Dynomotion

Group: DynoMotion Message: 1266 From: Bengt Sjoelund Date: 6/13/2011
Subject: Not square
Hi Tom,
We have some discussions on local forums here in Sweden as how to correct X/Y not in 90° square, i.e. Part drawn in CAD comes out slightly rhombic.

Question raised as some machines cannot be fixed mechanically.

Is there a way of correcting this in KFlop if a file with say Point-cloud is done probing the X/Y?

CAM folks say that is not doable as if any kind of compensation is applied like G68 - scaling - mirroring the correction is useless.
And I believe the same is with Mach3 Formulas.

Cheers
Bengt
Group: DynoMotion Message: 1267 From: carlcnc Date: 6/13/2011
Subject: Re: Not square
Bengt
I don't understand
If this is a typical machine with a single screw diving the X[orY]
down the center, and mechanically the machine is out of square[not orthogonal] or has slop in the bearings/carriage
no amount of software magic can overcome this.
Kmotion can map for "drunken" or erratic screws or racks and
compensate for a known amount of backlash ,which may be your problem.
but it can not "know" if or how much machine is out of square
Maybe ,if you know how much a machine is off. you could draw/distort a part to compensate?
CArl


--- In DynoMotion@yahoogroups.com, "Bengt Sjoelund" <cnc@...> wrote:
>
> Hi Tom,
> We have some discussions on local forums here in Sweden as how to correct X/Y not in 90° square, i.e. Part drawn in CAD comes out slightly rhombic.
>
> Question raised as some machines cannot be fixed mechanically.
>
> Is there a way of correcting this in KFlop if a file with say Point-cloud is done probing the X/Y?
>
> CAM folks say that is not doable as if any kind of compensation is applied like G68 - scaling - mirroring the correction is useless.
> And I believe the same is with Mach3 Formulas.
>
> Cheers
> Bengt
>
Group: DynoMotion Message: 1271 From: albertplatek Date: 6/13/2011
Subject: Re: Not square
Hi Bengt
I agree with Carl, you can only do:

- if you have "double" drive on Y/X, you can adjust home offset for them in Kflop to make machine be orthogonal.

- if your cnc router / cnc machine has only 1 drive on center Y/X,
and its not square, sorry but not possible to fix it. (its mechanical issue)

- if you have backlash on axis, you can compensate it by kflop


Best Regards
Albert Platek

--- In DynoMotion@yahoogroups.com, "carlcnc" <cebcnc@...> wrote:
>
> Bengt
> I don't understand
> If this is a typical machine with a single screw diving the X[orY]
> down the center, and mechanically the machine is out of square[not orthogonal] or has slop in the bearings/carriage
> no amount of software magic can overcome this.
> Kmotion can map for "drunken" or erratic screws or racks and
> compensate for a known amount of backlash ,which may be your problem.
> but it can not "know" if or how much machine is out of square
> Maybe ,if you know how much a machine is off. you could draw/distort a part to compensate?
> CArl
>
>
> --- In DynoMotion@yahoogroups.com, "Bengt Sjoelund" <cnc@> wrote:
> >
> > Hi Tom,
> > We have some discussions on local forums here in Sweden as how to correct X/Y not in 90° square, i.e. Part drawn in CAD comes out slightly rhombic.
> >
> > Question raised as some machines cannot be fixed mechanically.
> >
> > Is there a way of correcting this in KFlop if a file with say Point-cloud is done probing the X/Y?
> >
> > CAM folks say that is not doable as if any kind of compensation is applied like G68 - scaling - mirroring the correction is useless.
> > And I believe the same is with Mach3 Formulas.
> >
> > Cheers
> > Bengt
> >
>
Group: DynoMotion Message: 1274 From: Tom Kerekes Date: 6/13/2011
Subject: Re: Not square
Hi Bengt,
 
KMotionCNC has such a thing.  See:
 
 
It allows you to define a grid of points over your travel and correct for xy distortion as well as to make the plane flat in z.  But a simple "grid" of only 4 points could be used to correct orthogonality. 
 
