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Prop-based CNC/3D printer - Page 11 — Parallax Forums

Prop-based CNC/3D printer

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  • Cluso99Cluso99 Posts: 18,069
    edited 2011-11-08 19:31
    W9GFO: That is a really nice quality output from your printer. The aluminium version should be quite stable.
  • W9GFOW9GFO Posts: 4,010
    edited 2011-11-08 19:50
    Thanks! But I think you are referring to wjsteele's printer.
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-11-08 23:36
    I was too. Sorry, nice job Bill :)
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-11-16 15:56
    Completed build of the mechanical parts for modified Mendel Prusa.
    Includes modified Wad's extruder, GregFrost LM8UU X carriage with fan mount, and other mods per Sacha at PS1

    In the second picture, notice the hobbed bolt done free hand with a Dremel tool. It might work.
    In the third picture, the X-end motor mount was binding just above the screw and needed filing. The cog might be too big.

    The instructions said to true-up the sides of the Z-axis using a nut on a thread as a plumb line. This didn't work for me. I used shiny marble tile as a base and made it level, used a ruler to get all the edges the correct length. Once the triangles and cross members were the indicated length, the z axes slipped into place. All the motions are smooth.

    Tomorrow start assembling the MakerGear hot end.
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  • wjsteelewjsteele Posts: 697
    edited 2011-11-17 03:17
    Prof_braino, Nice job! Interesting mix of printed and cut parts. What hot end are you going to be using?
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-11-17 06:14
    wjsteele wrote: »
    Interesting mix of printed and cut parts. What hot end are you going to be using?

    Sacha's kit includes laser cut MDF parts, he has a laser cutter at the shop and those take minutes to make rather than hours for the same printed. And the seem to hold up for a while so they will be fine to get started.

    I got the same hot end that the PS1 guys used, the .5 mm hot end pack from MakerGear for $75. I also found a big hunk of PEEK, so I can make more if I want to experiment, but first I want to see a working example. I haven't found Teflon rod yet, so I had to get the kit in order to move forward.

    I also got the Sanguinololu board, so I can have a base line to compare with a prop version. I think I will be able to swap in cluso99's board at some point.
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-11-17 16:30
    Nice job prof and thanks for sharing.

    The laser cut mdf corner pieces look similar to my prototype that is still sitting here unfinished, except my timber corner pieces are quite rough and certainly not square. I thought that once I get the printer working I could print replacements. However, since yours are accurate, why bother???
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-11-17 17:54
    Cluso99 wrote: »
    I thought that once I get the printer working I could print replacements. However, since yours are accurate, why bother???

    Having the corners identical and square made it very easy to true up. Other folks could not get theirs tweaked properly using rough pieces, but maybe this is only a problem for beginners.

    The thing about MDF is its thick cardboard, and its useful life might be shorter than I'm used to from metal parts. So this rig is only to get me to the point where I can build a frame from aluminum extrusion, etc; and work towards a cutting capability. But they think it should last at least a year.

    The printed parts are said to be better than the case parts (made from molds of printed pats) like those from lulzbot. Distortion introduced from the mold making process, and from the casting process. So one thing there are looking at is improving the process getting to the mold and to the cast.

    One of the guys has a foundry, so we are looking at making cast metal parts from the printed ones when the design settles.
  • Graham StablerGraham Stabler Posts: 2,507
    edited 2011-11-18 00:56
    MDF is a good material as long as you keep it dry, very stable. I suspect laser cut parts will be better than those printed on the machines.

    Graham

    p.s. for Teflon rod search Ebay (also search for PTFE the chemical name). Lots of bar ends are sold.
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-11-18 08:03
    MDF is a good material as long as you keep it dry, very stable. I suspect laser cut parts will be better than those printed on the machines.

    Do folks paint or varnish MDF to seal it? The Braino Lab humidity is usually around 40%, but is occasionally sprayed with water due to ... various human factors.

    Also, does the PLA plastic absorb water? Does this also need to be sealed?
  • Graham StablerGraham Stabler Posts: 2,507
    edited 2011-11-18 08:47
    Sealing it is not a bad idea, you can use emulsion or latex paint as you guys call it as a primer, works better than the proper stuff, then sand and blow on some car spray paint or brush on anything you like that give a good seal. For quick and dirty stuff I use matt black spray direct, goes on well and sort of stains the wood leaving a cool matt effect.

