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Plastics, Epoxies, Resins, Photopolymerization, etc - Research, Development, Use, and Analysis -> http://objects.reprap.org/wiki/Plastics
Re: glass-bead thermistor - 17 years ago
For my takeoff on the Mk 2 I've dispensed with the thermistor altogether and control temperature by keeping track of how much current I'm running through the heater coil in the firmware via a software PWM routine. Running at a full 2 amps and no filament feed the extruder barrel stagnates at about 205-210 degrees C at a room temperature of 20 degrees. For the plastics I'm extruding that doesn'tby Forrest Higgs - General
Re: Foamcore boards - 17 years ago
Cool! I've got a chunk of MDF left over from building Tommelise. I'll cut a piece off of that and see how it works with HDPE.by Forrest Higgs - General
Re: Foamcore boards - 17 years ago
The xy working table on Tommelise is tempered float glass. I've not tried extruding directly onto it for the simple reason that it was hard to make and having a very hot metal extruder barrel touching whether by design or accident is not an experiment I'm happy about doing this minute. :-s So far I've extruded onto corrugated cardboard (too uneven), paper (too flexible and allows the cooling pby Forrest Higgs - General
Re: Foamcore boards - 17 years ago
***do you have to keep replacing foam boards?*** Yeap. OTOH, I can do about a dozen parts prints on one of them on one side. I'm not sure whether I ought to be using both sides yet. I can cut about 12 out of a sheet that costs about $7. That works out to about $0.60/sheet. Figuring on a dozen prints on one side and not using the other that works out at about $0.05/part for foamboard.by Forrest Higgs - General
Re: Foamcore boards - 17 years ago
I've just had to replace the foamboard and was able to cut across some of the HDPE tracks that I extruded across the surface. Those that I laid down on the surface caused no perishing of the foam beneath the paper. Those that I smeared across the paper with extruder head had significant recession of the foam beneath the tracks. Places where I parked the extruder head above the paper close by wby Forrest Higgs - General
Foamcore boards - 17 years ago
I've been using standard 5 mm foamcore of the sort that you matt pictures on for presentations as a base for extrusions. The .8 x 1 metre board (yes, those are true metric measurements) It was obviously pressed and cut to metric standards. A sheet cost me $7 retail. I can not recommend this material enough. HDPE extrudes onto it without warping, shrinkage or peeling. The HDPE sticks very fby Forrest Higgs - General
Re: Stripboard JDM - 17 years ago
Interesting, I never heard about needing a license to incorporate a USB connection into a system. It wouldn't surprise me, though. I'm using Microchip PIC 18F4610 which has USB support on-chip and that the compiler I'm using for the firmware has .ocx and .dll files so that you can talk to it via USB ports from your Wintel PC.by Forrest Higgs - General
Re: Stripboard JDM - 17 years ago
***Perhaps there's just something wrong with your JDM programmer (?).*** I don't see what it could have been. It's not like that's a very complicated circuit. In any case I dumped it many moons ago. I use the MeLabs programmer for all my work now.by Forrest Higgs - General
Re: Stripboard JDM - 17 years ago
***First I'm going to make the JDM - then I'll give Forrest's suggestion a shot.*** Sounds like a plan. :-)by Forrest Higgs - General
Re: Stripboard JDM - 17 years ago
***However in general I think you'll find all real PC serial ports (on-board, PCI, ISA, etc) will work.*** I can add to that that here in the US Dell Computer, otherwise a quite reputable firm uses crappy, non-spec RS232 ports even on expensive workstations like the one I have. Intel motherboards do the same thing.by Forrest Higgs - General
Re: Stripboard JDM - 17 years ago
I built the JDM and used it for quite a while. I found it to be a pig, mostly because it is built around a full RS-232 specification which means that you expect some fairly substantial voltage out of some of those pins. Unfortunately, a lot of very ordinary PCs' RS-232 ports are not built to a full RS-232 specification and do most definitely NOT give you the voltage you need to program them morby Forrest Higgs - General
Re: Circuit Boards Safety - 17 years ago
The heating element is no more dangerous than a soldering iron, in fact considerably less dangerous in my opinion in that it is in a fixed mount and not being waved around by some dude with an itch to solder components on a PCB. :-D I've fried myself far more often on my soldering iron. So far I've yet to hurt myself on the extruder barrel. As well, I've touched my extruder barrel many times wby Forrest Higgs - General
Re: Darwin Status? - 17 years ago
Vik, I don't know if Bart got round to sending you the links for this find of his... Being Meccano, it should be right up your alley. Moving this from Meccano to something we could print with a RepRap machine shouldn't be that difficult. The design could be considerably simplified, I think, from what is shown. It would also let us get at making small gears that our printers can't do prby Forrest Higgs - Developers
fab@home - 17 years ago
