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Openbuilds 4x8 cnc

Discussion in 'CNC Mills/Routers' started by Sam Keller, Aug 14, 2020.

  1. Sam Keller

    Sam Keller Well-Known
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    It really could be belt slipping, it only seems to happen when i walk away so i could never hear what went on. All i know is my motors seem strong and fast now so I'm going to carve that big headboard in the next week and see if is better. My acceleration was so slow that on 3d carvings it took a long time because of all the movements, I'm hoping it will carve faster now.
     
  2. chuck english

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    Do you have a 3D file that you mind sharing? We haven't gotten to 3D yet.... but I’d like to have one to see how you are designing/manufacturing in fusion. You are doing a bed head board?

    we have been messing around with the laser some, but I have been unable to figure out how to get any kind of markings on metal with our laser. It is really neat in wood, leather, etc. though.
     
  3. Sam Keller

    Sam Keller Well-Known
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    I still run my smaller z axis nema 23s at 24v, they seem to do fine. In fact i had to lower their amps because they got really hot. My large motors Didn't even get warm on 24v, now they get warm but not hot.
     
  4. ljvb

    ljvb Well-Known
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    No, he Blackbox won't run 48v. None of the controllers will run 48V, it's the external drivers. Mine run from 36 to 90v. I also have the 6 pack controller. As for your power supplies, are they designed to be run in series. I am using 2 (soon to be 3) 12V 40A HP server psu's in series, and then using a DC booster to boost the voltage to 60V. Took a big hit in the current (increase the voltage, the current decreases, and vice versa), it maxes out at 1500W total, but will only take up to 20A. in theory I should be able to max out the current to the full 7A my drivers use at 50V.. but for some reason I am only pulling 2A on the big steppers and drivers... Not sure why, whether its a problem with the booster, it's pretty basic, using pots to change voltage and current. When I add the third psu, to up to 36V, the boost to 60V should result in increased current.

    FYI.. Voltage = speed, Current = Torque.. find a good in between balance for good torque and speed.
     
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  5. Sam Keller

    Sam Keller Well-Known
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    Yes is a bed headboard about 2.5 x 4.5 with a tree carved in it. I'll post some pics and 3d models later today.

    Ya these lasers won't mark on metal unless its coated. They make laser marking spray for uncoated metal, it's expensive and I'm not sureif it works with diode lasers.
    Capture+_2021-01-12-10-58-39.png
    I like my laser but now i want a bigger co2 laser that will actually cut with 1 pass. I'm making plans to mount a 50w co2 laser tube on my gantry. Think i can do it four around $300. Almost ready to pull the trigger.
     
  6. ljvb

    ljvb Well-Known
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    Adding some pics. this is my temp mount till I get a box to put everything in.

    3C08907D-CF29-4349-AD8D-571333B8925F.jpeg E25225CE-5F8B-4A2A-A00C-24216C312DD1.jpeg
     
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  7. Sam Keller

    Sam Keller Well-Known
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    I'm still learning about the electrical stuff, i was a bit nervous about hooking them up together but i found a good video that really helped. I really like that 6 pack controller, I'm still working on getting the auto square function to work but I'm very impressed with the controller.
     
  8. chuck english

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    Wow. I haven’t seen any co2 laser close to that price. Can’t wait to see it.
     
  9. Sam Keller

    Sam Keller Well-Known
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    Well they are all sold out now... EBay had a50w tube for $100, $50 power supply, $100 mounting parts, $100 lens and mirrors. So i guess moor like $400 if i buy the cheap parts.

    Right now all thecheap tubes are sold out everywhere i look. Guess I'll have to wait a while...
     
  10. ljvb

    ljvb Well-Known
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    Are you on the discord channel?

    It all depends on the PSU you are using. Some can be connected in series.. some cannot without modification. I had to modify mine, and float the PSU (isolate the internal circuitry ground from the chassis ground to avoid short circuiting everything and burning down my house.. That is the blue marker on the PSU :) make sure I know which ones are not grounded like the others. The chassis is still grounded via the plug, the circuitry is grounded in the regular way. I had 6 extra PSUs from the servers I run since I only run 1 per server which has 2 PSUs in them.

    The 6pack is pretty slick, and relatively cheaper than many other controllers, although the cost goes up when you go external, or the higher end trinamic drivers, has a bit of a learning curve, and is very finicky. The TMC5160's don't work for most.. which disappointed me as those were the ones I wanted to run. I had issues with the 2130's as well, ultimately decided to go with external drivers. I plan on going larger at some point, so I went with the DM860s, they work with the bigger Nema 23's, but are really designed for 24s and 34s. and 8 wire uni/bipolar steppers, currently wired for bipolar parallel (5A/phase 7A peak).
     
