There are thousands of references in which you might have heard in theoretical concept and in various practical uses of lasers. They are used in many day to day things, right from the portable CDs to sophisticated system, Laser has several use. Laser stands for ‘Light Amplification by Stimulated Emission of Radiation’. Well here we will not discuss about the theoretical concepts and practical use of it in various aspect. Here we will discuss in depth about the implication of laser in welding.
Laser beam welding is the kind of welding technique which is use to join two or multiple pieces of meal by making use of Laser. Basically beam act as a heat source which allows deep weld at high welding rates. This process is highly used in the areas like automotive industry.
Laser Beam welding introduction:
Laser beam welding has high power density just like electron beam welding and it has order of 1MW/ cm2 which results in small heat affected zones. The spot size in laser beam welding varies from 0.2 mm to 13 mm. The depth of penetration depends on the proportion of the amount of power supplied; however aspects like focal point also play a vital role.
Implication of pulsed or continuous laser beam mainly depends upon the kind of application in which it has to be used. Continuous laser welding is used to employ where deep welding is required whereas pulse welding is brought into use where you need to weld thin material like razor blades.
Laser beam welding is seen to be a versatile welding process, which has the capability to do weld metals like carbon steel, stainless steel, HSLA steel, titanium and even aluminium. Good thing about laser beam welding is the quality you get while welding any kind of metal. The speed of welding is directly proportional to the amount of power being supplied and it also depends on the thickness of the metal on which welding is performed.
Type of Laser beam welding:
Solid state laser:
Solid state laser welding mainly operates at the wavelength of order 1 Micrometre. Compared to gas welding the wavelength used in solid state laser welding is much shorter, this results in the operators to wear special eyewear or special protection screen to prevent any damage to retina. Nd: YAG laser can be used in both kind of mode: pulsed or continuous. Solid state laser welding design comprises of single crystal shaped rod which is approx. 20 mm in diameter and can be long up to 200 mm. It is ground flat at the end. The round is surrounded by tube which contains krypton or xenon. When this kind of welding is used, the pulse of light emits which last for approx. 2 millisecond. In the current trend, disk shaped crystal is quite popular. Even the use of ruby laser is growing in the industry as it outputs the power of 10-20 W.
Gas laser is another type of laser beam welding and it makes use of high voltage and low current source to supply energy needed to excite the gas used as the laser medium. This type of laser is also operable in pulsed and continuous mode. The wavelength of the laser beam in gas laser is 10.6 ?m.
Fibre laser welding, as the name suggests is the welding type in which optical fibre gains the medium of laser. These kind of welding are capable of power up to 50 KW and are popularly being brought into use in robotic industrial welding.
Advantage of Laser Beam welding:
- Laser beam can be easily transmitted though air and you do not require any vacuum medium for performing the welding process on any metal.
- The process is easily automated with the use of robotic machinery or compute software application specially programmed to control the laser beam welding machines.
- X ray are not generated which make it safer to use.
- Laser beam welding results in high quality welding.
Equipment brought into use in Laser beam welding:
- Mainly two type of laser are commonly used in the laser welding. Laser and gas welding, they are also referred as ruby laser welding and Nd:YAG laser welding.
- Chromium, aluminium oxide, neodymium, crystal composed of aluminium garnet and neodymium is brought into use for laser welding in ruby and gas welding.
- For gas welding, mixture of gases like carbon dioxide, nitrogen and helium is brought into use as the medium.
Laser welding is applicable to wide range of ferrous and nonferrous metals; however there are various combinations of metals which even perform better than other. For instance the combination of 304 and 304L series stainless weld extremely perform well when laser beam welding is performed on it, whereas the combination of 303, 316 and 316L stainless are quite sensitive and they even get cracked many time while performing laser beam welding. Since stainless is popularly used because of its machine ability, it is possible to make components from 303 and 304L. The resulting alloy would be less sensitive and have better exposure to laser beam welding.
On the other hand laser beam welding perform on titanium, copper and on certain aluminium reflects better to heat transfer characteristics of laser beam welding. Laser beam welding can also be used to join dis-similar metals such as copper and stainless to certain type of bronze.
Similarities and Differences to Other Welding Processes
Laser beam has lots many similarities and difference with other type of welding processes. Laser beam welding is similar to characteristics of Gas Tungsten Arc welding. Just like laser welding, in Gas Tungsten welding, a fusion process is performed under the inert cover gas. Laser beam welding also as similarities with electron beam welding, as both of these welding are a high energy density beam process, however they both differ as laser beam welding do not require work piece to complete an electrical circuit. Laser beam welding can be performed with vacuum chamber hence it is also cost effective then electron beam welding.
So, these were the detail information on Laser beam welding. Do share you view on this post and also let us know what you want to know more on laser beam welding. We assure to come back soon with the information as per your interest.