Foreword
With the in-depth integration of electronic products into human daily life and work, PCBA process technology has gradually become an indispensable part of basic industry. If whether a city has an electronic product R&D and manufacturing industry is an indicator to measure whether a city has industrial advancement, the number of SMT factories and whether they are advanced or not is the spokesperson of this indicator.
The main process of SMT includes solder paste printing, component mounting, reflow soldering three major processes, solder paste printing quality inspection, patch quality inspection, solder joint quality inspection is the best supporting process, offline supporting processes also include solder paste inspection & storage, steel plate design acceptance storage, scraper technology, PCB & PCBA cleaning technology, first article inspection technology, automatic storage and automatic feeding technology, temperature monitoring and testing technology, product automatic transfer technology, information active scheduling technology, nitrogen technology, compressed air technology, etc.
Among the three main processes of SMT, component placement is the most critical and the most valuable equipment. This article will explain the pain points & difficulties & solutions of component placement technology in today's industry, the development direction and progress of SMT technology, the direct relationship between SMT technology and welding quality & management blind spots.
The industry's most advanced component placement technology today
Component placement technology is based on small steps and steady progress, and all equipment manufacturers have carefully carved out the details to improve the production efficiency and production quality of the PCBA industry. With the rapid and deep integration of portable products into people's daily life, electronic products not only need to meet the needs of light, thin and short size, but also need to meet the needs of improved performance, simple operation and humanization.
The other development route is the opposite, such as the base station of high-frequency communication, the size of which is larger than the original server. This trend of bigger and smaller seems to be contradictory, but it also promotes the development of SMT technology. It requires efficient, stable and high-precision work of equipment, and also requires to reduce the dependence on the skills of operators and maintainers, reduce the failure rate of equipment, and reduce maintenance costs and time.
At the same time, equipment is required to be more cost-effective and intelligent, and the good news is that equipment manufacturers have done it. Today's advanced component placement technology in the industry is only known to the author and used as follows for the reference of colleagues in the industry.
1. Minimum component placement capacityToday, a large number of components are mass-produced in British 01005 (metric 0402), and some equipment has the ability to place British 008004 (metric 0201) components.
2. Bare die placement capabilitySeveral head placement equipment have bare chip placement capabilities, and the feeding methods are wafer direct feeding-4 inches, 6 inches, 8 inches, and 12 inches wafer can be tray-tray-tray, and DDF can also be used.
3. Accuracy of component placement positionThe highest placement accuracy of today's placement machine in the industry is +5um.
4. Gentle ability of component placementAt present, the industry's lightest placement pressure is 03N, to ensure that the suction placement does not damage the components.
5. Component identification ability——Identification technology of transparent parts and special-shaped parts is a technical problem for some placement machines, and excellent placement machines can identify transparent parts such as glass components, reflective parts and special-shaped devices.
6. Component absorption capacityAt present, the industry's placement machine can absorb the smallest component metric 0201 (imperial 008004) and the maximum 10cm device.
7. Component specification measurement abilityWhen the first piece is produced, the equipment grabs the chip component and measures its specification value to ensure that the material is correctly remounted.
8. The ability of intelligent equipment to prevent the wrong direction of componentsIf the component is supplied in the wrong direction, the machine will automatically identify and adjust to the correct direction to ensure that the placement is correct.
9. The ability of intelligent equipment to prevent component receiving errors and feeding errorsFor example, the equipment automatically detects the material receiving port, and automatically measures whether the specifications of the material are correct.
10. Simplified equipment maintenance and maintenance, such as the overall quick disassembly of the patch head.
11. Flexible equipment functionsThe head can be flexibly replaced, such as the placement head and the dispensing head can be replaced, which can flexibly respond to the needs of the manufacturing process.
12. Intelligent equipment feeding capacity, bulk connector, blister tray connector feeding scheme. With the rising labor costs, the difficulty of recruitment, training and management of basic employees has increased, and many product designs use through-hole reflow soldering process to replace the traditional through-hole insertion welding process. Flexible feeding technology has made a significant contribution to solving this problem in the industry.
