I had some problems with the nichrome getting too hot and damaging the kapton, the thermistor broke, so the arduino thought the extruder was too cold and kept increasing the temperature. I also found the resistors a lot less fiddly to use, and harder to break with repeated disassembly of the heater. It's a personal preference really though, either would work.by james glanville - Plastic Extruder Working Group
Nice I'd be interested to know if you ever get excessive gear wear on the plastic gear because of the metal driver. What hot end are you thinking of? I'd definitely recommend power resistors compared to nichrome, my insanely-bodged extruder made from ceramic resistors and offcuts of wire has printed for >50 hours with no problems, while I've gone through 3 nichrome designs that have just infuby james glanville - Plastic Extruder Working Group
I'm finding reprapped objects somewhat annoyingly anisotropic as-is, with my poorly calibrated machine I don't entirely trust Z-layers not to delaminate under extreme conditions. Another thing is that with my extruder, it takes a second or two for extrusion to settle down and become reliable per-layer due to an annoyingly large melt volume. I'm wondering if I tried printing not at 45 degrees therby james glanville - General
I don't know a huge amount about this, I'm studying engineering and not enjoying materials science I think the biggest problem with experimenting like this is simply because the extrusion machines to make 3mm filament are expensive and not under the control (at least I don't think so) of any reprappers, and it'd be hard to justify buying significant amounts of experimental and possibly useless fby james glanville - General
I'd have the same problem, except my extruder takes a bit of a while to start going properly, thus compensating neatlyby james glanville - Skeinforge
How do you intend to move the 3 axes? The biggest problem I can see is that for an extruder you want lightweight, fast belt-driven axes, and you'd probably want something heftier for a cutting bit. My reprap uses bike chain, which might be a good compromise? It's got a lot more heft to it than I assume belt driven repraps do, but without sacrificing print quality too much:by james glanville - CNC Routers, Mills, and Hybrid RepRapping
If you're generating that much plastic dust, perhaps the idler is not pushing strongly enough against the filament? If it isn't tight enough, it'll slip, and grind through the plastic. I use a cobbled together extruder unlike yours, but tightening the idler helped it for me.by james glanville - General
I have a similar problem, I sometimes have to pull the filament out, snip the thicker blob of the end and refeed it to unjam it. I've been thinking that a slightly tapered ptfe barrier would help more than cooling. Worth a shot?by james glanville - Plastic Extruder Working Group
I'm using pla on a heated bed, so it may not be comparable, but I'm using about half the extruded filament diameter.by james glanville - General Mendel Topics
I found it easiest to tie the nichrome to stranded wire using a double sheet bend, then just twist the loose ends around each other. There's no crimp or anything, and it's held up just fine through many, many extruder rebuilds.by james glanville - General
What about a microwave? I know they'll heat some plastics up, CAPA certainly, and PLA may be polar enough as well. It would at least heat the inside of the part more than the outside.by james glanville - General
I like that idea, or at the very least at the top of the page something about who wrote it.by james glanville - Administration, Announcements, Policy
I wouldn't go for a peltier - they're expensive and unless you're using them to rapidly cool down the part afterwards probably not worth it. My setup is masking tape over aluminium for pla, though I'm going to move to kapton because it seems to work well for others. Raw aluminum/steel/marble probably won't stick well enough. Aluminium conducts heat so well that multi-heat zones probably won't savby james glanville - General
I found adding M105 (dud command i think) to .skeinforge/alterations/homing.gcode enables separate xy and z speeds, horribly arcane but it worked for me. I also had to enable homing in skeinforge. Might be worth a shot?by james glanville - General
I've found ptfe tubing on ebay before, pound or two per metre, in ~3m lengths. My bowden extruder isn't finished yet, but you really do want to reduce bending as much as possible, so this probably isn't the best place to cut corners. The tube I have barely stretches, but as you bend it it shortens a little, so I'm going to go for a fairly big loop. Microstepping the extruder motor helps as well,by james glanville - General New Machines Topics
