Solder paste inspection and acceptance method

Abstract

The invention discloses a solder paste inspection and acceptance method, which comprises the following steps of: 1, checking the type, the production series, the production batch and the type of the solder paste, particularly paying attention to distinguishing whether the solder paste contains lead or not and whether the solder paste is a special solder paste for an LED or not; step 2, pasting an inspection label, writing inspection time, an inspector and an inspection purpose clearly, opening a cover, observing the appearance and the color through visual inspection, and manually confirming the viscosity; step 3, setting solder machine parameters according to specifications, performing a tension test after solder machine welding, and confirming the welding condition; step 4, using a tool to pick up solder paste with the size of mung beans, flattening the solder paste on a glass sheet, placing the glass sheet below a microscope, using the microscope to observe the distribution condition and size of solder beads, and comparing with a standard picture to judge whether the solder beads are qualified or not. The invention relates to the field of solder paste acceptance, in particular to a solder paste inspection and acceptance method.

Description

Technical Field

[0001] The invention relates to the field of solder paste inspection and acceptance, and in particular to a solder paste inspection and acceptance method. Background Art

[0002] Solder paste is a new type of welding material that came into being with SMT. Solder paste is a complex system, which is a paste made of solder powder, flux and other additives. Solder paste has a certain viscosity at room temperature, which can initially stick electronic components to a predetermined position. At the welding temperature, as the solvent and some additives evaporate, the components to be welded are welded to the printed circuit pads to form a permanent connection.

[0003] Solder paste inspection should be carried out according to the type and specifications, because the difference in solder paste content will affect the melting point and welding effect. Some products require high-temperature solder paste, some require low-temperature solder paste, etc., and tensile testing after welding is also required.

[0004] We often encounter some problems in production, that is, the solder paste packaged in bottles cannot be used up at one time. Most manufacturers will seal the solder paste again and put it in the refrigerator. After taking it out, stir it or add additives for continued use. The repeatability of this method is limited, and the solder paste needs to be confirmed in this regard.

[0005] Finally, regarding the inspection data and process archiving, they must also be kept consistent with the product shelf life. Summary of the invention

[0006] The present invention designs method steps for solder paste acceptance and inspection, and adds the requirement of retaining the acceptance and inspection process for repeated use.

[0007] To solve the above problems, the technical solution adopted by the present invention is as follows: The present invention is a solder paste inspection and acceptance method, comprising the following steps:

[0008] Step 1: Check the solder paste type, production series and production batch. Pay special attention to whether the solder paste contains lead and whether it is LED-specific solder paste.

[0009] Step 2: affix an inspection label with the inspection time, inspector and inspection purpose written down, open the cover, visually observe the appearance and color, and manually confirm the viscosity;

[0010] Step 3: Set the soldering furnace parameters according to the specifications, and perform a tensile test after soldering to confirm the soldering condition;

[0011] Step 4: Use a tool to pick up a bean-sized amount of solder paste, smooth it onto a glass sheet, place it under a microscope, observe the distribution and size of the solder beads under a microscope, and compare it with the standard picture to determine whether it is qualified;

[0012] Step 5: Use a tool to pick up a bean-sized amount of solder paste, smooth it onto the carrier sheet, place it in an X-ray detector for scanning, and obtain data to determine whether it is qualified;

[0013] Step 6: Confirm the oxidation resistance of the solder paste and the welding condition after exposure. Pick up 20 grains of solder paste and apply them to 20 pads respectively. Place them in a ventilated place, observe the appearance at regular intervals, and heat them to confirm the welding condition.

[0014] Step 7: Use a portion of the opened solder paste for soldering in a tin furnace, and store the remaining portion in a refrigerator for 12 hours. Open the solder paste again, stir it, use a portion of it for soldering in a tin furnace, and store the remaining portion in a refrigerator for 12 hours. Repeat this method several times, keep the sample used each time, and test the solder point data for tensile testing;

[0015] Step 8: Use the notebook and camera to fully record the test process to facilitate subsequent quality traceability and review.

[0016] Furthermore, the manual observation and manual confirmation in step 2 must be performed by professional staff with long-term experience.

[0017] Furthermore, in step 3, since the melting points of various solder pastes are different, the solder furnace parameters must be strictly determined in accordance with the requirements of the solder paste specifications, and the specifications cannot be modified without authorization, otherwise it is impossible to determine whether the solder paste meets the requirements.

[0018] Furthermore, the diameter of the pad in step six is ​​30-60 mm.

[0019] Furthermore, the interval time in step six is ​​5-10 minutes.

[0020] Furthermore, the step seven is repeated 5-10 times according to this method.

[0021] Furthermore, in step seven, the refrigerator is set at a temperature of 2-4°C.

[0022] Furthermore, the time that the record in step eight needs to be kept needs to be one year longer than the shelf life of the product.