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  11. Sam Keller

    Sam Keller Well-Known
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    No haven't heard of discord before now, looks interesting though, I'll check it out more later.
     
  12. ljvb

    ljvb Well-Known
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    Yes, it's your best resource. It is run by Bart (the guy who created the 6 pack) and some of the other grbl_esp32 developers. Best place for help.
     
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  13. chuck english

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    I don't understand how the controller/drivers work. Is there a way to use the dm556 drivers that I have and connect them to the blackbox? Instead of using the internal drivers?
     
  14. ljvb

    ljvb Well-Known
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    I don't think you can use the Blackbox with external drivers.
     
  15. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    I'll just pop in here, and say, with such long belts, the skipping is much rather going to be mechanical than BlackBox, and even with 24v - properly chosen motors, on a belt drive, you should be getting speeds at which you'll never be able to keep up cutting (; - just a fair warning, a little tweaking can save a lot of cash
     
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  16. Sam Keller

    Sam Keller Well-Known
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    Would you send me an invite to the group? Keller#7655
    Thanks
     
  17. Giarc

    Giarc OpenBuilds Team
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    If it is with smaller diameter bits, it is probably because they are flexing when you are pushing them hard. You can actually see the bend in them.
     
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  18. chuck english

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    What causes the bits to flex? I know the cutting speed, depth of cut, and Step over will directly effect the bit flexing, but I guess my question is: why will some machines run an 1/8 flat end mill faster than others if the settings are the same? Bit quality?
    Also, if the machine getting off is bit flexing (which I believe 100% is a problem bc like you said you can see the bit flex) wouldn’t this still have to cause either a slip in belt or a stall of steppers in order for the cnc to “loose track” of where it should be?
     
  19. Giarc

    Giarc OpenBuilds Team
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    It may be bit quality, or it may be how they are cutting. I cut at 4000mm/min with a 1/8" ball nose with no issues at all. But, I am only stepping over 10% each time. I may try upping this to 5000mm/min.

    Are you saying that at the end the position has changed, or are you saying it is off because the part comes out the wrong size?

    I a definitely not an expert, but I believe that I see flex because I am only cutting with the first .5mm (or so) in aluminum with a 1.5 inch endmill due to cutting slots and small holes. If I had stock in a vice and came in from the side or was cutting a deep pocket and I was utilizing trochoidal milling so more of the cutting area of the endmill was being utilized, then I believe there would be less flexing. This is why I do a full depth finishing pass of about 0.3mm if possible. It takes those slightly oval holes and makes them round like they should be.

    I am an advocate for using the biggest endmill you can. A 1/4" endmill is twice the diameter, but 4 times the material so 4 times-ish less likely to flex while cutting and in my experience they cut so much better and faster. I spent $26 for a 4mm collet for my Makita because - in my experience - a 4mm endmill cuts significantly better in aluminum (and everything else) than a 3.175mm. Unless my math is wrong, it has about 37% more material in a comparable length and type of endmill as the 1/8". But, most of my endmills are straight shanked. I have just started experimenting with 1/8" (3.175mm) endmills that have a 1/4" shank. They too are way better (IMHO), but usually limit your DOC more.

    I recently cut a bunch of aluminum plates and needed the 1/8" endmill to mill the 4.1 and 5.1 mm holes (before I had 4 mm endmills). I took a couple 1/8" endmills to my vice and broke the shaft purposely to shorten them so I would get less flex.
    This one was 1.5 inches long before it met my vice. It cut a lot better.
    upload_2021-1-13_19-2-42.png

    Hopefully with a 10% stepover, this 1/8" (far right) won't be too "bendy." I need this for carving larger material on the lathe. The ones on the left have limited me on stock size - especially the short 1/8". Time will tell.
    DSC_0366.JPG
     
  20. chuck english

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    Great info. I am saying mine gets off and has the wrong start/end position. If I am cutting a perfect circle and it starts and ends each pass at the top of the circle, when mine messes up, (not that often, but it does happen when I push) the location of the path of the circle would be off. It would not go back to the original starting point of the cut. I just assumed it was because the belt had slipped, but I guess it could be because of the motors stalling... IDK

    I always try to use the larger bit if possible and they definitely to better. It makes sense what you are saying about more material in a larger bit. I have only cut in wood, and I am running 1/4" at about 100 in/min and 1/8" at 50 in/min. However, I am using a about a 40-50% step over. I guess I should look and see if I can increase speed and decrease stepover to get better faster results.

    We have taken longer bits and cut them down to prevent flexing as well, I think it has to help.
    I am a little confused about what you are showing in your before and after picture?
     
