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C-Beam cnc

Discussion in 'CNC Mills/Routers' started by Kyo, Jun 24, 2016.

  1. Giarc

    Giarc OpenBuilds Team
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    Where do they go? I am curious because I did not see them listed in the designer's BOM in the parts list tab.
     
  2. jdthome

    jdthome New
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    They are listed on the 4th step of the build manual.
     
  3. Kyo

    Kyo Veteran
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    It is a odd size, not commonly off the shelf. Ryobi and a few others make a low profile M5 x 27mm "Here" If you do not feel like modifying bolts. I cut down a few spare M5 x 30mm units to the required length. Just make sure to thread on a nut before cutting the bolt down this helps clean up the threads as you go to remove the nut after the fact.
     
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  4. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    Mount the wheels using the 30mm screws then break out the Dremel and saw the extensions off flush with the nuts. Any burrs will be inconsequential as there will still be sufficient room to loosen the nuts slightly as needed to make adjustments.
     
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  5. Kyo

    Kyo Veteran
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    That sounds a lot easier then what I did with a disc sander haha. I really should pick up a Dremel one of these days. Another way to deal with the extra length is to place a 3mm shim " OB Parts Store" under the head of each 30mm long bolt when a 27mm is required. No cutting or special bolts required.
     
  6. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    If you do, be sure and pick up a cut off kit to go with it. After a few uses, you'll wonder how you ever lived without it.
     
  7. cmwwebfx

    cmwwebfx New
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    I have plenty of lengths of 2040 but no 2060. Can I use 2040 instead for the base? If so, time to build the Sphinx. Also, my C-Beam is 600 long, does that give any issues having a longer Y axis?
     
  8. JustinTime

    JustinTime Veteran
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    Man...I was so happy to see this!!! That's what I've been needing for such a long time. BUT...I started to read reviews on this, thought I'll do it before I go out and buy it, and the majority is negative since the center ring pops out on them after a very short use. They are WAY to expensive to be used only a short time and then discarded.

    Too Bad! :(
     
  9. Metalguru

    Metalguru Veteran
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    Justin:

    I just use the screw mandrel that comes with the Dremel:

    [​IMG]

    Along with the reinforced 1.25" cutoff wheels which are much stronger than the standard wheels that come with the Dremel:

    [​IMG]

    Shop around, if you buy generic brand these can be as little as $10 for 100 pcs.

    And yes, they are fragile, but at 10c each I dont care if I break them.

    MG
     
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  10. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    I'm well into my second batch and have never had a problem with any of them coming apart. From the reviews there may be a QC problem or it may just be simple user error. Always let the tool do the work.
     
  11. Jdog

    Jdog New
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    Hey, noob here to Openbuilds projects. I have started building my Sphinx "XL" (1 meter C-beams) and also saw the Y-gantry mini V-wheel M5 bolts needed to be cut down to 27mm. I do not have a belt sander or Dremel, just a hacksaw. I was worried about accuracy of getting the M5's at 27mm, and not taking a long time to cut multiple 30mm M5's.

    I 3D-printed a small block with 4 holes @ 1" spacing, then soldered in brass M5 threaded inserts to use as a cutting jig. I threaded the 30mm M5 bolts through, used a 3mm spacer as a depth gauge on the cutting side, and on opposite side tightened flanged nuts to lock bolts in place. The PLA did get chewed up, but it worked OK -- all were about 27mm length. I might do this a little different next time, but I guess that's how you learn.

    M5_cutting_jig_heat_inserts.JPG M5_cutting_jig_flange_nuts.JPG M5_cutting_jig_spacer-offset.JPG


    I would like to say that Kyo did an awesome job on Sphinx documentation (BOM, PDF, video, etc), Chris Laidlaw's Sphinx plates are of great quality workmanship, and this and other Openbuilds forums have been a great source of guidance and definitely inspiration to build. (But, my wallet has suffered...).
     
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  12. Kyo

    Kyo Veteran
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    I caved and finally picked one up lol :thumbsup: . Snagged a deal online cheaper then my local-(ish) box stores. This is the kit I picked up "Here"
    It has a number of tools with it including some cut off wheels. I am looking forward to putting it to use... :D
     

    Attached Files:

  13. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    Congratulations on the new baby. I expect you'll be spending a lot of nights up late with it.;)
     
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  14. good1228

    good1228 New
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    Do you have a BOM for 1500x1500? Or 1000x1500? I love this design. I think I want to go bigger though, I plan on cutting out cabinet pieces and furniture.
    Thanks a ton!

