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CD/DVD mechanisms and cartesian thinggie[s?]

DVD-laser-etcher, dremmel-router, possibly a 3D printer? Who knows!

Similar projects worth following
Surely inspired by someone, somewhere, likely found on HaD...
(See the excellent example in the links )

But also, shan't neglect the fact that in many a hacker's possession, at this very moment, is some crazy number of old/non-functional CD/DVD drives in various states of disassembly... an acknowledgement of the fact that "surely *something* could be done with these parts", and plausibly even a vague [or not-so vague?] idea as to what the/an end-goal might look like.

How could anyone dispose of [precision] linear actuators?! And most CD/DVD drives have [at least] two!

INTERESTED IN JOINING this project? Do feel free to request to join! But no requests will be granted without meeting the criteria listed in the Details section. ;)

INTERESTED IN JOINING this project? Do feel free to click that "Request To Join" button! But no requests will be granted without either A) at least 3 (three) paragraph*-long reasons regarding "Why I [you, not me=the writer of this project description] Hate 3D Printers" or B) at least 4 (four) reasons regarding the afore-mentioned hatred for 3D-printers, at least 2 (two) of which must be at least a paragraph* long or C) (UPDATED per @frankstripod's evil ploy to take over the world) The full solution to the #itanimulli Puzzle project in a private message.

(* NOTE: a "paragraph," as used here, is defined as at least 3 (three) sentences related to a singular topic. Groupings of three+ (>=3) sentences in which less than three (3) sentences relate to the topic-in-question will not be considered as meeting the Join-Request criteria).

(WARNING: This project includes ideas for 3D-printers.)

LOG Table Of Contents-ish And Related Links:

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  • 2 × Scavenged CD/DVD drives/players

  • First CNCed Toner-experiments

    esot.eric08/01/2016 at 08:02 0 comments

    Thin Slurry Feedrate 30mm/min

    Thick Slurry Feedrate 80mm/min

    The third test-run, Thick Slurry 160mm/min, had about as much improvement in visual quality (fewer burn-throughs, etc).

    But, interestingly:

    In the second-experiment, wiping up the un-melted toner was easier.. the traces seemed to stay adhered to the copper-clad OK... If I'd've been a bit more careful, they might've even stayed-adhered as all the un-melted toner was wiped-away.

    In the third-experiment, the traces actually wiped off *before* the unmelted toner.

    So, apparently, the toner melted to itself, but probably the coldness of the copper prevented it from adhering to it.

    Plausibly: Heat the copper to something slightly lower than the toner's melting-point before lasering...?

    Though, it seems there's also some importance in choosing a feedrate that is based on the path-taken by the laser... Note the pads always seem to "burn through"

    Same feed-rate, but the laser passes much more quickly over these areas, nearly (if not) repeatedly.

    Note that the circles formed at the joint between two traces are *almost* the size of a stepper-step... When the traces are drawn sometimes you'll get two passes side-by-side, or other times you'll get two passes right atop each other... so you can see that when the pads are drawn, it's quite likely there are *multiple* passes on the same path, in the same *step*, which causes the toner to melt more than a single-pass...

    So... either adjust the feedrate depending on what's surrounding, or adjust the laser-intensity... Doable...

    Or just find a *really* fine-tipped permanent-marker, add a solenoid, or throw in a rotary-tool, and avoid all these problems :/ But TSSOP with isolation-routing and a rotary-bit? Maybe not... (I still don't own a laser-printer, so toner-transfer isn't an option).

    The lasering-toner-method is *really cool*, but it's a bit of work (and mess) mixing up the slurry every time, getting it just right... and when stored for even a few minutes it seems to "settle." Could probably be assisted with a well-sealed container and one of those magnetic mixing gadgets would probably help dramatically... hmm...

    LOL, or shit... maybe I've got it all wrong... Maybe a *really light* pass over the toner, and isolation-routing...? Seems completely backwards, but look again at that image:

    Those traces peeled up *easily* compared to the surrounding (un-melted) toner!

    This one started as a strange-accident... I dropped it on the ground, and those pads lifted on their own:

    Hmmmmmmm....

