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What is SMT production line?
May 05, 2018

SMT is about to compress traditional electronic components into a device that is only a few tenths of the size of a device that directly attaches and solderes surface-mount components to a predetermined position on a printed board surface. Compared with traditional technology, SMT has five characteristics: high density, high reliability, low cost, miniaturization, and automation of the sound field.

SMT production line type


SMT production lines can be divided into two types, according to the degree of automation can be divided into automatic production lines and semi-automatic production lines; according to the size of the production line can be divided into large, medium and small production lines.


The automatic production line means that the entire production line equipment is a fully automatic equipment, and all production equipment is connected to a production line through an automatic loading machine, a buffer connecting line and a unloading plate machine;


The semi-automatic production line means that the main production equipment is not connected or not completely connected. The printing press is semi-automatic and requires manual printing or manual loading and unloading of the printed board.


The main components of the SMT production line are: surface assembly components, circuit substrates, assembly design, assembly process;


The main production equipment includes printing presses, dispensers, placement machines, reflow ovens and wave soldering machines. Auxiliary equipment includes inspection equipment, rework equipment, cleaning equipment, drying equipment and material storage equipment.


After simply understanding the basics of SMT, we will focus today on the importance of SMT testing.

The importance of SMT testing


SMT quality inspection is an important step to improve the quality of SMT products. It can improve product quality and strive to achieve "zero defects."


The cost of assembling the instrument to find the fault is several dozen times the cost of finding the fault when assembling the printed circuit board.


The cost of discovering a fault after putting the product into the market will be hundreds of times more than the cost of discovering a fault when assembling the printed circuit board.


In order to ensure the quality of SMT products during operation, it is necessary to conduct effective inspections to detect defects and failures in a timely manner and repair them, thereby effectively reducing the cost of manufacturing faulty products and repairing them.

The basic contents of SMT quality inspection technology mainly include: testability design; raw material incoming inspection; process detection and assembly inspection after assembly.


SMT quality inspection can be divided into incoming materials inspection (referred to as IQC), process detection (abbreviated as IPQC), finished product testing (abbreviated as FQC), and factory inspection (abbreviated as OQC) from the testing location. From the detection methods, it can be divided into: Visual inspection, online testing (ICT), automatic optical inspection (AOI), X-ray inspection (X-ray or AXI), functional testing (FCT), etc.


ICT tester


ICT is the abbreviation of In Circuit Tester. The Chinese meaning is an online tester. It is a test equipment for PCBA (Printed Circuit Board Assembly) produced by modern electronics companies.


The scope of use of the ICT, the high accuracy of the measurement, and the clear indication of the problem to be detected, make it easy for a worker with an average level of electronic skill to deal with a problematic PCBA.

ICT working principle and classification


The most basic instrument used for electrical testing is the In-Circuit Tester (ICT), which uses a component-level test method to test each component on the assembled circuit board.


ICT can be divided into needle bed ICT and flying needle ICT.


The flying probe ICT basically only performs static tests. The advantage is that fixtures are not required and the program development time is short.


The needle bed ICT can perform simulation and even digital device logic function tests with high failure-to-failure rates.

On the SMT production line, time represents efficiency.


The use of ICT can greatly increase production efficiency, reduce production costs, and the on-line tester can detect fault coverage of up to 95%. Its rational configuration on the production line can detect manufacturing faults as soon as possible and repair them in time, or adjust the production process in a timely manner. Effectively reduce the cost of manufacturing faulty products and repairs.


Therefore, it is especially important to select an ICT tester that can save testing time and increase production efficiency.


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