Strong demand for contract manufacturing coupled with a shortage of skilled labor places new stress on companies trying to maintain product quality and grow their businesses. Training unskilled workers for specific assembly and test jobs takes time, and may prove unsatisfactory if quality cannot be maintained. Further, with the added requirements of ISO 9000 certification, faults in procedure or documentation could create problems for the company's customers and reputation. PC-based test automation addresses many of these problems, particularly for contract cable assembly shops. This article discusses the approach one cable tester manufacturer has taken to automate test, fault isolation, labeling, and documentation to ensure test consistency and reduce susceptibility to human error.
Strong demand for contract manufacturing coupled with a shortage of skilled labor places new stress on companies trying to maintain product quality and grow their businesses. Training unskilled workers for specific assembly and test jobs takes time, and may prove unsatisfactory if quality cannot be maintained. Further, with the added requirements of ISO 9000 certification, faults in procedure or documentation could create problems for the company's customers and its reputation. PC-based test automation addresses many of these problems, particularly for contract cable assembly shops and OEMs. We review the approach CAMI Research Inc. has taken with the CableEye ® tester to automate test, fault isolation, labeling, and documentation to ensure test consistency and reduce susceptibility to human error
Manufacturing errors are inevitable. Through quality control, we seek to keep those errors to an absolute minimum. Achieving this depends largely on reducing human error in assembly and test. Our PC-based approach to cable testing advances the technology by:1 - maintaining a secure, accurate cable database,
The balance of this article shows exactly how these capabilities help the operator avoid errors and improve throughput. It is important to note that the attributes of our tester result from the PC's high-resolution color graphic display, hard disk mass storage, programmability, and graphics printer drivers. Lacking a PC, these attributes would not be possible.
Reliable testing depends absolutely on accurate comparison data ("golden" cable data). Given accurate data, we must also ensure that the operator loads this data into the tester flawlessly. Uncertainty on either of these requirements can only reduce our confidence in the test results. A computerized database offers many advantages in these regards:
1 - The cable data you store will never change and can be managed by one responsible quality control engineer. You may then distribute it by the company's network to remote PC-based test stations.
2 - Data backup, a critical element of any system wide quality program, is easy and fast, and can even be made automatic.
3 - You may easily exchange cable data with your customers, or with an overseas factory, using modems or e-mail. By entering cable specifications in computer-readable form at the beginning, you are simultaneously creating model data for the tester, and eliminating any chance for keystroke or transcription errors. This same data may then be used to generate schematics and documentation automatically, eliminating another potential source of error.
4 - You may save cables under their true part number. You no longer need a "signature" or other arcane numbering scheme with which to code cables. Using a cable's part number to identify it in the database is more meaningful, and reduces the chance of operator error in loading data, recording results, or making labels.
5 - The database holds much more information than just cable wiring. With each record, our CableEye system stores the wire list and schematic, connector types, label text, and descriptive notes. The text you enter may be of arbitrary length and include vendor information, customer data, assembly or setup instructions, cost, related part numbers, color codes, and operator name.
Test consistency plays a large role in determining reliability. By completely automating the test process after the operator attaches a cable, we eliminate any chance that testing or documentation will differ from one cable to the next. We accomplish this with "Macros," which are small programs assembled by the test engineer using English-language instructions. A Macro can be as short as three instructions, although we show a more typical one in Figure 3. Macros pause when they reach the instruction WAIT FOR PB to let the operator mount the next cable to be tested. When ready, a pushbutton on the tester, or a footswitch, is pressed to continue.
Figure 4 shows a Macro that prints labels for correct cable assemblies, logs test results to disk, and prints an error report (the "difference list") should any problems be found.
The first line of this Macro brings up an entry screen that allows the operator to enter the name of the assembly to be tested. Alternatively, you may use a bar code reader in place of the computer's keyboard to enter this information. If desired, you may embed the count value produced by the Macro within notes or label text to create serialized labels and documentation.
Our experience shows that test technicians who have not previously worked with PCs, experience a fairly short learning curve in adapting to this equipment. We rely on predictable, stable, menu-driven software with easy-to-understand messages, and an on-screen help system with page references to the User's Guide. Within a week, most technicians are comfortable with their CableEye test system, productive, and have no wish to look back at their old benchtop testers.
Richard Eich, Electronics Design Engineer
Handi Quilter Inc.
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CableEye testers are highly versatile, expandable and upgradable diagnostic and Pass/Fail check Cable and Harness Test Systems that are PC-based. They are used for assembly, prototyping, production, and QC of standard or custom wire cables and harnesses The entire suite of products is powered by the same easy-to-use operating software and, with the help of its signature easy-to-interpret color-coded graphics, instantly identifies not only when there is a fault, but what type of fault and where.
Low Voltage M2 Series
For diagnostic and Pass/Fail Testing - Find, display, log, & document continuity (opens, shorts, miswires, intermittent connections).
Low Voltage M3 Series
For all of the above plus resistance (contact, isolation, embedded), and diodes (orientation, forward voltage, reverse breakdown).
Low Voltage M4 Series
For all of the above plus precision resistance (4-wire), and capacitance (twist wire relationship, length of cable, length to break, capacitors).
Low Voltage and High Voltage HVX Series
For all as described for M3 plus HiPot (dielectric withstand voltage and insulation resistance). 4-Wire Kelvin Measurement and Advanced Measurement Options (capacitance, twist wire relationship, length of cable, length to break, capacitors) are available.
photo credit: Progressive Image
photo credit: AP Technology
"Our production guys find it simple to setup and use. Our clients love it as it provides complete traceability for each and every cable assembly we manufacture."
AP Technology, UK