Laser cleaning machine has the characteristics of high efficiency, low cost, small wear and high cleanliness. With the development of laser technology, more laser equipment is used in the field of mold cleaning.
Laser cleaning is a fine cleaning process, according to different pollutants and different substrate materials to choose the appropriate parameters, to achieve the perfect cleaning of pollutants and not hurt the base material. Therefore, the setting of the laser parameters in the laser cleaning mold is very important. Only by fully understanding what each laser parameter will affect the cleaning effect, can we set the precise parameters with ease, and only set the appropriate parameters can achieve the perfect cleaning effect.
The principle of laser cleaning mold is that the laser and pollutants interact, the light energy is converted into heat energy, and the pollutants are gasification in a very short time to achieve the purpose of cleaning. The basis of laser cleaning is to absorb laser energy. To absorb laser energy, it is necessary to choose different laser wavelengths. Different substances have different absorption rates for different wavelengths, so the laser wavelength with the highest absorption rate should be selected. But this is only theoretical, the actual situation from the perfect ideal gap is still very large. For example, the domestic laser leader Ruike, Chuangxin, Jiept and other laser manufacturers, can choose the laser wavelength is not more than 3 kinds, for example, Chuangxin laser only has a wavelength of 1064nm fiber laser, so the domestic laser equipment mostly uses a wavelength of 1064nm fiber laser. But it does not mean that the laser has only one wavelength, nor does it mean that the laser of this wavelength has the highest effect, it is only the most widely used in the field of laser processing, because it is relatively easy to maintain, cost-effective, long life. This is like only one kitchen knife in the home, all the places with the kitchen knife to solve, this is also a special period in the process of laser development, later more wavelength laser will be applied to the processing field.
In this context, to understand the laser parameter setting, since the laser wavelength is not much selective, then its cleaning principle has changed. Theoretically, the pollutant absorbs laser energy and instantaneous gasification to achieve the purpose of cleaning, but in the actual mold cleaning, the mold itself absorbs laser energy to produce thermal stress, and the thermal stress is greater than the adhesion force to achieve the purpose of cleaning. Under the guidance of such a theory, the parameters to be paid attention to in the laser cleaning mold are as follows:
1. Laser energy density. Laser energy density is one of the most important parameters in laser processing, and the laser energy density must be somewhere between the cleaning threshold and the damage threshold. Just can achieve the cleaning effect of laser energy density value called cleaning threshold, just damage base material laser energy density value called damage threshold, between cleaning threshold to damage threshold is a very narrow range, laser energy density is below the cleaning threshold, no matter how long, no matter how many times scan can achieve the purpose of cleaning, if the laser energy density is higher than the damage threshold, will cause irreparable damage to the die material. Laser energy density is not calculated in the actual operation, but through the experiment, so it is necessary to find a piece of waste mold to test the parameters before cleaning the mold, and the parameters are appropriate and then used in regular cleaning.
2. Laser repetition frequency. The combination of laser pulse width and repetition rate affects the laser energy density. When the laser repetition frequency increases, the peak power will decrease, the energy of a single pulse will decrease, the peak power seriously affects the laser energy density, but also seriously affects the cleaning effect. So the final laser parameter is the balance between pulse width, laser power and repetition rate. In the actual operation, the pulse width should be as low as possible, the laser power should be determined according to different machines, and the repetition frequency should be taken as small as possible, but it should be appropriate.
3. Light beam quality. In the process of mold cleaning, optical fiber wire is often used to transmit the laser. In the transmission process, the laser beam will be "shaped", and the divergence Angle and spot diameter of the laser are adjusted. The smaller the divergence angle, the longer the focal depth, and the farther the scanning head is from the mold. The smaller the spot diameter, the greater the energy density, and the spot diameter also closely affects the laser energy density.
4. Pulse number. The pulse number can affect the cleaning threshold and the damage threshold, and their cleaning threshold is different under different pulse numbers.
In short, the laser energy density is the most important parameter in the application mold of the laser cleaning machine. The laser wavelength, laser repetition frequency, laser beam mass and pulse number all affect the laser energy density at different angles, and finally form a stable laser output in the balance of the square. DH LASER Has many years of laser cleaning machine application experience, in the laser cleaning mold industry is also has its own unique insights, welcome to customers and friends to come to exchange and discuss.