We added it mainly for nonlinear systems such as our "Gizmo".  See:
 
 
In this case non-linear Kinematics (see Kinematics3Rod.cpp) were used to make the CAD space fairly linear.  But it is very difficult to define the equations and Kinematic parameters well enough to make the CAD space perfect.  So a geometric correction grid is used for any fine correction.   Between grid points a bi-linear interpolation method is used.  In your case a simple single grid (4 points) may be enough.  
 
There is also a feature in KMotionCNC that will automatically build the table for you if you have a "perfect" square that you can measure with the machine.  By moving the tool to each of the 4 points and pushing the "measure" button on KMotionCNC.  You must first setup the measurement file with the number of rows and columns (2 in this case) and the spacing in x and y.
 
If you are interested we can look at it in more detail.
 
This correction is only applied with KMotionCNC and not for Mach3.
 
Regards
TK
 
 


--- On Mon, 6/13/11, Bengt Sjoelund <cnc@...> wrote:

From: Bengt Sjoelund <cnc@...>
Subject: [DynoMotion] Not square
To: DynoMotion@yahoogroups.com
Date: Monday, June 13, 2011, 5:38 AM

 
Hi Tom,
We have some discussions on local forums here in Sweden as how to correct X/Y not in 90° square, i.e. Part drawn in CAD comes out slightly rhombic.

Question raised as some machines cannot be fixed mechanically.

Is there a way of correcting this in KFlop if a file with say Point-cloud is done probing the X/Y?

CAM folks say that is not doable as if any kind of compensation is applied like G68 - scaling - mirroring the correction is useless.
And I believe the same is with Mach3 Formulas.

Cheers
Bengt
Group: DynoMotion Message: 1281 From: Bengt Sjoelund Date: 6/15/2011
Subject: Re: Not square
Hi Tom,
I remember that I have watched the Gizmo video last year and that raised the question about orthogonality.
Many of the 'problem' machine owners are Mach users, hopefully I can convert some 'souls' to buy KFlop.

I will come back if the local CNC community has more questions.

Cheers
Bengt

Albert/Carl
I am aware of what is best that is fix it mechanically but in one case it is not doable as the machine is built with small errors.




--- In DynoMotion@yahoogroups.com, Tom Kerekes <tk@...> wrote:
>
> Hi Bengt,
>  
> KMotionCNC has such a thing.  See:
>  
> http://www.dynomotion.com/Help/KMotionCNC/ToolSetupScreenFiles.htm#Geo_File
>  
> It allows you to define a grid of points over your travel and correct for xy distortion as well as to make the plane flat in z.  But a simple "grid" of only 4 points could be used to correct orthogonality. 
>  
> We added it mainly for nonlinear systems such as our "Gizmo".  See:
>  
> http://dynomotion.com/Videos/Gizmo.wmv
>  
> In this case non-linear Kinematics (see Kinematics3Rod.cpp) were used to make the CAD space fairly linear.  But it is very difficult to define the equations and Kinematic parameters well enough to make the CAD space perfect.  So a geometric correction grid is used for any fine correction.   Between grid points a bi-linear interpolation method is used.  In your case a simple single grid (4 points) may be enough.  
>  
> There is also a feature in KMotionCNC that will automatically build the table for you if you have a "perfect" square that you can measure with the machine.  By moving the tool to each of the 4 points and pushing the "measure" button on KMotionCNC.  You must first setup the measurement file with the number of rows and columns (2 in this case) and the spacing in x and y.
>  
> If you are interested we can look at it in more detail.
>  
> This correction is only applied with KMotionCNC and not for Mach3.
>  
> Regards
> TK
>  
>  
>
>
> --- On Mon, 6/13/11, Bengt Sjoelund <cnc@...> wrote:
>
>
> From: Bengt Sjoelund <cnc@...>
> Subject: [DynoMotion] Not square
> To: DynoMotion@yahoogroups.com
> Date: Monday, June 13, 2011, 5:38 AM
>
>
>  
>
>
>
> Hi Tom,
> We have some discussions on local forums here in Sweden as how to correct X/Y not in 90° square, i.e. Part drawn in CAD comes out slightly rhombic.
>
> Question raised as some machines cannot be fixed mechanically.
>
> Is there a way of correcting this in KFlop if a file with say Point-cloud is done probing the X/Y?
>
> CAM folks say that is not doable as if any kind of compensation is applied like G68 - scaling - mirroring the correction is useless.
> And I believe the same is with Mach3 Formulas.
>
> Cheers
> Bengt
>
Group: DynoMotion Message: 1282 From: Tom Kerekes Date: 6/15/2011
Subject: Re: Not square
Hi Bengt,
 
I would think Mach3 would have some way to handle that.
 
