No idea, it came with a 220v PSU not that that means diddly squat - so if I tear it down to the point I can reach the screws how do you do measurements, the same as measuring the pitch on a normal screw?Quote:
Originally Posted by Swarfing
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No idea, it came with a 220v PSU not that that means diddly squat - so if I tear it down to the point I can reach the screws how do you do measurements, the same as measuring the pitch on a normal screw?Quote:
Originally Posted by Swarfing
I get 1500.68 :hororr: methinks I did summut wrongQuote:
Originally Posted by Ricardoco
Carl measure the pitch of the leadscrews
OkQuote:
Originally Posted by Carlb1058
200/ (52-3) x 100
or
200 / 49 x 100 = 408.16
where 200 is the original steps per and 49 is the output cut measurement minus the tool diameter, multiplied but the input cut measurement..
is that a Bit easier?
Its a brain doo'er i know
LOL
Rick
why not just follow 1 path at a time then the chap wont get too confused..Quote:
Originally Posted by Swarfing
Rick
Agreed......
Just turned it over and measured the Y and I get 3 to a cm - whatever that works out to *shrug*Quote:
Originally Posted by Ricardoco
3 turns to a cm yes? What ever they are i suspect the pitch is not the same for x and yQuote:
Originally Posted by Carlb1058
Rick
Just a tad - cheers :) I ended up with 409.62 using 3.175 as the tool diameterQuote:
Originally Posted by Ricardoco
Yep 3 to a cm the biggest problem with trying to measure the X is it is fully enclosed and I'd pretty much have to tear it apart to get to it but I shall attempt to get a close as damn first :)Quote:
Originally Posted by Ricardoco
Once we have got both axis to move the same amount i can do the math again and give you the imperial equiv, then we can change the system to old school as like swarfing said it could be a yank model. but we will get it for you then of course that will rule out the mechanical and software stuff as the source of your trouble, leaving only the electrics but they may be fine and just need proper BOB and stepper drivers should you be so inclined..Quote:
Originally Posted by Carlb1058
Rick
Dont bother it can be worked out with the software al be it a little long winded..Quote:
Originally Posted by Carlb1058
Rick
well that was easier than expected, managed to get a 1cm wide flat file between the frame work and as near as damn the X is 3 turns as is the Z, so all the screws are the same sizeQuote:
Originally Posted by Carlb1058
confused but could be possible?
7.26TPI 0.13774" 3.499mm pitch is about as close as you could get to that. Stick with tuning it out for now like Rick said before. Imperial or not you would still like it working with what you have. Sorry i took this away from that.
No drama, it's always good to learn new stuff :)Quote:
Originally Posted by Swarfing
Got to hit the sack, hope get somewhere soon
Paul
Lightweight...LOLQuote:
Originally Posted by Swarfing
Rick
NN mate
Looks like im a lightweight too Im off to bed as well, speak tomorrow CarlQuote:
Originally Posted by Ricardoco
Rick
no problems - all the help so far has been greatQuote:
Originally Posted by Ricardoco
Why not get Mach to do the work for you ? go into "Settings tab", just above the reset button "set steps per unit" start with X enter 100 measure how far it moved then tell it how far it moved and will set steps up for you.
Do the same for all axis do a test cut if not correct go though it again.
Phill
Yep that would be better, ide forgot about that.Quote:
Originally Posted by phill05
Rick
I dislike just scaling the step/mm values to make it work as it can mask more fundamental issues, and generally isn't as accurate. You should be able to measure the ballscrew pitch and work it out. The comment earlier saying the 'the Y however seemed to jerk' implies it could be stalling as the motion should be very smooth. If that is the case you need to find what's causing that, else the distance readings for that axis are meaningless.
Instead of just measuring a small distance along the screw, measure say 20 turns and divide the result by 20. Assuming you can access the motors, you shouldn't have to dismantle anything. Just measure the distance between the axis and a convenient point, turn it 'n' times by hand and measure the distance again. Divide the difference between those distances by 'n' and you have the pitch. If you've got a digital caliper then measure it over about 150mm to get the most accurate reading.
Doing a test cut is not the best way either, since spindle runout and tool deflection can introduce small errors and it's not possible to measure in wood that accurately anyway. Instead measure how far the axis moves. Measuring the distance between two parallel lines would be easier, and a bit more accurate, than measuring the length of the line, since you're measuring between straight edges not arcs.
Assuming the '3 turns per cm', i.e. 3.3mm pitch is reasonably accurate, the step/mm values we've ended up with don't make much sense. The motors are run from TB6560 ICs, which only support microstepping settings which are powers of 2 up to 2^4 (16). Assuming (as there's a slight chance it may not be) the motors full step resolution is 200 step/rev, that means your motors can be set to 200*2^n where 0<n<4. We need to find steps per mm, so divide by the pitch-> 200*2^n/3.3 = 60.6*2^n, where 0<n<4. That means the correct step/mm value could be one of the following (rounded to 2DP); 60.61, 121.21, 242.42, 484.85, 969.70. None of those seem anywhere near the 408.1 and 512.8 you tried... so I reckon there's something else causing problems here.
