Show all posts by user
Page 2 of 3
Pages: 123
Results 31 — 60 of 62
I was looking into that idea, with the hollow-shaft stepper. I'll let you try that... in the mean time, I'm gonna try using a regular old hex nut mounted atop my extruder nozzle (I'm using a modified Prussa-Mendel), and use herringbone gears to transfer the motion over. Then, I'll play with the size of the gears to find a good RPM.
by
Wissing
-
Mechanics
I got a servo to work off an Arduino... it didn't seem that complicated, and it was pretty cheap. Now, the higher-torque ones will probably be more expensive.
Would it be feasible to use a regular 1-RPM DC gearmotor, and attach an encoder, or would that cause too much backlash? Would it be feasible to make my own encoder by mounting a laser pointer to reflect into a photocell?
My goal is to sti
by
Wissing
-
Mechanics
I would need 25 of these made. I have a 3d printer of my own, and have successfully printed this exact file in black ABS, 25% infill.
How much would that cost?
Thanks!
by
Wissing
-
Job Shop: I make stuff!
Pun intended. This thread is a spinoff of the 'hobbed bolt optimal depth' thread, in that I wanted to specifically talk about an idea I had for an alternative to the hobbed bolt method of extrusion.
It's a pun, because my idea involves both spinning and threads.
So here's what I was thinking... the problem with the hobbed bolt is that A.) it tends to slip if there's too much back pressure, B.)
by
Wissing
-
Developers
mihai Wrote:
-------------------------------------------------------
>
>
> at what speed do you need to rotate the tapped
> hole ?
> can a stepper motor achieve those speeds ?
a 6-32 thread pulls filament nicely, I've found. So that's 32 threads per inch, or 1/32" per rotation. Currently, my Wade's extruder has a gear ratio of... I forget exactly, but it's close to 5. If we can
by
Wissing
-
Developers
I wonder how much a problem it would be to just let the filament rotate (if using a single tapped hole, rotating). I would think the majority of the force would point down, with only residual friction tending to twist the filament. Couldn't that be resolved with some sort of guide or piping directing the filament from the spool into the extruder?
by
Wissing
-
Developers
Yaknow... it seems to me like this isn't the best way to extrude plastic.
I know there are extruders out there (big industrial ones, anyway) that use a big screw to push pellets of plastic through a tubular chamber, with the walls closing in.
Has anyone tried using something other than a hobbed bolt to push the plastic? I was thinking maybe a 3mm (or 6-32) tapped hole that rotates, pulling the
by
Wissing
-
Developers
No, I have no intention of using steppers. Servos will be my first attempt.
I'm actually foregoing the plastic and using aluminum cross-links in a sort of accordion style motion (like a scissor lift on its side, more or less). That will give me a radial displacement, and hopefully a good ratio between moment of inertia and weight.
I've realized I'll have to actually introduce at least 1 extra d
by
Wissing
-
Mechanics
Thanks for the input!
Yeah, I meant a robot arm, I guess. The appeal is precisely that - more complicated math, but less hardware. I see it as more efficient. Although I don't see why calculation power diminishes precision.
by
Wissing
-
Mechanics
This is a general discussion on precision movement for 3D printers, or related CNC machines as they may lend techniques to the development of 3D printers.
It seems like there are a couple rules of thumb I've come across:
1.) You have to have a stationary ground (rails, guides, dovetail block, etc).
2.) You have to have a moving stage to hold the tool (extruder, spindle, etc.).
3.) The closer you
by
Wissing
-
Mechanics
Has anyone ever heard of using an interferometer to judge a wide range of distances?
I was thinking trying to make one that simply tracks motion (not absolute distance) by counting the number of times a red laser flits from red to black as it scans across an object.
Has it been done? Is it feasible? Anyone know what I'm talking about?
Thanks!
by
Wissing
-
3D Scanners, Book Scanners, and Optics
I've never heard of feeding it without hotend. That doesn't make sense to me. Probably better just to calibrating using the same setup as you will to run it - hotend and everything. It takes me very little time to calibrate:
1.)Wait for it to heat up.
2.)Mark 100mm
3.)Extrude 50mm
4.)Measure again to the mark - call the new measurement "M"
5.)Open your firmware and look at the value of steps. Ca
by
Wissing
-
Reprappers
I'm having a problem with Slic3r, when I try to enter new values for things like "Bed Temp", "Perimeters (minimum)", "Solid Layers (top/bottom)", etc. The preset I have will say, perhaps, "1 perimeter", and I want to change it to "3". So I enter "3" and hit save. As soon as it finishes saving, it erases the value I put, and reverts back to the "1" it had originally.
