EnlightX I think nophead was referring to the use of an offboard switching solution, like the SevenSwitch PCB that Traumflaug noted above. (The IRFZ044 is rated at a far higher max current and voltage than is used for the heater, so it should be VERY solid.by xiando - General
There really isn't much of an issue on having a FET for this purpose *on a printed board, as long as the subcircuit - uses a dedicated and isolated supply line (so you're not forced into sharing the power supply for the processor/etc with that of the heater) - has sufficiently large traces that are properly placed on the board - uses a sufficient FET for the purpose (imo over-engineered rather thby xiando - General
The hot-end should warm up in ~10 minutes or less, from what I've seen on my buddys' machine (mine is still in build). Step 1) Check the wiring to the hot-end at the board end of the wiring for continuity, by first removing one or both leads (both would be better) It should show a small resistance but test valid with a multimeter set to continuity (the setting that beeeeeeeeeeeps when you shortby xiando - General
yup. that sounds about right. In any case, ventilate.by xiando - General
Some variant on clear acrylic. I think I read in a few topics on the net that implied the community was using that acronym to refer to it. Sorry for the confusion.by xiando - General
Here's a tip for safety. Ventilate. I worked for years in an environment in which Stoddard fluid (Napthalene, "white gas" in Britain, etc.) was used as a working fluid. It lists as essentially harmless, but I know from years of being "immersed" in it that while the paperwork says it's ok, fact is, I got headaches and nausea from being around it, regardless of whether the MSDS signs off or not. Anby xiando - General
Sorry, I missed that it was solid core. The image appeared to be stranded wire, but I must not have paid close enough attention on the ebay item. The point, of course, is still that stepper motors should be wired with shielded cable, because otherwise you can both transmit and receive noise that can compromise your system and those around you.by xiando - General
"In case that is the problem... what can I do to fix it or shield the com chips? " IF it is the motor cabling, replace it with proper motor cable, ie, four wire, shielded, twisted pair. That's what the motor mfg's recommend,. and it's what test specs require in "real" installations. For this app, 24ga if you can get it, or 20-22ga, which I'm pretty sure is readily available. Something like , (eby xiando - General
No, it doesn't go up with time I'm just offering one probable cause of communications failures. I have no real insight into the quality of your build and it could be any number of things. I was specifically asking about the motor cabling because it is a known source of high energy noise that can "hump" a communications channel and I've seen it dozens and dozens of times in the field in my profeby xiando - General
I'm not going to cover every possible problem source, but I'll just start the replies off by asking this: Are you operating with shielded motor cable? Steppers can generate some nasty noise, and comm chips can easily be taken down by the noise currents generated by the motors.by xiando - General
re: reamer. Good point. However, at a guess I'd say that many or even most of us don't own or have access to a set of reamers, and a decent set isn't a small purchase. In my experience, a drill bit is fine for enlarging a 0.1875" (4.763mm) hole to 5mm, as long as a steady hand or a drill press/lathe is used, the bit is sharp, and oil or proper coolant is used. I might even be inclined to use a haby xiando - General
Agreed re: lathe or drill press (I abbreviated on the drill press to "press")., but even with a hand drill, it should not be too hard to get a clean, centered hole if the existing hole diameter is relatively close to the target, since the bit will want to auto-center itself, as long as the OP drills slowly and carefully. Just don't use step drills (the ones that electricians use that have multiplby xiando - General
Sure. you didn't offer the diameter of the existing hole. Is it an SAE pulley with a slightly undersized hole or significantly undersized? If significantly undersized, idk...you may be SOL if there isn't enough material to allow the set screw to do its job and will have to order the "right" part. If not, a #8 drill bit will cut a slightly oversized hole (5.0546mm). For a true 5mm hole, you'llby xiando - General
to prevent the shaft from turning, use a small vise grip or similar. then just file it using a small (fine) machinist file, although I suppose a dremel *could be used to accomplish it as well. You'll want to file back onto the shaft a little farther than the location of the set screw on the gear so it has something to grip please forgive the image. it's just something I *very quickly threw togeby xiando - General
what shaft diameter and what hole diameter? There are practical limits. As far as flats are concerned, a flat will hold a set screw better than a round, so there's some value in it...if the pulley uses set screws.by xiando - General
Yes, all cement begins to absorb moisture, if the container has been opened or is otherwise in contact with the air (unless I suppose, if someone lives in Death Valley or somewhere else with really low humidity). And moisture absorption kills it. I have a bag of mortar-mix in the basement that got left in the basement about a year ago that's worthless due to soaking in the humidity. It's not a coby xiando - General
Enlight: I noticed that about the power resistor. It's a very tight fit, so I'll be buying a few extras in case I have to rebuild the head. I doubt they'll hold up to being removed and reinserted, or maybe better said I would not trust in it. Same goes for the thermistors, due to the "gluing", and I've already ordered a few extras of them as replacements. Polyonhell, thanks for point about air eby xiando - General
The Openrail project is interesting, but if I may ask, why are you bothering with aluminum as a rolling surface? You could as easily attach steel bar stock as using hardened aluminum bar stock for the rails, with far less concern about long-term wear.by xiando - General
Thanks for the advise, the tin foil trick seems like a pretty good solution for maintaining thermal contact. I don't have any glass-rope cement, but I do have a bucket of refractory cement. I'll keep in mind the recommendations about allowing it to cure for a few days.by xiando - General
Hi all, Building up my first Prusa. I just received my hot-end, a 3mm filament x 0.35 nozzle, J-head. So I'm wondering this. IF I choose to cement the thermistor into the body (there's a pre-drilled hole for the sensor that's a bit oversized for the thermistor body), what kind of cement is recommended? I realize that many may say "just tape it in..." but I can't bring myself to that. Too manyby xiando - General
I really don't know about anyone else, but IMO, it's all about affordable rapid prototyping at home. Many useful parts can be made of extruded plastic using the simple variation on a 3D milling machine that "in the old days" would either have to be cast in plastic or milled from metal stock.by xiando - General
Dremels come with a variety of chucks. (I have four different ones with mine) The smallest is suitable for 8-15 mil bits.by xiando - General
Probably not, although if one knows the dimensions and uses the same object every time (not just the same object *type, ie any old nickel), and as you noted, uses a square print instead of a round hole to calibrate, it might not be so bad. It kinda depends on how accurate one really needs it in the first place. At a certain point, it starts to tread on the areas of bearing performance, the type oby xiando - General
I haven't tried making a nozzle for this project yet, but I have drilled tiny holes in both aluminum and brass in the past, up to ~4mm of depth. Brass is very "chewy", so careful and steady and slow is the way. 1) slow drill rotational speed 2) cooling fluid (keep it wetted with machining fluid or at least oil) 3) very slow penetration speed. up then down, up then down, etc. blowing off materiaby xiando - General
I happen to have a coffee can full (pocket change is annoying when it begins to accumulate and wears holes in my pants pockets) ... So...I just measured about two dozen to see if it confirms the expectations. the results ranged from 21.15m to 21.28mm. My caliper was calibrated in March of 2010, so the absolute measurement may be off by a few hundredths, but the variance can't be accounted by anyby xiando - General