Using the CATT System
Possibly one of the best features of the CATT system is its ease of use. Data collection and analysis is straight forward and very little operator training is required. There are basically four steps for performing a tap scan. The basic steps in producing a scan are to 1) connect system components and configure the software, 2) attach a grid template to the area to be inspected, 3) tap the area using the manual tap probe or the semi-automated inspection cart, and 4) analyze the data. These steps are briefly described below.
Step 1. Connect system components and open the CATT software. The system consists of a computer interface box that connects to a computer and a tap unit. Depending on the inspection application, the manual tap probe or the semi-automated inspection cart may be used. The manual tap probe is useful for performing spot checks and for performing tap scans on curved surfaces. The inspection cart significantly speeds the collection of data when inspecting relatively flat surfaces.
The CATT software is Windows-based. On the main window, the individual tap duration values are displayed so that the system performance can be checked and spot tests can be performed. Clicking on the "Set Up A Scan" button brings up a window where the scan parameters are entered.
Scan Set Up Screen
Step 2. Attach template to surface. Templates of nearly any size may be used and grid spacing of 1/4, 1/2 and 3/4 inch are commonly used. The smaller the grid spacing the higher the resolution of the scan image.
Step 3. Tap the area using the manual tap probe or the semi-automated cart. When the manual unit is used each square of the grid on the template is hand tapped. When the inspection cart is used, it is pushed along each of the grid lines and the cart taps at a regular interval. The tap spacing can be set to 1/4, 1/2 or 3/4 inch. The tap duration data is fed into a spreadsheet where it is displayed as shown below. Visual and audio ques are provided to assist in the data collection.
Step 4. Analyze the data. When the area has been completely tapped, the tap duration and stiffness plots are displayed. The analysis program can then be launched for additional data analysis and display options. For example, the tap duration can be displayed or the component surface stiffness can be calculated and displayed in absolute or relative terms. The C-scan images can be displayed as 2-dimensional or 3-dimensional surface plots.
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Test Panel Inspection Using the CATT System