A workaround might be to use two extra Dummy Axes with no output that Mach3 would control.  Then use a KFlop User program to set the Destination of two "real" axes based on some math equations with the Dummy Axes as inputs.  Actually to do only orthogonality you would only need one dummy axis.  The "real" Y axis would be a function of the Mach3 Y axis with a little X mixed in.  Such as:
 
  double NewY;
  NewY = ch1->Dest + 0.001 * ch0->Dest;
  MoveExp(7,NewY,0.001); 
Regards
TK

--- On Wed, 6/15/11, Bengt Sjoelund <cnc@...> wrote:

From: Bengt Sjoelund <cnc@...>
Subject: [DynoMotion] Re: Not square
To: DynoMotion@yahoogroups.com
Date: Wednesday, June 15, 2011, 7:47 AM

 
Hi Tom,
I remember that I have watched the Gizmo video last year and that raised the question about orthogonality.
Many of the 'problem' machine owners are Mach users, hopefully I can convert some 'souls' to buy KFlop.

I will come back if the local CNC community has more questions.

Cheers
Bengt

Albert/Carl
I am aware of what is best that is fix it mechanically but in one case it is not doable as the machine is built with small errors.

--- In DynoMotion@yahoogroups.com, Tom Kerekes <tk@...> wrote:
>
> Hi Bengt,
>  
> KMotionCNC has such a thing.  See:
>  
> http://www.dynomotion.com/Help/KMotionCNC/ToolSetupScreenFiles.htm#Geo_File
>  
> It allows you to define a grid of points over your travel and correct for xy distortion as well as to make the plane flat in z.  But a simple "grid" of only 4 points could be used to correct orthogonality. 
>  
> We added it mainly for nonlinear systems such as our "Gizmo".  See:
>  
> http://dynomotion.com/Videos/Gizmo.wmv
>  
> In this case non-linear Kinematics (see Kinematics3Rod.cpp) were used to make the CAD space fairly linear.  But it is very difficult to define the equations and Kinematic parameters well enough to make the CAD space perfect.  So a geometric correction grid is used for any fine correction.   Between grid points a bi-linear interpolation method is used.  In your case a simple single grid (4 points) may be enough.  
>  
> There is also a feature in KMotionCNC that will automatically build the table for you if you have a "perfect" square that you can measure with the machine.  By moving the tool to each of the 4 points and pushing the "measure" button on KMotionCNC.  You must first setup the measurement file with the number of rows and columns (2 in this case) and the spacing in x and y.
>  
> If you are interested we can look at it in more detail.
>  
> This correction is only applied with KMotionCNC and not for Mach3.
>  
> Regards
> TK
>  
>  
>
>
> --- On Mon, 6/13/11, Bengt Sjoelund <cnc@...> wrote:
>
>
> From: Bengt Sjoelund <cnc@...>
> Subject: [DynoMotion] Not square
> To: DynoMotion@yahoogroups.com
> Date: Monday, June 13, 2011, 5:38 AM
>
>
>  
>
>
>
> Hi Tom,
> We have some discussions on local forums here in Sweden as how to correct X/Y not in 90° square, i.e. Part drawn in CAD comes out slightly rhombic.
>
> Question raised as some machines cannot be fixed mechanically.
>
> Is there a way of correcting this in KFlop if a file with say Point-cloud is done probing the X/Y?
>
> CAM folks say that is not doable as if any kind of compensation is applied like G68 - scaling - mirroring the correction is useless.
> And I believe the same is with Mach3 Formulas.
>
> Cheers
> Bengt
>