Methods, advantages and applications of plastic laser welding machine
Laser welding, as a Technology of Welding plastic products, is mainly used to connect sensitive plastic products, such as circuit boards, electronic sensors for plastic parts, plastic products with complex shapes, and medical equipment and other plastic products that require strict sealing and cleanliness.
When using laser welding technology to weld two plastic parts, the parts need to be clamped together first, and then the wavelength is 810 ~ The 1064 nm near infrared laser is transmitted through the first component, and the laser is absorbed by the second component after transmission. The absorbed near infrared laser is converted into heat energy, the contact surfaces of the two parts are melted to form a welding zone.
Laser welding process can produce welding joints that exceed the strength of raw materials.
Common welding methods for plastic laser welding in practical application, there are several different welding techniques for plastic laser welding.
Sequential peripheral welding, the laser moves along the contour line of the plastic welding layer and melts it, gradually bonding the plastic layer together;
Or move the sandwich along the fixed laser beam to achieve the purpose of welding.
Synchronous welding, laser beam from multiple diode lasers, laser beam shaping through optical elements, laser beam is guided to the contour line along the welding layer, while generating heat at the weld, so that the whole contour line is melted and bonded together at the same time.
Scanning welding, scanning welding is also called quasi-synchronous welding. Scanning welding technology combines the above two welding technologies of sequential peripheral welding and synchronous welding.
The mirror is used to generate a high-speed laser beam at a speed of 10 m/s, moving along the part to be welded, making the whole welding place gradually heat up and fuse together.
Irradiation mask welding, laser beam positioning through the template, melting and bonding plastic, template only exposes a small and accurate welding position on the plastic layer below, the laser beam only heats the part of the product that is not covered by the mask.
High precision welding as low as 10 microns can be realized by using this technology.
The advantages of plastic laser welding the advantages of laser welding applied to the welding of plastic parts include: precise and firm welding, airtight and watertight sealing, less resin degradation and less debris in the welding process, the surfaces of the product can be tightly connected around the weld.
Laser welding has the advantage of no residue, making it more suitable for pharmaceutical products and electronic sensors controlled by the State Food and Drug Administration.
Easy to control, can weld small size or complex structure of the workpiece.
Because the laser is easy to be controlled by computer software, and the output of the fiber laser can flexibly reach all the fine parts of the parts, the laser welding can weld the areas that are not easily reached by other welding methods, welding Products with complex shapes and even three-dimensional geometry.
Compared with other welding methods, laser welding greatly reduces the vibration stress and thermal stress of products.
This means that the aging speed of products or internal components of the device is slower and can be applied to easily damaged products. Can weld many different kinds of materials.
For example, it can connect polycarbonate which transmits near-infrared laser and black polybutylene terephthalate reinforced by glass fiber together, however, it is impossible for other welding methods to connect two polymers that are so different in structure, softening point and reinforcing material.
Plastic laser welding application laser welding is a vibration-free welding technology, so it is especially suitable for precision electronic components such as mice, mobile phones, connectors, etc, as well as those complex parts that need to be welded in a cleaner way, such as plastic products containing circuit boards, medical equipment, etc.
In the automobile industry, laser welding plastic technology can be used to manufacture many automobile parts, such as automatic door lock, keyless entry and exit equipment, fuel nozzle, gear rack, engine sensor, cab rack, hydraulic oil tank, filter rack, headlights and taillights, etc.
Other automotive applications include the manufacture of intake pipe optical manifolds and the manufacture of auxiliary water pumps.
In the field of medicine, laser welding technology can be used to manufacture liquid storage tanks, liquid filtration equipment, hose connectors, ostomy bags, hearing aids, implants, microfluidic devices for analysis, etc.
The laser can also weld the plastic film together. It moves along the edge of the film and forms a package structure for packaging through bonding. The operation process can be completed very quickly.
The application research of new material activated laser welding shows that the transmittance of polymer to near infrared laser is at least 20-
50%, laser welding technology can obtain excellent welding effect.
Most natural color plastics and many colored translucent plastics can meet this light transmittance requirement. In other words, laser welding can be applied to most plastics.
On the other hand, the absorption rate of plastic to near infrared laser is also an important factor affecting the laser welding effect.
Most thermoplastics can greatly improve their laser absorption rate by adding an appropriate amount of carbon black, but for some materials, the application of laser welding still has certain limitations.
For example, if both materials are transparent or white, the near infrared laser can transmit through, resulting in extremely low absorption of the material to the near infrared laser. In this case, laser welding cannot be used.
Another typical example is PPS and LCP plastic. The transmittance of the two materials to near infrared laser is very low. If the two materials are filled with carbon black at the same time, laser welding cannot be carried out because the laser cannot penetrate.
In addition, many mineral-filled compounds are not suitable for laser welding. In order to overcome these limitations of laser welding, some plastic manufacturers actively research and develop new materials that help to improve laser transmittance and absorption rate, and has made gratifying progress, bringing a broader application prospect for laser welding technology.