Difference between revisions of "VTube-LASER End Point Deviations"

From ATTWiki
Jump to: navigation, search
(→‎How to Understand the Tangent Data)
(→‎BEFORE-TRIM Deviations)
 
(6 intermediate revisions by one user not shown)
Line 14: Line 14:
  
  
−
== Three Main End Point Deviations ==
+
== Three Types of End Point Deviations ==
  
 
<table cellpadding=10>
 
<table cellpadding=10>
 
<tr valign=top>
 
<tr valign=top>
−
<td width=800>
+
<td width=300>
  
−
There are three main end point deviation values calculated during an alignment of the MEASURED to the MASTER tube.<br><br>
+
There are three types of end point deviation values calculated during an alignment of the MEASURED to the MASTER tube.<br><br>
 
</td>
 
</td>
 
<td width=700>
 
<td width=700>
Line 31: Line 31:
 
<table cellpadding=10>
 
<table cellpadding=10>
 
<tr valign=top>
 
<tr valign=top>
−
<td width=800>
+
<td width=300>
 
The end length deviations are found at the top of the Inspection menu.
 
The end length deviations are found at the top of the Inspection menu.
 
<br><br>
 
<br><br>
Line 45: Line 45:
 
<table cellpadding=10>
 
<table cellpadding=10>
 
<tr valign=top>
 
<tr valign=top>
−
<td width=800>
+
<td width=300>
 
These are found in the first T1 value and the last T2 value in the Tangents grid.
 
These are found in the first T1 value and the last T2 value in the Tangents grid.
 
<br><br>
 
<br><br>
Line 57: Line 57:
  
  
−
<br><br>
+
====3D Length Deviations ====
−
 
+
−
== How to Understand the End Point Deviations ==
+
−
 
+
−
===Automatic Internal Trimming of End Points for Shape===
+
 
<table cellpadding=10>
 
<table cellpadding=10>
 
<tr valign=top>
 
<tr valign=top>
−
<td width=500>
 
−
Even though the end points are not tangents, we can still use them in the chart because they qualify the part the same way that tangent points do.<br><br>
 
−
A key in understanding the T1d of straight one and the T2d of the last straight is to remember that the deviation is not the same as how long or short the straights are relative to the master tube shape.  See the illustration on the right to understand why.<br><br>
 
−
The MASTER to MEASURED end point deviation in the Tangent grid is 1.9mm.  The measurement is the distance between the two lines at the corresponding end points - as if the MEASURED WERE TRIMMED.<br><br>
 
−
(The Measured part is the pink part.  The Master part is white.)
 
−
</td>
 
 
<td width=300>
 
<td width=300>
−
[[image:vtube-laser-t1d-end1.png|500px]]
+
These are found in the Intersection grid values.
 +
<br><br>
 +
The 3D deviations represent for the first and the last points represent the total radial deviation between the MASTER and the MEASURED end points in this alignment orientation.
 
</td>
 
</td>
−
</tr>
+
<td width=700>
−
</table>
+
[[image:vtl before-trim deviations.png|700px]]
−
 
+
−
===Untrimmed End Points for Lengths===
+
−
<table cellpadding=10>
+
−
<tr valign=top>
+
−
<td width=500>
+
−
However, the end length is 90.2mm too long.<br><br>
+
−
 
+
−
In this application, the customer bent the part 90mm too long on purpose in order to give the bend arm clamp die enough material on the first straight to grip.<br><br>
+
−
 
+
−
Notice that, even though the part is significantly too long, the BEST FIT algorithm didn't use the actual measured end point in the alignment.  The alignment was based on the trimmed point on the measured centerline that was nearest the master end point.<br><br>
+
−
 
+
−
So, in this case the part shape in space is qualified - but it needs trimming by 90.2mm to also qualify the end length (another critical qualifier).
+
−
 
+
−
</td>
+
−
<td width=300>
+
−
[[image:vtube-laser-endlength.png|500px]]
+
 
</td>
 
</td>
 
</tr>
 
</tr>
Line 96: Line 72:
  
  
−
=Typical Industry Tangent Point Tolerances=
+
<br><br>
−
<table cellpadding=10>
+
−
<tr valign=top>
+
−
<td width=500>
+
−
In working with  thousands of customers over the past few decades, we've seen some trends in accepted envelope deviation tolerances. Here are what we commonly see:
+
−
 
+
−
====Aerospace and Automative Fluid Lines====
+
−
<table cellpadding=10 width=400>
+
−
<tr>
+
−
<td bgcolor=#9999CC>
+
−
Diameter Range
+
−
</td>
+
−
<td bgcolor=#CCCCFF width=200>
+
−
Envelope Tolerance
+
−
</td>
+
−
</tr>
+
−
 
+
−
<tr>
+
−
<td>
+
−
12.7 mm (0.5 inch) diameter tubes or less
+
−
</td>
+
−
<td>
+
−
+/- 1 mm (0.039 inches)
+
−
</td>
+
−
</tr>
+
−
 
+
−
<tr>
+
−
<td>
+
−
Greater than 12.7 mm (0.5 inch) 
+
−
</td>
+
−
<td>
+
−
+/- 2 mm (0.078 inches)
+
−
</td>
+
−
</tr>
+
−
 
