Hello everyone, today I will answer the following questions for you. Many people still don’t know about the benefits of combining ICT with functional testing and what the ICT online tester does. Now let’s take a look!
1. Do you know what the difference is between a functional test fixture and an ICT test fixture?
1. We know that a test fixture is a fixture that is specifically used to test the function, power calibration, life, performance, etc. of a product. According to different test functions, it can be divided into drilling tools, functional test fixtures, ICT test fixtures, tin furnace fixtures and other test fixtures. However, due to the similar application scenarios of functional test fixtures and ICT test fixtures, many users often don’t know what the difference is. Here, the fixture manufacturer Hongwo Technology will introduce it in detail.
2. First of all, the test functions are different. A functional test fixture is a device used to test semi-finished products/finished products or a process in the production process. It is mainly a device for testing the function of the product to determine whether the object under test has achieved the purpose of the initial designer. It is a mechanical auxiliary fixture; while the ICT test fixture is a standard test equipment that tests the performance, principle and electrical connection of online components to check production defects and component defects. It has the characteristics of simple operation, fast and rapid, and accurate fault location.
3. Secondly, the application scenarios are different. Functional test fixtures are mainly used for testing analog, digital, memory, RF and power circuits, etc., mainly including voltage, current, power, power factor, frequency, duty cycle, brightness and color, character recognition, sound recognition, temperature measurement, pressure measurement, motion control, FLASH and EEPROM burning and other test items. The ICT test fixture is mainly used to check the open and short circuit conditions of single components and circuit networks online, batches of boards, high value-added and finalized boards, as well as the functions of analog devices and the logical functions of digital devices.
4. The third production principle is different. The main consideration of the functional test fixture is the positioning and fastening of the workpiece and how to implement functional testing; while the ICT test fixture punches the DIP pins and test points on the circuit board according to the mechanical dimension diagram of the circuit board, and then inserts the pins, and leads out the network (NET) in the circuit board, that is, the PCB routing, so that the internal circuit structure can be tested by the instrument outside.
5. In fact, whether it is a functional test fixture or an ICT test fixture, they are a category under the test fixture. The purpose of using them is the same, in order to improve the quality of the product and reduce the defective rate of the product.
2. What are the functions of ICT online tester
ICT, In-Circuit Test, is a standard test method to check the manufacturing defects and component defects by testing the electrical performance and electrical connection of online components. It mainly checks the open and short circuit conditions of individual online components and various circuit networks, and has the characteristics of simple operation, fast and rapid, and accurate fault location.
Flying probe ICT basically only performs static testing, and the advantage is that no fixture is required and the program development time is short.
The needle bed ICT can perform analog device function and digital device logic function tests, with high fault coverage, but a dedicated needle bed fixture needs to be made for each single board, and the fixture production and program development cycle is long.
Check the electrical performance of online components on the manufactured board and the connection of the circuit network. It can quantitatively measure resistors, capacitors, inductors, crystal oscillators and other devices, perform functional tests on diodes, transistors, optocouplers, transformers, relays, operational amplifiers, power modules, etc., and perform functional tests on small and medium-sized integrated circuits, such as all 74 series, memory type, common driver type, switching type and other ICs.
It detects manufacturing process defects and component defects by directly testing the electrical performance of online devices. Component types can check out component value out-of-tolerance, failure or damage, memory type program errors, etc. For process types, faults such as solder short circuit, component mis-insertion, reverse insertion, missing installation, pin lift, cold soldering, PCB short circuit, broken wire, etc. can be found.
The faults tested are directly located on specific components, device pins, and network points, and the fault location is accurate. Repairing the fault does not require much professional knowledge. It adopts program-controlled automated testing, which is simple to operate and quick to test. The test time of a single board is generally from a few seconds to tens of seconds.
Online testing is usually the first test process in production, which can timely reflect the production and manufacturing status and is conducive to process improvement and improvement. The faulty board tested by ICT can greatly improve production efficiency and reduce maintenance costs because of accurate fault location and convenient maintenance. Because of its specific test items, it is one of the important test methods for modern mass production quality assurance.
ICT testing must achieve accurate fault location and stable testing, which is closely related to circuit and PCB design. In principle, we require that each circuit network point has a test point. The circuit design must isolate the states of each device and not affect each other. The design of boundary scan and Nand-Tree must be installed with testability requirements.
3. What are the advantages of ICT online tester
1. Data transfer: ICT counts the pass rate and the number of errors of each component during the test, and transfers the effective data to the management level to supervise the production process before the test.
2. Increased output: ICT inspection speed is faster than personnel inspection, and the output can be greatly increased. ICT belongs to static testing. Some protective components may be missed in functional inspection, but they can be accurately inspected on ICT, so the quality and stability are also greatly improved.
3. Reduce costs: a-Reduce the number of inspection operators; b-Increase production; c-Reduce the cost of components damaged by misjudgment; d-Reduce maintenance costs.
4. Minimum fault repair time: When the ICT test finds a fault, the faulty components or error points will be accurately printed out by the printer, and the maintenance worker can quickly find the cause of the fault and repair it according to the printed list.
5. High-speed testing: The inspection speed of the ICT online tester is very fast. For example, a circuit board with about 1,000 components can be fully inspected in about 7 seconds.
6. Reduce misjudgment errors: ICT is accurate and stable in error inspection, avoiding personnel's wrong guesses about faults.
7. Reduce operating costs: ICT tests the entire circuit board at one time, and can even test multiple parallel boards at the same time, with only one operator.
8. Reduce maintenance costs: Avoid damaging the components and ICs of the power supply part during the functional test of over-powering.
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