tag:blogger.com,1999:blog-4339813531032979196.post4971617975719595764..comments2024-02-28T07:32:59.864+00:00Comments on HydraRaptor: Cool mapsnopheadhttp://www.blogger.com/profile/12801535866788103677noreply@blogger.comBlogger19125tag:blogger.com,1999:blog-4339813531032979196.post-65015490493696845932017-09-01T15:17:40.390+01:002017-09-01T15:17:40.390+01:00Hello,
It would be interesting to test heatmap for...Hello,<br />It would be interesting to test heatmap for this <a href="https://www.thingiverse.com/thing:2434945" rel="nofollow">https://www.thingiverse.com/thing:2434945</a>. It would open new possibilities if simulation is comparable to real world ... ledvinaphttps://www.blogger.com/profile/15678963252768297866noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-9718807427426730162016-05-03T15:33:05.068+01:002016-05-03T15:33:05.068+01:00Just a random thought - the wind-tunnel people see...Just a random thought - the wind-tunnel people seem to use a matrix of drinking straws between fan and tunnel to straighten out their airflow - any mileage in that? Or maybe print a few fins in the duct, reducing the bridging problem at the same time?<br /><br />Wish I had time to play with this stuff again!Alasdairhttps://www.blogger.com/profile/05998355955381716829noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-84048950002701866242016-04-07T20:37:46.074+01:002016-04-07T20:37:46.074+01:00Thanks for looking at my design.
I started with a...Thanks for looking at my design.<br /><br />I started with a more tangential approach, it looked something like this:<br /><br />https://gist.github.com/GilesBathgate/fde54e3ab1b8bd47fb3b94ccdf3e4873<br /><br />I think I still have a problem with the curved bridge, and the pipe is now exiting in the wrong place to meet up with the fan (in its current mounting place) see:<br /><br />https://d17kynu4zpq5hy.cloudfront.net/igi/prusa3d/iMoPpKBCi4TGYQbQ.huge<br /><br />Here are cross sections of the P-Shape which I think illustrates it better:<br /><br />https://imgur.com/a/8bsah<br /><br />The other problem I am having is that when printing the tapered bit its cutting corners when printing the perimeters :(<br /><br />Regards,<br />GilesAnonymoushttps://www.blogger.com/profile/17207320619551063718noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-53746631452769231252016-04-07T12:05:40.250+01:002016-04-07T12:05:40.250+01:00Hi Giles,
I think it is probably better for the ...Hi Giles,<br /> I think it is probably better for the straight part of the duct to meet tangentially rather than radially.<br /><br /> No I don't print the current duct upside down but I probably would for a P shaped one.nopheadhttps://www.blogger.com/profile/12801535866788103677noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-53211456981775358812016-04-06T21:34:22.335+01:002016-04-06T21:34:22.335+01:00Hi Nophead.
I am trying to design a P-shaped fan ...Hi Nophead.<br /><br />I am trying to design a P-shaped fan shroud that will fit my Prusa i3-Plus (1.75mm)<br /><br />This is what I came up with so far. <br /><br />https://gist.github.com/GilesBathgate/9ff023bbd3a2f3b7b56e8ddc6fb51bb1 <br /><br />The flow of the air is far from desireable at the moment, but I am trying to get from an akward fan position (behind the extruder). I hope to fix that up later, at this stage its more of a sketch idea.<br /><br />The main problem I have is printing it, because I have created an area which requires bridging a circular edge. Doh!<br /><br />I was wondering if you could offer any design improvements? Do you print the mendel90 shroud the other way up? Anonymoushttps://www.blogger.com/profile/17207320619551063718noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-40860185413258882672016-04-01T16:09:58.818+01:002016-04-01T16:09:58.818+01:00You want to keep the whole object just below the g...You want to keep the whole object just below the glass transition not just the air close to the nozzle. It makes most sense energy-wise to have a heater chamber at that temperature and simply blow the same air around to cool the new layer quickly.<br /><br />Second best is probably a heated bed and a hot air gun to cool the part. That way you could blow on a part without it increasing the warping.nopheadhttps://www.blogger.com/profile/12801535866788103677noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-53893073833227300662016-04-01T15:51:37.665+01:002016-04-01T15:51:37.665+01:00Heyhey,
thanks for this article! While I could nev...Heyhey,<br />thanks for this article! While I could never replicate your research, but there's a lot to take away from this even for fan duct design, even on a less scientifically optimized level. I'd definitely love to hear from your P-shaped duct<br />Regarding the air ideally having glass-transition temperature, maybe instead of a heated chamber one could simply install an additional thermistor at the outlet of the duct close to the part being printed? With the air that is sucked in generally being cooler than the GT-temp, wouldn't it be enough to always bring in just enough "fresh" air that the area surrounding the nozzle has about those 55 °C? Or rather, a temperature at the measuring point offset by a tweakable amount, so that the resulting temperature of the plastic is just right.<br />Unfortunately I can't code this, but maybe this low-tech approach is good enough and still better than guessing the required fan-speed in Slic3r when no heated chamber is available?