability to the support islands, but it also greatly increases print time and support removal difficulty. I think most browsers should play this video: https://www.instagram.com/p/CfKd1oqDCpV/ The part ran with a bunch of Cura generated supports around a bunch of 3 pass wide brace walls that were added to the CAD model in Creo. The uppermost horizontal walls were a bit wonky as a result of my added walls ending too soon and the Cura supports wobbling a bit. This wonkiness stopped when these islands were merged into the overall part perimeter, which was pretty stable due to the CAD added bracing. So these parts are all good enough for initial assembly, dyno and track testing, but there will definitely be a round 2 once that all happens. When I do this part again (and actually for some other parts too), the supports will be revised to something like this: Basically, after orienting the part I will take the edges that are above the build plate, drape them down to intersect the build plate, then thicken them to 3 print passes. This will eliminate any isolated islands on the print bed and it will also convert the part from long, spindly and unstable fingers and supports to a stable closed profile with few supports. The rest of the fairing is about 5mm thick, and done with 2 walls and 10% gyroid infill. The result is that the added walls are 'solid' where they merge into the part so can be trimmed off without breaking through to the infill. The added part volume seems to be a decent amount less than the support structure it is replacing, and because they are usually long smooth print moves can be done at a consistent realized 150mm/sec, so also print decently faster than constantly reversing support movement. I found that cutting these style ribs off was pretty easy with an oscillating handheld cutters (dremel mm35). No melting and with the right blade shape (standard one included in package) it was easy to get near flush cuts. No nicked fingers, either! This last print was 52hrs. The printer has been going almost continually since 5/16 with no more than a few hours between prints. I've gone through about 28kg of filament so far. The only failure was the filament stepper fan, which burned out. Turns out it was a 12V fan running at 24V. I may add some shielding between the chamber heater elements and the build plate, as on the previous failed print it did seem that the heater on one side caused some of the single wall tree supports that were directly opposite it to sag. Other than that, the printer has been mechanically sound, which is great.