4 Axis Wrapping and The Wrapping Group

Introduction

This topic will explain the 4 Axis Wrapping Group, will explain where to find it, its context menu, and will provide links to related topics.

4 Axis Wrapping Group

The Wrapping Group in the CAM Tree is used to create hole drilling, 2-axis, and 3-axis milling features that are used for 4-axis machining. You edit the wrapping parameters in the Wrapping Group dialog box before adding features to the wrapping group as explained in this topic.

 

Important: Wrapping Groups are only available with the 4 Axis Standard, 4 Axis Pro, 5 Axis Standard, and 5 Axis Pro modules.

Wrapping from Unwrapped Geometry

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Wrapping from Wrapped Geometry

To create a Wrapping Group:

 

 

The Wrapping Group is created and added to the Machine Setup.

 

After creating a Wrapping Group, you can also:

 

 

The Wrapping Group is created and added to the Machine Setup below the current Wrapping Group.

The Wrapping Group Shortcut Menu

Right-click Wrapping Group to open a shortcut menu with the following items.

 

Wrapping Group

 











The Wrapping Group Dialog

After adding a wrapping group to the CAM Tree, you right-click the name of the wrapping group and click Edit to open the Wrapping Group dialog box with the parameters as explained next.

Wrapped Geometry

The Wrapped Geometry check box determines whether the geometry that you assign to features in the wrapping group is drawn unwrapped (flat) or is selected directly from wrapped (cylindrical) geometry. Note that if you change this option after creating features, you must change the geometry selection and compute the feature to update the toolpath for the existing operations to use the new setting.

 

Select the Wrapped Geometry check box when you want to select wrapped or cylindrical geometry.

 

 

 

Clear the Wrapped Geometry check box when you want to select unwrapped or flat geometry.

 

Show Toolpath as Wrapped

You can display any wrapping toolpath (whether selecting flat or wrapped geometry) as either flat or wrapped. Note that changing the state of this option automatically updates the toolpath display in the graphics area (you do not need to recompute).

 

Select the Show Toolpath as Wrapped check box when you want to display the calculated toolpath as wrapped (or cylindrical). This option displays the toolpath as it is cut on the machine.

 

 

 

Clear the Show Toolpath as Wrapped check box when you want to display the calculated toolpath flat.

 

Wrapping Diameter

The wrapping diameter can be set in one of two ways. You can manually enter the value, or you allow the software to use the diameter from the stock defined for the job.

 

 

Tip: To achieve the most accurate stepover in wrapping toolpaths, it is recommended that you set the Wrapping Diameter using the diameter at the bottom of the feature (geometry) you are cutting.

 

 

Important: If you change the Wrapping Diameter after you have already computed a toolpath, you must re-select the geometry for the feature and recompute the toolpath. Re-select in this context means to click Re/Select and just OK the selection (you don't have to actually click the geometry again unless you are changing it).

Unwrap Controls

The unwrap controls are used when you select wrapped (cylindrical) geometry. The software automatically unwraps the geometry in the background before calculating the toolpath. The unwrap controls are used by the software when unwrapping the geometry. These controls are unavailable when the Wrapped Geometry check box is cleared. When selecting geometry that is a significant distance from the wrapping diameter, the tolerance plays a more significant role in the toolpath calculation.

 

Wrapping Axis

The wrapping axis parameters are used to define the center of rotation and direction in reference to the machining origin location on the part (machine setup coordinate system). Properly settings these values is required to create a proper wrapping toolpath. Note that the available parameters change slightly depending on the type of job as explained next.

 

Origin

The X, Y, and Z boxes are used to define the distance from the machine setup coordinate (machining origin) to the wrapping axis origin (or center of rotation) of the part. For example, for wrapping around the X-axis with a four-inch cylinder and the machining origin at the center of rotation, the values are X0Y0Z0. If you were to move the machining origin to the top of the cylinder, meaning that it is moved up along the Z-axis, then you must report the difference. In this case you would enter values of X0Y0Z-2. An example image of the distance is shown next.

 

 

 

Axis Direction (Mill Jobs)

When using wrapping groups in a Mill job, you can select the wrapping axis as follows. For Mill Turn jobs, the wrapping axis is always the Z-axis, so these controls do not display in the dialog box.

 

Zero Degree Location

This option is only used when selecting unwrapped geometry for features in the wrapping group. These parameters become unavailable when the Wrapped Geometry check box is selected. The zero degree location is most easily understood if you first think of the machining in a flat plane. The zero-degree location is a distance from the machining origin. This location is aligned with the zero-degree of the wrapped machining. (The zero-degree of a cylinder is the vertical Z-axis or the twelve o'clock position.)

 

View the How to Create a 4 Axis Wrapping Feature example to learn more about the zero degree location.

 

Important: When creating toolpath patterns using the 3D Rotate option, the toolpath pattern is not applied to any features that are contained in a Wrapping Group.

Geometry Selection Tips for Wrapping Groups

When creating features under a wrapping group, you can select either wrapped or unwrapped geometry. The drawing plane for unwrapped geometry is determined by the job type.

Unwrapped Geometry for Mill Jobs

When selecting unwrapped geometry for Mill jobs, the geometry must be on the XY plane of the machining origin (machine setup) coordinate system defined for the feature.

Unwrapped Geometry for Mill Turn Jobs

When selecting unwrapped geometry for Mill Turn jobs, the geometry must be on the YZ plane of the machining origin (machine setup) coordinate system defined for the feature.

Tip - Wrapping Output is Mirrored

If the output of a wrapped operation is mirrored (or cutting in the wrong direction) on the physical machine's rotary axes, you can resolve the issue by reversing the sign for the appropriate wrapping axis in the post processor, for example from 2 to -2.

Example

The following image shows the result of the 4-axis wrapping tutorial after backplotting the result. The image shows that the text is cut backwards or mirrored from the expected result.

 

 

This issue is easily resolved with the following example steps.

 

  1. Open the post processor for the job in any text editor.

  2. Go to questions 442-444.

  3. Locate the wrapping axis that needs reversed from one of these questions.

    For this example, the rotary axis is along the X-axis, as for typical 4-axis machines.

  4. At the end of question 442, we change the sign from 1 to -1.

  5. Save the file to update the post processor.

  6. Post the program in BobCAM (with the updated post processor), and compare the result to the previous NC program.

 

For this example, the change we made reverses the direction of the A-axis rotation angles in the NC program.

 

After posting the program with the modified post processor and backplotting, the expected result is achieved.

 

Related Topics

How to Create a 4 Axis Wrapping Feature