    So, then, the idea would be to isolation-route the traces with the laser passing *very quickly* (so the copper-clad behind doesn't heat up), then wipe away the melted-toner, rather than the unmelted toner... Then throw it in the oven for a bit to set the remaining unmelted toner (where the traces are)...

    Hmmmmmmmm.....

  • ESOT: Eric Systematically Overanalyzes Things

    esot.eric07/31/2016 at 11:39 5 comments

    This guy's properly-scaled. HPGL-Settings were a bit off (stupid diagonals through the holes), but otherwise, that's a TSSOP (ATtiny45) to DIP breakout, and it aligns. So, not *perfect*, sure, but definitely doable.

    I used a trace-width of 6mils, I measured the beam's burn-width to be 4mils, so I plugged 4mil as the pen-width in Eagle's HPGL output, so it draws each trace twice. This is important, I'll explain in a bit.

    This, BTW, is a paper grocery-bag which seems to burn darn-near perfectly every time... Though, with the Pads, the repeated zig-zagging causes it to burn through. That's OK for these early tests.


    Got a bit daunted after initially calibrating the system's steps/mm:

    Again with the breaks and overhangs, but this time they're not repeatable! Infact, most of the error is non-repeatable in these (now calibrated) tests.

    But then it occurred to me: When outputting a trace-width that's wider than the pen-width, it draws overlapping "sausages." Which might just make up for all those weird "breaks"...

    I tried to take into account the repeatable spacing... 18mils between traces looks pretty good in the spacing-tests, but I ran out of space trying to make this breakout board and just went for it... and the results, again, are much better than I expected. Again, that's a TSSOP... I don't plan to work much smaller than that!

    One more time... in case my overanalyzing scared yah off:

    TSSOP is fine.

  • More Experiments + microstepping resources

    esot.eric07/30/2016 at 12:00 0 comments

    The bottom two test-runs are identical settings, just testing repeatability. The upper test-run was after bumping my motor-driver's voltage from 5V to 12V (those motors were HOT).

    Click to zoom that biznitch and look at the circled portions. Note that the upper portions of the diagonals are often sloped shallower than 45deg. Why? And note that it's less-apparent (if not non-existant?) when powered with 12V. So, I'm thinking that maybe the laser-sled, since it moves vertically, might be having some gravity-effects which are less-apparent when the motor's got a bit of momentum and also when it's got more power...

    Consistency-wise, it seems all three test-runs show nearly identical characteristic oddities in most other cases...

    E.G. the uneven spacing of each triad... why aren't those center "traces" centered? And why is it consistent on *all* test-runs...? Am guessing that these are full-steps and the microstepping configuration just isn't strong enough to hold the sled between two steps (but it's OK when moving...?) And, then, wouldn't they have little "tails" from the microstepped position it would've started at when moved to the starting-position, then a straight-line where it settled...? Not seeing that on the perpendicular traces, but it's kinda what I'm imagining to be responsible for the shallow-diagonal-"tails".

    Note also that this test-run (melting into an old floppy-disk) is much more consistent than the original cardboard-test-run...

    I've since done several more cardboard-test-runs, and have gotten pretty flakey results. I think it's *just* past the threshold of actually burning the material, so any differences in the fiber-density, (maybe skin-oils from handling?), etc. would show up as "breaks" in the traces. In several of the re-runs, the majority of the "traces" didn't seem to burn-in at all. (too bad, the smell of burning paper is much nicer than that of burning plastic, and the resolution/contrast is much higher).

    And... In the floppy-disk-test-run I don't see the really bad "overhang" on the far-left "triad"... it might be due to the width of the melt, or it may be that the clothespins might've been bumped or otherwise settled during the cardboard-test-run.

    (Interesting, I don't see the shallow-sloped-"tails" on the cardboard image... huh. Could it not be a vertical/gravity issue, and instead be a horizontal/momentum issue?)

    Also noting the consistency of the triads' bases, which should be aligned. Each of the plastic-test-runs seem to have the same error in alignment... again, likely due to the direction from which they were approached...?

    More analysis to be done...

    (Note, again, that my PWM-microstepping method varies the *voltage* not the *current* applied to the winding... So may be a bit less accurate because of it. Also, plausibly, the PWM frequency might be slow enough that it might be effectively oscillating between microsteps at some speeds... hmm...)


