Difference between revisions of "VTube Reverse Calc from MIL-D-9898C Absolute Bender Data to Centerline XYZ Data"
(→VTube Absolute LRA Data Rules) |
(→VTube Absolute LRA Data Rules) |
||
Line 70: | Line 70: | ||
* The Absolute LRA grids are in both STEP and LASER modes of VTube. They are automatically calculated when you import a model or enter centerline XYZ data.<br><br> | * The Absolute LRA grids are in both STEP and LASER modes of VTube. They are automatically calculated when you import a model or enter centerline XYZ data.<br><br> | ||
* You can Reverse Calc to XYZ data from Absolute LRA data by entering data in the Absolute LRA grids in either VTube-STEP and VTube-LASER. When entering data to reverse calc, be sure to keep the mouse in the grid while you are entering new data to prevent the XYZ to LRA calculator from overwriting your entries..<br><br> | * You can Reverse Calc to XYZ data from Absolute LRA data by entering data in the Absolute LRA grids in either VTube-STEP and VTube-LASER. When entering data to reverse calc, be sure to keep the mouse in the grid while you are entering new data to prevent the XYZ to LRA calculator from overwriting your entries..<br><br> | ||
− | * The LAST length value is always the length of the last straight of the tube.<br><br> | + | * The LAST length value is always the actual length of the last straight of the tube. So this value has a different meaning than the rest of the L values in this grid.<br><br> |
* All other lengths should start with larger values, then decrease as you move down the tube.<br><br> | * All other lengths should start with larger values, then decrease as you move down the tube.<br><br> | ||
* None of the lengths should be larger than the Cut Length - or negative incremental length values may be calculated.<br><br> | * None of the lengths should be larger than the Cut Length - or negative incremental length values may be calculated.<br><br> |
Revision as of 23:56, 26 January 2017
This military spec bender chart data chart can converted by VTube-STEP and VTube-LASER in the LRA grid section of the Part Data menu. |
Contents |
General Principals for the Military 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). |
|
VTube Absolute LRA Data Rules
|
Reverse Calc with Absolute LRA Data
Press the Reverse Calc button above the grid to recalculate new centerline XYZ data. |