sales@ipcb.com
ICT = In-Circuit-Tester, ICT is an automatic on-line tester, is a modern electronic enterprise must have PCBA production test equipment, ICT use a wide range of measurement accuracy, the detection of the problem of clear instructions, even if the general level of electronic skills of workers to deal with the problem of PCBA is very easy. Even for workers with average electronic skills, it is very easy to deal with problematic PCBAs. ICT can greatly improve production efficiency and reduce production costs.
ICT is mainly used in PCBA charge detection, can be imagined as a high-grade multimeter, it does not have to remove the electronic parts from the motherboard can be through the pinhole to test the motherboard on all parts of the charge and its soldering whether there is an open/short-circuit failure problems.
ICT test principle is to use the needle bed connected to each other on the motherboard layout a good bit of test cases to achieve the test purpose, ICT must use the pinhole placed in all the parts of the contact foot to widen out the test cases can be accurately measured, accurate measurement of resistance, capacitance and operating voltage.
ICT checks the electrical performance of the components on the PCBA wiring and the connection of the circuit network. It can quantitatively measure resistors, capacitors, inductors, crystals and other devices, functionally test diodes, triodes, optocouplers, transformers, relays, operational amplifiers, power modules, etc., and functionally test small- and medium-sized integrated circuits, such as all 74-series, Memory-type, commonly used driver-type, and switching-type ICs.
ICT detects manufacturing technology defects and defective electronic components by directly testing the electrical performance of in-line devices.Components can be detected to find out the over-value, failure or damage of components, and program error of Memory class. For the technology category, it can detect faults such as solder short-circuit, component insertion error, insertion reversal, leakage, pin warpage, virtual soldering, PCB short-circuit, disconnection, etc. The faults of ICT test can be directly localized to the manufacturing technology defects and component defects.
ICT test faults are directly located in the specific components, device pins, network points, fault location is accurate. Fault repair does not require more specialized knowledge. Automated testing using program control, simple operation, fast and rapid testing, single-board test time is generally a few seconds to tens of seconds.
ICT's general function
1.ICT can be in just a few seconds, the full test assembly motherboard parts: resistors, capacitors, inductors, transistors, FETs, LEDs, general diodes, regulator diodes, optical couplings, ICs and other parts, is not in our customized specifications within the model run.
2.ICT can find out the manufacturing defects in advance, such as short circuit, short circuit, parts leakage, reverse direction, wrong parts, empty soldering and other kinds of difficulties, thanksgiving feedback to the enhancement of manufacturing.
3.ICT can print out the above common faults or defective news information with a paper feeder to test the results, including common fault areas, part quota values, test values, so that maintenance workers can refer to. Can further reduce the person in charge of R & D technology dependence, no need to master the product quality distribution lines, still have the ability to repair.
4.To be able to test poor news information statistical analysis, production managers to analyze, to find a variety of bad reasons for the formation, including human factors, so that each processing, sound, correct, in order to improve the circuit board production and quality standards.
The role of ICT
1.Electrolytic Capacitor Positive and Negative Pole Detection Technology
Electrolytic capacitor reverse direction, leakage 100% can be detected.
Parallel Electrolytic Capacitor Reverse Direction, Leakage 100 percent detection.
2.The working principle of electrolytic capacitor positive and negative electrode detection technology
ICT is to add a new excitation signal on the top of the electrolytic capacitor through the third pin, and tunnel the response signal between the third point and the positive or negative terminal.
ICT utilizes DSP (Data Signal Solver) technology to calculate and transform the signal into a set of spatial vectors (Vectors) through DFT (DiscreteFourierTransform) and FFT (FastFourierTransform) calculations, and then measures the signal. The reflection signal is transformed from t(time) domain (oscilloscope signal) to f(frequency) domain (spectrum analyzer signal) as a set of spatial vectors.
After Learning to obtain a set of normative values, and then the DUT (DUT-DeviceUnderTest) tunneling detection value and then through the PatternMatch (characteristics of the identification of technical verification) and the original standard values to determine whether the DUT positive and negative polarity is correct.
ICT test point design specifications and layout requirements
Coverage rate of NET test points ≥ 95%.
ICT test pad diameter should be ≥ 1.0mm, if limited by PCB space, ICT test pad diameter can be reduced to 0.9mm.
Center-to-center distance between test points ≥1.27mm.
The safety distance between ICT test points and SMD pads should meet the following requirements to ensure that there is room for component milling and test pin installation.
No. SMD component type ICT test point edge and SMD pad edge distance
When the height of SMD components<5mm ≥ 0.3mm
When the SMD component height 5-8mm ≥ 1mm
When the SMD component height ≥ 8mm ≥ 1,5mm
In case of selective soldering, the edge of ICT test point is ≥4mm from the edge of THT pad on the soldering surface.
ICT test point edge from board edge ≥2mm.
ICT test point edge should be ≥3.0mm from the edge of PCB positioning hole of single board.
Via holes are not recommended as test points.
ICT test points should be placed on the same side of the PCB as far as possible, and evenly distributed on the surface of the PCBA to avoid excessive local density.
If the test points must be placed on both sides of the PCB due to layout constraints, the number of test points on the Top side should be less than that on the Bottom side.
The total number of ICT test points on the board is limited: 1/2 of the number of boards * The number of test points on a single board ≤ 1100 points, with a limit of 1200 points.