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One advantage I can see with 1.75 mm filament is that you need more steps per mm of extruded filament, allowing your extruder to be more accurate in the amount of filament extruded while also maintaining its ability to push filament quickly. If you want to make really small features with 3 mm filament you will have to push the filament a very small amount, which is hard to do accurately when taki
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destroyer2012
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Plastic Extruder Working Group
criswilson10 Wrote:
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> What do we really need? An educated population
> that realizes you don't have to kill babies to do
> cell or stem cell research.
I agree with everything you said. I suppose I was going a bit overboard with my comments about engineers taking the science the wrong way. I think what I want to say is, building or
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destroyer2012
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Tissue Engineering
Perhaps the issue is with plastic stretching/contracting with temperature. Try to monitor the temperature while printing and see if the mis-sizing is correlated. As the plastic cools after printing it will contract, so try printing with a lower bed temperature and see if you can cut down on variation, then scale up your object to compensate for the shrinkage once you can get the dimensions consis
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destroyer2012
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Printing
How much overhang is possible really depends on what sort of shape you are making. If you are making a round overhang like a wine glass you can probably get it to work at a much shallower (more horizontal) angle than if you were making something with square overhangs. I've seen some people even claim to get 90 degree overhangs (completely horizontal) if they stretch the plastic right and make rou
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destroyer2012
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General
Try putting a hose clamp on the plastic piece? If it has worked itself loose on the nozzle threads then maybe squishing it will help to hold it tight.
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destroyer2012
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General
Are you using M109 to wait for the temperature to be reached? When I use that my fan turns on when it should be off, which is a problem. That's why I preheat for every build and manually remove M109 commands from the gcode. Another option is making a duct for the fan so it blows ONLY on the hot end tip. That greatly reduced HBP cooling for me, while retaining desired fan effects.
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destroyer2012
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General
Update: Turned fan on 60% all the time, now overhangs are perfect, and no delamination. Thanks for the hints guys!
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destroyer2012
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General
In light of the "common toolhead interface" idea, I propose we go back to RS485 communication between motherboard and toolhead. That way, different heads could each have arduinos embedded, and just tell the motherboard how to control them (i.e., what gcodes get to be forwarded) when they are queried. That way, future heads could be compatible with current firmware, since controlling a head amount
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destroyer2012
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RepLab Working Group
@gtg252b you keep your fan on all the time? I have it set to only turn on for small layers and bridges (cool setting in slic3r). I've had issues where layers after the fan turns on delaminate from layers before. I guess if the fan is on all the time then that wouldn't be a problem.
Will post results after I get a chance to try it. I Just hope it doesn't cool the lower layers so much that they c
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destroyer2012
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General
I hope not.. in fresh air I get extrusion size of 0.8 mm; when squished I get 1.12 mm, printing 0.4 mm layers. That doesn't seem like it's too squished does it? You think I should increase my layer thickness? My layer adhesion is already not perfect on smaller pieces :/
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destroyer2012
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General
Hey guys, I recently got my Mcwire-based repstrap printing and I am having a bit of trouble producing overhangs. When printing the whistle It comes out almost perfectly except the "cable tie loop" at the back does not print at all. When laying down the first layer containing the overhang part, it curls up and subsequent overhanging layers dont have anything to print on. Besides the whistle I've
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destroyer2012
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General
VDX Wrote:
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> ... this is one of the main goals, bio- and
> gen-engineering try to achieve since the discovery
> of DNA/RNA and the first glimpses on the applied
> 'functions'.
SO my point is: Why waste time trying to print an organ when you can instead spend time working on the lofty goal of growing one? The challenges in printi
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destroyer2012
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Tissue Engineering
Awesome! Thanks for the hint Traumflug. Here's what I did:
I uncommented DEFINE_HEATER(fan, PORTB, PINB5, OCROC) and changed it to DEFINE_HEATER(fan,AIO2) (because my heater is connected to analog pin 2) then below I uncommented #define HEATER_FAN HEATER_fan
And now it works! Of course I had to connect the fan pin to my sanguino mainboard at analog 2. It would be nice if it worked with the sepe
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destroyer2012
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Firmware - experimental, borrowed, and future
I know there was a mention about this at some point in the past, but I still don't understand so I'm going to make another thread.