    I did, however, find some resources suggesting I might not've been too far off in my theorizing about microstepping's accuracy... and whether a two sine-waves is really the most-effective/accurate way to drive 'em... (without feedback)

    This is a random-dump of highlights:

    Microchip - AN822, Stepper Motor Microstepping with PIC18C452
    But in practice, the current in one winding is kept con-
    stant over half of the complete step and current in the
    other winding is varied as a function of sinθ to maximize
    the motor torque, as shown in Figure 22.

    Never heard of this elsewhere, but it's an intriguing concept.

    Microstepping Concepts and Configuration

    Motors driven by microstepping drives show non-linearities between full steps. Plotting the desired position vs actual position, where the center of the graph is a full step position, would look like a sine wave rotated about the center by 45 degrees. A full cycle of the sine wave would occur between two full steps.
    ...This is caused by the magnetic attraction to the pole that the motor coils are unable to overcome as well...
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  • Bipolar [Single/Micro-] Stepping Thoughts, ctd.

    esot.eric07/26/2016 at 10:49 0 comments

    Alright, a tiny bit more research...

    This is a good resource:

    http://www.allaboutcircuits.com/textbook/alternating-current/chpt-13/stepper-motors/

    Here's a "Hybrid Stepper Motor" (simplified), (from that page):

    (simplified, further:)

    "Hybrid stepper motors" are a bit more sophisticated than those in your DVD drive, but they're the ones I've taken apart, so I can understand this one a bit better. These are the big-ol' NEMA# motors used in most 3D printers. They can come in both unipolar and bipolar form.

    As far as a bipolar stepper motor, the rotation shown in the second image is acquired by the more-complicated form of single-stepping, described in my last log:

    As far as *typical* bipolar-driving goes, this method is less-typical, as it requires more sophisticated circuitry that not only can reverse polarity, but *also* can disable power to the windings. But let's go with this for a second, because, again, this is *much* more closely-related to the typical *microstepping* method used for bipolars.

    So, what you see in the image (repeated because... scrolling. Wee!):

    So, what you see in the image is the South-Pole of the rotor, and between its teeth you can see the North-Pole which is behind. Note that the teeth on opposite poles are 180 degrees out of phase.

    Alright, that's not much different than the simple "bar-magnet" drawing from before. I won't repeat it, here.

    This image shows single-stepping where the teeth of the rotor align perfectly with the powered teeth. These positions are *strong*.

    But, here's a half-step:

    (This is modified from the original image shown above, from allaboutcircuits.com):

    Note that each tooth is only 3/4ths aligned with the nearest tooth on the associated phase-winding... OK, so we've already lost 1/4 of the magnetic holding power just from that factor, alone.

    Now, consider that the teeth on the *opposite* pole on the rotor are also now 1/4 aligned with the teeth on the phase-windings. This guy is now pushing back, *against* the phase-winding's magnetic-field. So, I don't know physics to this extent, but I imagine that means it's essentially depleting the overall holding power by something like yet another 1/4th.

    So, with my bar-magnet example from the previous log I guessed something like: Put in 2x the power of a single-step (by powering *both* phases' windings, instead of just one) and get something like 1.414x the holding-strength.

    And, here, it seems similar might be true... Again, we do have *both* phases powered, this time, rather than a single one (as in the full-steps shown in the original image), so we should have *more* holding-power than single-stepping, but definitely less than double.

    Further, when moving from one full-step into the next half-step, we have an interesting scenario where the "other" magnetic-pole is *resisting" that motion. If merely single-stepping, as in the image shown earlier from (a) to (b), *all* the magnetic-force created would go into *pulling* the rotor into its new position. Well, rather, the South pole teeth on the rotor would be pulled to the north winding's teeth (as in (b)) and the North pole teeth on the rotor would be pushed away from the north winding's teeth. So, all the magnetic-force created by the windings goes into moving the rotor to its next step. BUT when half-stepping from (a) to my Half-step image, the opposite poles are acting to *resist* the motion.

