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Nowadays, when it comes to electronic components and equipment, the first word that
Do you know the difference between these two, and which one is suitable for your PCB
In this article, PCBasic will take you on a journey to understand what is SMT, what
There are multiple reasons and benefits implementing SMT in the PCBA fabrication process:
1. Lead time reduction - compared with traditional plug-in components (DIP components), the lead time required for through-hole manufacturing is reduced or sometimes even eliminated. This results in the ability to produce a volume of SMT electronic products in small components SMD count. The volume of electronic products processed by SMT chip processing techniques instead of using DIP techniques can effectively reduce the lead time by 40%~60%.
2. Functionality - High reliability and function, strong anti-vibration ability, not easy to be affected by vibration which can ultimately cause component failure.
3. Solder paste defects - The defect rate of solder joints during this technique is considered low, which ultimately improves the placement efficiency.
4. Automation - SMT is an automated process, saving labor, time, and cost during the placement of the components.
SMT is a multi-stage process that involves multiple stages and complex techniques in order to be accomplished. eventually, SMT will result in a great PCBA finished product. Let's walk over the stages to understand what does the standard SMT process looks like:
SMD materials (components, integrated circuits, etc… ) are provided by customers or purchased by SMT manufacturers directly.
After receiving the materials, the warehouse will check the quantity and check the correctness to check whether the materials are consistent with the pads.
At the same time, The engineer in charge of the SMT process will make the SMT production program according to the Gerber files and BOM table that was provided by the customer during the project submission and evaluation process. Once this stage is complete, the engineer will upload the program files to the corresponding production line to prepare for production.
At this stage, The PCB manufacturer and associated engineers will check whether the stencil is in line with the PCB designs provided by the customer. The engineers will also check whether the stencil has blocked holes and whether the solder paste was used correctly. After the inspection, stencil fixes will be applied to the printing machine and the engineer will run a debug program to ensure the printing machine operating properly.
During the normal printing process, the operator should regularly check the tin to ensure that the solder paste doesn’t overflow. If an overflow is detected, the engineer will collect the overflowing solder paste to ensure the SMT process goes smoothly. IPQC (process quality control) software will conduct a visual inspection on the first 5-10 sheets printed, and inform the operator whenever to continue the production or stop it if the printing quality doesn’t match the expected results.
SMT assemblers and fabrication facilities analyze the changes in the reflow oven
This kind of advanced machinery powered by AI and computer vision enables SMT
Due to the nature and characteristics of BGA components, the soldering state and result cannot be visually inspected and AOI machines cannot detect the specific details either. For that reason, it is necessary to use the X-RAY penetration using X-RAY equipment to detect the electronic components' solder paste state which will help to check, verify and judge if the SMT solder waste was soldered successfully.
In such situations, timely detection of de-soldering, voids, cold welding, bridging, displacement, incomplete melting of solder balls, solder beads, and other defects will drastically improve the quality control of the assembled products. However, X-Ray inspection equipment is relatively expensive, and many small SMT assemblers are hesitant to purchase such equipment. This will eventually result in the inability to effectively detect poor soldering of BGA Assembly.
1. Maintain constant temperature and humidity in the SMT workshop, the specified temperature is 25±3℃, and the humidity is 65%±5%RH.
2. The use of solder paste should follow the principle of first-in, first-out.
3. When the solder paste is opened and used, it needs to go through two processes of re-warming and stirring.
4. Ensure electrostatic protection, and control the electrostatic voltage that may be generated to keep it under a safe threshold for the most sensitive components.
5. Pay attention to the daily maintenance of SMD machines and equipment.
6. Always pay attention to the setting of the process parameters of reflow soldering, and the furnace temperature must be tested twice a day.
7. In the process of SMT production, it is necessary to use a class of solvents such as anhydrous ethanol, flux, etc. The SMT production area needs to pay special attention to fire safety design.
8. Regularly conduct random spot checks on products on the production line, and deal with abnormalities in time.
Standardized SMT production processes can guarantee high-quality PCBA boards. Efficient placement is the best way to ensure a speedy project delivery date according to tight schedules and short lead-time.
Choosing a suitable and professional SMT placement company is the most important decision to ensure fast delivery of assembled electronic boards and excellent quality of products.
Follow us at PCBasic, In the next article will explain what DIP is and why and how it differentiates from SMT explained today.PCBasic is a one-stop PCBA manufacturing service provider, contact us and we will provide you with the best quality and consistency for your next PCBA project.
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