Any ideas?
by
Wissing
-
Slic3r
I guess the solder is pretty goopy. Although that setup looks like it could be improved. Big old nozzle there. Noisy too.
Another thing is this: I'm wondering if the brass nozzle would jam up with solder (brass is an alloy containing copper - a solder wick). Or does something else in brass neutralize that effect?
dgm3333: I agree that aluminum would be more of an interest. For one thing, there'
by
Wissing
-
Reprappers
So tin.
I'll put the welding idea on hold for now, cause I think that deviates a bit too much from the RepRap - foraging into the area of "not tried and true" can take a lot of time that I don't have.
But I didn't realize tin melted so low. I guess I sorta knew, because it's used in solder.
Back to the original questions then: could I use a stainless steel nozzle? I've got one being built righ
by
Wissing
-
Reprappers
Hmm... sounds like a hi-res print. Tell you what, send me the file at prototypesplusnc@gmail.com and I'll print you a free sample - I can't imagine it would take too long.
by
Wissing
-
North Carolina RepRap User Group
Yeah I'll bet that would work. Something along those lines anyway. Although I don't know if I would start from TIG. If we're gonna have to mod something, it seems like there would be less modification required if the feed system and gas was already done. I've played with a MIG quite a bit, and as long as you get the speed/voltage ratio right, you can usually eliminate shorting.
The tough part, I
by
Wissing
-
Reprappers
I had this jamming issue. The whole pull-it-out-when-luke-warm trick didn't work so well for me. I ended up modding my hotend by rigging up a stainless steel heating element holder, with some copper washers and aluminum foil for makeshift cooling fins. I haven't had the problem since (although I also haven't tried extruding PLA again since either). But if you can't get the fans working, you could
by
Wissing
-
Reprappers
Mine isn't skipping, but it is making a weird rattling noise whenever the y-axis moves. It's a prusa-mendel. I'm wondering if it's the bearing. It *was* skipping a lot on the y-axis until I kicked in the acceleration control on my G-code.
by
Wissing
-
Reprappers
Well, alumina ceramic rod stock is readily available. Would that react with aluminum?
It would be nice, because ceramic apparently comes in pre-made tubing with inner diameters as small as .78mm; which could possibly mean no machining. I could just get a larger ID ceramic tube and a smaller ID ceramic tube, and put the smaller inside the larger halfway in, to make a reducer to push the aluminum
by
Wissing
-
Reprappers
I was having trouble with the PLA too. When I first started the print, I would already notice it spewing out, hitting the bed, then working its way up the side of the nozzle. I lowered the temperature to 165 and it seemed to work.
You could also try calibrating the extrusion speed. It's toward the bottom of the config file in Marlin I believe. First, measure out 100mm of spooled plastic above a
by
Wissing
-
Reprappers
so... is it possible to soften aluminum to the point where it bonds with itself, but does not yet have the fluidity to screw up the stainless steel?
secondly, what do you mean by "react" ... is this a slow corrosion, over weeks, or is it abrupt?
thirdly, what effect would chromium have on stainless steel, with regards to molten aluminum? It supposedly drives up the corrosion resistance...
by
Wissing
-
Reprappers
Quick answer: get the same one. I'll bet the $20 or so you pay for it would be far cheaper than the time it would take you to modify the circuitry and firmware.
Long answer:
You'd want the same wattage, torque ratings, and step size, I'd imagine.
A wrong wattage would be hard to compensate for.
Most other things could be finagled if you dare. Wrong torque or speed could be compensated for wit
by
Wissing
-
Reprappers
cool. well maybe I'll try it out.
by
Wissing
-
Reprappers
Stainless reacts with aluminum? Hmm well what do they make MIG welding electrodes out of? I'd bet that would stand up. I know you can MIG aluminum. Or aluminum casting... what container do you keep it in?
by
Wissing
-
Reprappers
isn't the point of a big gear reduction to give better precision? if you have direct drive, every step in the stepper motor is an order of magnitude larger. bigger steps is not a problem?
or, is it the case that bigger steps with smaller plastic ends up cancelling out?
by
Wissing
-
Reprappers
glue em back together with acetone
by
Wissing
-
Reprappers
Has anyone tried extruding aluminum?
The obstacles I can think of are as follows:
1. A hot end material that will not melt itself
2. A temperature indicator that will not burn out
3. Obtaining over 660C
3b. Staying over 660C consistently without damaging the heat source
4. A build plate that will not melt or catch fire
5. Cooling
5b. Localizing the heat so that it does not creep up the aluminum
by
Wissing
-
Reprappers
Page 2 of 3
Pages: 123