    This observation isn't regarding the holding-power, but regarding the *moving* power... It would kinda *dampen* the motion... In a way that's nice, it *smooths* it a bit, rather than creating a sudden jerk between positions. But, it also means that now *time* is more of a consideration. Sure, an *unloaded* stepper would eventually wind-up at that half-step, but getting there is a slower process, a bit like pouring syrup rather than water(?).

    Then, when you consider external forces, say a spring pulling the rotor counter-clockwise, it's quite likely not only will the motion be slowed even further, but that it might...

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  • Bipolar Single-Stepping Thoughts

    esot.eric07/25/2016 at 06:50 0 comments

    The sled-motors in most DVD-drives are usually Bipolar Stepper Motors. These are stepper-motors with only 4 wires (whereas Unipolar Steppers usually have 5 or 6 wires).

    In a bipolar stepper, the wires are paired-up to electromagnet-windings. But the separate pairs are not connected to each other (again, unlike a unipolar stepper).

    One way this is often viewed is thusly:

    So the motor's shaft is attached to a fixed-magnet with North and South poles, and opposite electromagnets are paired together.

    Right.

    So, it might be apparent from that picture that for this simplified motor to rotate 180 degrees, the polarity of the horizontal-windings must be reversed... Thus "bipolar" requiring the voltage applied to the windings to switch polarity in order to create motion. (These windings are often called "phases").

    Now, as I understand, the typical way to drive a bipolar stepper with "single-stepping" is to use two square-waves 90-degrees out of phase. Quadrature, essentially.

    (Where the upper waveform applies to the "vertical" electromagnets, and the lower waveform applies to the "horizontal" electromagnets).

    The "shaft" in this case is shown similar to a compass, its fixed-magnet is pointing North.

    The waveform shown causes this motor to rotate counter-clockwise. The upper waveform "leads" the lower-waveform, its rising edges occur first. To reverse the direction, change which waveform "leads" and which "lags."

    Alrighty, looks pretty good.

    Except, look again at that first picture.

    Notice something about that "compass"? It consists of, essentially, a bar-magnet.

    Now, in this picture, that bar-magnet is *strongly* attracted to the horizontal electromagnets because its surfaces are *really close* to the surface of the electromagnets. Remember magnetism is much weaker in air than in a magnet (or metal)... The less air, the stronger the attraction.

    So, revisiting the two cases:

    Because of the small air-gap, we have a strong attraction to the rotating-magnet between the single powered-winding/phase on the left, and we have a weaker attraction to the rotating-magnet between either of the * two* powered-phases on the right.

    The image on the right, again, is the way "single stepping" of bipolar-motors is often implemented (again, using Quadrature).

    Interestingly, as I understand, when both of the winding (pairs) are powered-down, and the shaft is turned by-hand, the stepper-motor will have a tendency to "step" between steps shown on the left. Because, again, when the windings themselves are powered-down, the magnet on the shaft will be most-strongly attracted to the metal in the windings, rather than the air-gaps in-between them.

    So, already, when using quadrature, "single-stepping" is, in effect, already suffering many of the difficulties introduced by "micro-stepping."

    I dunno the math (and physics) off-hand, but basically if you're applying 2x the power (1x power to each phase) then you're achieving something like only 1.414x the effective strength of a single phase's being powered. AND, if I understand correctly, that's *neglecting* the tremendous effects of the increased air-gap.

    There is another way to power the windings, rather than using (digital) quadrature. And, still, this would be considered "single-stepping." In fact, I'd consider this *more* "single-stepping" than the other method, as it actually stops at the steps where the motor would stay if it were unpowered.

    Note, now, the magnets on the shaft are most-strongly attracted to the powered phase, because the air-gap is small. This, however, requires a bit more logic (and circuitry) than the typical "[digital] quadrature" single-stepping; it requires a phase to be either positively-powered, not-powered, or negatively-powered. AND, the "1x power" described above is likely weaker (though much more efficient) than the "1.414x power" described earlier.

    So, where do we go from here...? Electromagnets aren't particularly efficient, right? Throwing more voltage at 'em will result in more heat. If the stepper's...

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  • Resolution Experiments and flow...

    esot.eric07/24/2016 at 13:19 0 comments

    Tonight some resolution-experiments...


