How to Clean and Scrap SMT Stencils

 

After the Production Line Has Stopped Running:

1. Disassemble the stencils. Remove any remaining welding paste from the front of the stencil using a scraper and throw away the dried paste.

2. Spray a cleaning agent evenly onto the stencils and wipe them with the wiping paper until the welding paste is gone and there are no impurities visible on either the upper or lower side of the stencil.

3. Wipe the stencils on both the upper and the lower side with two pieces of wiping papers, using a cleaning agent. Continue until there is no visible welding paste residue.

4. The stencil holes should be blown out thoroughly using an air gun, in order to blow them from top to left and from bottom to right. Pay special attention to BGA, QFP and the smaller spacing IC area.

5. Repeat the cleaning process until the stencil holes are clean.

Shenzhen Guangming District, SMT Processing Factory: Scrapping Stencils

1. After confirmation by the engineering staff, stencils that are damaged and cannot guarantee normal silkscreen characters will be scrapped. The stencils that have been scrapped should be marked outside the outer frame, and then placed in the scrapped-stencils area.

2. If the tension of the steel plate 55*65 is less than 30N/cm or that of the stencils 42*52 is less than 25N/cm and the maximum tension difference is greater than 10N/cm then it should be scrapped.

3. This steel plate must be scrapped if the total number of productions and prints exceeds 50,000.

4. The engineering staff confirms that it was a result of the PCB upgrade and discards it.

5. The stencils must be reopened due to the quality improvement. The stencils that were used before the improvement are discarded.

评论

发表评论

此博客中的热门博文

The Complete Guide to 2025 PCB Assembly Costs

图片
  Concerned about the expense of PCB assembly? Precise PCB assembly estimations are crucial. Being aware of this can lower your expenses. You can use this advice to make well-informed judgments on cutting  PCB assembly  cost s . 1.  8 Key Factors Influencing PCBA Cost 1.1 PCB complexity （1） PCB layers Single-layer and double-layer PCBs are the least expensive. Due to increased material prices and routing complexity, multilayer PCBs are more costly.. According to the general belief, PCBs cost increases with increasing layers. （2） Dimensions PCB The size of the PCB determines its cost. The more space there is on the PCB, the easier it will be to add components and circuits for the intended purpose. Larger PCBs are more expensive because they can be used for large and medium devices. Smaller PCBs need fewer parts and are less expensive. As the PCB grows in size, the assembly costs increase. （3） PCB minimum hole diameter Drilling requires a drill bit. Compared to drill b...
阅读全文

Comprehensive Guide of PCB Silkscreen

图片
  In the intricate ecosystem of electronics manufacturing, the  Printed Circuit Board (PCB)  is often celebrated for its conductive copper pathways and protective solder mask. However, there is a “silent communicator” on the board that bridges the gap between complex hardware and human intelligence: the PCB Silkscreen. While it may seem like a mere aesthetic addition, the silkscreen layer (or legend) is a critical engineering component. For professional engineers, PhD researchers, and hardware students, understanding the nuances of silkscreen is essential for optimizing the assembly process, ensuring maintenance feasibility, and maintaining signal integrity in high-frequency designs. This guide provides an exhaustive technical analysis of every facet of the PCB silkscreen layer. At its technical core, the PCB silkscreen is a layer of non-conductive, specially formulated epoxy ink applied to the surface of a printed circuit board. The term itself originates from the tradit...
阅读全文
图片
A Complete Guide to Aluminum PCB   Aluminum PCB are built for heat. Learn what makes aluminum circuit boards essential for LEDs, power tech, and high-efficiency electronics. Aluminum PCBs don’t get much attention. They should. These boards are quietly powering LED lights, automotive electronics, power supply units, and so much more. Why? Because when things heat up, literally, aluminum circuit boards step in. Heat is the enemy of performance. If you’ve ever held the back of an LED lamp or a phone charger and noticed it’s warm but still working perfectly, you’ve probably encountered an  aluminum PCB  board without realising it. In this guide, I’m walking you through everything: what aluminum PCBs are, why they’re a smarter choice in high-heat environments, where they’re used, and how to avoid wasting money on low-grade options. Whether you’re sourcing for production or just exploring your options, you’ll want to understand how aluminum printed circuit boards have quietly b...
阅读全文