    #170 chuck english, Jan 14, 2021
    Last edited: Jan 14, 2021
  21. Giarc

    Giarc OpenBuilds Team
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    Sorry. I put that picture in another post a few weeks ago. The "before" was the length of endmills I used for carving on the lathe which limited my work stock diameter a lot, especially for the finishing pass with the 1/8" ball nose. Now I can put up to 8" diameter in there and carve without having to worry about the collet hitting when plunging down into deeper pockets.

    I can't recommend them yet because I have not tried them. Currently all the wiring is being redone on my lathe because I built an enclosure for it.
     
  22. KramE

    KramE New
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    Just poking in. I'm hoping to build a mini version of this in the next couple of months!
     
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  23. Sam Keller

    Sam Keller Well-Known
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    So, I added an 80W co2 laser to my machine and made some other changes.

    I changed to an esp32 grbl controller with wifi.
    6 Pack Universal CNC Controller by Bart Dring on Tindie
    This controller does everything. It has 6 stepper motor outputs, with external or internal drivers. I can switch between laser mode and router mode and I have auto squaring on my x and z axis. And I hooked up an iot relay plugin to turn my router and dust collector on and off automatically.

    I also moved the stepper motor from the gantry cart to the gantry in order to remove weight on the cart because the laser engraves at 600-800 ipm.

    I added a cooling system, air assist, and fume extractor.
    20210205_084628.jpg 20210205_084607.jpg 20210205_084555.jpg 20210205_084544.jpg 20210205_084534.jpg 20210205_084521.jpg 20210205_084511.jpg Message_1612117357896.jpg 20210120_103333.jpg 20210120_200833.jpg
     
  24. KramE

    KramE New
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    Daaaang! Don't shoot your eye out!
     
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  25. chuck english

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    Sam, looks awesome! You know I've got questions though..... Hope you don't mind.
    1. Where did you end up finding your laser tube? ebay?
    2. Estimated cost for co2 laser setup? Do you have a list of items you purchased? It looks like you added a c-beam linear rail across your x axis to mount the tube?
    3. How does it compare to your diode? It is obviously much faster engraving, have you cut anything? what thickness can you cut?
    I have been overall pleased with the diode I added to my machine. I haven't tried to cut anything with it really, but I have done some engraving and then cut with the router....wish there was a way or program that would combine the tool paths to engrave with laser and then cut with the router. I have been doing it manually via lightburn and then fusion/openbuilds. I am thinking more about adding plasma cutter to mine, but who knows when or if I'll ever get to it. I kinda ran out of stuff that I could think of to laser pretty quickly.
    I still want to play around with doing some 3d carving, but don't know where to start. If you ever get a chance, could you post one of your 3d carve fusion designs/files for me to check out. I'd like to see what you did. Thanks and good job!
     
  26. JustinTime

    JustinTime Veteran
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    Sam, is the CO2 tube mounted on the gantry and goes along for the ride when the
     
  27. Sam Keller

    Sam Keller Well-Known
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    Well, I ended up spending $1000 or so on this laser (don't tell my wife). I originally was going to put a 50w on but they sold out over the holidays so I got the 80w on ebay (the one I wanted in the first place). I also bought a good set of American made lenses and mirrors. So i could have spent $400 or so less on a smaller laser and Chinese lenses.
    The 80w cuts up to 3/8 wood like butter, up to 3/4 with a couple passes. It engraves at 800 ipm. It cuts acrylic and many other materials too.
    I haven't seen any problem mounting the tube to the gantry. I do all my fast moments for engraving on the gantry axis so the tube doesn't move around fast.

    Capture+_2021-02-08-17-01-53.png Capture+_2021-02-08-17-03-51.png Capture+_2021-02-08-17-01-26.png Capture+_2021-02-08-17-00-51.png Capture+_2021-02-08-17-00-07.png Capture+_2021-02-08-16-59-30.png Capture+_2021-02-08-16-58-58.png Capture+_2021-02-08-16-57-27.png Capture+_2021-02-08-16-58-32.png Capture+_2021-02-08-16-57-55.png Capture+_2021-02-08-16-56-12.png
     
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  28. KramE

    KramE New
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    Thank you for continuing to share your progress and I really appreciate your BOM lists. It really makes a difference!
     
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  29. Mark Carew

    Mark Carew OpenBuilds Team
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    @Sam Keller Wow man, super inspiring build and so much fun to follow along with.The way you are using the system is exactly whats its all about.
    Keep up the good work brother :thumbsup:
     
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  30. KramE

    KramE New
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    I think technically all you need now is a cute little plush toy to ride on the gantry as a mascot and as something to blame when there's a failure.
     
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