Ultraviolet Laser Processing Application In PCB Industry
- Jan 27, 2018-
For laser cutting or drilling PCB industry, only a few or more than 10 watts of UV laser can, without kw level of laser power, in consumer electronics, automobile industry or manufacturing technology of the robot, the use of the flexible circuit board is becoming increasingly important.Due to the UV laser processing system has a flexible way of processing, high precision machining effect and flexible and controllable process, thus become the flexible circuit board and thin PCB laser drilling and cutting of choice.
1: CO2 laser (left) is compared with the UV laser (right) cutting slot.UV laser has a small thermal effect, and its cutting edge is clean and neat.
Today, laser system configuration of long life laser source is basically close to maintenance, in the production process, laser level is level 1, safety does not need other protection devices.The LPKF laser system is equipped with a vacuuming device that does not cause harmful emissions.With its intuitive and easy-to-use software control, laser technology is replacing the traditional mechanical process, saving the cost of special tool.
CO2 laser or UV laser?
For example, when PCB is split or cut, the wavelength is about 10.6. The CO2 laser system of mu m.Its processing cost is relatively low, the laser power that provides can reach several kilowatts.But it produces a lot of heat in the process of cutting, resulting in severe carbonization of the edges.
UV laser wavelength is 355 nm.This wavelength of laser light is very easy to focus on.The UV laser with a laser power of less than 20 watts has a diameter of only 20 m - and its energy density is even comparable to that of the sun.
UV laser processing advantage.
UV laser is especially suitable for the cutting and marking of hard plate, soft and hard board, soft board and auxiliary materials.So what are the advantages of this laser technology?
The UV laser cutting system shows great technical advantages in areas such as the PCB boards in SMT industry and microdrilling in PCB industry.Depending on the thickness of the PCB material, the laser is cut along the required profile once or more.The thinner the material, the faster the cutting speed.If the accumulated laser pulses are lower than the laser pulses needed to penetrate the material, only scratches will appear on the surface of the material.Therefore, the marking of qr code or bar code can be carried out on the material so as to follow the information of the subsequent process.
2: multiple components of a substrate, even if the line is close to the safety board.
UV laser pulse energy on the material only microsecond time, beside the incision JiWei meters, there is no heat affected obviously, there is no need to consider the heat damage of components.Lines near the edge and solder joints are intact, without burrs.
In addition, LPKF UV laser system integration CAM software can directly import the exported data from the CAD, edit for laser cutting paths, forming laser cutting contour, processing parameter database, choose suitable for different material can directly laser processing.The laser system is suitable for mass production and production.
The through-hole in the circuit board is used to connect the front and back of the double panel, or to connect any interlayer line in the multilayer board.In order to conduct electricity, the hole wall should be coated with metal layer after drilling.Now, the traditional mechanical method has been unable to meet the requirements of the hole diameter smaller and smaller, while improves the spindle speed, but the radial drilling tool rate will decrease due to the diameter is too small, can't even get to the requirements of the processing effect.In addition, it is also a limiting factor to consider the tool consumables that are easy to wear.
For the drilling of flexible circuit boards, LPKF has developed a new type of laser drilling system.LPKFMicroLine 5000 laser equipment is equipped with 533mm x 610mm working table, which can be rolled to the automatic operation of the volume.When drilling, the laser can first cut through the center of the hole to cut out the outline of the microhole, which is more accurate than the normal method.The system can drill a micro-hole with a minimum diameter of 20 mu m on the organic or non-organic substrate under the condition of high diameter and depth ratio.Flexible circuit boards, IC baseboards or HDI boards require such precision.
Semi-cured film cutting.
In the manufacturing process of electronic components, which conditions require the cutting of semi-cured sheet material?In the early stages, the semi-solidified sheet material has been applied to multilayer circuit boards.The various circuit layers in the multilayer circuit board are pressed together by the action of the half-cured film.According to the design of the circuit, the semi-solidified pieces in some regions need to be cut open and then pressed.
3: the laser process can be used to form a precise contour on the sensitive coating.
Similar processes apply to FPC mulch.The mulch usually consists of polyimide and the thickness of 25 mu m or 12.5. The rubber layer of mu m is formed and easily deformed.A single area (for example, a solder plate) does not need to cover the membrane so that it can be assembled and connected in the later stage.
This kind of thin material is very sensitive to mechanical stress - it can be done easily by non-contact laser processing.At the same time, the vacuum adsorption table can hold its position well and maintain its flatness.
Soft and hard binding plate processing.
In the soft and hard bonding board, the rigid PCB and the flexible PCB are pressed together to form a multilayer board.Pressing process, the flexible PCB is not above the rigid PCB pressing and bonding together, through laser cutting depth to cover lid on flexible PCB rigid cutting, separation, leave a flexible part, combined with hard and soft formation plate.
This kind of deep processing is also suitable for the blind groove processing of the surface embedded integrated elements in the multi-layer plate.The UV laser will precisely cut the blind slot of the target layer separated from the multilayer circuit board.In the region, the target layer is not connected to the material covered above.
PCB and FPC high efficiency board.
The SMT split-board is the circuit board that has been assembled for various electronic components, and the process is already at the end of the production chain.For boards, different techniques can be selected: for PCB commonly used, traditional knife cutting, stamping and contour milling are preferred.For more complex electronic circuits and thin substrate, especially for mechanical stress, dust and size deviation, the UV laser cutting board is more advantageous.The following three charts evaluate these three methods from different factors.
4. Comparison of board methods: other methods cannot achieve the quality of the UV laser.
For the cutting of the complete contour, the German LPKF company suggests that the thickness of the cutting material should not exceed 1 according to the different laser sources used.6 mm.For some thicker materials and expensive assembly components, safety and quality are preferred, while cutting duration is secondary.
5: in tab-cut, laser cutting breakpoint split board.
Cutting breakpoint splitter, the laser system cuts the connection point through a process described above.This cutting process can be close to the edge of the components, for thicker circuit board is also very economical.
Due to the short wavelength of UV laser, it can be applied to most materials processing.For example, it can be used in the field of electronic industry:
Processing TCO/ITO glass with no damage to the base.
To drill holes in flexible or thin materials.
Resistance welding layer or covering film opening.
A rigid flexible/flexible circuit board.
The repair of the assembly or unassembled circuit board.
The cutting of sintering ceramics.
Precision cutting LTCC.
The UV laser processing application in PCB industry is not limited to the processing of circuit boards. The UV laser system can also complete the cutting, direct writing and drilling of LTCC components simultaneously in a processing operation.
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