foehnsturm

I doubt if 25mm fans give enough air flow. I have one here, the blades are ridiculous small and it produces just a very, very gentle breeze. 4 x 25mm will be inferior to 1 x 45mm. The fan I use is rated with 33m³/h (19,42cfm). I assume that flow resistance of the flex hose and the print head kills about 30 to 50% of that.

@all who asked for pulleys after the deadline There are still 5 original orders lacking response to my messages. A few days after the Ultimaker 2 release hype, I will give out all remaining sets to you - first come, first serve.

I was wondering how bridging works when closing large open areas: Box: 40 x 80 mm wide, 4 infill layers KISSlicer, 0.12 mm layer height, infill / solid infill speed 50 mm/s Ultimaker: xy-jerk set to 4 Jerk has considerable influence, with the default setting some 5% infill lines didn't bond to the perimeter. ... no lines lost.

Hi, I noticed that after mounting on one of two of my sample pulleys as well. I had an eye on it before ordering the first batch. But so far, after some 100 hours printing, the belts look fine and the black powder didn't become more.

@MadOverlord I will post the designs. But stupidly, the file for the best working duct has been overwritten. So I will have to "reverse engineer" it. You would also need the print head, fan mount, aluminum parts, see http://umforum.ultimaker.com/index.php?/topic/2435-new-fancooling-design/?p=18362 The center block of the print head will be redesigned as well as I switched from FreeCAD to Moi3D (Moment of Inspiration) thereafter, which I'm absolutely in love with now.

Thanks Simon! Well, I'm using a radial fan, so static pressure is an issue. Some designs failed because the air duct added to much resistance to the overall system. The two-folded ducts worked almost as well as the four-folded. But as you already mentioned, they are more sensitive to part geometry and orientation. The best design has medium-sized orifices. Larger openings seem to reduce flow velocity to much. I tried to increase the distance to the nozzle in order to cover a larger area with cold air - no success, maybe due to the reduced flow velocity at the nozzle as well. I would like to aim directly at the tip of the nozzle, but this is always a compromise. You want some clearance to the print bed as well as having a chance to see what's happening when printing the first layers. I have like 3 designs quite similar to the one which is mounted, aiming a little higher and a little lower. But this one performs slightly better. Honestly, I don't know why.

Tried some air ducts now ... However, with the racing vase 90-100 mmm/s and 1 sec layer time seems to be the maximum for my setup. Immediate cooling of the extruded filament works very well, which allows to print bridges of arbitrary length without any sagging (each bridge consists of 2 layers with 0.12 mm height and 4 lines). On the other hand, heat accumulation caused by the print head returning before sufficient heat dissipates, is difficult to tackle. Some times, small objects or tiny details stay within the cooling air flow long enough, sometimes not. It just depends on the object geometry and the print head path.

... see page 7, this thread is way too long ... http://umforum.ultimaker.com/index.php?/topic/1611-fixing-pulley-innacuracy/page-7&do=findComment&comment=16549

@MakingZone, Actually, I currently use only one screw. Due to the 8H7 bore there is virtually no play. @TZAdvantage, Happy to hear that. My z-axis coupler had horrible bore holes as well (about 0.2 mm to wide). Impossible to fasten without massive wobbling.

Hi Dimitri, as I posted two weeks ago, everything is ready but I need the shipping address for calculating shipping costs and tax. You are not the only one ;-) one half of the orders is still waiting for shipping for that reason.

A quick test run with old cura and joris enabled. The silicone pad almost eliminated the temperature drop when cooling at low height. There is still room for improvement as only one side starts to show small artifacts at high speed.

@owen, Just look at http://umforum.ultimaker.com/index.php?/topic/2435-new-fancooling-design/ (lower half) @gr5, I'm planning to do some test prints with my camera running. Just have to find the time. So far I used exactly scottvader's cura settings. I will try your z setting (only doubled the default so far). The funny thing is, when printing fast enough you not only get the ugly blob but also a hole thereafter, because of the pressure plunge in the hotend. I'm wondering if slicers could handle the pressure drop at z movement a little smarter.

... investigating in this issue as well. Since lately, I'm able to throw a lot of cool air almost concentric beneath the nozzle. The current setup is good for printing scottvader's racing vase with up to 100 mm/s with perfect surface all around (BTW: printing speed doesn't translate to layer time because the - ugly - seam takes considerable additional time). But I'm still far away from knowing what is exactly happening and why. Bridging and printing overhangs works considerable better. But I also get a huge "ground effect". If I turn on the fan below 2-4 mm height there is a massive temperature drop (> 10°C). Almost nothing happens at greater heights, so the cold air doesn't reach the nozzle directly but after being reflected by the print bed. However, the object geometry has a massive influence. It not only affects the amount of thermal input in certain areas (e.g. slower moving print head in tight corners) but also how much cooling air can reach those areas (e.g. how fast the print head with the attached cooling moves away ).

Pulleys are ready to dispatch. @all guys who ordered: Please do me a favor and send a message with your delivery address (If you haven't done already) I have to calculate shipping costs and tax application in order to send the payment info. @latecomers There is at lest one set left. Please have a little patience.