13. The specifications of absorbing and grabbing components can be expandedThe author saw that the 10cm high connector of a certain enterprise can be placed and welded normally, which saves the plug-in personnel before reflow, and also ensures the quality of through-hole reflow soldering. It should be noted that the use of wave soldering in this product cannot meet the demand for tin penetration, due to the huge heat capacity of the device & PCB via, wave soldering, selective soldering, and manual soldering cannot meet the production quality requirements.
14. The placement strength can be selected, and the maximum force can reach 10kg for single-pin insertion crimping terminals, which eliminates the need for follow-up crimping process, which has mature applications in the field of automotive electronics.
15. Artificial intelligence, double-sided automatic laying of support pinsIt avoids the damage and plate bending caused by the abnormal manual laying support. This technology is well established in today's industry.
Pain points & difficulties in the component placement process
While SMT component placement technology is mature, resources are constrained for most PCBA fabs. The author summarizes the problems encountered in the daily production process of various enterprises as follows for your reference, so as to add them to the consideration scope of new equipment evaluation and avoid technical bottlenecks after equipment purchase
1. The height of the components that can be grabbed by the placement machine is limited, and the components beyond the height range cannot be placed, although the incoming materials are standard rolls or trays, and the production can only be manually hand-swamped.
2. The placement machine cannot effectively identify the component positioning column, resulting in inadequate placementThe metal kink feet of the metal housing components cannot be recognized, resulting in inadequate placementThe inclination of the through-hole insertion terminal cannot be identified, resulting in inadequate placement, and manual manual insertion is used in production.
3. The physical center of the special-shaped component does not coincide with the physical center of gravity, resulting in inadequate placement.
4. The component has KINK feet, the pressure of the placement head is insufficient, and the pressure exceeds the standard during placement.
5. The camera recognition ability is insufficient, and the pin or terminal size is 0Less than 1 mm cannot be recognized.
6. Transparent and reflective elements cannot be recognized.
7. The turning angle of the vitreous element and the overweight element is not in place (slip rotation angle).
8. The nozzle configuration is not in place, and the special-shaped components absorb the vacuum.
9. BGA solder ball oxidation The size ball cannot be effectively identified, resulting in BGA virtual soldering and HIP.
10. The cutting deviation of the surface mount filter (such as the bottom 5 pads) cannot be identified by mounting.
11. The diode and triode are mounted in reverse white.
12. Resistors, filters, etc. are mounted with anti-white.
13. Large-size connectors cannot be recognized, and there is no segmentation identification ability.
14. The nickel sheet is abnormal during placement, and the double chip is abnormal after repeated placement after manual processing.
15. The bare chip wafer cannot be supplied, and the manufacturer must change it to REEL before it can be absorbed.
16. The large-size connector cannot be fed, and the incoming material is in the blister tray mode or bag mode.
17. The compatibility of special-shaped nozzles is poor, and special-shaped materials cannot be used, such as Nozzle Bank does not support special-shaped nozzles.
18. The ultra-thin component sucks up the missing parts, the minimum suction force is too large, and there is no non-contact suction function.
19. The minimum placement force is 2N, and the wearing components are damaged.
20. QFN components, tray materials, and a certain material cannot be effectively identified and intercepted in reverse.
21. The production line changes the feeding method, such as the roll package is changed to the tray package, the feeding direction changes, the placement direction is wrong, and the equipment cannot effectively identify and intercept.
22. Bulk materials such as bagged materials and stub materials cannot be fed.
23. The static control of coil charging and packaging materials is not strict, and the materials are taken away by the material film when feeding.
24. The material film is too long and needs to be manually sheared.
25. The workshop environment is not good, and the ultra-fine material nozzle is easy to be blocked.
The above are some of the current component placement problems of some enterprises in the industry, due to space limitations, the follow-up will explain them one by one and give effective solutions, welcome to continue to pay attention to the follow-up articles. Industry colleagues are welcome to write and share their solutions and experiences.
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