<br />Just an idea, might be stupid, I'm no engineer.<br />Thanks again either way!CMJoehttps://www.blogger.com/profile/15319713883157693739noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-33771760598839990412016-03-31T16:56:29.162+01:002016-03-31T16:56:29.162+01:00Brilliant reserch and analasis and temprature maps...Brilliant reserch and analasis and temprature maps of the cooling process<br />As the radial blowers were easier to mount/direct onto the print I've been using them.<br />Never thought of air spinning just didnt like the idea of polo effect/hub motor position.Anonymoushttps://www.blogger.com/profile/11790019375326311849noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-22858719652970544092016-03-29T22:28:20.975+01:002016-03-29T22:28:20.975+01:00Excelent work, Regarding to Gnuplot, I used to use...Excelent work, Regarding to Gnuplot, I used to use it. <br />Nevertheless I would recommend you tikz. It library has given to me<br />cleaner and customized plots. wgaonarhttps://www.blogger.com/profile/03024837632768456451noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-80972370077117134822016-02-20T01:15:14.815+00:002016-02-20T01:15:14.815+00:00i always get a little smarter when i read your stu...i always get a little smarter when i read your stuff, thanks for being a scientist, sharing your discoveries and experiments and for being accessible & providing thoughtful replies.<br />i wish i had neighbors like you.garcadhttps://www.blogger.com/profile/11892814788792651844noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-50390304182919569302016-02-15T08:56:58.929+00:002016-02-15T08:56:58.929+00:00The primary reason for part cooling is for printin...The primary reason for part cooling is for printing small to medium sized PLA parts. PLA has a very low glass transition at ~55C. Above that temperature it is like rubber / jelly until you get to the melting point where it becomes a liquid. To maintain an accurate shape you want the previous layer to have set rigid before you lay the next layer on top of it. I.e. it needs to have cooled from ~200C to ~55C.<br /><br />On the down side the strength of the bond to the layer below is proportional to how long the interface is above the melting point, so cooling makes the interlayer bonds weaker. <br /><br />With plastics like ABS, that sets at ~100C, it is more important to keep them warm to prevent warping and get good layer adhesion, so I don't use a fan.<br /><br />Bridging and overhangs benefit from cooling because they make the plastic set faster but I haven't tried just having the fan on just for bridges myself yet. I mainly print ABS and so don't have a fan fitted.<br /><br />The idea of this duct is to have as directed a flow as possible without blowing on the actual nozzle itself.<br /><br />Ideally, when used with a heated bed it should blow air at the same temperature as the bed, i.e. just below the glass transition of the plastic. That would set the plastic quickly without increasing warping. Something I plan to try at some point. That goes hand in hand with having a heated chamber at that temperature but that is a problem with a machine made from plastic. <br />nopheadhttps://www.blogger.com/profile/12801535866788103677noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-69859058825539917032016-02-15T02:32:19.757+00:002016-02-15T02:32:19.757+00:00could you elaborate a bit on the usefulness of coo...could you elaborate a bit on the usefulness of cooling?<br />afaict, apart from bridging, keeping the part warm to reduce strain is a typical problem.<br />i'll even wonder if the heated bed's beneficial effects are mainly concerned with it heating the ambient which reduces the part's cooling.<br />if cooling is for bridging, then why not a highly directed flow as from a nozzle?garcadhttps://www.blogger.com/profile/11892814788792651844noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-67639029690101918152016-02-09T16:35:43.025+00:002016-02-09T16:35:43.025+00:00An interesting read on the effects of cooling.
I...An interesting read on the effects of cooling. <br /><br />I am not sure I believe the reports of backwash. I.e. air coming out backwards from a fan in a duct. You can't feel airflow as pressure from such a small fan, you feel it as the cooling of your skin and so can't tell if it is sucking or blowing. Whenever I have tested it with smoke or a small piece of paper the input side of the fan is always sucking air in and it must be for the duct to be blowing. It just gets very inefficient with an axial fan into a small duct.<br /><br />The CFM rating for the blowers is actually much less than an axial fan. They move a much smaller volume of air but at a higher pressure and velocity.nopheadhttps://www.blogger.com/profile/12801535866788103677noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-77769015246364296452016-02-08T19:33:47.308+00:002016-02-08T19:33:47.308+00:00Interesting, I hadn't realised that cooling ef...Interesting, I hadn't realised that cooling effects the quality of overhanging places. I just happened across this http://www.desiquintans.com/coolingtests, which reminded me of your post.Anonymoushttps://www.blogger.com/profile/17207320619551063718noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-56136004192836684942016-02-07T12:03:04.228+00:002016-02-07T12:03:04.228+00:00Hi Giles, thanks.
