alaris2

hmm. I scratched my head for several hours trying to decide how to do shells without massively slowing everything down. I haven't come up with anything yet. any suggestions welcome, otherwise it looks like Daid is well ahead so I'll pass the thread over to him congrats Daid and good luck, but make sure you address all the features people wanted - we expect only the best from you

insets = shell?

Daid is best placed then to overtake our efforts and achieve world domination! go Daid!

we should all be writing one slicer (ideally one where I do no work and everyone else makes a perfect slicer I can use instead there are at least 4 people writing a new slicer here - this is a dilution of effort any chance the others could hurry along with their code a bit (I'll go and play minecraft for a month so that mine becomes redundant?

I forgot to sanity check the dimensions of the model I downloaded, so yes, 64m. First time l sliced it I had debug on and ran out of HD space. g-code is in progress I hope. I'm negotiating with Daid to have it integrated with Cura-it Makes no sense for me to reinvent wheels that he's already done such a good job of.

that's slice 76 incidentally, in case anyone cares so yes, it progresses - unfortunately I don't get much time to work on it, so slowly.

well I was replying about 2 hrs ago and then photobucket drowned in adware scripts and all my cookies vanished and I had to re-enter every single p/w for everything.. ;( so I'll try again with imageshack.. not nearly as exciting after all that effort but it's a 64m long wind turbine blade, which I accidentally sliced at 0.08mm layers. it took almost 3 minutes to slice too :( needless to say, I didn't print it. did you know they're not quite round like that?

The Tg is variously listed as 47, 53, 57 and 75C. some of this will be due to different variants of nylon and/or impurities added. however, even with the hotbed much hotter than this, I still can't completely eliminate warping. that's a bit different from PLA and ABS where the Tg seems related to the hotbed temp. Do let us know if glass works (presume you're using borosilicate?) I avoid the funny shape line myself (star shape for example) because the extruder isn't really designed for it, but it may still be useable. the cheapest stuff seems to be circular(ish), works fine, and if there are any 'fillers' they melt and go through the nozzle without a single blockage in the 2-3 months I've been using nylon the colors info is really very good - I tried sharpie pens early on and they work but not very well. this looks much better so I'll try this next. but the info varies across the site, from very good and technically correct, to pure sales statements like "If you're not printing nylon with taulman's 618, you're printing nylon with one of his rejects!" - as with all persons hawking their own goods, caveat emptor

allegedly, nylon sticks to nothing except other hot nylon (if you believe what you read) but experience shows that if you skwish it hard enough onto a surface it will stay there for a short time (which is why people early on recommended cardboard) I can print on the blue tape.. but only for about 5 layers before it starts curling off! hence the hotbed is a necessity - I've not tried hot glass I'm afraid, but kapton tape seems to work OK. I also tried printing directly to metal, which works if the surface is roughed a bit first. you're right that temperature is the key thing tho - you won't stick to anything if it's cold. and combined with raising the air temperature has given the best results so far (a chambered approach with turkey bags or whatever else you have to hand). best results I've had were with ambient temperature about 35C (as warm as I could get it with a hair dryer and turkey bags) and hotbed at 105C (+-10C cos my temperature readings seem a little off for the hotbed atm and I can't get it any hotter than this :( this isn't perfect, there's still a little curl, but it's no worse than printing cold PLA so might be 'good enough' for most people. I'm revamping my hotbed to go hotter right now and suspect the 'right' temperature is more like 120-130C - I'll let you know with some photos of my success (or otherwise) (note - the necessary temperature seems to be much higher than the quoted glass transition temperatures) regarding smell - not really. this is one of those urban legends that get propagated as scare stories, usually with names of chemicals like hydrogen cyanide. as with nearly all plastics, you want to avoid setting fire to it, and also avoid reaching the thermal decomposition temperature (about 310C) or you will get some nasty smells indeed. a good extrusion temperature is more like 240-260C. to say there is absolutely no smell would be a lie, but it smells no more (or worse) than PLA or ABS. as with PLA, lower temperatures = less smell. that doesn't mean I'd recommend sitting there sniffing it or working in a very enclosed space - I vent my UM by opening the window occasionally regardless of what I'm printing with. PLA fumes give me a headache if I sit in them for a few hours, whilst others claim the smell is like 'maple syrup'. no accounting for taste i suppose the only thing 'weird' about nylon is the hissing spitting noise the hotend will make (apparently water turning into steam in the head) - it doesn't seem to do any damage or ruin the print, but it sounds disconcerting at first. since i've only really used the nylon long term on my metal hotend, I can't say if the more enclosed space in the V1/V2 hotend will have long term problems with steam - you might get more popping or pressure build up perhaps?

