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  • February 19, 2014 at 11:13 am in reply to: CNC mill conversion G0704 Grizzly – cheap #5438
    flightfollowing
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    Riley,
    Can you respond to this quote about some of the limitations of tinyg compared to a Mach 3, what g code features are yet to be implemented in tinyg?
    “1 – First, all of them only use only a subset of the RS-274 g-code command library. The codes that are incorporated are the very basic ones. Many of the ommitted codes I find very useful. Some examples of ommitted codes are G40, G41, G42 (cutter diameter comp), G43 (tool length offset), G81 through G89 (Drilling and boring cycles). I’m sure there are others, but most of the microcontroller based G-code interpreters don’t have enough memory to allow for the program overhead to include these.”

    February 19, 2014 at 9:20 am in reply to: CNC mill conversion G0704 Grizzly – cheap #5437
    flightfollowing
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    The site seems to strip a hrefs, and I didn’t see an easy way to upload images:
    http://www.cnczone.com/forums/benchtop_machines/212088-g0704_tinyg_controller_simple_ugly_cheap_parts.html#post1440486

    February 19, 2014 at 1:11 am in reply to: Bug in retaining Z at run start #5433
    flightfollowing
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    Here is the nc code for both identical runs:
    ( Made using CamBam – http://www.cambam.co.uk )
    ( TestMM 2/15/2014 10:01:03 PM )
    ( T4 : 4.76 )
    G21 G90 G64 G40
    G0 Z3.0
    ( T4 : 4.76 )
    T4 M6
    ( Profile1 )
    G17
    M3 S1000
    G0 X12.62 Y10.0
    G0 Z1.0
    G1 F300.0 Z-1.0
    G2 F800.0 X8.69 Y7.731 I-2.62 J0.0
    G2 Y12.269 I1.31 J2.269
    G2 X12.62 Y10.0 I1.31 J-2.269
    G1 F300.0 Z-2.0
    G2 F800.0 X8.69 Y7.731 I-2.62 J0.0
    G2 Y12.269 I1.31 J2.269
    G2 X12.62 Y10.0 I1.31 J-2.269
    G1 F300.0 Z-3.0
    G2 F800.0 X8.69 Y7.731 I-2.62 J0.0
    G2 Y12.269 I1.31 J2.269
    G2 X12.62 Y10.0 I1.31 J-2.269
    G1 F300.0 Z-4.0
    G2 F800.0 X8.69 Y7.731 I-2.62 J0.0
    G2 Y12.269 I1.31 J2.269
    G2 X12.62 Y10.0 I1.31 J-2.269
    G1 F300.0 Z-4.9
    G2 F800.0 X8.69 Y7.731 I-2.62 J0.0
    G2 Y12.269 I1.31 J2.269
    G2 X12.62 Y10.0 I1.31 J-2.269
    G0 Z3.0
    M5
    M30

    February 19, 2014 at 1:06 am in reply to: Bug in retaining Z at run start #5432
    flightfollowing
    Member

    Here is a link to a video with proper operation, run immediately after zeroing. The z drives to 3mm above part, then makes the first pass at -1mm, then -2mm, then -3mm, then -4mm, finally -4.9mm, then it completes the job, and resets the X Y and Z positions to random numbers.

    Here is the link with a 1mm jog of the z axis above the part, then the exact same run. Note that the z drives to 3mm above part, then down to +1mm, then down to -2mm on the next pass. It should have driven to -1mm just like the first video.

    Running firmware .96, build 380.08, hardware ver 8, hardware id 1h4973-ejr
    tgfx version .95, build 2.404

    February 19, 2014 at 12:15 am in reply to: CNC mill conversion G0704 Grizzly – cheap #5430
    flightfollowing
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    Here are pics of the parts I had to fabricate. A great resource is g0704.com, he sells plans, videos, parts lists, cad drawings, etc as a package. However, most of the parts I built were not of his design, but simplified (and not as nice, but work fine and were cheap and relatively easy to fabricate).

