Basic NC lathe programming course! (1) ~Coordinate system, origin, input method

Taught by an active lathe operatorFirst Basic NC Lathe Programming CourseIt is!

This is a programming course, but I will explain the basic knowledge that you need to know before programming!

By first understanding the concepts of axes and origin handled by the lathe, you can learn programming smoothly.

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Lathe uses two axes.

Basic 3 axes of coordinate axes
The coordinate system used in lathes is X-axis and Z-axis

The three basic coordinate axes are represented by the X, Y, and Z axes as shown above.

As an image, it is OK to think of the X axis in the horizontal direction, the Y axis in the depth direction, and the Z axis in the height direction.

Eventually,The latheprogrammingX-axis and Z-axis are used inIt is.

The radial direction of the workpiece is the X-axis and the longitudinal direction is the Z-axiswill be.

Take the program origin here

The program origin is almost always taken here

How to make NC programs,Program Reference PointsThe reference point must be determined, and the reference point isstarting pointIt is called.

In most cases, shown in red in the image.Take the right finished end face as the originThe following is a list of the most common problems with the

The origin of the X axis is fixed at the center of the workpiece,The only origin to be set is the Z-axis.will be!

Decimal and integer input

To move the tool, numerical values are entered, but there is a key point in entering these numerical values.

FANUC] Even if you input "50", it becomes a positional command of 0.05mm!

If a machine has a minimum unit of travel of 0.001 mm, entering "50" will result in a command of 0.05 mm. The reason,FANUC controllers basically express coordinates in multiples of the smallest unit (most are 0.001 mm).From.

For exampleIf "50" is entered, the result is 0.001 times 50, which is 0.05 mm.So.

This input method.integer inputIt is called.

On the other hand,Add a dot at the end and type "50." to indicate 50 mm as shown in the figure.The following is a list of the most common problems with the

This input method isdecimal point inputIt is called.

Because it is a source of mistakes,Always use decimal point input when programming.Make sure to do so.

Okuma's controller works according to the input values.

The above story is the case of Fanuc controls.

I use it at my place of employment.Okuma's control unit (OSP) indicates 50 mm when "50" is entered.Therefore, you can input data without thinking.

Absolute and incremental methods

There are two methods of command to move the blade.

Absolute and incremental methodsIt is.

absolute method

First.absolute methodThe following is an explanation of the case of

This method is,All points shown are expressed in terms of coordinates from the program originThe following is a list of the most common problems with the

So, using the above figure as an example...

Start at point P0 and move to point P1:X4.Z6.

Move from P1 to P2:X2.Z5.

Move from P2 to P3:X2.Z3.

Move from P3 to P4:X1.Z2.

Move from P4 to P5:X1.Z-2.

The image is as follows. If you enter the coordinates of a point, it will move to that position.

incremental system

nextincremental systemIt is.

Basically, you will be using the Absolute Directive, so if you are not interested, please skip this section.

However, when programming the program, you will need to include code that indicates the absolute method, so it is important to know about the incremental method to understand the meaning of selecting the move method!

Incremental method commands by distance and direction from the current point

In incremental, the amount of movement is entered with respect to the current location.

This is the same diagram as before.

This is what happens when this is commanded in an incremental fashion.

Start at point P0 and move to point P1: U-1.W-3.

Move from P1 to P2: U-2.W-1.

Move from P2 to P3: U0.W-2.

Move from P3 to P4: U-1.W-1.

Move from P4 to P5: U0.W-4.

Only the absolute method is used.

When programming, to prevent mistakes due to method errorsUse only the absolute methodWe will try to do the same.

X-axis direction is commanded by diameter value, not radius value.

The program on the NC lathe is,X-axis direction is commanded by diameter value, not radius value.The following is a list of the most common problems with the

For example, point A in the figure is commanded as X50.Z0. instead of X25.Z0.

Keep this in mind, especially if you have experience in machining, as it is easy to get mixed up!

Next time, finally, the program!

In this issue, we introduced the basics before learning the program.

Next time, we will finally introduce the actual program!