Thank you for the follow up - it was an interesting discussion to follow
(along with the "how long will a rotary table turn?" one that Marcus
started)
John.
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Site24x7 APM Insight: Get Deep Visibility into Application Per
As promised, here is the follow up:
1. After extensive testing of the A axis running a
non-integer-step-producing angle several thousand iterations it
appears, just as John K said, that the "leftovers' are dealt with
within the planer in an intelligent way and there are no measurable
residual
On 1/3/2016 8:00 AM, Cecil Thomas wrote:
> As I have designed my program there are many more moves in one
> direction than in the other so I assume that the "shortness"
> accumulates over a large number of moves. My calculations for the
> accumulation of error in my system seem to match the measu
Great explanation Peter!
Happy New Year.
John Dammeyer
> -Original Message-
> From: Peter Homann [mailto:gro...@homanndesigns.com]
> Sent: January-03-16 5:36 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Lost fractions of a step
>
>
> It d
It depends on the drive that you have.
Geckodrives morph from 10 microstepping to full stepping by the time the motor
reaches a few revs per second, so no torque is lost. You get the best of both
worlds, very smooth slow speed movement and the torque of full stepping.
Also, a lot of people do n
Thanks to everyone for their input. John answered the right question.
The bottom line appears to be that Linuxcnc does "round" both up and
down to the "nearest" step as opposed to just dropping the "leftover"
So it already does what I was proposing to do with the MOD operator.
Apparently the
On 3 January 2016 at 21:35, wrote:
> ,I too have a similar problem. Built a rotary table (small, about 4" dia).
> Ordered a worm and wheel pair from Boston Gear, thought I ordered a 72 tooth
> worm wheel, which moves 5 degrees per one rev of the worm, divided by 400
> steps, resolves to 0.0125
>
> Cecil
>
>
> --
>
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> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
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Me
On Sun, Jan 3, 2016, at 01:02 AM, Cecil Thomas wrote:
> My question is about what happens to the "leftovers" when the
> precision of the g code commanded position cannot be met by the
> hardware executing it.
LinuxCNC does not work in steps. It uses floating point values
for all internal calc
The book which has a selection of standards is Gears for small
mechanisms by W.O. Davis, it was reprinted by TEE publishing ISBN
1857610156
Note the correct form has a rectangular root which stops the end mill kludge.
We just used the Thornton cutters to get it right.
The cycloidal form has a numb
On Sunday 03 January 2016 12:37:55 Kirk Wallace wrote:
> On 01/02/2016 10:02 PM, Cecil Thomas wrote:
> ... snip
>
> > Several years ago I wrote a program to "generate" involute gear
> > teeth by making multiple cuts of the same tooth from differing
> > angles with a rack shaped cutter. This elimin
On 3 January 2016 at 17:37, Kirk Wallace wrote:
> I'm also working on a New Haven clock that seems to use custom screw
> threads (#3-40?) that don't appear in Machinery's Handbook or anywhere else.
I thought it might be a watch pendant thread, or Progress, but I can't
find anything that coarse a
On 01/02/2016 10:02 PM, Cecil Thomas wrote:
... snip
> Several years ago I wrote a program to "generate" involute gear teeth
> by making multiple cuts of the same tooth from differing angles with
> a rack shaped cutter. This eliminates the need for the different
> cutters when making only one cut
On Sunday 03 January 2016 10:00:50 Cecil Thomas wrote:
> I guess I wasn't as clear as I had hoped about my question.
> To be more specific:
> When the commanded value for a move is converted into steps (or
> microsteps) and that number of steps contains a fractionWhat
> happens to the fraction
The internal numbers in gcode are floats there is no rounding down
unless you put small constants in your gcode, I calculate the tooth
angle in gcode so internally it is as accurate as needed.
eg do not calculate yourself use a line such as
#=[360/#]
I never see your problem and have been using
I guess I wasn't as clear as I had hoped about my question.
To be more specific:
When the commanded value for a move is converted into steps (or
microsteps) and that number of steps contains a fractionWhat
happens to the fractional part of a step
I am not speaking of dropped steps as wou
On 3 January 2016 at 06:02, Cecil Thomas wrote:
> My question is about what happens to the "leftovers" when the
> precision of the g code commanded position cannot be met by the
> hardware executing it.
It should all even out over multiple moves.
The commands to the step generator are absolute p
Just chipping in...
So on your rotary axis, you have 60 000 steps per revolution. If you set up
a dial gauge and do a simple G1 with 600 000 steps, or 10 rev's, is there
much residual error?
Otherwise, if the accuracy is good enough for one rev, then, in fake code;
- home rotary
- cut one tooth w
In my experience of watch and clock gear cutting, heating is almost
non existent as an error source, for steel one cuts under a lubricant
which cools and brass is cut dry with a sharp cutter and often the
clamping washers if used will keep it cool. Only one "brass" wheel
gave me a problem and that
I suspect that if you were indeed to cut each tooth completely and
sequentially you could get the spiral wave of material heat extending that
would cause even stranger errors! In the effort to cut a little of each I
would use the Fibonacci number applied to 360degrees - as I remember aprox.
137 de
And another thing, almost all rotaries have backlash, do make sure
this is removed in gcode before you start cutting this will result in
a single tooth error.
Dave Caroline
--
_
I forgot to mention, I had no accumulated step loss in my tests, I
started each test with encoders at 0 and they completed with 48000 and
2, not even a +-1 digit error which surprised me.
Dave Caroline
--
Microstepping increases resolution but not accuracy, you can easily
lose torque in intermediate positions, any stiffness in the rotary
will just add error.
Perhaps the worst thing I have seen though is rotary error itself, the
lower the reduction ratio usually means a greater error from the
worm/wh
Good year to all,
I have a board that can do microstepping but I would not use
microstepping because the manual says that while it rises the precision
it also reduces the torque.
On Sun, 2016-01-03 at 01:02 -0500, Cecil Thomas wrote:
> My question is about what happens to the "leftovers" when the
My question is about what happens to the "leftovers" when the
precision of the g code commanded position cannot be met by the
hardware executing it.
Several years ago I wrote a program to "generate" involute gear teeth
by making multiple cuts of the same tooth from differing angles with
a rack
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