    I used Eagle for the first time since college, what, a decade ago? (Holy snap, how long has there been a Linux version?) And one nice thing I discovered is *really* good HPGL support.

    Note the paths used to fill the pads and fill-layers... it also fills wide tracks, and even pays attention to "pen"/tool-width. Awesome.

    (PCB design from #Mumai, written-up recently on the blog.)

    I'm using grbl. (I'd intended to use HPGL from the start, as I've already done motion-control projects with it, before... but that's another story. And the PC-side grbl tools are pretty sophisticated these days, what with rendering, etc.) And that means I need to convert that HPGL output to G-Code. And low-and-behold the friggin' search-fu finally worked in my favor... "hpgl to g-code" resulted almost immediately in exactly what I needed! Howto PCB from Eagle - RepRapWiki

    Cool.

    (Note that most G-code (and similar) output from PCB applications seems to be aimed at mills/routers, which cut the material surrounding the traces, rather than drawing ink (or toner #Mini PCB printer!) where the traces are located, as I'm doing).

    OK. So, Eagle -> HPGL -> hpgl2gcode (requires python3) -> G-Code -> Universal G-code Sender -> grbl -> stepper-motors.

    The output of hpgl2gcode is quite straightforward (as is the HPGL), so it's not difficult to modify the Z-movements into 'spindle' start/stop commands, if you're using the 'spindle' output to drive a laser, as I am.

    Yes, that's cardboard, and yes the laser burns some cardboard... especially with slower feed-rates...

    Here's the PCB layout...

    Three traces parallel spaced at 2mil to 20mil (1mil traces, 1mil pen-setting in HPGL).

    Drawing the text was pretty slow, so I ultimately removed that from the raw gcode.

    Here's the visualizer from the Universal Gcode Sender (UGCS) (a *very* nice feature, that definitely makes conversion to g-code worthwhile even if you have a device capable of HPGL):

    Interestingly, it doesn't draw all the paths in the same direction, guess it's trying to save time as best as possible. Also, though, it turns out to be a handy test of the precision of the system...

    Here's the cardboard:

    At first it looks darn-near awesome... but upon closer inspection it's easy to see some odditites.

    Yeah, I could expect some breaks, likely due to the cardboard fibers varying in various locations, rendering it more difficult to burn... But then there's some overlaps, and those ain't right. Then there's the traces which clearly aren't evenly-spaced... and that ain't right either.

    So, I thought, hey, there's a lot of conversion going on 'round here... Who knows where it's coming from, but I can easily think of conversions from floats to ints, then back to floats, then back to ints, and probably even more. So... maybe... And then there's the fact that my PWM-based "microstepping" is pretty much non-sophisticated, but we'll come back to that.

    So I spent *way too much* time trying to get a side-by-side between the actual output and the rendering... And discovered many flaws in my thought-process along the way.

    Big One: cameras taking close-ups distort the image. Below is a scan (from a flatbed scanner) overlayed (and slightly shifted upwards) atop the photograph:

    Note how the two line-up at the edges, but in the middle they're quite far off. Makes sense, but took quite a while to figure out while comparing the photo directly to the rendering. Won't bother showing that. (Oh, yeah, and apparently one of my steppers is wired backwards).

    Here we have the rendering compared to the scan:

    Kinda hard to see, there, (are there click-throughs to zoom? I forget).

    Here's a highlight:

    You can clearly see the path to be taken by the machine (in white) isn't exactly consistent for each trace... But the points do all align. So, it appears the most-visible errors aren't due to all those conversions. There must be some error in the software (which I modified) running on the machine, and/or with the steppers themselves.

    So, that...

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  • DVD-Lasered Jolly-Wrencher

    esot.eric07/14/2016 at 12:26 2 comments

    The moment We've all been waiting for... Or at least I have.

    Not sure why Inkscape decided to draw every line twice, something about edge-detection? And where'd it get the curves in the wrenches? Dunno.

    USE GOGGLES, and Open The Window. That be burning-plastic smoke you see in the video.

