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In-Depth Applications of Laser Cutting Machines in Key FPC Processes
1. High-Precision Contour Cutting: From Regular to Complex Shapes
In the FPC contour processing link, laser cutting machines demonstrate excellent adaptability:
· Rigid-Flex Board Cutting: For rigid-flex transition areas (rigid FR-4 and flexible PI), dynamic power adjustment technology is used. When cutting rigid parts, an energy of 80-100mJ/mm² is applied, and for flexible parts, it is reduced to 50-60mJ/mm² to avoid edge cracking caused by material hardness differences. An electronics manufacturer indicate that this process increases the yield rate of rigid-flex boards from 75% to 95%.
· Micro-Connecting Bridge Processing: In the cutting of 0.15mm-wide connecting bridges, the laser cutting machine uses 50ns ultra-short pulse technology to control the heat-affected zone within 20μm, an 80% reduction compared to the 100μm heat-affected zone of traditional mechanical cutting, effectively preventing connecting bridge breakage and ensuring FPC integrity.
2. Micro-Hole Processing: Breaking Through Size Limitations for Aperture Control
For FPC via and mounting hole processing, laser cutting machines have achieved a leap from "usable" to "precise":
· Sub-100μm Micro-Hole Processing: Using 355nm UV laser, the high energy density of its short wavelength enables processing of 50μm-diameter micro-holes with a hole wall roughness ≤5μm, meeting the micro-hole needs of high-density interconnect (HDI) FPCs. Data from a PCB processing factory shows that the first-pass rate of laser-processed micro-holes reaches 98%, a 25-percentage-point increase over traditional mechanical drilling.
· Multi-Layer Hole Alignment: Through the linkage of a visual positioning system (precision ±3μm) and laser processing, the hole position deviation during the processing of stacked FPCs with more than 3 layers can be controlled within 10μm, solving the hole position deviation problem caused by uneven stacking pressure in traditional mechanical processing.
3. Surface Treatment: Non-Contact Fine Processing
In addition to cutting functions, laser cutting machines also have innovative applications in FPC surface treatment:
· Coverlay Windowing: When processing 50μm-thick polyimide coverlay for windowing, the laser cutting machine can achieve 0.1mm-wide slit cutting with no edge curling or residual glue, saving 40% of the process time compared to traditional chemical etching and avoiding chemical pollution.
· Gold Finger Forming: In the cutting of 0.05mm-thick gold-plated layers, energy gradient control technology is used. High energy is first used to cut the underlying PI substrate, and then low energy is used to fuse the surface gold layer, avoiding gold layer burrs and edge oxidation caused by traditional mechanical cutting and improving subsequent welding reliability.
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What are the precautions for operating a laser marking machine?
1. It is strictly prohibited to start the laser power supply and Q-switching power supply when there is no water or the water circulation is abnormal.
2. The Q power supply is not allowed to operate without load (i.e., the output terminal of the Q power supply should be left floating).
3. In case of any abnormal phenomenon, first turn off the galvanometer switch and the key switch, and then conduct a check.
4. It is not allowed to start other components before the krypton lamp is lit to prevent high voltage from entering and damaging the components.
5. Pay attention to leaving the output terminal (anode) of the laser power supply suspended to prevent sparking and breakdown with other electrical appliances.
6. Keep the internal circulating water clean. Regularly clean the water tank and replace it with clean deionized water or pure water.
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What should we do when laser intensity decreases and the marking is not clear enough?
1. Turn off the machine and check if the laser resonant cavity has changed; Fine-tune the resonant cavity lens. Make the output light spot the best;
2. The acousto-optic crystal is offset or the output energy of the acousto-optic power supply is too low;
Adjust the position of the audio-visual crystal or increase the working current of the audio-visual power supply;
3. The laser entering the galvanometer deviates from the center: Adjust the laser;
4. If the current is adjusted to around 20A but the light sensitivity is still insufficient: the krypton lamp is aging. Replace it with a new one.
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How to maintain a UV laser cutting machine?