[0023] The beneficial effects achieved by the present invention using the above structure are as follows:

[0024] 1. For bottled solder paste, the cap can be opened repeatedly, and detailed verification can be carried out for storage. The temperature and time can be set to verify the number of times the solder paste can be opened repeatedly. This is of great significance to the use of solder paste, feeding standards, and product quality.

[0025] 2. Record data and images throughout the solder paste testing process and keep them for a period of time that depends on the shelf life of the end product, which is helpful for finding and tracing quality problems. DETAILED DESCRIPTION

[0026] Example 1

[0027] The present invention is a solder paste inspection and acceptance method, comprising the following steps:

[0028] Step 1: Check the solder paste type, production series and production batch. Pay special attention to whether the solder paste contains lead and whether it is LED-specific solder paste.

[0029] Step 2: Attach an inspection label, specify the inspection time, inspector and inspection purpose, open the cover, visually observe the appearance and color, and manually confirm the viscosity. Manual observation and manual confirmation require professional staff with long-term experience;

[0030] Step 3: Set the soldering furnace parameters according to the specifications. Perform a tensile test after soldering to confirm the soldering condition. Since the melting points of various solder pastes are different, the soldering furnace parameters must be strictly set according to the requirements of the solder paste specifications. The specifications cannot be modified without authorization, otherwise it is impossible to determine whether the solder paste meets the requirements.

[0031] Step 4: Use a tool to pick up a bean-sized amount of solder paste, smooth it onto a glass sheet, place it under a microscope, observe the distribution and size of the solder beads under a microscope, and compare it with the standard picture to determine whether it is qualified;

[0032] Step 5: Use a tool to pick up a bean-sized amount of solder paste, smooth it onto the carrier sheet, place it in an X-ray detector for scanning, and obtain data to determine whether it is qualified;

[0033] Step 6: Confirm the oxidation resistance of solder paste and the welding condition after exposure. Pick up 20 grains of solder paste and apply them to 20 pads respectively. Place them in a ventilated place. The pad diameter is 30mm. Observe the appearance every 5 minutes and heat to confirm the welding condition.

[0034] Step 7: After using a portion of the opened solder paste for soldering through a tin furnace, put the remaining portion in a refrigerator for 12 hours. The refrigerator is set to a temperature of 2°C. Open the solder paste again, stir it, use a portion of the solder paste for soldering through a tin furnace, and put the remaining portion in a refrigerator for 12 hours. Repeat this method 5 times, keep the sample used each time, and test the solder point data for tensile testing.

[0035] Step 8. Use a notebook and a recording camera to fully record the test process to facilitate subsequent quality traceability and review. The record needs to be kept for one year longer than the product shelf life.

[0036] Example 2

[0037] The present invention is a solder paste inspection and acceptance method, comprising the following steps:

[0038] Step 1: Check the solder paste type, production series and production batch. Pay special attention to whether the solder paste contains lead and whether it is LED-specific solder paste.

[0039] Step 2: Attach an inspection label, specify the inspection time, inspector and inspection purpose, open the cover, visually observe the appearance and color, and manually confirm the viscosity. Manual observation and manual confirmation require professional staff with long-term experience;

[0040] Step 3: Set the soldering furnace parameters according to the specifications. Perform a tensile test after soldering to confirm the soldering condition. Since the melting points of various solder pastes are different, the soldering furnace parameters must be strictly set according to the requirements of the solder paste specifications. The specifications cannot be modified without authorization, otherwise it is impossible to determine whether the solder paste meets the requirements.

[0041] Step 4: Use a tool to pick up a bean-sized amount of solder paste, smooth it onto a glass sheet, place it under a microscope, observe the distribution and size of the solder beads under a microscope, and compare it with the standard picture to determine whether it is qualified;

[0042] Step 5: Use a tool to pick up a bean-sized amount of solder paste, smooth it onto the carrier sheet, place it in an X-ray detector for scanning, and obtain data to determine whether it is qualified;

[0043] Step 6: Confirm the oxidation resistance of solder paste and the welding condition after exposure. Pick up 20 grains of solder paste and apply them to 20 pads respectively. Place them in a ventilated place. The pad diameter is 45mm. Observe the appearance every 7 minutes and heat to confirm the welding condition.

[0044] Step 7: After using a portion of the opened solder paste for soldering through a tin furnace, put the remaining portion in a refrigerator for 12 hours. The refrigerator is set to a temperature of 3°C. Then open the solder paste, stir it, use a portion of the solder paste for soldering through a tin furnace, and put the remaining portion in a refrigerator for 12 hours. Repeat this method 7 times, keep the sample used each time, and test the solder point data for tensile testing.

[0045] Step 8. Use a notebook and a recording camera to fully record the test process to facilitate subsequent quality traceability and review. The record needs to be kept for one year longer than the product shelf life.