    Grbl has been hardware-abstracted and ported to PIC32, per the last log. Also added direct-support for PWM-microstepping output within grbl, to be fed directly into H-bridges, rather than the normal "step/direction" output usually fed into an EasyStepper. (The PWM output is a sine-wave fed into the two windings, 90degrees out-of-phase).

    Other tools: Universal G-Code Sender (java-based), Inkscape with the Gcodetools extension, (Inkscape CNC (G-Code) tutorial - YouTube), Grbl, 2 DVD drives (the burning-laser is, I think, from a 20x drive, running at 250mA, just remove the focussing lens, and the focal-point is about a foot away),

  • grbl + usage-TODO?

    esot.eric07/13/2016 at 07:51 0 comments

    (Update: Adding this link: https://github.com/ericwazhung/grbl-abstracted/tree/master)

    So, nowhere in these logs is information about using grbl...


    Over the past countless weeks I've been working up to using grbl... Why so long? Well, for one I don't have any unused AVRs with enough pins/memory to load it on. So I've been working on porting it to my PIC32s.... And today I've accomplished motion, for the first time... more on that later.

    If you don't know what grbl is, as, believe it or not, I didn't only a few months ago...

    grbl is software you can run on a microcontroller to accept G-code (CNC commands) sent from a computer, and convert that into motion via stepper-motors.

    As I recall, back in the day, using G-Code to control a CNC-machine meant running a Real-Time Operating-System (such as RT-Linux). So, I guess, what makes grbl special is that it offloads the realtime aspects of the motion-control to a microcontroller (usually an AVR), then the host-computer only needs to send high-level motion-commands (e.g. "move to a point") via serial-port whenever there's enough buffer-space on the receiver. No real-time stuff necessary... run it from any computer with a serial-port, or USB-to-serial converter.

    The cool thing, I guess, is that it's *really well supported*. I mean, seriously, check out this page: https://github.com/grbl/grbl/wiki/Using-Grbl

    OK, that's that.

    There're some things I've learned along the way, the hard way, that I haven't seen explicitly-stated elsewhere... e.g. the limit-pins don't seem to have any effect unless you *enable* them, so if you don't [have the knowhow/patience/pins to] wire-'em-up, you can still get a system running likely without even having to modify the code...

    So, notes like these, I wouldn't mind being written-up somewhere. (if someone knows a link, by all means, lemme know and save me the trouble!)


    Alright, so I've been working on porting grbl to my PIC32s.... And today I've accomplished motion, for the first time.

    So here's some big TODONEs:

    Hardware-Abstraction

    Everything other than the EEPROM has been abstracted to the point of macros and function-calls that can be written for nearly any architecture... I've obviously done it for PIC32, and the original AVR code has been moved to *_avr.c/h files. The architecture can now be selected in the Makefile, and it will include/compile the *_<architecture>.c/h files as appropriate.

    EEPROM/No-EEPROM

    The EEPROM stuff is, frankly, a bit excessive... It's easy to do on devices (like an AVR) with an EEPROM built-in, but many microcontrollers don't have it. One alternative is to implement it in FLASH (read/write an unused portion of program-memory). That's doable on most architectures these days, but it is *very* architecture-specific, and I didn't have the patience to do it for PIC32. Another alternative is to use I2C or SPI EEPROM chips... Again, pretty hardware-specific. Could easily be done, but wasn't within my patience-level. The Alternative I chose was to make an option for NO_EEPROM. In this case the system acts as though it's brand-new/unconfigured, thus using default/hard-coded values, each time it's booted. OMG... 'cause, frankly, most people probably don't change those settings anyhow. And, they can easily be changed in a source-file if necessary.

    Byte-Identical!

    Despite all the above hardware-abstraction functions/macros, it can still be configured to compile BYTE-FOR-BYTE identical to the original grbl-master compilation. This is KEY, as, as I understand, grbl has been *well* supported for quite some time. Doing all this hardware-abstraction results in *zero* changes to the original functionality... Even additional function-calls would result in changes in terms of context-switching, pushing/popping the stack, etc. This configuration-option shows that even despite *all* the hardware-abstraction, there's NO CHANGE to functionality, speed or otherwise. And, thus, it's easy to see what changes have been made, (when the Byte-Identical test is disabled) in...