    Many plastics do absorb water but they will not change shape much because of it, polycarbonate for example must be dehumidified before being thermo formed otherwise steam bubbles appear. Keeping your printing plastics dry will help, on our uprint if not in use for a long time they go in a sealed bag, the spools themselves contain a big bag of silica too.

    Graham
  • Martin_HMartin_H Posts: 4,051
    edited 2011-11-18 09:18
    prof_braino, nice looking 3D printer build.
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-11-21 15:59
    OK, I got my sanguino to talk. This arduino stuff is a bear!

    The "uploading to I/O board" gets an error:
    Binary sketch size: 29868 bytes (of a 63488 byte maximum)
    avrdude: stk500_getsync(): not in sync: resp=0x00
    avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

    Hitting the reset button immediately before initiating the the upload gives the "upload complete" message, apparently the USB com port needs to be manually configured to set /RTS on
    exit.

    http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1281560891
    http://www.ftdichip.com/Support/Documents/AppNotes/AN_107_AdvancedDriverOptions_AN_000073.pdf

    This seems to be a very common problem, and the suggested fixes range from "manually set the USB configuration" to "build your own parallel port programmer and reload the boot-loader".

    I guess I am spoiled with the prop.

    EDIT -
    this describes the error and a work around http://reprap.org/wiki/Sanguinololu#Troubleshooting
    this page talks about an "Autoreset Enable" jumper http://sanguino.cc/hardware
    this states the "Autoreset" jumper is added to Rev 1.3a "http://reprap.org/wiki/Sanguinololu#Revision_History"

    Adding the jumper allows the PC reset the Sanguino board programming and interactive sessions.
    Removing the jumper allows the printer to run in standalone mode, that is, it will not reset mid print when the PC is disconnected or reconnected.

    So the fix is present, but its kind of hidden in the release notes. There's a lots of work needed on the documentation. I don't have bandwidth for another project, but duty calls. OK, I'll update the page just this once.
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-11-21 22:39
    Thanks prof: Sometimes it's nice to sample the grass on the other side of the fence :)
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-11-23 05:25
    If anybody wants to see my notes, I've collected some of them here:

    http://reprap.org/wiki/PrusaBuildNotesBraino#Prof_Braino.27s_Prusa_Build_Log
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-11-24 11:45
    Motors and end stops in place and working! This is a big deal for a software guy.

    Now to look at micro-stepping and current settings before I move on to connecting the thermistor and heater core.
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  • RonPRonP Posts: 384
    edited 2011-11-25 22:36
    prof_braino and all,

    Fine looking Machine you have there.

    Before attending a the Riverside Robotics Expo last Saturday I had no interest in 3D Printers. I had always thought that the plastic was real weak and would snap if sneezed on, but after seeing a makerbot printing and being able to handle a printed piece I found that the plastic is actually pretty strong. I said bye to the robots drove home and started research immediately. I have spent the last 7 days researching and ordering this and that. I have everything on the way. Details: Prusa Mendel, Wades Extruder, Prusa's Heated Print Bed, Budaschnozzle hot end, Sangduinololu 1.3a and the LU88 linear bearing mod thing. Expense close to $700 that's with 2 x Sangduinololu & Motor Drivers. I ordered the boards form ebay and parts from Mouser I ordered the Motor Drivers x5 (one extra) from Pololu on Wednesday then on Friday Pololu had a sale and I bought 5 more motor drivers.

    So I joined the 3D printer club. I am not that bright but after looking at the schematic and code together with what little I have learned about C/C++ programming. I can see that the Propeller is ideal for this application IHMO. Can't wait to get it put together and working. Once I understand the machine well enough I to would like to look at what it would take to use the Propeller for this application. Following this thread now. And going to read your Build Notes on the RepRap site next.

    :smile:

    -Ron
  • wjsteelewjsteele Posts: 697
    edited 2011-11-26 03:22
    Welcome to the 3D Club, Ron! I also snatched up 5 of the Pololu boards ($57) yesterday. I'll be using them for my Prop based version of the Makerbot Cupcake (entirely printed case and hardware store bought vitamins.) The steppers I bought for $20 off of eBay. So far, my total cost in this makerbot has been around $100... and I only need the hotend which I think I can do it for about $20. If so, it'll be the cheapest 3D printer I've ever seen!

    It joins two "real" Cupcakes, a Thing-o-matic (with a waterjet alumimum chassis) and a Reprap Mendel Prusa.

    Ping me if you need any help asssembling the Mendel. (I recommend using Google Sketchup and ReplicatorG for the software... seems to be the easiest to use and there is a config XML file for your machine.)

