To ensure that your custom cable assembly meets required specifications, the fabricator needs a well-equipped laboratory. The laboratory requires a wide variety of specialized test equipment to ensure that the cable harness assembly, which is manufactured for you, meets and exceeds expected results. Typical required laboratory equipment includes high voltage test units, environmental salt spray chambers, state of the art temperature cycling units, ultraviolet aging simulators, strain and stress relief measuring equipment, and bending and flexing test equipment. Cross-section metallurgical as well as accurate 3D measuring equipment and quality microscopes are also used.
Salt Spray Chamber
This is designed to speed up the effect of long-term exposure of metal and plastic parts to corrosive environments. A salt spray test is performed by exposing metal, overmolded parts, connectors, and other assembly and cable parts to a simulated ocean-based environment, typical of acid and salty conditions.
- Typical test conditions: C concentration of NaCI: 40-60g/KG, PH value: 6.5 - 7.2
- 24-hour test, with a test temperature of 47 ±1° C
- Typical test items: Uses USB/D-sub metal housing, metal terminal, screws and metal housings, cable subassemblies as well as connectors
- Quality control: A complete inspection of parts is required for rust or corrosion after exposure to salt spray
UV Accelerated Aging Test Unit
Within the cable industry, many parts can and do have UV sensitivity. A top lab is equipped with an ultraviolet accelerated aging test unit. The purpose of this test is to expose cable or connector parts to typical outside UV conditions. The part is exposed to high levels of UV radiation and alternating cycles of moisture at controlled elevated temperatures. The objective is to accelerate the aging and then inspect and note the aging damage. This test simulates typical customer use in extreme conditions where outdoor use in high UV conditions is expected.
- Equipment used: Ultraviolet aging chamber
- Test condition: UV Wavelength, 280-315nm for 96 hours, with water misting
- Test temperature: Up to 50℃; test part rotation, speed: 4-5 RPM
- Typical test Items: Raw cable, plastic/PVC over molding, harness parts, stress relief connectors
- Quality control: A complete and exhaustive inspection for brittleness as well as color change and any damage, electrical or mechanical will be performed on the tested part
Thermal Shock Test
The thermal shock test exposes parts to alternating high and low temperatures as well as high humidity over time, stressing the part to expose early reliability problems, similar to in use conditions.
- Test condition: a constant temperature and humidity chamber.
- Test temperature: -40℃ to 150° C
- Typical test, as specified by customer: 8 hours at -30° C, then 8 hours at 110° C, humidity 90%
- Humidity in the test chamber is adjustable from: 0–98%
- Typical test items: Raw cable, connectors, test leads, completed assembly, overmolded parts
- Quality control: Inspection for any physical damage or electrical change in component
Bend Stress Test
Utilizing a high angle repeatability bending test unit, the sample is continually bent over a specified sized mandrel for specified number of cycles, while measuring resistance during the test. Any faults will show up as a lower number of bend cycles or minor change in resistance indicating the start if a failure.
Cable Pull Pressure
To test and measure the pressure required to damage the strain relief overmolding or separation of a cable from a solder on connector. Also used to measure strain on a wire, until failure.
Cable Rotation Tester
A specialized machine which mechanically rotates the cable repeatably over 360 degrees over a specified diameter mandril. This test is used to gauge reliability of a cable, or a cable to connector attachment and its strain relief device.
Drop Ball Impact Tester
Determines the possible damage to connectors or assemblies from dropping or from sustaining a hit from a larger object, during normal application circumstances. Diameter, weight of the ball and height dropped from are usually specified.
Cable Jacket Coating Abrasion Test
A very special machine is used to rub the jacket on a cable repeatedly over time, simulating actual in use conditions such as cables being dragged on the floor or rubbing against an automobile chassis.
High-voltage power supplies and leakage measuring units will detect an arc over or damage to insulation during lab tests. This is required for many certifications such as UL, CSA and UE approvals.
Over Current Test Unit
By passing excessive current through the cable and connectors, this tester measures temperature rise, as well as operations function. It is used to determine the assembly or cables ability to survive over currents.
High-Temperature Aging Test
The wire harness or component is tested by exposing the assembled products or parts to a high temperature for a long period of time.
The chamber should be a high-quality oven with digital controller High voltage arc tester.
- Test Condition: Temperature up to 300° C
- Typical test Items: Raw cable, connector, assembled cable, probes, overmolded components
- Typical customer specified test: 110° C for 168 hours
- Quality control: Inspect for physical damage such as melting or warping, check electrical properties for short or open, as well as high voltage dielectric strength
The Purpose of the waterproof test is to check for moisture leakage by exposing the products to water at a specified depth for a specified time. Electrical continuity test using high quality meg ohm meter.
Typical test condition: Depth of water up to 10 meters
Typical test items: Assembled cable at 17° C, 2 meters under water, as specified for one hour
Quality control: Check resistance after time immersed, with a high-quality meter resistance leakage must be greater than 5 meg ohm
All these tests ensure the cable assembly you require will last in use applications for the desired lifetime of the product.
Cooler Cao is an engineering manager at Cabletree Industrial Company. Cables, cable assemblies and wire harness are, more than ever, an integral part of today's electronics. With the development of automotive and medical diagnostics, electric automobiles, solar and wind power has come the design and develop of newer and more sophisticated connection devices.