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  • The second "duh-moment" revealed + Interesting Materials!

    esot.eric06/10/2016 at 12:01 2 comments

    (Update 2: Another photo from mirrored-plastics-burning)

    (Update: Adding results for potato-chip-bags/"mirrored" plastics)

    Alright, the last-log I led-up to this... second "duh-moment" which reduced weeks of over-engineering down to little more than gravity and binder-clips...

    As described in the last log, I turned the upper-axis sled/laser mechanism on its side in order to do some experiments with lenses of different focal lengths (and discovered the focal-length of the lens--*under* the drive's adjustable-focussing lens--the one I originally presumed to be a collimating-lens--to be durn-near exactly the focal-length I was looking for (about 10inches). Cool!

    But the second discovery came from those experiments and had nothing to do with them... intentionally, anyhow. The second discovery is that the upper axis doesn't have to be "upper" (facing down) at all!

    Here's the new setup... it's *way* easier to adjust focus, square, parallel, and much more... And doesn't even require any screw-adjustments to do-so!

    Gravity can be your friend...

    The laser/sled axis is the one closest to us... It originally traveled with the laser facing down onto a horizontal surface. Now that surface is upright (why not? We've gotta clamp the material down somehow anyways...)

    (Sorry for the blurry image, later images will be more clear, this just happens to be the only one with the laser lasering... And a fore-sorry for the sizes of the following images... I should probably write an imagemagick-script again soon... what's reasonable these days...? 1280x960?)

    So, that's the "Big Duh" which reduced quite a bit of mechanical design and failure to... unnecessary.


    Now for some results...

    We all know "black [electrical] tape" is cuttable with a laser-diode... And there are a few other such materials which just make sense, such as (as I discovered a while back) floppy-disks (the magnetic/media part),

    I didn't take a photo, from a while-back (Update added at the end), but another interesting result was cutting *through* potato/corn-chip bags... We're talking the heavy plastic that's *mirror-finished* on the inside. So, cut yourself some mirrors!

    I'da sworn that mirror-stuff would've gone all the way through, so all I expected was to burn off the ink on the outside of the bag, leaving a mirror-finish behind the "cut." Instead, the ink apparently sucked up enough heat to even burn through the mirroring. COOL. (even weirder, it seemed to work perfectly fine with *red* bags, which I'd've expected to be *reflecting* the laser-diode's red color...)

    Here are some more recent results, some quite surprising, as well...

    Colored Tissue Paper:

    (Note the diagonal line... that same pattern used in all the experiments)

    This pretty much cut completely through the paper, except in a few places where it left some white fibers... Maybe the ink isn't consistent... and obviously the thickness isn't, as it can clearly be seen-through in several spots and not at all in others).

    (Would it work with Construction-Paper?)

    Etch Plastic... (This one's in the "expected" category, as I'm sure we've all seen people've etched their names on their cell-phones...)

    This happens to be a back-cover from an LCD monitor. Seems to work best on Matte-finished plastics, *really smooth-finished/shiny* plastics not-so-much. Though, it probably has to do with the actual type of plastic as well...

    But this one was a shocker to me...

    Burn/Etch Wood!

    I figured it wouldn't work, because it doesn't do anything to light-colored paper... I even tried (pink) carbon-paper and (white) thermal-paper with zero-results. But here's a very-light-colored *wood* that burnt darn-near perfectly.

    That led me to a strange conclusion... Maybe bleaching has something to do with why it doesn't do anything to paper...(?) So, I thought I'd try some unbleached paper...

    Paper Bags.

    I thought it just burned like the wood, until I picked it up... nope, it cut right through.

    Etch Corrugated Cardboard?

    (Use during calibration-experiments!)

    So, I think maybe corrugated...

    Read more »

  • 2-axis "duh-moment"

    esot.eric06/08/2016 at 08:52 0 comments

    I'mma keep working on this, pictures/explanation to come later...

    But let's just say I had a major "duh" moment... And I think the results will be quite a bit easier for most 2-axis systems.

    It wasn't an *easy* duh-moment... In fact, it was the result of many iterations of over-engineering-reduction. And, by "reduction" I mean... extra-engineering to accommodate flaws in said-over-engineering to the point that it got completely unwieldy and eventually that "duh-moment" *finally* struck...