    February 15, 2014 at 12:54 pm in reply to: CNC mill conversion G0704 Grizzly – cheap #5414
    flightfollowing
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    A really ugly video milling a 1 inch hole in 3/8″ aluminum is here:

    February 15, 2014 at 12:51 pm in reply to: Driving 8 wire stepper with 2 outputs? #5413
    flightfollowing
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    Riley,
    I posted a little something in the projects threads, as you will see I am not a videographer.

    CNC mill conversion G0704 Grizzly – cheap

    I am working through some issues with tinyg and tgfx, using cambam for gcode and linixCNC format (?) machine code. Seems like I am having a Z axis issue at the beginning of runs, and the machine does not return home when finished?

    Cliff

    February 7, 2014 at 9:00 am in reply to: Driving 8 wire stepper with 2 outputs? #5379
    flightfollowing
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    Thanks very much for the feedback. My questions might have been premature as I am pretty happy with the tinyg driving the G0704 directly without any external driver or dual outputs to a single motor. After slowing down the fastest transit rates a bit, switching from 1/8 steps to 1/2 steps, and tuning/lubing the mill it works great. Now you just need some more tinyg’s in stock for ordering for another machine, (and getting tgFX out of beta!). Thanks.

    February 4, 2014 at 12:52 pm in reply to: Driving 8 wire stepper with 2 outputs? #5344
    flightfollowing
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    Those are the same motors I am using. I did receive my tinyg yesterday and hooked it up to the mill and got things up and running pretty easily in a draft mode, only two axis as I am waiting for one more part for Z. Turned up the pots pretty much all the way, but I can still get stalling when running at full speed even without a load (but the mill needs to be lubed and tuned). When running slower it seems to do fine when simple resistance is applied by hand.
    I don’t have very heavy milling requirements so not achieving top speed may not be a problem and it would work fine as is, but I can tell I will be limited with the tinyg at 28V and the 2.8amp motors, so I might be interested in more output with either the dual output 8 wire from the tinyg or else the KL driver.
    However, you mention some issues I should be aware of, specifically the 3v output formats, the pulse stretching and the untested KL’s.
    If you have any more insight into using the KL, or if you have a wiring and configuration plan for dual outputs from the tinyg to an 8 wire motor, feel free to let me know and I could give it a try (unless you try it yourself as a test 🙂

    Couple of other questions: If I were to use a KL driver, where physically would it get its step-dir-enable outputs from, the J17, J18, j19, or J20 headers on the board? Or are these matched to the existing motor drivers 1-4? This is confusing and does not appear documented in the schematic.
    Also, are their any settings or tricks to deal with backlash using the tinyg? Or if not in the config files, maybe in creating the gcode?
    Thanks

    January 29, 2014 at 7:46 pm in reply to: Driving 8 wire stepper with 2 outputs? #5311
    flightfollowing
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    Alden,

    Thanks for the interesting reply. I bought the tinyg for a shapeoko sized cnc router I am building. However, I have a g0704 3 axis mill that I am considering using the tinyg on, with 3 of the 428oz 2.8amp nema-23 8 wire motors on each axis leaving an extra driver spare, running at 27V with an existing power supply. Converting the mill to cnc is pretty quick, but the tinyg sounds marginal to drive it (please offer any advice here, I am new to cnc) according to:
    http://www.g0704.com/G0704_electronics.html#hoss

    My tentative plan will be to try out the tinyg for this mill with these motors and see how it works, with fan cooling on the tinyg. If it has problems, I have a few options: adding the 4th tinyg driver to the extra coils on the Z axis as per this thread, or getting something like:
    http://www.automationtechnologiesinc.com/products-page/kl-stepper-drivers/microstepping-driver-kl6852
    to the Z axis connected to the tinyg, or else removing the tinyg completely (using it for the router) and getting something like:

    3 Axis DSP Based Digital Stepper Driver Max 60 VDC/6.0A, MX3660

    I would welcome any advice as I do not know what I am doing. If you think the dual output on the 8 wire stepper might be feasible, it will be at least a few weeks before getting to that point and I would definitely get your advice on wiring it up and testing it.

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