Test Verification using Signature Analysis
HIGHLIGHTS
Defects detected:
- Missing nozzles
- Blocked nozzles
- Restricted nozzles
- Automatic PASS/FAIL analysis and display to operator
- 6 digital inputs and outputs for PLC handshaking and error
- proofing
- Easy to use menus and graphic interface
- Minimal time required to integrate with production process
The correct assembly of piston cooling nozzles is crucial to the reliability of a diesel engine. Nozzles may be obstructed, blocked, or even omitted during the assembly process, leading to severe engine damage and costly warranty repairs.
By incorporating a Sciemetric SigMETER into the piston cooling nozzle assembly line at the nozzle insertion station, a manufacturer was able to simplify and speed the verification test and produce an immediate PASS/FAIL result.
The verification test applies a low pressure airflow to the nozzle oil galleries in the engine, measuring the back pressure with a standard pressure transducer. Blocked or obstructed nozzles have a back pressure that is much greater than the expected pressure (detectable level of obstruction varies from part to part). No back pressure builds in the part when nozzles are missing, and the mean value is much lower than expected.
The Signature Analysis System analyzes the data from the pressure transducer and converts it to a time/pressure signature, which it compares with an envelope and mean value developed from known good parts. It then transmits a 'PASS' or 'FAIL' to either the operator via the panel meter display, or to the PLC via a digital output. Programs can be saved, edited and reloaded as required, which extends the versatility of the system and minimizes the time needed to integrate it into the production process.
Incorporation of Sciemetric's SigMETER and Signature Analysis technology into the piston cooling nozzle assembly line immediately resulted in advanced defect detection.
Prior to the incorporation of the SigMETER, undetected defects had resulted in costly end-of-the-line teardowns and warranty claims.
