Difference between revisions of "VTube-LASER Split Bend Feature"

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The Split Bend feature is VTube-LASER's unique method of measuring tubes with 180-degree bends or greater with accuracy.

We invented Split Bend to solve a legacy measuring issue in the tube fabrication.

When bend angles reach and exceed 180-degrees, we lose the intersection point between the two adjacent straights.

See the illustration to see why this is the case.

When bend angles reach or exceed 180-degrees, then VTube-LASER must form the single bend with two intersection points.

If any bend as potential to reach and pass 180 degrees, then VTube-LASER must be setup to use the SPLIT BEND method to measure and solve for the centerline formed between the two intersection points in the 180-degree (or greater) bend.

Split Bend setup is controlled in the Bend Setup tab of the Master Tube menu in VTube-LASER, and in the Bend Setup tab in VTube-STEP. Both modes of VTube allow you to configure Split Bends.

To turn a Split Bend ON for a straight section, you enter the Split Bend window and select the straights that should be treated as Split Bends.

The Split Bend window is on the Bend Setup tab in the MASTER TUBE menu. Click into that window.

In the Split Bend window, set any straight that will be treated as a Split Bend.

Close the window. VTube will now understand which straight to treat as a Split Bend during measuring.

VTube-LASER knows that benders still like to refer to the 180-degree bends as a SINGLE bend.

To do handle this, it automatically compresses the LRA data when you turn the SPLIT BEND feature on for any bend.

See the starting data in the top image (before Split Bend is turned on).

For this tube, we turn the Split Bend ON for straights 2 and 4, and the LRA data automatically compresses.

This step is identical to regular reverse-engineering measuring.

When you arrive at the split bend to scan, VTube-LASER will make a special sound and tell you to scan the OUTSIDE of the bend. Scan as much data as you want - up to 250 stripes. The goal is to be sure that at least one point in one of the stripes touches the highest point of the outside of the bend. So you can take as many stripes of data as you want - VTube will take them all in without a problem.

During scanning, release the green button, and look at the screen. You should see a large area of surfaces that pass the point of the outside of the bend. Press the RED button if you are finished scanning the outside and have not come to 250 stripes.

Now scan the center of the inside. Be sure that at least one point in one stripe passes the center inside of the bend. If you are not sure, then release the green button and look at the screen to see if you have points and surfaces that appear to be in the right place. If you know you've scanned the center, then press the RED button to move on to the next straight.

If you want to see a Split Bend measurement then see video 40 in VTube-LASER_Videos.



Press FINISH and APPLY Measure when the measurement is completed.

Because the MASTER data row count is greater than zero, the Measurement Complete window will offer to allow you to ALIGN the measured tube.

However, do NOT align at this point - because there are only ZEROS in the MASTER Data fields.

Rather - press the Build Measured Tube button.

The new measured tube will appear as a blue tube like this.

Copy Measured to Master Data in the Data Handling menu. This will overwrite the MASTER data ZEROS with the MEASURED tube data.

When you press this button, the MEASURED data will be copied to the MASTER data menu and the MASTER data menu will display automatically.

Some customers prefer to translate the new MASTER data so that the first point is at 0,0,0.

View the new MASTER tube by switching the display of the Master tube on, then redrawing and zooming all.

In this case, the MASTER tube is translated in space from the measured tube because the coordinates were zeroed in the previous step.

This is a cross-check to be sure the process was performed properly. Enter the Inspection Results menu, and press Recalculate for the alignment.

Since VTube is aligning a part to itself, the deviations should be exactly zero.

Press the Project Save button in the Toolbar, choose the project save path and filename, and save the VTube Project file.