    No, not even then, actually... In fact, if I gotta get my facts straight, the "duh-moment" was the result of something entirely different, *after* all that over-engineering got in the way, then was "reduced" (which, again, means that it was actually even more over-engineered, until it was too much to bare... But Even Then, I didn't see the obvious duh-moment... until giving up on that and beginning to deal with an entirely different aspect deserving of "duh" as well.).

    So, actually... *TWO* "duh-moments".

    I'll tell of the latter...

    Read more »

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Dr. Cockroach wrote 01/24/2017 at 00:40 point

I found a 5 cd deck with record option in the roadside trash the other day. Was thinking of using the power supply but now you have given me more ideas ( Like I need more projects ). Thanks for the neat ideas :-)

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esot.eric wrote 01/24/2017 at 07:37 point

Right on! :)

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Stefan Lochbrunner wrote 01/23/2016 at 12:20 point

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esot.eric wrote 01/26/2016 at 08:25 point

only a tiny bit more complicated than the Voltage-Regulator design ;)

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John Pfeiffer wrote 11/12/2015 at 07:22 point

I love those little leadscrew steppers... I remember about 10 years ago taking a pair of optical drive chassis and making a little X-Y table that I drove with an Arduino and the Adafruit motor shield...

It was little more than an experiment at the time, since for starters it was rather poorly put together with crudely hand-fabricated parts...but if I ever find a practical use for a ~40x40mm travel cartesian robot, I'll have to revisit it...

Since now that I have a 3D printer, not to mention a mill and lathe, I can make all the custom parts for it I want.  (And god knows, I've got boxes of gutted optical drives.)

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esot.eric wrote 11/12/2015 at 17:47 point

heh, crudely hand-fabricated seems to be the phrase that pays 'round here. YAY!

Yeah, it's definitely worth saving those parts, but yeah, what can really be done with such small motion...? Itty-bitty things, I guess. 

If you come up with any ideas, lemme know!

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John Pfeiffer wrote 11/13/2015 at 07:43 point

Ironically I just recently noticed a bunch of new Chinese desktop laser cutters popping up... It's a bunch of optical disc chassis in a laser cut acrylic frame, but it's using a large 300mW laser module as a tool head.  Cost just over $100.

As for what I would do with 40x40mm of travel...  Precise little knife-plotter for cutting Rubylith film positives for circuit board prototypes? UV laser-based plotter for exposing photoresist on PCBs? Make just the table move under a stationary spindle and use it to route or drill PCBs? Things along those lines... Oftentimes people don't need or want to make boards much larger than that.

At any rate, 'upcycling' a handful of optical drives is a lot simpler than sourcing all the parts for something like this, and you don't lose THAT much travel: http://www.diyouware.com/ (I still want to make one of these pretty badly though.)

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alpha_ninja wrote 09/02/2015 at 23:33 point

I have some of these laying around, but haven't done anything with them (yet). Can you still achieve excellent precision without the use of steppers as motors?

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frankstripod wrote 09/03/2015 at 00:27 point

The HaD blog link (top left) uses drives with steppers and avoids motors from older drives. Other than that, I know I have a lot of old stuff I need to do something with.

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esot.eric wrote 09/12/2015 at 23:12 point

There's no sense in leaving my long-rambling hypothesizing comment here, so I've moved it to a log...

https://hackaday.io/project/7535/log/25050-ramblings-on-precision-and-non-steppers

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j0z0r pwn4tr0n wrote 09/02/2015 at 22:14 point

I really like this idea, building a 3D printer from junk is a dream of mine. And for most things that I need a 3D printer for, the small print volume would be fine. Plus it would be an excellent way to learn about the ins and outs of 3D printing. I will submit a request to join this project when I get home and can type up the required document, lol

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esot.eric wrote 09/02/2015 at 23:16 point

I'm sorry, my friend... you're already off to a bad start with all this "Wooo! 3D Printing!" Mumbo Jumbo. You're going to have to work extra hard on your Cover Letter. And be sure to bring me an Apple at the interview!

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