The internet is a mine of misinformation. it's amazing how fast an individual can persuade people to part with money by telling them he has something new, has cornered the market and how dangerous it would be to buy from anywhere else. so you should give him all your money. tracing the scare stories nearly always leads to one source - the person who stands to benefit most. fools and money etc. nylon seems to be one of these areas. I've been printing with nylon for some time now and would therefore recommend: 1) buy the cheapest weedwacker nylon you can lay your hands on. the cheaper the better. some expensive brands may try to add impurities to improve endurance (you'll always be able to spot these, because they claim to be '50% better than the ordinary line'). 2) 2.4mm line is fine for the UM. if you buy 3mm you may find the tolerance isn't great and it might get stuck in the bowden tube. usually 3mm = 3.05mm for strimmer line, whereas 3mm=2.84mm in our world. 3) a temperature of 240-260 is about right, no higher. 4) retraction doesn't work well with nylon, expect to have to clean up afterward. an all metal hot-end allows you to control the hot zone and improve retraction, the UM V1/V2 hotend is better suited to PLA. 5) you NEED a hot bed. nylon curls like a cheese sandwich otherwise. ignore the silly advice about printing on cardboard, it makes a negligible improvement, is a pain to set up and takes ages to clean afterwards. just get a hot bed. 6) by all means spend hours cooking your nylon before printing to remove moisture. or just print it regardless and live with the fact it will hiss and spit a little occasionally - it won't make much difference to the final model. in short, don't imagine you MUST buy nylon from expensive sources and ALWAYS question the scare stories. buy from your local hardware store, or from, eg.amazon. something like this (but in 2.4mm) http://www.amazon.com/dp/B001BKZT1S/ref ... T1_SC_dp_1 or this (again you want a thicker variant) http://www.amazon.co.uk/Black-Decker-A6 ... 888&sr=8-3

k'slicer is better for speed and quality. but has a silly name and a terrible UI. but hold your horses a month or so since we're working on a brand new awesome slicer instead which will upgrade Cura to 'legendary' status.

pleased to see I'm not the only one working on this - tho I'm jealous of your large empty workshop compared with my cramped conditions do you intend to share the new extruder design? I used a heat spreader and double fan like that in my initial tests with nylon (as did the reprap boys) - how did you find it? I eventually decided it was too big and heavy and replaced it.. all the best, nik

for reference, here are the ideas submitted so far in one post to save you having to trawl through the whole thread again - 1) Ability to flip STL models around properly. (also rotate, etc. - transformation matrix) 2) Ability to handle large CAD models. 3) Fixing the issue whereby the infill does not properly touch the walls 4) Making it have the ability to set wall thickness in 3D, (avoids staircase effect & holes in the top of thin arches) 5) Ability to print infill in different material from the main body. (as well as support) 6) More options for infill patterns. So square, circle, hexagon, straight lines only, waves, concentric infill 7) Individual speed settings for the different types of lines being put down (outer shell, inner shell, infill, support etc) 8) Ability to user define areas where support should exist, not just based on an angular parameter, but by perhaps entering sets of XY co ordinates of the bedplate defining squares where support should exist. Or not. 9) Smart bridging that can look at a bridge and decide what will create the shortest jumps etc. If you're going to span a 20mm*5mm hole you'd make it jump the 5mm distance first for example. 10) Being able to specify roughly where the z-scar will end up 11) When printing more than one separate object at once, pick where the printer will jump between the objects (to minimize surface imperfections). 12) Something similar to Netfabb's half height outer shells. And not just the lazy skeinforge way of stacking two half height layers straight on top of each other. They should follow the outer shape of the object. 13) Different kinds of top-/downskin patterns 14) Speeed, lots and lots of speed 15) look at the gcode visualisation 16) variable speed for different parts of the model 17) "Good support". eg. starts small and then as it gets closer to what it's supposed to support it branches out - reduces material waste and makes it easier to clean. 18) support material with no raft on top - instead, very thin infill, then a raft, then finished off by a proper solid top layer. allows support to be dissolved to leave a nice surface finish 19) commandline slicer which produces GCode (doesn't print it) 20) Comments to see different "sections" of the GCode, layers/skirt/fill/outlines stuff like that. (for GCode preview and the "per type" speed adjustments). 21) Progress report on console output, with option model error output. 22) Slicing EVERYTHING, even is the model is bad, not manifold, contains holes etc. 23) Combing, staying inside the model during moves is important for print quality. 24) Thicker first layer 25) versions for 26) ability to define different regions for different amount of infill. (for parts which contain both aesthetic & structural elements) 27) different layer heights depending on where more detail is needed. 28) pause at height feature 29) handle the thin wall problem - if a wall is say 1mm thick some slicers will leave a gap between the two shells. (crowning in KS)

those are great ideas Robert - I'm compiling a list, I'll summarize the current features requested in a moment when I've finished formatting it. don't worry about how mad or difficult the idea is - if it's too far off the wall I can only say no as it happens, your second idea is something i wanted too, and I've found a way to achieve it I think.

