焊接機(jī)器人激光器是一種利用受激輻射光放大原理產(chǎn)生的單色定向聚焦能量束。可以獲得直徑小于001毫米、功率密度高達(dá)10W/m2的能量束。焊接機(jī)器人激光焊接是利用可見(jiàn)光或紫外光作為熱源，對(duì)工件進(jìn)行熔化和連接的焊接方法。激光能量的實(shí)現(xiàn)不僅僅是因?yàn)榧す獗旧砭哂蟹浅８叩哪芰?，還因?yàn)榧す饽芰扛叨染劢乖谝粋€(gè)點(diǎn)上，這增加了它的能量密度。

Welding robot laser is a monochromatic directional focused energy beam generated using the principle of stimulated radiation amplification. Energy beams with a diameter less than 001 millimeters and a power density of up to 10W/m2 can be obtained. Welding robot laser welding is a welding method that uses visible or ultraviolet light as a heat source to melt and connect workpieces. The realization of laser energy is not only due to the high energy of the laser itself, but also because the laser energy is highly focused on a point, which increases its energy density.

在激光焊接中，激光照射被焊接材料的表面并與之相互作用。一部分被反射，一部分被吸收，進(jìn)入物質(zhì)。對(duì)于不透明材料，透射光被吸收，金屬的線性吸收系數(shù)為107 ~ 108/m。

In laser welding, the laser irradiates the surface of the welded material and interacts with it. Part is reflected, part is absorbed, and enters the material. For opaque materials, the transmitted light is absorbed, and the linear absorption coefficient of the metal is between 107 and 108/m.

對(duì)于金屬來(lái)說(shuō)，激光在金屬表面被吸收并轉(zhuǎn)化為0.01 ~ 0.1m厚度范圍內(nèi)的熱能，使金屬表面溫度升高后傳遞到金屬內(nèi)部。原始的激發(fā)能通過(guò)一定的過(guò)程轉(zhuǎn)化為熱能。激光除了像其他光源一樣是電磁波外，還具有其他光源所不具備的一些特性，如高方向性、高亮度(光子強(qiáng)度)、高單色性和高相干性。

For metals, laser is absorbed on the surface of the metal and converted into thermal energy within a thickness range of 0.01~0.1m, causing the surface temperature of the metal to rise and then transfer to the interior of the metal. The original excitation energy is converted into thermal energy through a certain process. Laser, in addition to being an electromagnetic wave like other light sources, also has some characteristics that other light sources do not possess, such as high directionality, high brightness (photon intensity), high monochromaticity, and high coherence.

在激光焊接中，材料吸收的光能在很短的時(shí)間內(nèi)(約10s)轉(zhuǎn)化為熱能。此時(shí)，熱能被限制在材料的激光輻射區(qū)域，然后熱量通過(guò)熱傳導(dǎo)從高溫區(qū)域傳遞到低溫區(qū)域。金屬激光的吸收主要與激光波長(zhǎng)、材料特征溫度、表面狀態(tài)和激光功率密度有關(guān)。

In laser welding, the light energy absorbed by the material is converted into thermal energy in a very short time (about 10 seconds). At this point, thermal energy is limited to the laser radiation area of the material, and then heat is transferred from the high-temperature area to the low-temperature area through thermal conduction. The absorption of metal lasers is mainly related to laser wavelength, material characteristic temperature, surface state, and laser power density.

一般來(lái)說(shuō)，金屬的吸收率隨著溫度和電阻率的增加而增加。目前，焊接領(lǐng)域主要使用兩種激光器:YAG固態(tài)激光器(YTTRI-um YTTRI-um-al-石榴石，簡(jiǎn)稱YAG)和CO2氣體激光器。

Generally speaking, the absorption rate of metals increases with the increase of temperature and resistivity. At present, two types of lasers are mainly used in the welding field: YAG solid-state laser (YTTRI-um YTTRI-um al garnet, abbreviated as YAG) and CO2 gas laser.

蒸發(fā)的金屬可以防止剩余能量被金屬反射。

Evaporated metal can prevent residual energy from being reflected by the metal.

如果焊接金屬具有良好的導(dǎo)熱性，它將獲得更大的穿透力。激光在材料表面的反射、透射和吸收本質(zhì)上是光波與電磁場(chǎng)和材料相互作用的結(jié)果。當(dāng)激光波入射到材料上時(shí)，材料中的帶電粒子按照光波電矢量的速度振動(dòng)，使光子的輻射能量變成電子的動(dòng)能。物質(zhì)吸收激光后，產(chǎn)生一些粒子的剩余能量，如自由電子的動(dòng)能、束縛電子的激發(fā)能、剩余聲子等。

If the welded metal has good thermal conductivity, it will achieve greater penetration. The reflection, transmission, and absorption of laser on the surface of materials are essentially the result of the interaction between light waves, electromagnetic fields, and materials. When a laser wave is incident on a material, charged particles in the material vibrate at the speed of the light wave electric vector, converting the radiation energy of photons into the kinetic energy of electrons. After absorbing laser, substances first generate residual energy of some particles, such as the kinetic energy of free electrons, the excitation energy of bound electrons, and residual phonons.