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  1. #101
    If you do go for a slow speed-up on the spindle and let the G-code start it just before the cutting begins you may need to add a delay to let it come up to speed. I've found this necessary using CamBam and LinuxCNC (though I cannot remember exacltly what my acceleration setting is, I'm sure I took the advice on this forum). I manualy add a line 'G4 P6' just after the spindle start line to add a 6 second delay.
    An optimist says the glass is half full, a pessimist says the glass is half empty, an engineer says you're using the wrong sized glass.

  2. #102
    Spindle wired up and powered on, very carefully !
    Press Run and it runs ok but for some reason goes straight to 24000 rpm and the front speed control does nothing?
    I tried setting Pd002 to both 0 and 1 but made no difference. The "J1" jumper is also shorted pin 2 and 3 e.g VR not VI.
    The spindle spec sheet also says pd070 should be at 1 which it is.
    Am I missing something ? Otherwise 'll try UCCnc control instead and see if that works !
    Last edited by CNCRY; 24-05-2020 at 08:58 AM.

  3. #103
    Still no speed control on the spindle when connected to AXBB-E
    Cabled as above with VFD>AXBB-E
    FOR > O2
    DCM > 24V0
    VI > AO1
    ACM > 5V0 (power out)

    Click image for larger version. 

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    When I enter in MDI M3 S2500 - the O2 pit diagnostic lights up and spindle FOR lights up and stops flashing, like this:

    Click image for larger version. 

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    But Speed sits at 0!
    I checked the voltage between AO1 and 5v0 at S2500 and it seems to be 0 so possibly the issue.

    Here are my settings

    Click image for larger version. 

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    I noticed "SPINDLE CW" light comes on in UCCNC diagnostics too.
    Am I missing some config here or something obvious as I'm stumped!

    Thanks
    Ryan

  4. #104
    Sorted it ! It's not obvious in the documentation but there is an extra I/0 configuration screen where PWM channel has to be set to 1 not default of 0.
    Oddly taking the jumper off the Axxb-e still won't output 0-10v, so ended up leaving VFD PD070 @ 5V control too.

  5. #105
    Nice catch. I did have a quick look through the AXBB manual buy didn't spot that (the port/pin config looked suspicious but I've had Chinese motion controllers that ignore port/pins before so not entirely unrealistic). Not got/tried the AXBB myself - just keep your jumper setting in mind - unlikely but possible it'll mode on a reboot (your behaviour might be different next time you power-up... or maybe not), Peculiar that it doesn't behave as expected. You've set the max-spindle speed correctly, of course?

  6. #106
    For anyone's reference in future this is the setting:
    Click image for larger version. 

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    Initially I set the spindle min to 5000, max 24000 which I assumed meant it would just not allow a command below S5000, but figured out that meant 5000rpm = 0v, so when I set 10000rpm I would get 7500ish instead! So set min to 1, max 24000 and all good (to the nearest few hundred anyway).

    Playing around in UCCNC reminded me of a couple of other things
    - is it worth setting max velocity and acceleration at this point, set to 2000 units, so 20m/m which I expect is faster then it will go.
    - Is there any worthwhile tuning of steppers needed - these are the hybrid steppers so slightly less common. I see there are 4 switches which can be used to set pulse/rev but no idea if these are worth changing?
    Or maybe I'm just thinking up ideas while waiting on parts:) Feels like I'm on the home stretch now, just need to figure out my workholding and spoil-board which doesn't eat up the Z distance.
    I also couldn't find an obvious answer on this - can I use normal 1/2" router bits in the spindle or does everyone use endmills? Obviously something like a Lock Mitre bit would be a bad idea, but the simple 2 flute straight bits, chamfer etc..

  7. #107
    JAZZCNC's Avatar
    Lives in wakefield, United Kingdom. Last Activity: 11 Hours Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 8,426. Received thanks 1,443 times, giving thanks to others 108 times. Referred 1 members to the community.
    Quote Originally Posted by CNCRY View Post
    Playing around in UCCNC reminded me of a couple of other things
    - is it worth setting max velocity and acceleration at this point, set to 2000 units, so 20m/m which I expect is faster then it will go.
    2000 is the units ie: mm or inch value so if you want 20m/m it needs to be 20,000 not 2000. Read below and it will make more sense, if not just ask.

    The velocity and acceleration are very important and you can't just womp them up and leave it at that because you'll just get stalling motors.
    This is the bit that you'll see mentioned as motor tuning and it's a balance between velocity and acceleration, If you increase one it will affect the other at some point and you'll have to decrease one of them.