so, before the end of the world, I figured a quick update of where things got to - 1) I can now load any .stl files, including damaged ones that meshlab won't load 2) I can slice and create support (simple only) any geometry, including inside-out, non-manifold, intersecting objects (-ve space) and all the other billions of combinations of broken geometry that seems to exist in stl files. no wonder so many slicers just barf at it. phase 2 took somewhat longer than i expected, but I can now slice (almost correctly, see below) pretty much anything - even Ian's files! (if you're reading this Ian - what is the difference between checoo and monboo?) I said almost anything - there are 2 outstanding geometry errors I have no current fix for. I'm hoping they aren't very important in the real world.. 1) infinitely thin faces (a face defined as being double sided has 0 thickness) - did you want these to print? or are they 'invisible' ? 2) incredibly thin triangle faces pointing along the z axis - these appear to give rounding errors when exported to stl (may also happen with a very dense mesh) which results in the surface not being watertight. this is no problem in that I can ignore it, but may occasionally give rise to miniature support structures or other anomalies as a side effect. not too late to throw in your ideas for features - but I'd like to 'freeze' the feature list beginning of next year so the first version is well defined.

you did on google, and there were several people there who apparently weren't aware that at least 3 of us have been printing in nylon for some time now. but of course we're not famous enough to be on hackaday.. :( in retrospect, I probably should have named the thread something more obvious and made a bigger deal about it

stainless steel, yes. it's even better if you feel like adding the heat break and have a lathe handy, but it's not a necessity. the reprap boys did a ton of tests on this - the link to their thread is included somewhere earlier in this discussion - and came to similar conclusions so I'm not sure we'll ever know why UM decided to use (and keep) the PEEK.

SG has said the most important thing I was going to respond with - having learnt from bitter experience (re-made the head about 7 times now) the brass inner tube to PFA tube is key and having an insulator around it (PEEK or otherwise) simply exacerbates the problem. I didn't have the luxury of being able to work SS, which was why I bought the E3D kit, but if you can make a SS tube, that's definitely the best investment. you then don't need an insulator anywhere (it serves no purpose), instead take the SS tube into an AL block and join it with the existing Al bottom plate on the head to spread the heat. for PLA temperatures, I can easily touch this (no active cooling required) at 20C ambient. I can also leave the UM on, at temperature and not have to worry about jams which is nice (and not possible with the V2). everything you're saying makes a lot of sense - especially about not much needing to change. I'd propose the thing(s) to change is (in order of how much effect it has) - 1) brass tube -> SS tube 2) press fitting the bowden against the tube -> introduce an air gap of a few mm 3) PEEK -> AL block. for my hybrid V1/V2 i've not bothered with #3, or even with #1 - this works fine for PLA, but for nylon I have to actively cool the tip of the brass tube or I get instant jam as you describe. for my all metal hotend, that problem doesn't occur, even at 30C ambient. I can attach a photo if it helps (not sure if my description made sense or not) - I guess the jist of what i'm saying is that rather than trying to keep heat in with insulators, it seems to be better to spread and remove it - whether active or passive isn't so important. nik

I have to ask it.. why does being in Glasgow affect any of the answers?

what problem(s) do you anticipate with an active cooling system with the fan switched off or removed (ie. pretty passive really at 300C? if the answer is 'the bowden tube' then simply don't have it in contact with the metal. a number of us (me included) have suspended the tube above the opening. air is an excellent and really cheap insulator we called this design a hybrid V1/V2 nozzle - it includes a V1 nozzle, and either the V2 teflon insert or 'thin air' insert - maybe it's similar to what you have, I can't be sure, but it's discussed in detail in another thread. the 'active' can be switched off if ambient temperature permits, or material temperature is low (I don't use it for PLA for example, actually I don't even have a fan attached at all right now) the only reason for the active is when you move to a chambered approach with a heated chamber or you want to carefully adjust the print temperature quickly or accurately (eg. printing with wood) MSU is right tho, it's always more fun to make something than buy it, so we look forward to seeing some photos! good luck!

wow, long post. interesting stuff too. but.. erm. why? just use the £50 hotend I used from E3D. all metal. no temperature limits. has been in service now for several months and is totally outperforming V1 and V2 UM nozzles. basically it just kicks ass. why reinvent that wheel? if you want a smaller nozzle, use one of the makergear ones for extra accuracy. if you want to keep the heater and thermistor electronics from UM, just reuse the heater block. it's all interchangeable. no 'popping' no blockage no mess no hard work reinventing wheels I'm building a dual head version now it was so successful. nik

holy moley! i'm running on a crapped out 1-core P4 :(

ooh, maybe I should just wait and let you do all the work that's pretty good Troy!

that's definitely a novel idea there Ian! I'll await the stl with excitement!

I might do that - the trouble is that if someone fills the build area with insane detailed model I'll either have to crash miserably or make it work at the expense of 99% of sane models. to decide where the split needs to be - does anyone have any feel for how large their typical models are? is a z-height of 10cm too small for example? on a similar note, does anyone have a feel for the finest resolution detail they want to see reproduced (within reason of the nozzle spec obviously) 0.1mm?