fyi for those of you who haven't already seen this... ____________________________________________________________________________________ The fish are biting. Get more visitors on your site using Yahoo! Search Marketing. _______________________________________________ Developers mailing list Developers@reprby Forrest Higgs - Developers
Re: Java comms - 17 years ago
***Playing with the machine a bit more would be fun though.*** My point exactly. :-Dby Forrest Higgs - Developers
Re: molex power connectors - 17 years ago
If I was sure of what I was doing I'd just solder the connector wires directly onto the board and be done with it. Sadly, I'm a long way from being that confident.by Forrest Higgs - Developers
Re: Java comms - 17 years ago
When are you going to take a break and get that beautiful printer you built actually printing something cool?by Forrest Higgs - Developers
Printing on Tommelise (second try to post) - 17 years ago
Okay guys! I've just crafted my first shot glass in AoI and pulled an stl off of it. Now do see whether I get a shot of Macallan's in hours, days or weeks. ____________________________________________________________________________________ TV dinner still cooling? Check out "Tonight's Picks" on Yahoo! TV. _______________________________________________ Developers mailing liby Forrest Higgs - Developers
Re: molex power connectors - 17 years ago
I just haven't found a connector which is either cheap or particularly good, never mind both. I settled on using twin pole screw connectors that I can plug into my board and solder tight. They're nice in that I can salvage them when I dump the board. At $0.50 they're darned expensive, though. Indeed, the aggregate cost of them is the most expensive part of of my electronics parts list. That'by Forrest Higgs - Developers
Re: Darwin Status? Oops! - 17 years ago
What your remailer for the forum can't recognise is Microsoft's "rich text" format, which is what the Yahoo defaults to. I can't blame it. RTF is one of the nastiest "standards" that Microsoft ever inflicted on the world. I had to write some code that spoke RTF format for a report generator about 8 years back. It wasn't a particularly life-affirming experience. ----- Original Message ---- Frby Forrest Higgs - Developers
Re: Darwin Status? Oops! - 17 years ago
Sorry, forgot to turn on "plain text". ***If it works (and there's no reason to suppose it won't), then we'll be in a position to send out kits of parts from the Strat to the core developers.*** Weren't you going to print the kits on Darwin? I thought that you said that at one point. ----- Original Message ---- From: Adrian Bowyer To: developeby Forrest Higgs - Developers
Re: Getting Reprap software to work on Windows - 17 years ago
Simon! Ah good! There is the information that you need, Bart.by Forrest Higgs - General
Re: Getting Reprap software to work on Windows - 17 years ago
Wait a minute. Correct me if I'm wrong but aren't you trying to do RS232 comms with some sort of different circuitry than the Max232 board approach that goes with RepRap?by Forrest Higgs - General
Re: Getting Reprap software to work on Windows - 17 years ago
***I'm surprised that you couldn't get communication going with a the standard pic.*** I actually didn't have problems doing comms with the standard pic control board way back when. Simon had set up a little control panel written in Java to drive the stepper motors that worked without hiccoughing on my Wintel PC first time out. Of course, the control panel wasn't trying to do much of anything bby Forrest Higgs - General
Re: Getting Reprap software to work on Windows - 17 years ago
I think that the question to ask is whether any of the developers have a RepRap or at least the control board system for a RepRap actually running on a Wintel machine. If the RepRap Project is serious about being anything but a Linux-only undertaking this HAS to happen. I may well be wrong, but to the best of my knowledge to date it hasn't happened. I believe that Simon has come as near as anyby Forrest Higgs - General
Re: Getting Reprap software to work on Windows - 17 years ago
ROTFLMAO! Good luck, Bart! :-Dby Forrest Higgs - General
Re: pcb group buy - 17 years ago
You've got 25 people buying or are you building a parts inventory for when Darwin takes off?by Forrest Higgs - General
Re: Automated Circuit Production - 17 years ago
The point I was trying to make is that Adrian already has a non-profit. No need to make one up. If you can get all that stuff in a padded envelope like you said you'll find airmail rates very attractive and with delivery in about a week.by Forrest Higgs - General
Re: Automated Circuit Production - 17 years ago
***if we end up doing this group buy and can find the right price, i'd be willing to throw down a few hundred dollars and then provide boards to newbies for cost + shipping.*** Be very careful. When you require a mandatory payment for something, even when you've deliberately set the price to only recover costs, most taxing authorities will treat what you've done as a sale and will require you tby Forrest Higgs - General
Re: Polymorph injection molding - 17 years ago
Shouldn't be any trouble with injection moulding it. You just have to run the machinery at lower temperatures than usual.by Forrest Higgs - General