+
−
</table>
+
−
 
+
−
====Automotive Exhaust Pipes====
+
−
<table cellpadding=10 width=400>
+
−
<tr>
+
−
<td bgcolor=#9999CC>
+
−
Diameter Range
+
−
</td>
+
−
<td bgcolor=#CCCCFF width=200>
+
−
Envelope Tolerance
+
−
</td>
+
−
</tr>
+
−
 
+
−
<tr>
+
−
<td>
+
−
50 mm to 76 mm
+
−
</td>
+
−
<td>
+
−
From +/- 2 mm to +/- 3 mm
+
−
</td>
+
−
</tr>
+
−
 
+
−
<tr>
+
−
<td>
+
−
76 mm to 102 mm 
+
−
</td>
+
−
<td>
+
−
+/- 3 mm
+
−
</td>
+
−
</tr>
+
−
 
+
−
<tr>
+
−
<td>
+
−
Larger then 102 mm
+
−
</td>
+
−
<td>
+
−
+/- 3 mm or greater
+
−
</td>
+
−
</tr>
+
−
 
+
−
</table>
+
−
 
+
−
====Shipbuilding====
+
−
<table cellpadding=10 width=400>
+
−
<tr>
+
−
<td bgcolor=#9999CC>
+
−
Diameter Range
+
−
</td>
+
−
<td bgcolor=#CCCCFF width=200>
+
−
Envelope Tolerance
+
−
</td>
+
−
</tr>
+
−
 
+
−
<tr>
+
−
<td>
+
−
All Diameters
+
−
</td>
+
−
<td>
+
−
+/- 6 mm
+
−
</td>
+
−
</tr>
+
−
 
+
−
</table>
+
−
 
+
−
 
+
−
====HVAC====
+
−
<table cellpadding=10 width=400>
+
−
<tr>
+
−
<td bgcolor=#9999CC>
+
−
Diameter Range
+
−
</td>
+
−
<td bgcolor=#CCCCFF width=200>
+
−
Envelope Tolerance
+
−
</td>
+
−
</tr>
+
−
 
+
−
<tr>
+
−
<td>
+
−
All Diameters
+
−
</td>
+
−
<td>
+
−
+/- 2 to +/- 3 mm
+
−
</td>
+
−
</tr>
+
−
 
+
−
</table>
+
−
 
+
−
====Structural Tubes (Frames)====
+
−
<table cellpadding=10 width=400>
+
−
<tr>
+
−
<td bgcolor=#9999CC>
+
−
Diameter Range
+
−
</td>
+
−
<td bgcolor=#CCCCFF width=200>
+
−
Envelope Tolerance
+
−
</td>
+
−
</tr>
+
−
 
+
−
<tr>
+
−
<td>
+
−
All Diameters
+
−
</td>
+
−
<td>
+
−
+/- 2 to +/- 3 mm
+
−
</td>
+
−
</tr>
+
−
 
+
−
</table>
+
−
 
+
−
====Tighter Tolerances====
+
−
 
+
−
Sometimes customers will required +/-0.75 mm - but this is very rare.  We've never seen tube shapes that must be qualified with a deviation tolerance of less than +/- 0.75 mm.
+
−
 
+
−
</td>
+
−
<td width=300>
+
−
[[image:aerospace_envelope_tolerance.png|400px]]<br>
+
−
[[image:exhaust_envelope_tolerance.png|400px]]<br>
+
−
[[image:shipbuilding_envelope_tolerance.png|400px]]<br>
+
−
</td>
+
−
</tr>
+
−
</table>
+
  
 
=Other Pages=
 
=Other Pages=
  
 
* See also [[VTube Intersection Point Tolerances]]
 
* See also [[VTube Intersection Point Tolerances]]
 +
* [[What are Centerline Tangent Points and Why Are They Important in VTube-LASER?]]
 +
* About [[VTube Intersection Point Tolerances]]
 +
* About [[VTube End Length Offsets]]
 +
* [[The Limitations of Qualifying Tube Shapes using Bender Data]]
 
* Back to [[VTube-LASER]]
 
* Back to [[VTube-LASER]]

Latest revision as of 02:09, 31 July 2020

Vtube-laser logo 1.96.png This page describes how to find the END POINT deviations.

Vtl screen hd scanner without logo.png


Contents

Three Types of End Point Deviations

There are three types of end point deviation values calculated during an alignment of the MEASURED to the MASTER tube.

Vtl three end point deviations.png

END LENGTH Deviations

The end length deviations are found at the top of the Inspection menu.

These deviations show you how much to trim a part to make it fit within the current alignment better.

Vtl end length deviations.png

AFTER-TRIM Deviations

These are found in the first T1 value and the last T2 value in the Tangents grid.

These deviations show the expected radial deviation if the tube were trimmed.

Vtl after-trim deviations.png


3D Length Deviations

These are found in the Intersection grid values.

The 3D deviations represent for the first and the last points represent the total radial deviation between the MASTER and the MEASURED end points in this alignment orientation.

Vtl before-trim deviations.png




Other Pages

Retrieved from "http://www.advancedtubular.wiki/index.php?title=VTube-LASER_End_Point_Deviations&oldid=40900"