Hi all, The pulleys will arrive next week - but we are on holidays from August 10 to 24. I will send the paying information and do the shipping immediately afterwards. Markus

It took me 7 iterations to find a way to arrange 2 linear bearings, bowden tube and accessories within a 45x45 mm box while maintaining the airflow and dividing it almost equally at the bottom. But I'm not a specialist in that. As the print head is not longer centered to the x/y rods, I have to redesign the sliding blocks or move the end stops to maintain the printing area.

Actually not because I'm squeezing those tubes between the head and the frame (but of course the cooling won't work completely when using the outmost 5-10 mm of the printing area.)

It is called "Suction-pressure coil hose PUR light 30mm Standard"; see: https://www.landefeld.de/artikel/en/suction-pressure-coil-hose-pur-light-30mm-standard/PUSPL+30. It is definitely a matter of free cross sectional area. But the drawback is that you need to maintain this cross section besides the print head, which is almost impossible with the standard one. I tried ulbie's idea of running the air through the standard head (modified top plate) and the two big holes in the base / aluminum plate as well. But with my fan this proved to be a bottleneck. This is the sole reason for those weird, self-made latex tubes, which can be squeezed easily during print head homing.

Hi, Nice and clean work. Can you give an estimate how much airflow you get compared to the standard cooling fan? I'm currently testing a radial fan concept with a flex hose. Don't laugh at me it is just a proof of concept ;-) But it is working very well. The good news are: the fan generates enough static pressure to get a lot of air through the hose, you can still control the cooling fan speed (difficult with pumps) and the hose doesn't add any moving resistance to the print head. You have to prevent the hose from swinging, which is easy. The main issue is still the off-centered design of the print head with no space for ducts all around at all (collision with sliding blocks). It is much easier with pumps/compressors and small diameter tubes to get the air to all sides of the nozzle. Therefore I started to design a new print head for the standard hot end with large integrated air ducts and a centered nozzle position. Due to the centered nozzle you would need to move the end stops quite far, which don't like. So I'm currently trying to adapt Nicks's brilliant Reptar blocks idea.

@amano, yes, I will send messages when I know the delivery date, but I keep the list of orders on page 7 up to date ( easy to overlook, I know). Markus

I placed the order yesterday.

Thanks Calum! I corrected it. (recently learned the logik behind tolerances but still mixing up the upper/lower case)

Hi guys, I will order another batch in the second half of July. Prices are only slightly changed (mainly due to PayPal's inscrutable fee policy). In detail: [*]20 teeth, effective circular diameter same as original pulleys[*]dimensions: 17 mm (outer diameter) x 16.7 mm [*]8H7 or 5H7 center bore [*]two m4 threads with grub screws [*]vibratory deburred Prices: [*]Set for Standard Ultimakers (10 x 8 mm, 2 x 5 mm): 70 € / 94 US$[*]Set for direct drive Ultimakers (8 x 8mm) 47 € / 63 US$ VAT and customs duty not included. Payment via bank transfer or Paypal Shipping: Deutsche Post, insured letter within Germany: 7 € anywhere else: 12 € / 16 US$ Binding orders: MakingZone (Elbozo), TZ Advantage, mpoint, Take 1, JonnyBischof, Urban (2), hreedijk, Piranha, Sserpent, Reprogue, scottvader, amano, mr_clark, Nicolinux Pre-orders so far from: Antiklesys Please send me a message with your detailed order, address and email. Order-DEADLINE: July 15th Markus

It's a PLA/PHA compound and I suppose the PHA share is quite small. But it definitely alters the material characteristics. The manufacturer emphasizes the extended elongation. Most people in the colorfabb thread praise the colors and the somewhat smooth touch. That's true but not the point for me. Heated to recommended temperature (210-220°), the viscosity is significantly lower than PLA. It is almost liquid and drops out of the nozzle if the printer stands still. Once you have started printing it extrudes very consistently and I assume the extrusion process window is considerable larger. But PLA/PHA is more prone to blobs and stringing. Bonding between layers is like normal PLA, but the surface is less sticky to my heated glass bed. With PLA/PHA my standard hot end setup comes close to the 10-15mm^3/sec barrier Joergen mentioned (like in the stress test video). With normal PLA unfortunately, it stays far away from it. Anyway, for high quality prints I set perimeter speed to 50-100 mm/s because of the motion quality. Extrusion speed is not an issue. That is the point you are emphasizing. But frequently infills make up 50 to 90% of the extruded volume. Printing with 200 mm/s instead of 100 mm/s there would significantly reduce overall printing time. My mechanics could do that, my standard hot end can't (with PLA).

I tried the same gcode with white PLA from German Reprap today. The speed difference to the colorfabb PLA/PHA is impressive. Infill is only fine up to approx 170 mm/s, even with increased temp and flow rate. Lars, it would be interesting to see how the PLA/PHA filament works with your hot end redesign some day. It's less viscous and therefore more prone to the issues you are adressing.