How to Create a 4 Axis Outside Wire Feature

Introduction

Example File

If you are connected to the Internet, the part file for this example can be downloaded automatically by clicking the following link: Wire EDM 4 Axis Outside Example 1.bbcd

Once you download and saved the zip file, extract the files on your system in an easy place to remember. You can then open the file to use with this tutorial. All files for the tutorials in this help system available for download can be found by clicking on the following link: http://www.bobcad.com/helpfiles.

 

In the example file provided, the stock and machine setup are already defined for the part.

 

Part 1) Add the Feature and Assign Geometry

One main difference between 2 Axis and 4 Axis Wire EDM features is the geometry selection. While 2 Axis features only require a single profile, 4 Axis features require an Upper Profile and Lower Profile. In addition to the two profiles, you can also select Sync Line geometry to determine the alignment of the wire between the upper and lower profiles.

 

The following is a step-by-step example of creating a 4 Axis feature and assigning geometry.

 

Feature and Feature Geometry

 

1. In the CAM Tree, right-click Machine Setup, and click 4 Axis Inside.
   
   The Wire 4 Axis Wizard displays.
   
   

2. To assign the upper profile geometry, click Select Upper Profile.
   
   The Feature Geometry Picking dialog appears and the Upper Geometry list is given focus.
   
   

3. In the graphics area, right-click the inner surface edge at the top of the model, and click Constant Z.
   
   
   
   The entities are added to the Upper Geometry list.
   
   

4. Click in the Lower Geometry list to give it focus.
   
   

5. Right-click the lower surface edge, and click Constant Z.
   
   
   
   The entities are added to the Lower Geometry list.
   

 

Chain Direction and Start Point

1. Below the Start Point & Direction group, click in the Upper Profile Chain list to give it focus.
   
   
   
   The geometry highlights in the graphics area with the start point and direction shown with an arrow.
   
   

2. Select the middle of the entity seen in the image below.
   
   
   
   

3. Click in the Lower Profile Chain list to give it focus.
   
   

4. Select the middle of the entity seen in the image below.
   
   

 

Setting a Stop Point

1. Click in the Stop Points list to give it focus.
   
   

2. Select the snap point seen in the image below.
   
   
   
   

3. Click OK.
   
   The Feature Geometry Picking dialog closes and the 4 Axis Wizard
   

 

Important: You can select geometry for 4 Axis features using solid edges (as shown), or you can select wireframe geometry. Either way the software projects the Upper Profile to the top of the stock and projects the Lower Profile to the bottom of the stock defined for the job. The point here is that regardless of the Z location of the selected profiles, they are always projected to the top and bottom of the stock.

The following image shows the result of this example where the stock is one unit larger than the part model.



You will notice in this image the taper angle of the cut geometry no longer matches that of the model due to the projection of the geometry.

Part 2) Feature Parameters

Feature Settings

In the Feature page of the Wire EDM Wizard, the Stock Thickness displays the height of the stock defined for the job. (This value is for informational purposes and cannot be edited in the Wire EDM Wizard.)

 

1. Click Next>> to go to the Feature settings.
   
   

2. The Upper Guide and Lower Guide positions are positive incremental values in reference to the top and bottom (respectively) of the stock defined for the job. For this example, we use the default values.
   

Note: Most modern controllers do not require the output of coordinates from the guide positions, because they are handled at the control. In most cases, these values are only utilized for simulation purposes.

 

3. Under Glue Stop Options, confirm that Use Glue Stop with Leads is selected.
   
   When Use Glue Stop is selected, the first operation in the feature does not cut the entire profile. Instead it leaves a glue stop, defined by the Stop Distance, at the end of the chain. The glue stop is then cut using a separate Tab Cut operation. If you select No Glue Stop, then all feature operations cut the entire profile.
   
   

4. The default Stop Distance, 0.100, is used for this feature.
   
   

5. Click Next>> to go to the Machining Strategy.

 

Machining Strategy

 

1. In the Machining Strategy, the Default Strategy of 4 Axis Outside Strategy 1 is used.
   
   This adds a Rough Cut, Skim Cut, and Tab Cut operation to the Current Operations list.
   
   

2. Click Next>> to go to the Wire settings.

 

Wire Settings

The Wire settings of the Wire EDM Wizard contains an informational display of the Wire Diameter for the job, options to Enable Starting Cutting Conditions, and an option to set the Rapid Feedrate used for the feature.

 

Note: For more information, view the Wire EDM Wizard Wire Settings and How to Create Starting Cutting Conditions.

 

1. After making any necessary changes to the Wire settings, click Next>> to go to the Posting settings.

 

Posting Settings

The Posting page of the Wire EDM Wizard contains Arc/Spline Output Tolerance, or the maximum amount of variation between the selected spline, ellipse, or arc geometry and the line segments that are used to approximate them. The tolerance can be increased or decreased as needed. The Posting Order settings only apply to 2 Axis features in which you assign more than one profile to the feature. To learn more, view the Wire EDM Wizard Posting Settings.