    Every machine is different when it comes to tuning the motors because of friction and mass, voltages etc, so it's very much feel way your way thru and lots of little tweaks.
    Start low on both at say 4000mm/min on velocity and 500 on acceleration. Then adjust just the velocity until the motors stall, then reduce the amount by 25%, then do the same with acceleration. This will give you a base line and nice stable machine, you can tweak it up from there but again only adjust one at a time and test.

    Quote Originally Posted by CNCRY View Post
    - Is there any worthwhile tuning of steppers needed - these are the hybrid steppers so slightly less common. I see there are 4 switches which can be used to set pulse/rev but no idea if these are worth changing?
    Well first hybrid steppers are common as muck, probably the most common stepper on the market and it means NOTHING. I see this a lot that people get blinded by jargon and think that the word Hybrid means they are something special when all it means is they can be wired in several ways making them an Hybrid of several types of steppers.

    Again these switches are very important as they set the micro steps, infact THE most important bit because if you don't know this setting then you can't possibly set the correct Steps Per unit value in UCCNC and you won't get the correct amount of movement. It also affects the motor tuning because the higher these settings then the motor acts differently, going too high can give negative results as they are very close relationship with motor tuning and the system as a whole.

    There will be a chart on the stepper case that gives different micro step options and will tell you the positions those switches need to be set for each micro step amount.
    Set them up to give 1600 micro steps. There is no need to go higher as it starts to give negative results.
    Now you take this figure and do a calculation for the steps per unit value that you enter into UCCNC. Divide 1600 by the ball-screw pitch and any ratio you may have. So if it's direct drive with 10mm pitch then 1600/10=160 for the steps per.

    This will give the correct movement, the Steps Per setting is a none negotiable setting and you can't just use a random number, it must be calculated from the Drive settings. ball-screw pitch and any ratios applied to it.


    Quote Originally Posted by CNCRY View Post
    -I also couldn't find an obvious answer on this - can I use normal 1/2" router bits in the spindle or does everyone use endmills? Obviously something like a Lock Mitre bit would be a bad idea, but the simple 2 flute straight bits, chamfer etc..
    You can use what ever you like, stick a pencil up it if you like. Also no reason why couldn't use a Lock mitre bit provide it's not like 6" and 3kg in weight. I regularly use a 70mm surfacing bit which is bigger than a lock mitre bit.

    I often use my old worn out end mils that I've used on aluminium for cutting wood as they are still more than good enough for hogging out wood and often I've only worn the first 4-5mm out and I cut much deeper in wood. I then use a decent end mill for the finish passes.
    Last edited by JAZZCNC; 26-05-2020 at 09:26 AM.
    -use common sense, if you lack it, there is no software to help that.

    Email: dean@jazzcnc.co.uk

    Web site: www.jazzcnc.co.uk

  8. #108
    Quote Originally Posted by CNCRY View Post
    I also couldn't find an obvious answer on this - can I use normal 1/2" router bits in the spindle or does everyone use endmills? Obviously something like a Lock Mitre bit would be a bad idea, but the simple 2 flute straight bits, chamfer etc..
    One way to look at this is, "Would I use this cutter in a handheld 1/2" router at 26000RPM?" Or even a 1/4" router. If the answer is yes, then go ahead with it in a more powerful spindle with much better control!

  9. #109
    To be fair - a good many hand held routers are in a similar power band to the usual spindle, and similar RPM. I wouldn't sweat too much. Common sense applies, of course.

  10. #110
    Thanks all - I did see people using them but just wondered if there was something I'd missed before using standard bits. Seems like a really obvious question now:)
    The stepper drivers were set by default at 1000 according to switches so have changed the switches to 1600 in the table as recommended.
    I was thinking the "units" referred to cm - as UCCNC defaulted to 200 steps per unit, I took this as meaning 200 steps @ 1.8 degrees to make 1 revolution which would equate to 10mm of motion, so a unit being 10mm. I guess I was calculating the wrong way round!
    Does jogging use the same velocity settings - as jogging seemed to be about 10m/min which seems about right , even with microstepping on drivers set to 1000 and steps /unit at 200?
    With the hybrid steppers I mean that many build logs on here and other forums use "standard" steppers without an encoder, and wasn't sure if mine having encoders that had any bearing on the tuning. Assuming it being a closed loop the controller never knows any different anyway.
    Once I get the replacement ballscrew and right size drag chain I'll do some more testing and tuning.

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