    Bill
  • RonPRonP Posts: 384
    edited 2011-11-26 03:44
    Thanks Bill,

    You have some nice hardware there. About Google Sketchup, I find it the easiest to use I've tried blender it's kind of complicated it would take a while to get used to it. Is there an easy way to have Sketchup export an STL file? I have came across different methods to use it but I don't know if they are outdated and there is an easier way. I think the ATmega chip is pretty much used up running everything in these printers the Prop based version sounds very interesting. With a Propeller one could add some bells and whistles imagine a Propeller 2. The future looks bright.

    Ron
  • wjsteelewjsteele Posts: 697
    edited 2011-11-26 07:38
    Yes, there are a couple STL Exporters and one Importer that i use all the time. (Import someone elses STL into Sketchup and modify the design!)

    I've attached the two that I use all the time.

    Bill
  • RonPRonP Posts: 384
    edited 2011-11-26 09:53
    wjsteele wrote: »
    Yes, there are a couple STL Exporters and one Importer that i use all the time. (Import someone elses STL into Sketchup and modify the design!)

    I've attached the two that I use all the time.

    Bill

    Thanks Bill
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-11-26 13:34
    PB264981.jpg


    Printer has extruded PLA, two loops from a friend's spool. Now to order my own spool and start print calibration.

    I'm almost to the point where I can start writing requirements for a prop based 3D printer.
    • The mechanical parts should be the same as any Mendel Prusa, or RepRap class of CNC.
    • The prop electronics should replace the Sanguino between the Pololu A4988 stepper motor drivers and up to the USB virtual serial port.
    • The prop firmware should be a spin program or equivalent analogous to the Arduino SPRINTER.pde
    • The firmware should perform the driver functions of running the stepper motors, controlling the heating elements, and monitoring the thermistors.
    • The firmware should communicate with the PC interface application PRONTERFACE.py in the kliment printrun.

    This should provide a prop solution that is a drop-in replacement for the ardunio based hardware. The above should be sufficient for an initial prototype. Then apples to apples comparisons could be made for cost, performance, complexity, etc.

    Comments? This is a high level outline, there's probably lots more that needs to be addressed.
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  • wjsteelewjsteele Posts: 697
    edited 2011-11-26 13:51
    I think that's a great start. I'm holding a couple Proto USB boards aside for this project. I also have 5 Pololu boards and a Sanguinololu ready for experimentation.

    Bill
  • EffingWarrenEffingWarren Posts: 4
    edited 2011-11-29 07:57
    Hello all,
    I am new to the thread, but have been reading it for the last week or so (I follow all the links and do research along the way).

    I would like to start off by saying that you guys have a GREAT start and handle on the project. I look forward to integrating ideas and code from here in my upcoming cnc extruder/mill.

    I would like to drop a few comments about some research I have done, and experience gleaned from others in the maker community, as well as my own experience.

    1. Has anyone looked into the new MK7 extruder from MakerBot http://store.makerbot.com/toolheads/stepstrudermk7.html?
    From what I am reading, with the new heating element, the smaller filament diameter, and the nozzles in different sizes, they are having GREAT results. The smaller filament diameter along with the new heating element they are using is allowing for print operations at much higher speeds. Also, they are OpenSource, but their products are some of the more refined I have seen (not all of their parts are being spoken for here)

    2. OVER ENGINEER the machine frame. I have worked on numerous CNC/Automated machines over the years, and the one place where you can NEVER have too much is the overall body of your machine. In one machine I worked with we included a 2000 LB granite slab to the framework as an inertial dampener. Harmonics are not your only problem, you would be surprised at the deflections that can be caused by improper alignments. Build with T-slot, you can get the stuff so cheap now days, its really a no brainer, and if that were not enough, the most difficult part to get right (the ways) just got a whole lot easier. Check out (http://www.makerslide.com and their soon to open store http://store.makerslide.com)
    A 3D printer will function in a less robust framework, but to acheave higher speeds and tighter tolerances, the more rigid your framework, the better. You can use the body of almost any CNC machine with 3 or more axies to do 3D printing, but there are VERY few (with the exception of the MendelMax) that I would even TRY to mount a cutting head on, other than maybe a good old (bites pinky in a Dr. Evil esque manner) Laazzzzeeer...

