Scaling and Rotation for scribing

[rs7769]

Greetings all I have a question about scaling and rotation. I know that my params. are turned on my question is about the examples. The ones in the book are not that clear to me. What i am concerned with is the program structure what i have is the numbers 316 and i have them programed at .25 high letters i want to be able to shrink or expand them and turn them say 45 degrees.
I apologize if this is a repeat of another post i just dont have the time to go thru 105 pages of posts.

[sinha_nsit]

My notes on SCALING:

Scaling on CNC is similar to the SCALE command of AutoCAD, except that AutoCAD allows only positive and uniform scaling along all the axes, whereas CNC permits different scale factors along different axes, and some or all of these scale factors can be negative also to allow mirroring, thus providing for simultaneous scaling and mirroring. The scale centre is termed as base point in AutoCAD. Analyse the SCALE command on AutoCAD, in case of any confusion in the concept of scale factor and scale centre.

Scaling mode on CNC is invoked by G51 which is a modal code and remains effective till scaling mode is cancelled by G50. Its syntax has two formats – the first for a uniform (and positive) rate of magnification along all axes, and the second for different rates of magnification, including negative magnification required for mirroring. G51 must be specified in a separate block. After the programmed profile is enlarged, reduced or mirrored, G50 is commanded to cancel the scaling mode. The default mode is G50.

Scaling with uniform rate of magnification
G51 X_ Y_ Z_ P_
...
...
(Scaling mode active)
...
...
G50 (Scaling mode cancelled)

Scaling with non-uniform rate of magnification
G51 X_ Y_ Z_ I_ J_ K_
...
...
(Scaling mode active)
...
...
G50 (Scaling mode cancelled)

In the syntax given above, (X_, Y_, Z_) are the absolute coordinates (even if incremental mode is active) of the scale centre. If these are not specified, the current position of the tool is taken as the scale centre.
P_ is the uniform rate of magnification (scale factor) for all axes, in the range of +0.001 to +999.999 in the increment of 0.001 (or, +0.00001 to +9.99999 in the increment of 0.00001, depending on a parameter). If the P-word is omitted, a value specified in a parameter is taken as the scale factor. A negative value for P is not allowed.

I_, J_ and K_ are the rates of magnification along X-, Y- and Z-axis, respectively. Decimal values for I_, J_ and K_ are not allowed. These are 1000 times (or 100000 times, depending on a parameter) of the required magnification. If any of the I-, J- or K-word is omitted, the value specified in a parameter (which usually corresponds to scale factor 1) is used as the scale factor along that particular axis. Up to six digits can be used for I, J and K values. Negative values for I, J and K are allowed, which causes simultaneous scaling and mirroring.

So, for example, for doubling the size of the programmed profile in both X and Y directions, use P2.0 or I2000 J2000 K1000 (assuming the commonly used parameter setting for the scale range of 0.001 to 999.999). On the other hand, for doubling the size of the programmed profile along X direction and mirroring it in the Y direction (i.e., about XZ plane), use I2000 J-1000 K1000. For a two dimensional profile in XY plane, K need not be specified.

Note that both uniform and non-uniform scaling methods cannot be arbitrarily used all the time. Only one method can be used at a time. There is a parameter which selects the permissible method. Normally, this parameter is factory-set to allow non-uniform scaling, as this method of scaling is more flexible. If, however, you do not have applications for non-uniform scaling or mirroring, you may choose to use the method of uniform scaling (P method), after modifying this parameter. Also, even if you have selected the method of non-uniform scaling (I J K method), you may need to modify a parameter to allow negative scale factors (mirroring). Again, this parameter is factory-set to allow negative scale factors.

[James L]

You don't necessarily have to use rotation to have text at an angle. For example, if you had a round part and you wanted text to go around it, you can just set each letter's angle in the gcode that calls it. It can be a little cumbersome, but it allows you to work without the need of a rotation call.

[rs7769]

what i am trying to do is keep the same program intact so i can move it from machine to machine(same control) the people i have are just button pusher people they have no wish to learn anything more than they already know so i have to keep everything simple and be able to either place the text on the x or the y or at a 45 between anything more will be to much for them. so the factory g68 will have to do.