 

1. Confirm that the proper Work Offset Number for the feature is selected.
   
   

2. Click Next>> to go to the Parameters.

Part 3) The 4 Axis Rough Cut

Parameters

The Standard Profile is the only pattern available. The Compensation output for Outside features is defined as On or Off for both System Compensation and Machine Compensation in the wizard. The software automatically outputs the correct compensation codes based on your selections and the chain direction of the feature. For this example, we use System Compensation On and Machine Compensation Off to allow the software to compensate the wire diameter based on the offset values entered in the Cutting Conditions.

 

1. Set the System Compensation to On.
   
   

2. Set the Machine Compensation to Off.
   
   

3. At the bottom-left of the wizard, click Apply to All Operations.
   
   

4. Click Next>> to go to the Leads page.

 

Leads

In the Leads page of the wizard, the Start Hole Diameter of 0.00 can be left at default.

 

Besides the first Lead-in, all leads used in the feature will be the default Type, Perpendicular.

 

1. In the Lead-in group, update the Length value to 0.050.
   
   

2. At the bottom-left of the wizard, click Apply to All Operations.
   
   With all the other leads now set, we only need to update our Lead-in.
   
   

3. In the Lead-out group, clear the check box for Same As Lead-in.
   
   

4. In the Lead-in group, set the Length value to 0.275.
   
   

5. Click Next>> to go to the Cutting Conditions.

 

To learn more about leads, view the Wire EDM Wizard Leads.

 

Cutting Conditions

The Cutting Conditions page of each operation in the Wire EDM Wizard is used to add Pass Comments, define the Cutting Conditions, and define the Wire Speed and Tension for the operation. What is important to understand is that you have two ways to set the Cutting Conditions. You can either Link to Database, or you can manually enter the Cutting Conditions. When using Link to Database, the Cutting Condition parameters, Offset, Power Setting, and Feedrate, are all automatically populated from the currently selected database. The values that display here are determined using various factors from the job. The stock thickness, wire size, wire material, number of operations, and number of passes (Skim Cut operations) all determine what information is available from the database. You select the Cutting Conditions database for your machine in the Posting settings of the Current Settings dialog.

 

Note: If you are not using the values from the Cutting Conditions database, you can use the Edit Table option to set the Cutting Conditions for all Skim Cut passes in a single location. Remember that changing any of the three Cutting Conditions values (Power, Offset, or Feedrate) in the Edit Table automatically turns off Link to Database for each operation that you edit.

 

1. The Cutting Conditions will be left at default for all operations in this example, so click Next>> to go to the Parameters of the Tab Cut operation.

Part 4) The Skim Cut Operation

Parameters

 

1. Notice all of our settings have already been set by using the Apply to All Operations button in our rough operation.
   
   

2. In the Skims group, select Reverse Skims.
   
   The number of Skim Passes will be left to 1.
   
   

3. Click Next>> to go to the Leads.

 

Leads

 

1. Notice all of our leads have already been set by using the Apply to All Operations button in our rough operation.
   
   

2. Click Next>> to go to the Cutting Conditions.

 

Cutting Conditions

 

1. The Cutting Conditions will be left alone for now, so click Next>> to go to the Parameters of the Skim Cut operation.

Part 5) The Tab Cut Operation

Parameters

 

1. In the Patterns group, select Flip Pass Direction.
   
   Since we only have one reversed skim cut, flipping the tab cut will ensure it begins where the reversed skim cut ended.
   
   

2. Clear the Apply Stop Points check box.
   
   

3. Our other settings have already been applied so we can ignore the Leads and Cutting Conditions page.
   
   Click Compute.
   
   
   

Part 6) Viewing the Wirepath

1. In the CAM Tree, right-click the feature and select Blank/Unblank Toolpath.
   
   The wirepath is hidden.
   
   

2. Click each operation in the feature to view the path for that specific operation. In the rough, you will notice our stop point is noted with red section.
   

 

Rough Leads	Skim Leads	Tab Leads

 

Note: By unblanking our stock and viewing the rough, we can see our lead in begins off the defined stock.

3. From a top view, notice the path does not quite align with our surface edges. This is most evident in the radii at the bottom of the image.

 

Path alignment	Surface edges

Part 7) Adding Sync Lines

1. In the CAM Tree, right-click the Sync lines item in our feature and select Re/Select.
   
   The Feature Geometry Picking dialog appears with focus on the Sync Lines list.
   
   

2. In the graphics area select the surfaces edges on the left of the part as seen in the images below.
   
   
   
   

3. Click OK.
   
   

4. Right-click the feature and select Compute All Toolpath.

 

Path alignment	Surface edges

 

This is much better, but you will notice the wire is only aligned where the sync lines have been selected.

5. In the CAM Tree, right-click the Sync lines item in our feature and select Re/Select.
   
   The Feature Geometry Picking dialog appears with focus on the Sync Lines list.
   
   

6. In the graphics area select the surfaces edges on the left of the part as seen in the images below.
   
   
   
   

7. Click OK.
   
   

8. Right-click the feature and select Compute All Toolpath.

 

Path alignment	Surface edges

 

This is the desired result.

 

 

This completes the tutorial.

Related Topics

Wire EDM Tutorials

The Wire EDM Wizard

The Wire EDM Job