    Tony
     
  15. Giarc

    Giarc OpenBuilds Team
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    Go to the top of this page and click on the "Parts List Tab," If you want a bigger machine, just order the lengths of the extrusion and screws that you want. If you want 1500 mm, you will have to get larger screws which leads to larger anti-backlash nuts which leads to customization of some parts. You can get 1/2"-10 five-start precision screws in up to 6 foot lengths from McMaster- Carr. I used them in my own design which I also built for cabinet parts. I made my own anti-backlash nuts by making my own tap. It was fairly easy. They would fit in the cbeam channel, but due to a cbeam shortage at the time I decided to just use regular 2080 extrusion.
     
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  16. Canoe Shelburne

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    I know it probably says somewhere but how big a project can this CNC cut?
     
  17. Giarc

    Giarc OpenBuilds Team
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    Depends on what extrusions and screws you choose. Take those lengths and subtract the width of the gantry plates and anything else that will interfere with the gantry plates traveling the full length of the extrusion. TheSketchup files are there for you to get those measurements.
     
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  18. Kyo

    Kyo Veteran
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    Here is a quick set of drawings going over the most common build sizes I think one would undertake. I believe for aluminum the ideal size is as per the original build at 500x500. I would probably chose either a 750x500 or 1000x750 if I was to start another build today, this would allow more flexibility with some projects / builds I have in the works. :D

    Besides extrusion length you will also need longer lead screws. A good rule of thumb is axis length + 40mm this gives you enough for bearing engagement and securing the stepper coupler. OpenBuilds part store has this extra built into there offerings. If you go with other screws / suppliers you will need to take it into account.

    All remaining fasteners , hardware, plates, electronics , ect. Remain the same for any given build size. This is great as it allows flexibility and growth. You can start with one size and expand as your needs or projects require at little cost ( extrusions and lead screws. )

    500 x 500

    500x500.jpg

    750 x 500

    750x500.jpg

    1000 x 750

    1000x750.jpg

    1000 x 1000

    1000x1000.jpg

    1500 x 1000

    1500x1000.jpg
     
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  19. Michael.M

    Michael.M Veteran
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    Yeah when I was in the planning stage, I was trying to be mindful of my X axis length (width?). I have seen some very wide Sphinx builds and even on mine, I can get some flex out of the X axis cbeam if I push down on the spindle. I'm sure there are ways to reinforce this though.
     
  20. Canoe Shelburne

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    Thanks for the info. This will be my first CNC build and I am doing my homework on the subject. I am thinking I would like to be able to do projects up to approximately 24" x 36". So that being said how much longer and wider does the frame need to be.
     
  21. Giarc

    Giarc OpenBuilds Team
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    If you look at the Sketchup drawing of the plates, you will see the Y gantry plates are about 159 mm wide and the X plates are 110 mm. That is how much cutting area you will loose (at minimum) from the extrusions on each axis. So, 36 inches=914.4 mm. You will need 914.4 + 159 = 1073.4 mm to be able to cut 36 inches. Of course you need a few more mm for whatever size bit you choose.
     
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  22. Andreas Bockert

    Andreas Bockert Well-Known
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    I've been running my 1x1 Sphinx for a while now. One annoyance that I've found is that the lock collars have a tendency to become loose and are hard to tighten.

    I have been upgrading the 5/16" (about 7.94mm) clamping collars. These seem to be much more robust. (eBay link: (4) 5/16" 2PC FULL DOUBLE SPLIT NEW SHAFT COLLAR BLACK OXIDE CLAMP SC31D SC031D | eBay) Perhaps this is something for the parts store to stock?

    In the future I plan on upgrading the screws and nuts used for the wheels on Z to class 10.9. Another upgrade that's planned is to use springs to take out the slack on the lead screws.
     
  23. CNCMD

    CNCMD Journeyman
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    Truly one of the weakest links in the system if you ask me. Openbuilds really needs to go with 8mm Clamping Lock Collars and get rid of the set screw version.

    I will say in my opinion, but I know other members that share the opinion as well that the set screw versions are poor for the task at hand. Unless you make a flat in the leadscrew, and that would have to be placed perfectly, the set screw will always shift the collar to be at an angle, this introduces backlash in the system.

    I have recently replaced all of my collars with a clamping style and things have improved significantly in terms of accuracy.
     
