There are several common lasers in the market, which are ultraviolet, green and infrared lasers. Infrared light is also divided into near infrared light (such as wavelength 1064nm YAG laser, fiber laser) and far infrared light (such as wavelength 10640nm CO2 laser).
V is currently recognized as the following two principles of plastic marking.
"Cold" refers to the use of high photon negative energy, can break materials (especially organic materials) or the surrounding medium within the chemical bond between laser and material, so that the non thermal effect of surface damage, and the nearby area of the workpiece does not produce heat or thermal deformation etc.. This "cold working" is of special significance in the processing of laser labelled processing
As mentioned above, "enough short wavelength can cause the dissociation of material molecules and lead to color change, which is the most perfect effect". What we call "ultraviolet laser" (wavelength 355nm) can achieve the best effect.
"Processing" refers to a laser beam with high energy density (concentrated energy flow), irradiation on the surface of material to be processed, so that surface absorption of laser energy, and produce thermal excitation processes in the illuminated area, so that the surface of the material (or coating), produce abnormal temperature rise, melting and ablation evaporation phenomenon.
The common laser for "hot processing" is a laser with a wavelength of 1064nm, such as a YAG laser, a fiber laser and so on. With the development of science and technology, now the infrared laser has been able to control some of the laser parameters flexibly. By adjusting these parameters, we can play the effect of UV laser on some materials. Another reason is that fiber lasers have incomparable advantages over traditional lasers, such as small volume, light weight, strong stability, maintenance free, air-cooled technology and good beam quality. The following will focus on the 1064nm wavelength fiber laser.
Effect of parameter adjustment of V 1064nm fiber laser on plastic identification
Pulse width
The width of the pulse width is the width of the laser pulse, which refers to the time that a beam of light acts on the surface of the material, so it is a time measurement parameter. For plastics, the length of laser acting on the surface is very important: too short time, there is not enough energy to react, only some light and Blister light marks. Over a long time, there will be serious carbonization and ablative cracks. So a proper pulse width is chosen to make the plastic surface change properly and get the effect we want. Whether the laser pulse width can be adjusted is a very important reference condition to judge whether the laser can handle the plastic products well.
Frequency
The frequency is called the repetition frequency of the laser, which means how many beams of light are emitted by the laser per second. The frequency of the laser is usually high and low, which corresponds to the speed of the laser scanning. However, the higher the frequency represents between each beam of light interval is short, plastic is a poor conductor of heat, heat dissipation is usually not ideal, the high frequency will produce heat accumulation, the heat accumulation is not what we want, it will make the material surrounding heat damage. The marking places will also appear bubbles, melting and cold, ablation subsidence phenomenon. Therefore, the processing should be based on the different melting points of each kind of plastic, and choose the appropriate frequency to achieve both effect and efficiency. For lasers, having enough range of laser frequency regulation will bring more possibility of plastic engraving.
Beam quality
The beam quality of M2 laser is an important parameter is the ratio between the actual and theoretical calculation of beam emitted from the laser beam quality, the ratio is close to 1 as possible, greater numerical means that the beam quality becomes worse, it is the most direct is through laser energy distribution after focusing, excellent beam quality after let the laser focusing and uniform beam quality difference is big and the focus after the divergence. M - the worse then available energy will be less, the excess heat will lead plastic marking we don't want the "heat affected zone", so that the effect tends to poor direction.
Peak power
The peak power of laser is the maximum power that can be achieved by a single beam of light. The higher the peak power, the more effective available laser energy is, the less the residual heat generated is, which will make the material vaporize or carbonize in the condition of no deformation and no melting. The mechanism is similar to the beam quality.
To sum up, for the plastic materials, processing a variety of optional laser light source, ultraviolet light, infrared light, green light can be competent, and when we decide to choose the infrared laser using 1064nm to do plastic marking, if the laser pulse width adjustment function, can have a larger frequency range, and the beam quality is good enough, the peak power is high enough, it is more likely to bring up a satisfactory effect.
By GEM LASER LINITED
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