Linear superimpositioning of a circular path

Application

You can linearly superimpose a movement programmed in the working plane, thereby creating a spatial movement.

If, for example, you superimpose a circular path, you create a helix. A helix is a cylindrical spiral, such as a thread.

Requirements

Description of function

A helix is a combination of a circular path CP and a linear motion perpendicular to this path. You program the circular path CP in the working plane.

Helices are used in the following cases:

  • Large-diameter internal and external threads
  • Lubrication grooves

Dependencies of different thread shapes

The table shows the dependencies between machining direction, direction of rotation and radius compensation for the different thread shapes:

Internal thread

Work direction

Direction of rotation

Radius compensation

Right-handed

Z+

DR+

RL

Z–

DR–

RR

Left-handed

Z+

DR–

RR

Z–

DR+

RL

External thread

Work direction

Direction of rotation

Radius compensation

Right-handed

Z+

DR+

RR

Z–

DR–

RL

Left-handed

Z+

DR–

RL

Z–

DR+

RR

Programming a helix

 
Tip

Define the same algebraic sign for the direction of rotation DR and the incremental total angle IPA. The tool may otherwise move on a wrong path.

To program a helix:

    1. Select C

    1. Select P

    1. Select I
    2. Define the incremental total angle IPA
    3. Define the incremental total height IZ

    1. Select the direction of rotation
    2. Select radius compensation
    3. Define the feed rate, if necessary
    4. Define a miscellaneous function, if necessary

    Example

    This example includes the following default values:

    • M8 thread
    • Left-handed thread miller

    The drawing and the default values allow deriving the following information:

    • Internal machining
    • Right-hand thread
    • RR radius compensation

    The derived information requires the machining direction Z–.

    Dependencies of different thread shapes

    Specify and calculate the values below:

    • Incremental total machining depth
    • Number of thread grooves
    • Incremental total angle

    Formula

    Definition

    The incremental total machining depth IZ results from the thread depth D (depth) and from the optional thread run-in values RI (run-in) and thread run-out values RO (run-out).

    The number of thread grooves n (number) results from the incremental total machining depth IZ divided by the pitch P (pitch).

    The incremental total angle IPA results from the number of thread grooves n (number) multiplied by 360° for one complete revolution.

    NC programs contained in this User's Manual are suggestions for solutions. The NC programs or individual NC blocks must be adapted before being used on a machine.

    Change the following contents as needed:

    • Tools
    • Cutting parameters
    • Feed rates
    • Clearance height or safe position
    • Machine-specific positions (e.g., with M91)
    • Paths of program calls

    Some NC programs depend on the machine kinematics. Adapt these NC programs to your machine kinematics before the first test run.

    In addition, test the NC programs using the simulation before the actual program run.

     
    Tip

    With a program test you determine whether the NC program can be used with the available software options, the active machine kinematics and the current machine configuration.

    11 L Z+1,25 R0 FMAX

    ; Pre-position in the tool axis

    12 L X+4 Y+0 RR F500

    ; Pre-position in the plane

    13 CC X+0 Y+0

    ; Activate the pole

    14 CP IPA-3600 IZ-12.5 DR-

    ; Cut the thread

    Alternatively, you can also program the thread with a program section repeat.

    Subprograms and program section repeats with the label LBL

    Example