Wire End Quality Assurance - In-Process Strip & Seal Inspection

Wire processing involves high speed precision cutting and stripping, and often the placement of a weather seal onto the wire before the terminal is applied. 

To ensure absolute quality through every step of this high speed process, leading wire harness manufacturers employ 2 different methods to assure quality; an ‘in-process inspection device’ to check the strip and seal application prior to crimping, and the other is a ‘process variation monitor’ for crimp quality.

Crimp force monitors, more appropriately called crimp process variation monitors, detect process variations that can be directly correlated to crimp defects, tool wear, incorrect alignment or adjustment, etc. that might result in defective parts, accumulation of unnecessary scrap, and rework.  However, crimp process monitors have some inherent limitations and should not be considered to be the sole solution for every potential failure mode in the process of wire stripping, seal application, and terminal crimping. 

Detection of pulled wire strands, strands crimped outside of the core crimp due to wire splay, incorrect positioning of the insulation shoulder relative to the terminal crimp, or insulation entry into the core crimp are a few examples that can evade detection by crimp process monitor systems and are best managed with a strip & seal sensor prior to the final crimping of the terminal.  

The application of weather seals onto the wire and the industry trend toward small gauge conductors has introduced even more potential for quality defects including seal not present, incorrect seal orientation, and improper seal position on the wire.  

How It Works:
The LPA series of strip & seal sensors from OES capture a complete profile image of the end of the wire as it passes on-the-fly through a sensing window.  The sensing window consists of a laser “line-generator” that projects a beam across a sensing window onto the receiver array. As the wire passes through the sensing window, the laser beam is interrupted along the array.  A high resolution image of the end of the wire is captured and processed for determination of PASS or FAIL based on the tolerances and inspection criteria configured in the initial setup.  

The LPA compares each production part to a reference or learned profile of a wire.   This method ensures that every wire is within the specified tolerance and enables the following defect detection capability: strip length errors, pulled strands, conductor diameter faults, improper seal orientation or position, or splayed strands.

A LEARN feature ensures simple and fast changeover to a new process.  WIRE-SCAN is supplied with “WireScan.NET™” application software which can be loaded onto any Windows based operating system for monitoring, data collection, and configuration.

The LPA56B technology ensures that a comprehensive inspection of every wire is made within milliseconds. Connecting the built-in pass or fail logic of the system with the appropriate cutter or press control device can virtually eliminate quality problems related to faulty wire strips or faulty placement of a seal on the wire.

The use of a WIRE-SCAN LPA56B  for strip and seal inspection, in conjunction with a crimp force monitor for the critical crimping application, offers wire harness manufacturers the maximum ‘zero defect’ quality monitoring possible – all without adding time to the process, or cost to the part produced.