    3. GO MODULAR!!! I like that most of you guys are using a modular approach to the electronics. This is KEY in a project of this type. When in doubt, break it down. I have seen SOOOO many hours and dollars wasted on re-design and re-fabrication of parts simply because it was a "good idea" to combine functions on one board to save a few pennies.
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-12-01 03:09
    Hi EffingWarren

    Welcome to the forums! Thanks for the good inputs. Some of us are still working up to your level, but life is the journey, eh?

    The MK7 extruder looks cool, but at $229 its pretty expensive. This would be a good option if I went into some production mode and needed high reliability at any cost. At the moment, I'm in learning mode, and get more benefit from building parts myself. The MakerGear hot end I got was only $75, and I got that only due to being in a hurry. The posted instructions jumped around a lot and lead to a few mistakes, But the part is really simple. Making a hobbed bolt by hand took only two tries, and was essentially free since I used scrap from my threaded rods. The motor gear, the large gear, the main extruder peice, and the filament lever were all in the kit of printed parts I bought. If you start from person you can talk to for printed parts, this is a much better way to go. You learn more, it's cheaper, the the person can provide a simple answer to a question that would delay one for days.

    I saw the makerslide, those look pretty cool. I can see large heavy cutters in our future. Right now the guys I talk to are looking at the other extreme, using felt bearing on the extrusion printers. I might try those on a second build.

    The granite slab is a really good idea, it also helped in truing up the machine. Mine weighs substantially less, but gets the job done.

    cluso99 is all over the modular thing. His units look like the way to go once we get to replacing the electronics with a prop. For me, the snaguino is easy for the time being, since it is known to work, and represents the entire set of electronics to be upgraded.

    An aspect I try to keep in mind is "minimum necessary and sufficient" to do the job. Defining and understanding this is the biggest challenge and most time consuming part of the project. Its also the most fun if done well.
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-12-01 03:22
    So, I got the motion calibrated, and my filament came in. I want to start test prints to do final calibration. Now the real fun starts....

    I'm trying to go :"by the book" and get a "standard set up". So I want the most common or typical tool chain. I have been advised against skeinforge.

    So I found the calibration models for cubes, circles, etc, at thigiverse, these are in STL format. PRONTERFACE uses G-code, so I need an STL to G-code converter.

    The simplest application I found that runs on Windows is KISSlicer. Per the instructions, the output files are named with the original file name plus the string "_gcode.bfb" appended.

    What do we do with the BFB files? Do we just chop off the "_gcode.bfb" and replace it with ".gcode"?

    Where is the print origin, do we start from "home" position or from the center of the build platform?

    I could not find any further instructions. I hestitate to simply fire it up and let it go to see what happens, the machine took too long to build.

    Is this a good place to start, or should I go with something else? Right now there are too many options, and all have weak points where either the use is too complicated, the instructions not sufficient, or the software requires linux.
  • wjsteelewjsteele Posts: 697
    edited 2011-12-01 07:23
    I actually use ReplicatorG to do my conversions. It had a toolchain built in called Skeinforge which does the STL to G-Code conversion. There is even a RepRap config file that should work with your machine. It's a simple extract to install procedure to get it to work.

    Bill
  • lonesocklonesock Posts: 917
    edited 2011-12-01 08:08
    I'm actually working on a GUI version of KISSlicer right now...want to beta test?

    I'm using a RapMan 3.1, so I'm not sure about your firmware, but in my printer's firmware:
    • the 0,0 point is in the center of the build bed
    • the warmup commands automatically move the head to a printer specific warm-up spot
    • you just have filename.bfb on a SD card...anything .bfb is recognized and listed
    • never delete or rewrite files on the SD card! (The SD reading code isn't as robust as FSRW or Kye's!)
    • you can set the speeds to be extremely slow for your 1st run, to make sure you don't slam into any limits
    Let me know if you have any questions, or want to beta test!

    thanks,
    Jonathan
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-12-01 08:44
    I see what my first problem was. I tried to install Skeinforge first. I'll give replicatorG a try.

    Thanks!
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-12-01 08:49
    lonesock wrote: »
    GUI version of KISSlicer right now...want to beta test?

    Just noticed the post--

    Sure! Thanks! I'm always up for testing and review. But I tend to make a lot of comments, of course, you choose which one you want to act on.

    I have Sprinter on Sanguino, and Printrun-PRONTERFACE.
    As far as I know, 0,0,0 is same as home, does that sound right?
    Thanks for the tip on SD card using .bdb as file name extension.
    I keep getting SD init fail error, so maybe I did solder it up correctly.

    I'll PM with email etc.
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