Yes it turns out there are seve...Hi Giles, thanks.<br /><br />Yes it turns out there are several OS CFD programs, although it doesn't sound easy to use them: http://caewatch.com/why-open-source-cfd-solution-is-not-for-everyone/<br /><br />It looks like Josef's design blows a small jet from one side. I think that will give both anisotropic printing results and significant cooling of the nozzle, which is exactly what I was trying to avoid with the ring design. <br /><br />This is an object I printed a long time ago with a fan at one side: http://hydraraptor.blogspot.co.uk/2008/11/key-things.html. The overhang is much neater on the side facing the fan and is what made me realise the importance of all-round cooling. <br /><br /><br />nopheadhttps://www.blogger.com/profile/12801535866788103677noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-34493978193205713222016-02-07T11:14:51.831+00:002016-02-07T11:14:51.831+00:00Hi Nophead, This is a fantastic piece of research!...Hi Nophead, This is a fantastic piece of research! I wonder if there are any open source fluid dynamics applications that could be used to optimise the duct even further? I also wondered if you could test some of the simpler designs which probably have no consideration for the airflow at all, such as the Prusa i3 Plus design: http://shop.prusa3d.com/en/3d-printer-parts/71-prusa-i3-plus-285-mm-to-175-mm-upgrade-kit.htmlAnonymoushttps://www.blogger.com/profile/17207320619551063718noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-60335765306808020142016-02-06T19:46:11.284+00:002016-02-06T19:46:11.284+00:00Yes that is why I originally expected there to be ...Yes that is why I originally expected there to be more flow at the back and less at the front. However I don't see much front back variation except with the 40mm one that has a relatively small diameter pipe for its ring. I don't have lots of separate nozzles, just a continuous ring. The cross section of the loop is much bigger than the exit so it seems the air has no problem getting to the front and with the powerful fans tends to have more exiting there than the back despite having travelled further.<br /><br />I am hoping that by running it round in a circle it will go round and round spiralling downwards to eventually exit. My theory is that will give an even output flow.<br /><br />Yes I agree that some vanes might help with the axial fans but my new design will be with the radial one. nopheadhttps://www.blogger.com/profile/12801535866788103677noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-20132919241917504042016-02-06T19:12:58.409+00:002016-02-06T19:12:58.409+00:00Thanks for bringing some science to a topic that o...Thanks for bringing some science to a topic that often involves a lot of guess work! I wouldn't necessarily try to stick to a constant cross section duct. If the duct is a constant section and the nozzles are equal size and spacing, then the flow speed will vary in the duct (as air is lost out of the nozzle) so there won't be an even incentive for the air to go through the nozzles. A tapering duct might lead to more even flow front to back. Obviously the other trick to consider is flow straightening vanes, to reduce the effect of swirl coming from the fans rotation. If you really want even flow out of many nozzles, you need all the flow to travel the same distance, through the same restrictions. If one bit of air has to travel further or turn more corners, the flow will be different.Mark Mellorshttps://www.blogger.com/profile/10479972621128981140noreply@blogger.comtag:blogger.com,1999:blog-4339813531032979196.post-36971911274392289312016-02-06T17:01:46.124+00:002016-02-06T17:01:46.124+00:00As always, thanks for the great work and all info....As always, thanks for the great work and all info. I'm hoping that in the future we can start to incorporate this kind of cooling data into our product listings at MatterHackers.<br /><br />BTW: It was great reading about the fan duct printing. I've printed that part many, many times here in the States for customers, and it was a walk down memory lane.<br /><br />I also tried MatterControl on it. MatterControl has similar errors to the other slicers. However, the fan duct has some very interesting qualities to it that can help our understanding of what to do to with these types of bridges. <br /><br />To describe what is going on; Bridging consideration happens (at least for CuraEngine and MatterSlice) by figuring out the intersection between the area needing filling (the potential bridge) and the previous layer of the part, then using those calculated islands to create the best bridge. <br /><br />For the fan duct there are either two islands when the perimeters are very low (1 perimeter) or three when the perimeters are larger (3 with .4 nozzle). We got the 2 island situation working better by excluding any islands that are internal to other islands, and then treating the problem as a single island needing convex consideration, and that works well. The 3 island case is much more complicated and brings us to what really needs to happen. We need to be much more explicit creating tool paths to accommodate all the bridging that is possible, rather than simply choose an angle for the infill. This will be a much longer project but it is exciting to have these test cases. <br /><br />Thanks again,<br /><br />Lars Brubaker<br />MatterHackersLarsBBhttps://www.blogger.com/profile/16684212913611125419noreply@blogger.com