I have a seperate extruder controller board (Arduino 168) that talks to my motherboard via rs485. How do I set up the firmware to control a fan attached to the extruder board? There's a FAN_PIN setting in the config.h of the extruder board, and I've set that to a pin
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destroyer2012
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Firmware - experimental, borrowed, and future
So I've heard a lot of talk about these resistors mounted in aluminum blocks used to heat extruders, and it seems to me like a move in the wrong direction. I've prepared a list of percieved advantages and disadvantages of nichrome vs resistor designs:
Resistor Disadvantages
- excessive mass
- wasted heat
- requires precisely milled aluminum block to acheive press fit over hot end
Resistor Advant
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destroyer2012
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Plastic Extruder Working Group
Cells have the ability to build themselves.. Why assemble an organ with external means when you can just.. induce the organ formation by feeding stem cells the right signals. All we need then is to know what those signals are and replicate them. No need for 'reprap' in that case. Sure it might take longer but im not convinced that printed organs will work at all. Organ structures are a consequenc
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destroyer2012
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Tissue Engineering
Sorry if I'm going a bit off topic here but I don't understand why these new reprap designs have two motors for the z axis. Is there some advantage to having two motors as opposed to one motor with a belt to drive the other leadscrew? To me it seems like a pointless expense.
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destroyer2012
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General
I have a direct drive splined shaft pinch wheel extruder with 400 steps/rev and I came up with 33133 steps per meter of 3 mm filament (abs).
Works ok (no blobs) now. Oh and using relative E codes.
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destroyer2012
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Firmware - mainstream and related support
I think it is supposed to be meters of filament pushed into the extruder and NOT meters of extrusion coming out.
At least for me, I tried using slic3r and setting the E-codes to be relative, which yielded values on the order of 0.001
in the gcode file.
Definately seems like a measurement of plastic sucked in vs plastic squirted out.
And I believe that teacup wants the E values to be relative.
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destroyer2012
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Firmware - mainstream and related support
Just an update:
Bought a couple of these
〈=en&site=us&keywords=Z2521-ND&x=0&y=0
Seemed like the right choice given my bed only draws 0.8 amps and the bigger relays go up in price pretty quick.
Wired them up in parallel (just to be safe!) to power my heated bed.
Temperature control works fine (set to bang bang) and I don't have to worry about the relay wearing out and getting
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destroyer2012
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General
Switched to pin 12, which is not a pwm-capable pin on the arduino diecimila 168 right? According to this it is not, so i should be safe there.
Still clicking.
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destroyer2012
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General
Just to clarify my symptoms a bit: During ramping the relay turns on fine (only once) and if I then set the temp back to zero it turns off correctly. When the heated bed reaches the set temperature the relay starts clicking really fast.
I could not figure out how to do the equivalent of millis() without screwing up everything else in the teacup firmware (if you include millis() it will try to re
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destroyer2012
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General
Thanks a lot for those suggestions jamesdanielv, I will see if I can put them to use.
I think my issue is not with the PWM but with the PID control wanting to switch it too fast.
One problem is the teacup firmware is written entirely in C and doesn't use functions such as "analogWrite" or "millis" so I am having some trouble just figuring out what does what. The fact that I have it working for
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destroyer2012
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General
I have recently installed the teacup firmware on my custom Gen 2 hardware and it works mostly, but when switching my heated bed on and off (which uses a relay to control mains current), the relay switches way too fast and I'm afraid it will break. Does anyone know of an easy way to change the firmware so it waits like 1 second between issuing commands to the heated bed?
Thanks
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destroyer2012
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General
So how well does heated masking tape work with ABS? I haven't found any conclusive data on the subject. Is it worth doing?
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destroyer2012
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General
Yes well that's why this is a repstrap... Intended to print out the parts for an actual reprap which works better.
Although with my leadscrew drive I get ten times the accuracy you get... Not that it really matters with my crappy print bed.
In any case I tried to print a reasonably sized object (10x40 mm footprint) on my sugar-bed and it resulted in warping and lifting the bed up about 1 cm dur
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destroyer2012
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General
Hey guys! Long time lurker first time poster (and printer!)
After an excessively long gestation period my McWire-based repstrap is finally online!
Still trying to figure out the right settings to get decent prints so I can make myself some Mendel parts.
Here are some pictures:
Some specs of my setup:
Cartesian robot:
Stainless Steel Threaded rod/ captive nut axis drive
Max speed 4mm/s
Pr
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destroyer2012
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General
Forrest Higgs Wrote:
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>
> BTW! Why is your sugar red?
No clue. It's baker's sugar, if that makes any difference. Gonna mess with my extruder's speed and try again. Maybe I can get better extrusion thickness. Maybe it has to do with the temperature at which I melted it?
Doing this in an oven seems like overkill. I was thinking of u
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destroyer2012
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Mechanics
I just tried extruding ABS onto sugar today and it worked! I did not have time to finish making the object, and clearly there is a lot of work that still needs to be done before it works flawlessly, but the ABS stuck to the sugar very well.
I melted the sugar in an aluminum foil 'cup' and then poured it onto an aluminum foil surface, then flattened it with the underside of a pan. The surface was
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destroyer2012
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Mechanics
Progress: GCode interpreter flying success! I was able to print out the first layer of "motor clamp" using a pen tacked onto the Z-stage.
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destroyer2012
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California, Los Angeles RUG
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Pages: 12345