[0046] Example 3

[0047] The present invention is a solder paste inspection and acceptance method, comprising the following steps:

[0048] Step 1: Check the solder paste type, production series and production batch. Pay special attention to whether the solder paste contains lead and whether it is LED-specific solder paste.

[0049] Step 2: Attach an inspection label, specify the inspection time, inspector and inspection purpose, open the cover, visually observe the appearance and color, and manually confirm the viscosity. Manual observation and manual confirmation require professional staff with long-term experience;

[0050] Step 3: Set the soldering furnace parameters according to the specifications. Perform a tensile test after soldering to confirm the soldering condition. Since the melting points of various solder pastes are different, the soldering furnace parameters must be strictly set according to the requirements of the solder paste specifications. The specifications cannot be modified without authorization, otherwise it is impossible to determine whether the solder paste meets the requirements.

[0051] Step 4: Use a tool to pick up a bean-sized amount of solder paste, smooth it onto a glass sheet, place it under a microscope, observe the distribution and size of the solder beads under a microscope, and compare it with the standard picture to determine whether it is qualified;

[0052] Step 5: Use a tool to pick up a bean-sized amount of solder paste, smooth it onto the carrier sheet, place it in an X-ray detector for scanning, and obtain data to determine whether it is qualified;

[0053] Step 6: Confirm the oxidation resistance of solder paste and the welding condition after exposure. Pick up 20 grains of solder paste and apply them to 20 pads respectively. Place them in a ventilated place. The pad diameter is 60mm. Observe the appearance every 10 minutes and heat to confirm the welding condition.

[0054] Step 7: After a part of the opened solder paste is soldered through the tin furnace, the remaining part is placed in the refrigerator for 12 hours. The refrigerator is set to 4°C. Then, the solder paste is opened again, stirred, and a part of the solder paste is soldered through the tin furnace. The remaining part is placed in the refrigerator for 12 hours. This method is repeated 10 times. The sample used each time is retained, and the data of the soldering points are tested for tensile strength.

[0055] Step 8. Use a notebook and a recording camera to fully record the test process to facilitate subsequent quality traceability and review. The record needs to be kept for one year longer than the product shelf life.

[0056] It should be understood that although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for inspecting and accepting solder paste, characterized in that: The steps include: Step 1: Check the solder paste type, production series and production batch. Pay special attention to whether the solder paste contains lead and whether it is LED-specific solder paste. Step 2: affix an inspection label with the inspection time, inspector and inspection purpose written down, open the cover, visually observe the appearance and color, and manually confirm the viscosity; Step 3: Set the soldering furnace parameters according to the specifications, and perform a tensile test after soldering to confirm the soldering condition; Step 4: Use a tool to pick up a bean-sized amount of solder paste, smooth it onto a glass sheet, place it under a microscope, observe the distribution and size of the solder beads under a microscope, and compare it with the standard picture to determine whether it is qualified; Step 5: Use a tool to pick up a bean-sized amount of solder paste, smooth it onto the carrier sheet, place it in an X-ray detector for scanning, and obtain data to determine whether it is qualified; Step 6: Confirm the oxidation resistance of the solder paste and the welding condition after exposure. Pick up 20 grains of solder paste and apply them to 20 pads respectively. Place them in a ventilated place, observe the appearance at regular intervals, and heat them to confirm the welding condition. Step 7: Use a portion of the opened solder paste for soldering in a tin furnace, and store the remaining portion in a refrigerator for 12 hours. Open the solder paste again, stir it, use a portion of it for soldering in a tin furnace, and store the remaining portion in a refrigerator for 12 hours. Repeat this method several times, keep the sample used each time, and test the solder point data for tensile testing; Step 8: Use the notebook and camera to fully record the test process to facilitate subsequent quality traceability and review.

2. A solder paste inspection and acceptance method according to claim 1, characterized in that: The manual observation and manual confirmation in step 2 must be performed by professional staff with long-term experience.

3. A solder paste inspection and acceptance method according to claim 2, characterized in that: In step 3, since the melting points of various solder pastes are different, the solder furnace parameters must be strictly determined in accordance with the requirements of the solder paste specifications. The specifications cannot be modified without authorization, otherwise it is impossible to determine whether the solder paste meets the requirements.

4. A solder paste inspection and acceptance method according to claim 3, characterized in that: The diameter of the pad in step six is ​​30-60 mm.

5. A solder paste inspection and acceptance method according to claim 4, characterized in that: The interval time in step six is ​​5-10 minutes.

6. A solder paste inspection and acceptance method according to claim 5, characterized in that: The step 7 is repeated 5-10 times according to this method.

7. A solder paste inspection and acceptance method according to claim 6, characterized in that: In step 7, the refrigerator is set at a temperature of 2-4°C.

8. A solder paste inspection and acceptance method according to claim 7, characterized in that: The time that needs to be kept in the record in step 8 needs to be one year longer than the shelf life of the product.