Difference between revisions of "VTube Reverse Calc from MIL-D-9898C Absolute Bender Data to Centerline XYZ Data"
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+ | ==How to Handle CCW Bend Angles == | ||
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+ | <td width=400> | ||
+ | In MIL-SPEC reports, by default, the bend angles moves in the CW direction while looking over the top of the bending image at the top. This is what the bending industry calls a "right-hand" bender.<br><br> | ||
+ | If a bend angle is followed by "CCW" in the chart, then this indicates that the bender-hand has changed to a left-hand bender before the bend occurs.<br><br> | ||
+ | <b>If bends switch between CW and CCW (or CCW to CW), then it is important to adjust those rotations by 180 degrees in the calculated incremental LRA data before performing a reverse calculation.</b> | ||
+ | <br><br> | ||
+ | If a bender chart shows either all CW or all CCW after all bender angles in every row - then you can be sure that there is no change to the rotation data. (Our best guess is that the bending direction may be included by a technician wanting to suggest which way he or she thinks the tube will bend best with the least potential bender collision. <b>You can safely ignore the direction if it never changes.</b>) | ||
+ | <td> | ||
+ | </td> | ||
+ | <td> | ||
+ | [[image:mil-spec_ccw_bend_angle.png|500px]] | ||
+ | |||
+ | </tr> | ||
+ | </table> | ||
+ | <br><br> | ||
==Other Pages== | ==Other Pages== | ||
Revision as of 20:17, 7 July 2022
Contents |
General Principals for the Specification
ABSOLUTE LENGTHS
This bender data spec uses ABSOLUTE LENGTHS between bends as if they were derived from a tape-measure attached to the Feed axis of a bender. CONRAC benders sometimes had tape measures riveted along the rail of the carriage that moves along the length of the bender. The lengths indicate where each bend begins. |
ABSOLUTE ROTATIONS
According to the spec, the bender data uses ABSOLUTE ROTATION data (twist angle between the planes of the bends). It is absolute because it always depends on the rotations in all preceding bends accumulated. The dial on an absolute rotation spindle reads from 0 to 360. |
DRAW BENDING
Although it seems to be ambiguous in the specification, most of the part data from this specification assumes DRAW bending versus COMPRESSION bending - which means the LENGTH values move the carriage so that the tube is positioned at the start of each bend (for clamping and drawing around the bend die that rotates with the bend arm) rather than the end of each bend (for clamping with rollers or wipers and compressing around the bend die that does not rotate with the bend arm). |
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VTube Absolute LRA Data Rules
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Reverse Calc with Absolute LRA Data Requires an Accurate Cut Length
Reverse calculation requires an accurate cut length, so this dialog will display to allow you to enter a correct Cut Length before VTube finishes the calculation. This Cut Length value will overwrite the value in the Part Setup menu. |
Calculating the Last Length "LL" value
Notice in the MIL-D-9898C bender chart that there is no LAST LENGTH value. However, VTube includes a LL (Last Length) value in the last row.
If these three conditions are true, then you can use this feature to accurately calculate the LL value in this chart. |
How to Handle CCW Bend Angles
In MIL-SPEC reports, by default, the bend angles moves in the CW direction while looking over the top of the bending image at the top. This is what the bending industry calls a "right-hand" bender. |
How to Handle CCW Bend Angles
In MIL-SPEC reports, by default, the bend angles moves in the CW direction while looking over the top of the bending image at the top. This is what the bending industry calls a "right-hand" bender. |
Other Pages
- See also VTube-LASER v2.7
- See also VTube-LASER
- See also VTube-STEP