  24. ITNavigate

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    @Kyo Thanks for awesome documentation, sharing and general opensoucedness (is that a word? not according to Chrome spellcheck :) )



    Hats off to all of you who have actually built a CNC machine - I've been promising myself that I wold build one for about 7 or 8 years, and even started collecting parts from old printers and scanners. Now I find myself in a position where I need to make some double sided PCB's, and I think that I can justify a CNC mill if it meets two requirements :

    1) The precision / accuracy is sufficient to etch proof-of-concept PCB's.
    2) Versatile enough to also cut and mill aluminium and wood.

    Now this Sphinx CNC can certainly fulfil part 2, so that just leaves me wondering about part 1.

    So after having read each post in this thread, and having tried a Google search to see if this question has already been answered, I hope I don't embarrass myself by asking a question that has already been answered:

    Has anyone used this mill for PCB etching? If so, what were your results like? Comments?

    Or any other comments re PCB's and Sphinx CNC.

    I am also wondering if @beardyblair 's XL will do the job, but I will await answers here before asking on his build blog.
     
  25. Metalguru

    Metalguru Veteran
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    I think a CNC for doing circuit boards is a bit of overkill. It is certainly possible, but the level of accuracy needed to do .008" traces on .008" spacing is pretty high. Also, the machining surface must be perfectly flat to within a couple of thou, which is difficult to achieve with a large CNC router. Finally, even though you could do double sided boards, registration would be fairly difficult. Careful design is needed, and jumpers from side to side are inevitable. No chance of solder mask or silkscreen, either.

    Don't get me wrong, it certainly is possible, but to pay off a $2000+ CNC machine by doing circuit boards would take a looooong time. Especially at the current cost of prototype PCB's. I have used EasyEDA, and double sided plate-through boards with solder mask and silk screen on both sides, along with tin plating, comes out to less than $0.25 per square inch, and took a week to deliver. There are tons of other prototype board services out there that are so cheap they might as well be free.

    You can't even come close to this making your own boards. (Fun as it may be)

    MG
     
  26. ITNavigate

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    @Metalguru, thanks for your feed back - much appreciated.

    Yep. Understood. Unfortunately, I was a little unclear in my earlier post. I'm looking for an *excuse* to dedicate some time and money to a build, not justification ;-). I know it will probably never return a financial profit, but think of all the fun making stuff!! So many uses flying through my head ....

    Hehe, not to mention tools required for that spacing.I'm only considering prototypes, and my components aren't that small (yet). What positional accuracy can be achieved with this CNC? 1mm? 0.5mm? 0.1mm? 0.05mm [I work in mm, 0.394", 0.197", 0.039", 0.02"]?
    I understand that it will come down to how well everything is constructed and maintained, but can I move the spindle 0.5mm accurately?

    Yep. Thought the well supported bed in this (relatively) small build would make this achievable. I would initially mill a holding frame into the waste board. This would serve 2 purposes - 1 to ensure that the bed is flat to the mill, and 2, allow me to drop the PCB into it and have it restrained accurately. With this mill, if I found that the bed had to much flex, I could of course, mill my own set of plates for a smaller mill. I know, backwards from where everyone else wants to go *shrug*.

    BTW, you still haven't put me off my build yet :)
     
  27. Metalguru

    Metalguru Veteran
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    Go for it! My intention is not to "put you off", but just to vent my opinion.

    With a belt drive machine like the ox, depending on what microstepping you use on the motor, you can get a position resolution of about 26-52 steps/mm, which is about 0.08-.04 mm per step. That's not bad, only a couple of thou. Resolution is not the same as accuracy, however. With a screw drive, you can get 4 times that or more.

    You numbers for decimal equivalents were off by an order of magnitude, 1mm=.0394", not .394".

    Milling a flat surface with the machine is a good way to get a perfectly flat surface pupendicular to the bit. Compensates for all the little misalignments of the machine.

    I'm not saying you can't make PCB's with a mill, but I certainly could find better uses for one. Precision work is best done with a smaller machine, less flex, etc. Signs don't require high precision, but need a large table. It's very hard to make a machine that does everything well.

    Also keep in mind that in order to mill metals like aluminum, the machine benefits from a small, stiff structure. Also, aluminum is quite difficult to machine, it requires lubrication and a lot of practice. And a spoil board that doesn't turn into oatmeal when it gets wet.
     
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  28. Andreas Bockert

    Andreas Bockert Well-Known
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    With 8mm leadscrew and 8 micro stepping you would get a accuracy of about 0.005. That’s in theory. But <0.1 mm is very much achievable with a Sphinx.
     
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  29. ITNavigate

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    *Blush*
    At least I waited for my second post to embarrass myself.

    Colin.
     
  30. ITNavigate

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    Thanks.
     

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