Design and Fabrication of Custom In-Process Test Fixtures and Instrumentation
DEFINITION
Test instrumentation specifically designed to perform functional tests on parts and sub-assemblies during the production process. These may include incoming inspection test sets, calibration aids and test fixtures at individual workstations, and combined functional test/environmental control equipment for the performance of HASS and HALT as part of the production flow. Associated software may be employed to collect real-time statistical data and identify variances and trends.
SITUATION
Essential for reliable manufacturing of complex systems, especially those employing multiple technologies, such as medical therapeutic and diagnostic devices, avionic and weapons systems, robotics, automotive sub-systems, and similar products. A thorough evaluation of potential system failure modes should first be performed; each failure mode is then analyzed to determine its probability of occurrence relative to other failure modes, and the earliest and latest stage of production at which it can be uniquely identified. From this analysis, optimal points within the production flow are pinpointed for in-process testing. Many of these tests operations may be performed with commercial test equipment and simple fixtures. Some tests will require custom electronic stimulus and data collection hardware to be designed, constructed, and deployed on the production line. Certain ATP (acceptance test plan) and/or regulatory requirements may dictate that data from these test stations be collected, archived, and reported with product lots.
OBJECTIVE
Identify faulty components; or preferably, continuously track and alert to changes in component parameters before they diverge from acceptable limits.
Exercise sub-systems using test fixturing that accurately mimics the performance of surrounding system components.
Provide platforms for calibrating, aligning, and adjusting assemblies where such adjustments cannot be eliminated by design.
Provide rugged fixtures and electrical interconnects which allow sub-assemblies to be powered and monitored while being subjected to extremes of temperature, vibration, and other environmental stresses.
Provide calibration and alignment equipment which presents simple, intuitive visual displays to production personnel, allowing them to perform required adjustments quickly and with a high degree of accuracy.
VALUE TO YOUR ORGANIZATION
It is widely understood that the earlier in the production flow that a defective component or improperly assembled structure can be detected, the lower the total cost of correction. Waiting until final test to uncover defects requires expensive destruction of work performed; it may be difficult or impossible to pinpoint the cause of the failure, thus requiring the unit to be scrapped. Early detection also allows corrective action to be initiated with respect to vendors and to training of production personnel. Production test equipment which provide immediate visual feedback to workers helps them to accurately carry out proper assembly procedures, speeding line flow.
RELIABILITY INTEGRATION
An example of Reliability Integration during the Design and Fabrication of Custom Test Equipment is as follows:
Assessing the value of possible in-process test equipment is an integral part of an overall failure mode and variability analysis. Each significant point of failure or variability is assessed to determine whether it can be eliminated through redesign of the part or re-specification of processes used. For those modes that cannot be eliminated, the next step is to determine the best point in the production flow to identify them. The entire set of such modes is then viewed and choices are made as to how to achieve the greatest quality benefit at the lowest overall cost.
METHODOLOGY
There are 3 main areas we cover:
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Analysis of Opportunities and Costs for In-Process Test
We will review product design and manufacturing plans, and identify optimal points for application of in-process testing. We will indicate whether such testing may be performed with available commercial test equipment or will require custom equipment. We will provide specifications for suitably robust fixturing, point out potential problems to be expected during stress testing and ways to solve them.
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Design of Custom Electronic Test Equipment and Mechanical Fixturing
We will provide design drawings for test fixturing, specifications for connectors and cables, specification of off-the-shelf data acquisition equipment, or, where required, designs for specialized data acquisition hardware. We will provide software for archiving and analysis of data acquired by test equipment.
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Fabrication of Custom Electronic Test Equipment and Mechanical Fixturing
We will provide complete turn-key service to develop, construct, and install in-process test systems in your facility.
