formulas for what? the formulas that are in the firmware for calculating the
position? that is different for different firmware.
Angles, sprocket size, chain length, chain tension, sled angles, sled weight, frame bar thickness… any formula/all formulas.
what you used to come up with what you have. Why does it have to be one or two?
most of that is ‘it works’, there wasn’t that much analysis done 
the sprocket sizes are the smallest available that fit the motors
chain length is ‘long enough to reach’, the 10’ top beam was that lumber comes
in that size and it seems reasonable and seemed to work.
Later investigation shows that there is a significant advantage in going to a
12’ top beam, most of the math showing this is available in the spreadsheet I
created. This shows chain tension, and experimentation has shown that more min
tension is better, and max tension can’t be too high or you have trouble in the
top center (again, with the original motors/power supply)
the math isn’t perfect, but it seems to be ‘good enough’
frame bar thickness is ‘2x4 is the default dimension for US lumber’ and the
prototype worked. It may be better to have a stronger top beam, but no real
analysis has been done.
frame angle, accidental testing that was done during the design of the new frame
(i.e. Bar not following my instructions in building a test frame ) showed us
that 20 degree tilt back is too much. We had someone test with 5 degree tilt
back and they found that the sled tended to push away from the workpiece instead
of drilling in. We haven’t had anyone test 10 vs 15 degrees (let alone anything
more specific) to see where the real sweet spot is.
As for the sled weight, before the first prototype, Bar did testing with lots of
things, including 6+ bricks on the sled, very heavy chains, etc and the result
ended up being the two brick weight ‘worked’.
Since then, we found all sorts of new info. We know that a sled that’s much
heavier runs into problems (the motors can’t move it near the top center), but
we really haven’t tested much with varying the weight. The early versions of the
code did nothing to account for the chain sagging (which will be more
significant with a lighter sled), and I don’t know of any testing that has been
done since holey calibration was invented which partially accounts for chain
sag.
mostly, this isn’t a matter of formula and calculations as much as ‘the
prototype worked and we’ve mostly followed along with that since’
- What are the dimensions (diameter/height) of the gears in the gearbox? Measure and post.
diameters don¢t matter, overall gear ratio does.
It matters if your scaling, customizing or replacing the plastic inside with metal.
if you are doing that, you should just build a complete new gearbox or purchase
the gears because there’s a lot more detail than just hight/diameter of the
gears.
- What is the gear ratio of each stage of the 4 stages of the gears in the gearbox? count the teeth of each gear and post.
why? only the overall ratio matters right?
It matters if your scaling, customizing or replacing the plastic inside with metal.
same answer
- Motor specs are motor specs. voltage, current, RPM, Torque, dimensions.
Get specs from manufacture and post or get the common model number
so community can look it up themselves.
umm, did you look at the BOM that lists this?
B.O.M. list specs of the gearbox only not the motor other than its voltage not even its model#.
ok, I posted a link to a motor in the same family, that should answer your
questions.
- What is the output speed of gearbox?
Measure RPM and post.
the stock motors will do ~20 rpm at max power
[/quote]
Thank you, one straight answer and yes, I did find this one in the B.O.M. this time, it wasn’t always there.
I not looking to argue or debate if it is required, I don’t care if everyone on the planet thinks it doesn’t matter. I do, and I know others do because have asked me if I found anything.
I would like that data available without the questions and the wasted five message exchanges like here.
Here is how it should go.
Example:
Question: What are the motor specs, please?
Reply: It is a Modle-775, 24V, 1A, 6000RPM dual ball bearing, 42mm dia X 66mm len.,.Shaft-5mm dia X 17mm len.
Courtesy reply:Thank you.
End example
See quick no fuss no muss. You got to help, member got their answer.
All are happy.
you are asking for information that nobody knows, and you are asking people to
go take apart their equipment to measure stuff, that doesn’t justify an
automatic ‘here are the details you are asking for’ response you seem to be
expecting.
David Lang