You could measure the voltages at the M1 and M2 pins of the TB6560 ICs on your driver board to determine what the microstep setting actually is. The datasheet here shows which pins to probe.
Hi Jonathan, this was initially to find out if it was an electrical or a mechanical problem, or indeed both, as i understand it there is no way to change the steps on the drivers that could be discovered. So Im glad you are here to cast your eye over it, we also dont know if the screws are metric or imperial although the chap has said they all measure the same..Quote:
Originally Posted by Jonathan
Rick
This won't fix your axis scaling issues but in general config are you set to exact stop or constant velocity? I'd recommend constant velocity for smoother movement and less chance of lost steps.
dislike just scaling the step/mm values to make it work as it can mask more fundamental issues, and generally isn't as accurate. You should be able to measure the ballscrew pitch and work it out. The comment earlier saying the 'the Y however seemed to jerk' implies it could be stalling as the motion should be very smooth. If that is the case you need to find what's causing that, else the distance readings for that axis are meaningless.
This is pretty much what I was going to do with the gerber when the time came so how would I go about setting that up? It's belt driven via gearing rather than being a ballscrew.
Hi Jonathan,Quote:
Originally Posted by Jonathan
Clarification on the following please:
1) measure the distance between the axis and a convenient point
Tipping the machine over gives me clear access to the Y screw, both X & Z have a lot of body work around them which seriously limits any access - so with that said, please define axis and convenient point, don't forget you're talking to a total newbie here, the only machines we had in school were a bench drill and lathe - damn, calculators didn't even surface until years after I left!!
2) measure the voltages at the M1 and M2 pins
All I have in regards to voltage measurement gear is a simple multimeter that I use for checking the wiring on the Meriden and my FLH will this suffice?
Measure how far the axis moves. So for example on X move the gantry to one end, then turn 20 turns (or whatever) and measure how far it moved. You don't need access to the screw.Quote:
Originally Posted by Carlb1058
The meter you have will be fine. Just connect the negative probe to negative, (i.e. ground) and the other one to the correct pins. You may have to unscrew the board to access one of them.
Access to the chips wasn't too bad - off all three I got a reading of between 2.2 and 2.3 and occassionally -2.2 & -2.3 but I'd say that's my multimeter playing silly buggers.Quote:
Originally Posted by Jonathan
As for turns per 20 on the X gave me 80mm, 10 on the Z gave me 40mm (couldn't turn it 20) and 20 on the Y gave me 62mm
Recheck Y in a couple of places and in both directions
Reason for this is 62 mm doesn't work out to a normal pitch and you did say y was jerky.
I'm wondering if you have a loose coupling or similar ?
I concurQuote:
Originally Posted by John S
Rick
Just measured it at centre of table and the other end to original and still got 62??Quote:
Originally Posted by John S
Addon bit: Just re-checked and made sure all connections were tight and they were, this is where it gets weird again - using a spanner on the opposite end of the Y screw I turned it 20 got 80mm, turn the knob on the end of the motor and get 62 but if I try and tighten the grub screws up any more all I succeed in doing is bending the allen key????
Is the knob on the end of the motor slipping ?
You need to sort this bit out first, try welding the stepper motor to the ball screw.
Just joking.
Welding - cool, now ya talking :encouragement:Quote:
Originally Posted by John S
The knob itself is on the motor that tight I'd break it if I tried to remove it so the only thing left is the coupling I might go tear the motor off and suss that lot out
Y now equals 80mm on 20 turns and I've got one bent allen key :witless:
Now your where you should be... thats cool it was the hardware(maybe LOL) not the electrics (maybe) All the clever ones are called john in one form or another LOLQuote:
Originally Posted by Carlb1058
Rick
Rick,Quote:
Originally Posted by Ricardoco
Yep gettin' there, just uninstalled, rebooted, re-installed, rebooted, re-setup Mach3, rebooted, loaded the g-code for the 100mm X line and the 100mm Y line and get 102mm on both. . .
used stock settings of 400 steps, 2000 velo, 200 accel for both X&Y, Z is 400s, 700v, 100a
its very odd because the measurements indicate that you have 4mm pitch screws.Quote:
Originally Posted by Carlb1058
Well at least they are both the same now.. LOL You can now try the math we talked about last night.. 400/ (cut length - tool dia) x input cut length= new steps per..
Rick
I'll try the new number (413.11 to the nearest dp) shortly, it's bucket'in down and the part time work I've got to keep me in toys keeps askin' me when I'm gunna do some so I best do some aye LOLQuote:
Originally Posted by Ricardoco
I'll let ya know how it goes. . .
The eBay listing indicates he has 4mm pitch screws and 20 turns moved it 80mm, which also indicates 4mm pitch screws as 80/20=4mm. So nothing to worry about.Quote:
Originally Posted by Ricardoco
The voltage readings are strange - should have got 5V or 0V, but nevermind as we now know they're set to 1/4 microstepping.
I didn't get anywhere near 5v, the readings I got were after atleast a dozen tests the first few were around the 2.7 - 3.2 range and they slowly dropped until they stayed pretty static at 2.2 - all three chips did exactly the same thing.Quote:
Originally Posted by Jonathan
I wonder if it's worth just throwing an extra 90 bux at it for a board with dip switches etc?