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PCBA Tech
Testing and components to be done after PCBA cleaning
PCBA Tech
Testing and components to be done after PCBA cleaning

Testing and components to be done after PCBA cleaning

2021-11-09
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Author:Downs

Let's discuss what testing needs to be done after the professional PCBA processing plant is completed. The inspection after PCBA cleaning is mostly carried out by visual inspection. For high-reliability products, special testing equipment and standard methods are needed to measure cleanliness. The measurement standards of cleanliness mainly include ion pollution and surface insulation resistance.

1. Cleanliness standards

1. Ion pollution The current PCBA processing plants do not have clear standards for ion pollution. Usually it refers to the military standard MIL28809 or the American Standards Institute standard ANSI/J-001B.

2. Surface insulation resistance (SIR) The surface insulation resistance is usually measured using a comb circuit. This method is intuitive and quantifiable, and has high reliability, but it is also the most difficult and requires a comb circuit for measurement. Usually requires surface insulation resistance SIR≥10 to 10/power power.

pcb board

2. Inspection methods of professional PCBA processing plants

The inspection of the cleaning process should be carried out according to the cleaning requirements of the product.

If it is military products, medical products, precision instruments and other products with special requirements, you need to use measuring instruments such as omega (Ω) meters to measure the degree of dyeing of Na ions. In addition, a shape test piece is usually used to test the surface insulation resistance.

The cleanliness of Omega (Ω) meter is measured by immersing the printed circuit board (PCBA) in a clean standard solvent, dissolving the ionic contamination on the PCBA surface into the standard solvent, and then calculating the standard solvent. Equivalent sodium ion content to provide the cleanliness index of the tested part. For the required product, it can be visually inspected.

The visual inspection method requires the use of a 4x microscope for inspection. The surface of PCB and components should be clean, free of beads, flux residues and other contaminants, and the standard for observing contaminants should be determined.

The development prospects of PCBA components

With the development of PCBA component research and development technology, components are moving in the direction of smaller size and higher integration, and the packaging of components is also moving towards smaller size, lighter weight, higher operating frequency, and more The direction of strong anti-interference and higher reliability is developed to meet the requirements of assembled products.

Modularization is the development direction of future components. As the size of components increasingly faces the limit, the precision of automated production equipment in professional PCBA processing plants is approaching the limit, and the compounding and modularization of chip components will be rapidly developed and widely used.

The main function of the PCBA printer is to apply solder paste on the designated pads of the printed circuit board. According to the degree of automation, printing machines can be divided into manual printing machines, semi-automatic printing machines and fully automatic printing machines.

Various parameters and actions of manual printers need to be adjusted and controlled manually, usually used for small batch production or low-difficulty products; during the clamping process of semi-automatic printers, in addition to manual placement of printed circuit boards, other actions are automatically completed by the machine. However, the alignment of the first printed circuit board and the position of the template window is achieved manually; automatic printers are usually equipped with high-precision optical mid-systems for mass production in professional PCBA processing plants.

The start-up operation of the printing machine in a professional PCBA processing plant is basically the same. Digital signal processor-1008 automatic printing machine is composed of frame, printing table, stencil fixing mechanism, printing head system and other options (charged coupled device, positioning system, wiper system, 2D and 3D measurement system, etc.). Equipped to ensure printing accuracy.

Professional PCBA processing plants should ensure that all employees pay attention to electrostatic protection during the production process, so that the electrostatic protection system project can be truly implemented, eliminate electrostatic hazards, ensure production safety, and improve product quality and reliability.