Yeah it'll be fine, the voltage wouldn't be more than 12v, and probably on 5v anyway.by james glanville - Reprappers
Could you speed drying with a heated bed, and by very gently blowing dry, warm air onto the object? I'm not sure about the current state of the acceleration code, but that would seriously increase print speed.by james glanville - Paste Extrusion Working Group
I definitely agree with martin about getting the most expensive lathe you can, and i'd add that if you get one, spend a good deal of time oiling it properly, making sure everything is as tight as it should be. I shattered a couple of tools straight away because the toolpost wobbled slightly, so the tool was thrown into the piece.by james glanville - General
It almost certainly won't make economic sense, a good lathe is pretty expensive and it'll never be worth making bolts/nuts. For extruder barrels, knurling steppers /maybe/ it's worth it if you'll have another use for the lathe. I love my mini lathe, but it's not going to pay for itself any time soon. The trouble with scrap metal is that it's usually in weird shaped parts, so needs a great deal ofby james glanville - General
The long thin tubes are going to give you a fair bit of friction, especially if you're turning at right angles. I've been toying with the idea of drilling three 3.5mm holes through a block of metal so they meet at a tetrahedral point, then having a very short thin hole to the nozzle. The shorter you can make the meeting point->nozzle distance, the less purging you're going to have to do to makby james glanville - Plastic Extruder Working Group
It's pretty difficult to express the accuracy of repraps in such a way, you don't just print in voxels. Your measurements would be very optimistic I think, especially if you don't want them to be misshapen blobs, because the extruder takes time to start/stop, and the plastic is stringy. What do you need such accuracy for?by james glanville - Plastic Extruder Working Group
hintss Wrote: ------------------------------------------------------- > so if the unused extruder is on the right and > you're printing from right to left, it dosen't hit > the part. He says that that is the whole point of > the pivot On my reprap the nozzle does skim over what its already printed, without snagging it at all. Surely you could just print with the finest nozzle first,by james glanville - General Mendel Topics
If they're both extruders, why not just have them both at the same level? I do think your idea would be great if you have something like a dremel where you might change the length of the cutting bit.by james glanville - General Mendel Topics
Oooh pretty Can you post a bit more information?by james glanville - Plastic Extruder Working Group
My darwin has longer bars, and much, much heavier axes, and there is no noticeable deflection. With the 8mm steel bars I'm using, 1m clamped at one end is very difficult to bend even by a fraction of a mm. I'm not sure why your calculations give such bendiness, but I don't think its much of a problem in practice. I think a better approach than stronger bars would be lighter axes if people are havby james glanville - General
Couple of reasons most people don't want to use parallel ports: Most modern computers, especially laptops, don't have parallel ports. If you have to buy a usb-paraller converter, it rather defeats the point. Using a microcontroller means that printing without a pc is just a firmware upgrade and a sd card away. With a parallel port you simply have to have a pc. With parallel ports, there is anby james glanville - General
The mendel extruder page is a bit unclear, your motor MUST have splines of some sort. You'd get no grip at all otherwise.by james glanville - General Mendel Topics
I print pla onto masking tape, so you could just cover the glass print area in tape. You'd maintain flatness, and masking tape is a good balance of being sticky enough to not peel and warp, but can be easily removed. Glass is a pretty lousy conductor of heat, so you should use a fairly even heat source.by james glanville - Reprappers
I can't comment on that specific glue, and its likely you won't be able to get enough information on it to know for sure, but I'd be quite suprised if it will withstand the high temperatures for prolonged use. In its advertised use for cpus/leds, it probably wouldn't get hotter than 100 degrees, whereas the surface of the nichrome can be much higher than the overall barrel temperature. Fire cemenby james glanville - Plastic Extruder Working Group
The pinchwheel is practically the same, its just a bit of a pain to make the parts without a printer already. I've also had much better results using a sprung idler wheel, which the official mendel extruder doesn't have.by james glanville - General