1. It is required to carry out regular cleaning every day, remove debris from the countertop, limiters and guide rails, and spray lubricating oil on the guide rails
2. The waste materials in the collection box should be cleared regularly to prevent excessive waste from blocking the exhaust port.
3. Clean the chiller once every 15 days, drain all the internal water, and then fill it with fresh pure water.
4. The reflector and focusing lens should be wiped with a special cleaning solution every 6 to 8 hours.
When wiping, use a cotton swab or cotton swab dipped in the cleaning solution to wipe from the center to the edge of the focusing lens in a counterclockwise direction.
At the same time, be careful not to scratch the lens.
5. The indoor environment can affect the lifespan of the machine, especially in damp and dusty conditions.
A damp environment is prone to causing rust on the reflective lenses and also easily leading to short circuits, discharge and sparking of the velvet laser.
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What accidents might be caused by the laser emission when using a laser cutting machine?
(1) A fire was caused by the laser coming into contact with flammable materials.
Everyone knows that the power of laser generators is very high, especially when it comes to high-power laser cutting machines, the temperature of the emitted laser is extremely high. The possibility of a fire being caused when a laser beam comes into contact with flammable objects is very high.
(2) Harmful gases may be produced when the machine is in operation.
For instance, when cutting with oxygen, it undergoes a chemical reaction with the cutting material, generating unknown chemical substances or fine particles and other impurities. After being absorbed by the human body, it may cause allergic reactions or discomfort in the lungs and other respiratory tracts. Protective measures should be taken when conducting work.
(3) Direct laser exposure to the human body can be harmful.
The damage caused by lasers to the human body mainly includes damage to the eyes and skin. Among the harms caused by lasers, the damage to the eyes is the most severe. Moreover, damage to the eyes is permanent. So when doing homework, you must pay attention to protecting your eyes.
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What is the focused spot diameter of nanosecond, picosecond and femtosecond laser?
Nanosecond: The light spot is 0.5-1mm.
Picosecond: The focused spot is around 0.02mm.
Femtosecond: Under the action of a laser beam with a high repetition rate of 100-200KHz and a very short pulse width of 10ps,
the focused spot diameter is as small as 0.003mm.
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What are the main applications of UV laser cutting machine?
The UV laser cutting machine can be used for cutting and depaneling PCB.
It can precisely cut and shape various types of PCB circuit boards with V-CUT and stamp holes, and open Windows and covers.
It can also be used for separating packaged circuit boards and ordinary smooth boards.
It is suitable for cutting various types of PCB substrates, such as ceramic substrates, rigid-flex boards, FR4, PCBs, FPCs, fingerprint recognition modules, cover films, composite materials, copper substrates, aluminum substrates, etc.
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Precautions for laser cutting machines to process various metal materials?
Copper and brass:
Both materials have high reflectivity and excellent thermal conductivity.
Brass with a thickness of less than 1mm can be processed by nitrogen laser cutting.
Copper with a thickness of less than 2mm can be cut. The gas used for laser cutting processing must be oxygen.
Copper and brass can only be cut when a "reflective absorption" device is installed on the system. Otherwise, reflection will damage the optical components.
Synthetic materials:
Processable synthetic materials include: thermoplastics, thermosetting materials and artificial rubber.
Aluminum:
Despite its high reflectivity and thermal conductivity, aluminum materials with a thickness of less than 6mm can be cut, depending on the type of alloy and the capacity of the laser.
When cutting with oxygen, the cutting surface is rough and hard.
When nitrogen is used, the cutting surface is smooth.
Pure aluminum is extremely difficult to cut due to its high purity.
Only when a "reflection and absorption" device is installed on the fiber laser cutting machine system can aluminum materials be cut.
Otherwise, reflection will damage the optical components
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What should be paid attention to when laser cutting stainless steel?
Laser cutting processing of stainless steel requires the use of oxygen, under the condition that edge oxidation is not a concern.
If nitrogen is used to achieve an edge free of oxidation and burrs, no further processing is required.
Coating an oil film on the surface of the sheet will achieve a better perforation effect without reducing the processing quality.



