MODEL LAC-2000, with QC/SPC Capabilities
The Jodon Model LAC-2000 is a major upgrading of the original Louver Angle Checking System, which was first introduced to the heat exchanger industry in 1979. Enhancements in speed, memory, data analysis, and display graphics have been added to the already versatile fin angle measurement system. The LAC-2000 is a stand-alone, off-line system for measuring louver features of convolution (serpentine), and plate type cooling fins. Defects in fin fabricating tooling (form rolls or star rolls), and fin machine alignment can easily be identified and analyzed using this sophisticated measurement system.
Long term degradation in fin machine rolls (or dies), caused by wear, can be tracked using the “percent Bulk Transmission” feature. The amplitude of light passing through the louver, at the angle of maximum intensity, is compared to the light amplitude which would pass through the louver if the panel was formed exactly to print. That ratio, called the “%BT” factor, will diminish as the fin tooling wears. Daily use of the LAC-2000 permits operators to determine when adjustments or changes should be made to ensure continued production of conforming louver products.
A single LAC-2000 measurement system can be used to qualify one, or dozens of production fin mills. Dedicated fin holding fixtures, and preprogrammed instructions and computer routines, ensure simplicity of operation, and preciseness of measurements.
By making use of contemporary PC computing power, the LAC-2000 provides a compilation of trend data for use in Statistical Process Control (SPC) analyses and graphical presentations. A data bank of on-going fin production performance can be instituted without data transfer to host computers.
HOW THE LAC-2000 OPERATES
The operator places a fin sample (e.g., radiator, heater, condenser, charge air cooler) into a simple fixture. The fixture is placed in a holder which is mounted to a computer controlled rotary stage. As the stage turns on command, the fin sample is rotated between a light source, and a sensitive light detector. Values of light amplitude are sensed, processed, stored and displayed as a function of fin angle. The complete test cycle takes less than one minute. During that time thousands of data points are recorded in the computer memory for each of four louver panel “windows”. The computer determines the maximum light amplitude-versus-angular position for each of the “windows”. Computations are then made of the peak and average values for the important fin angle, and percent bulk transmission (% BT) values.
The resulting measurements and computations are then tabulated and plotted on the computer SVGA monitor. The data is also saved in the computer memory for SPC and archival purposes.
LAC-2000 SPC Graphs 1) Control Charts A. Angle B. Bulk Transmission C. Louver Height
2) Histogram, Individual louver window A. Angle B. Bulk Transmission
3) Histogram, Averaged Top/Bottom louver windows A. Angle B. Bulk Transmission
4) Histogram, Averaged All louver windows A. Angle B. Bulk Transmission
TYPICAL LOUVER DATA
For a given louver type, 14 specific measurements and computations are generated each time the operator initiates a louver test. Measured and calculated results are full-screen displayed in less than a minute . This figure illustrates a typical screen presentation following the louver test.
System Type: Non-contact electro-optical angular measurement instrument
Parameters Measured: Primary: Louver Angle Secondary: %BT (Bulk Transmission)
Measurement Accuracy: Louver Angle: within 0.5 degrees %Bulk Transmission: within 5.0%
Light Source: Eye safe, LED, non-coherent
Operating Wavelength: 880nm LED Optical Power Output: Nil Stage Resolution: 0.032 degrees Steps Per Revolution: 11,250 Stepper Speed, Nominal: 500 sps Data Acquisition: 12-bit, multi-range
Computer Specifications: CPU: Pentium; 350MHz Ram: 64MBytes Floppy Disk: 3½ inch, 1.44MB Hard Disk: 10GBytes Backup: 100MBytes Zip Monitor: 15-inch, SVGA Windows 98 Ports: 1 Parallel (printer) Enclosure: Mid-Tower
- Standardized hardware platform using contemporary PC technology.
- Full screen (PC monitor) operator instructions and test menus provide easy operation.
- Louver test selection is made easily with the click of the mouse in the Windows environment.
- Test results are tabulated and graphically presented on the color monitor at the end of each test.
- Production test results are automatically stored in specific test louver registers for analysis, and archival purposes.
- Data analysis includes standard Statistical Process Control (SPC) computations, control charts, trend charts, and histograms.
- Center height can be manually entered into the database for SPC charting.
- Sensing system with proven eye-safe solid-state non-coherent light source.
- Screen selectable tests, controls and system diagnostics.
- Changes in louver tests and test information are made using 3.5″ floppy disks.
- Local Area Network (LAN) hardware can be added to allow remote monitoring of test results from other “desktop” computers.
- Optional color printer allows printout of charts, graphs, and other test results.
- Incoming Roll Inspection software permits complete and systematic characterization of tooling.