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Protonias Wrote:
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> PLEASE edit your post with the correct formula...
> It should be Volts = Amps * Ohms!
OOPS! Thanks for pointing that out. I have made the correction.
by
JohnWasser
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Controllers
"Given I figured that the resistance that the resistor is creating has to go somewhere. And that is given off as heat. So more resistance for a constant amps and voltage would give out more energy."
There is a simple relation between voltage, current (Amps) and resistance (Ohms).
Volts = Amps * Ohms
(Corrected. I originally wrote Amps/Ohms which is wrong. Sorry)
There is also a simple relation
by
JohnWasser
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Controllers
I just saw an article about the Paperduino on the MAKE blog:
Guilherme Martins in Portugal designed an Arduino clone built on a cardboard substrate. The component layout and wiring, top and bottom, are printed on paper and glued to cardboard. You poke holes with a pin and shove the component pins in the holes. Then you wire point-to-point following the printed wiring diagram:
It seems to
by
JohnWasser
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Plastic Extruder Working Group
I've worked with that stuff. It's made from silica sand, sodium silicate ("water glass") and colorants. The sodium silicate reacts with CO2 in the atmosphere to form silicon dioxide. The end result quite similar to glass... hard and brittle.
A thick enough layer (I'm guessing 1/4 inch) could be strong enough for an extruder insulator. The thicker the layer the longer it takes for the CO2 t
by
JohnWasser
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General
Yes. Two wires for he nichrome and two for the thermistor (or thermocouple). There's also two wires for a fan and two for the extruder motor. In future there may be several for the extruder motor shaft encoder and two for the anti-drip valve solenoid. Perhaps another two for a switch to sense when the plastic has run out.
by
JohnWasser
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Controllers
> 1) I don't see any build instructions on the "valve solenoid",
> but do see it on the single arduino wiring diagram
Earlier diagrams did not have the valve wiring. I think this experimental feature was added to the diagram but not the build instructions. I would ignore the "valve solenoid" wiring for now.
> 2) Why are the 4-pin all connected together in the picture?
The pin hea
by
JohnWasser
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Controllers
I would expect problems spinning a 5KG reel of ABS at high speeds but perhaps an oscillating motion (like use for cast-cutting saws) would also cause enough friction to melt the plastic.
by
JohnWasser
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Plastic Extruder Working Group
Ian Adkins Wrote:
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> if the Al is cheaper than steel you are
> buying the wrong steel!
Even switching to 5/16th" rod the cheapest 6' steel rods are $6.60 (about 50% more than the aluminum).
Strangely, the 5/16th" 6061 "mill finish" aluminum rod is more expensive than the 8mm 6061 "mill finish" aluminum rod ($8.92 vs. $4.39).
by
JohnWasser
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Mechanics
Wade Wrote:
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> Anyway, what's it worth to you, what do you think
> is a fair price? I suppose this is the sort of
> question that Ebay was designed to answer.
>
> Wade
EBay is an EXCELLENT idea! By auctioning you can determine a reasonable market value for the parts and as more people make parts and offer them for auctio
by
JohnWasser
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General
Larry_Pfeffer Wrote:
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> Is the Aluminum cheaper than non-stainless steel?
Yes. Less than half the price. The cheapest 8mm steel rod they have seems to be 12L14 (free machining leaded steel) which is over $11 for a 6' length.
The cheapest 8mm stainless seems to be Type 303 at $10.76/meter. That would be over $98 for 9 rods where the a
by
JohnWasser
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Mechanics
Forrest Higgs Wrote:
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> LOL! Shipping can sometimes be a problem for
> something six feet long.
Back in 2002 I ordered four 6' lengths of 5/16ths free machining brass rod from McMaster. They arrived at my home just fine so I don't anticipate a problem. I was just wondering if the aluminum would be strong/stiff enough for a Darwin.
by
JohnWasser
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Mechanics
Has anyone tried 8mm aluminum bar stock for the frame of a RepRap? I was looking at the choices available from McMaster and the 6061 Aluminum bar stock has some major advantages: It's available in six foot lengths and each length is only $4.39!
The six foot length is important because many of the cut parts are 500mm long and many of the less expensive steel bars only come in 36" (914.4mm) len
by
JohnWasser
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Mechanics
jajo Wrote:
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> I am using Generation Two Single Arduino. Where
> does the ground wire from the stepper drivers go
> to? Also, in the program's global preferences
> menu, I noticed ZAxisAddress, XAxisAddress, and
> YAxisAddress. What are those?
