1. What are the processing specifications of Mark?
1. The processing method of Mark, whether Mark is needed, place in the side of the template, etc.
2. Which side of the mark is placed on the template should be determined according to the specific structure of the printing machine (camera position).
3. The Mark engraving method depends on the printing machine. It has a printed surface, a non-printed surface, half-engraved on both sides, and full engraved vinyl seal.
Second, whether or not the pannel, and the pannel requirements. If pannel is made, the pannel PCB file should be given.
Third, the requirements for inserting the pad ring. Since the reflow soldering process is required for the plug-in components, a larger amount of solder paste is required than the smd components. Therefore, if there are plug-in components that require the reflow soldering process, special requirements can be made.
4. Modification requirements for the opening size and shape of the template (pad). Generally, the pad is larger than 3mm. In order to prevent the solder paste pattern from sinking recovery and to prevent solder balls, the opening adopts the "bridge" method, the line width is 0.4mm, and the opening is less than 3mm, which can be divided equally according to the pad size. Various components require template thickness and opening size.
1. The printing quality of μBGA / CSP and Flip Chip with square opening is better than that with round opening.
2. When using no-clean solder paste and no-clean process, the opening size of the template should be reduced by 5% ～ 10%:
3. The opening design of the lead-free process template is larger than that with leaded, and the solder paste covers the pad as much as possible
4. Appropriate opening shape can improve the processing effect of SMT. For example, when the chip component size is smaller than the metric 1005, due to the small distance between the two pads, the solder paste on the pads at both ends is easy to stick to the bottom of the component during smt, and the bottom of the component is easily generated bridge and solder balls after reflow soldering . Therefore, when processing the template, the inside of a pair of rectangular pad openings can be modified into sharp corners or arcs to reduce the amount of solder paste on the bottom of the component, which can improve the solder paste adhesion at the bottom of the component during smt. The specific modification plan can be determined by referring to the "Printing Paste Template Opening Design" data of the template processing factory.
V. Other requirements
1. According to the PCB design requirements, whether the test point needs to be opened is required. If there is no special description on the test point, it will not be opened.
2. Are there any electric polishing process requirements? The electro-polishing process is used for the template whose opening center distance is below 0.5mm.
3. Use (indicating whether the processed template is used to print solder paste or printed patch adhesive).
4. Whether the template engraved characters are required (the product code of the PCB, the thickness of the template, the date of processing, etc. can be engraved, not fully engraved).
Sixth, after receiving the Email and fax, the template processing factory will send back the fax "please confirm " according to the buyer's request.
1. If there is a problem, please call or fax to contact, until the demand side confirms, it can be processed.
2. Check whether the size of the screen frame meets the requirements, place the template flat on the desktop, and manually press the surface of the stainless steel screen plate to check the stretch net quality, the tighter the net, the better the print quality. In addition, the bonding quality around the frame should also be checked.
3. Lift the template to visually inspect the light, check the appearance quality of the template opening, and check for obvious defects, such as the shape of the opening and the distance between the adjacent openings of the IC pins.
4. Use a magnifying glass or microscope to check whether the bell mouth of the pad opening is downward, whether the inner wall around the opening is smooth and whether there are burrs, and focus on checking the processing quality of the narrow pitch IC pin opening.
5. Place the printed board of the product under the template, use the leak of the template to align with the pad pattern of the printed pcb board, and check whether the pattern is fully aligned, with or without holes (unwanted openings) and few holes (openings for floor drains).
6. If you find the problem, you should first check whether it is our own confirmation error, and then check whether it is a processing problem. If you find a quality problem, you should feedback it to the template PCB manufacturing processing plant in time and negotiate to solve it.