Emission Data and Costs for Environmental Measures During Laser Joining of Metals

Laser welding and soldering are important joining processes in the automotive industry.Typical examples are the production of the car body of the VW Golf or the automatic gearbox of the Mercedes-Benz A-Class.Furthermore, there is a general trend to increase the use of lightweight materials (e.g.Mg, Al, alloys), and to combine different metallic materials to produce complex components (e.g. in tailored blanks).In order to ensure good practices with regard to occupational health and safety as well as environmental issues, laser joining processes have to be analyzed in detail.Avoiding and controlling emission products caused by laser processing of metals or metal composites is an important task in this context.Typically, costs for environmental measures represent a significant percentage of the total manufacturing costs related to a laser process.In this work, emission measurements of several laser welding and soldering processes for metal sheets from steel and brass are reported.Different steel grades and surface treatments of the metal sheets have been taken into account: pure, zinc-coated, PTFE-coated, oiled, cold cleaner residues.The hazardous potential of these processes has been assessed by means of analyzing the specific emissions with respect to the relevant threshold limit values (TLVs).Based on the experimental results, the processes have been classified according to measures which are required by environmental legislation.Finally, a cost calculation for measures related to emission capturing is presented.It has been shown that these environmental measures are manageable for all industrial laser processes regarded here, and the costs for these measures remain acceptable, i.e. in many cases below 8 % of the total processing costs.The results are made permanently available in an interactive internet database.Using this database, the planning of appropriate exhaust systems for laser welding and soldering is facilitated significantly.