If I recall correctly the old PIC electronics used a token-ring-like network be
by
JohnWasser
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Controllers
(The "colon D" got converted to a laughing smiley. Changed the colon to "percent 3A")
by
JohnWasser
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Reprappers
Looks like you didn't build the 64-bit version of RXTX as described in the RepRp software installation instructions for Mac: .
"Note! For Mac OS X 10.5, Java 6 is 64-bit only, which means that the jni libraries below must be installed also in 64-bit version (see more info below)."
That page also mentions that the 64-bit version of RXTX has to be built from source:
"64-bit version (Java 6 on M
by
JohnWasser
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RepRap Host
The Arduino Diecimila has a built-in USB/Serial chip that works fine with my MacBook Pro. You just need a "Type A to Type B" USB cable such as used on most USB printers and some USB peripherals and hubs.
If you use the Sanguino or one of the other Arduino variants that don't include the USB/Serial chip you will need instead a $20 USB/TTL Serial cable:
by
JohnWasser
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Controllers
If you are looking for USB to Serial you should specify if you want TTL Serial or RS232 Serial. The logic levels are different.
by
JohnWasser
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Controllers
I think that part of the reason for using a microcontroller (like the Arduino) instead of a gate array is that there are many more people experienced with procedural programming languages like C++ than there are people experienced in programing gate arrays. I would have no idea how to implement G-Code or the Bresenham line drawing algorithm in a gate array.
by
JohnWasser
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Controllers
There is a free webcam community site called "Stickam.com" where you can make your RepRap webcam stream available to the public. It's a streaming system so you get moving video (not periodic frames) and sound.
by
JohnWasser
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RepRap Host
I'm pretty sure that's not an "inductive heater" but a low-voltage high-current resistance heater connected to line voltage through a step-down transformer. At least that's the way the "soldering guns" I've taken apart worked. There may be benefits to using low voltage and high current but it would require mounting the heavy step-down transformer on the extruder head or running fat conductors
by
JohnWasser
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Mechanics
carpenma Wrote:
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> Sweet, that's gonna cost alot... how much do each
> of those pieces weigh?
>
> -Matt
Each piece? I have no idea. For the total set of pieces I have read that a full set of printed parts weighs around 4 to 5 kg. Roughly 10 pounds.
by
JohnWasser
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General
Wade Wrote:
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>
>
> I think he was using a laser cutter to cut the
> cardboard
His site says he uses a CNC Router
by
JohnWasser
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General
davidgoodenough Wrote:
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> I am also confused as to how I come to load two
> images into the arduino at once.
I don't think you do load two images at once. If you mean the SNAP and the G-code versions of the Arduino code, you don't use them both at the same time. Perhaps someone who has tried both can tell you which they recommend a
by
JohnWasser
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RepRap Host
I remember seeing a mention of an individual who was designing a surfboard. The article was mentioned in at least a couple of tech news feeds and, I think, showed up here somewhere. I don't think the design is open source.
Gizmodo had the article under the title "What Happens When a Computer Programmer Decides to Build a Cheap Surfboard?" and that one points to the original article in Popular
by
JohnWasser
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General
I found the answer to my quandry in:
Appendix B
B.4 Milling Arcs
B.4.1 Radius Format Arc
"A positive radius indicates that the arc turns through 180 degrees or less, while a negative radius indicates a turn of 180 degrees to 359.999 degrees."
by
JohnWasser
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RepRap Host
Of course if you are making only one RepRap you might have to pay a lot more for parts than Ian does when he buys in bulk and puts together kits. If you source as much as possible from McMaster-Carr you will end up paying $384.52 for just the Cartesian Bot parts (no extruder parts). That would add about $300 to my estimates above. :-(
A minor part of the problem is trying to get metric parts i
by
JohnWasser
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General
Well, if you have no material costs for the RepRap that would eliminate the $45 for a reel of ABS. That would bring my guess down to about $450.
by
JohnWasser
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General
David Iscool Wrote:
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> About how much does it cost to clone a reprap?
> including printed and "nonprinted" parts? thanks.
You'll need the electronics, Arduino and cable: $190 plus shipping from RRRF.
A posting from January lists the "Steel Frame Kit Subtotal:
by
JohnWasser
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General
A new update to the Arduino development environment has been released.
Among the changes are: "Upgraded to newer versions of avr-gcc (4.3.0) and avr-libc (1.6). This provides support for newer Atmel chips, but may increase the size of sketches."
I imagine this may cause problems for the RepRap software which is very close to filling all available space in an Arduino Diecimila. It may be goo
by
JohnWasser
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RepRap Host