10-003591-01EN [Q7780031], Rev. 4, January 2020
Preparation for Inspection 33
It is recommended to scan using an overlap between scan lines, with the Index Res
value set according to the method above. For this, the Linear at 0° mode must be
selected (Focal Law > Configuration > Law Config. = Linear at 0°).
If an overlap is not required, or if you want to use beam angles that differ from 0°, you
need to use Linear mode (Focal Law > Configuration > Law Config. = Linear), and
you must set the encoder 2 Resolution linked to the indexing button [also named
Clicker] (Scan > Encoder > Resolution) to equal the Index Res value. As an example
of an index value setting, Figure 3-3 on page 32 shows an Index Res value that would
be transferred to the Resolution field shown in Figure 3-4 on page 32. However, if you
use this scanning method, the surface actually covered by the ultrasonic beam is
smaller than the Index Res value. This means that some portions of the surface may
not have been covered by the scan. Therefore, Linear at 0° mode is recommended.
3.4 Marking the Scan Lines
Before an inspection, it is recommended that you lay out and mark scan lines to
follow when moving the FlexoFORM scanner over a surface. The steps for
determining the line length and spacing for an elbow are detailed in “Setting Up the
Scan and Index Parameters for an Elbow” on page 31. However, it is also possible to
inspect without scan lines, as detailed in “Inspecting a Part without Marked Scan
Lines” on page 40.
To mark the scan lines
1. Define the required index value (encoder 2 Resolution).
See the example (56 mm/step resolution) procedure in “Setting Up the Scan and
Index Parameters for an Elbow” on page 31.
2. Determine your zero position (the middle, or center, of the scan line), and then
draw your zero line perpendicular to the part’s longitudinal axis, using the
flexible straightedge wrapped around the circumference as a guide (see left
illustration in Figure 3-5 on page 34).
3. Position the flexible magnetic straightedge so that one edge rests flat on the
longest (extrados) section of the elbow or part, and draw your first scan line
To Next Page
Loading...
