Thermal deburring

from Wikipedia, the free encyclopedia

The thermal deburring , including thermal deburring method (TEM; Engl. Thermal Energy Machining ) or Explosionsentgraten is a subtractive fabrication process , which uses the combustion principle to thin projecting ridges (sharp, resulting in a processing or manufacturing process edges fraying or splinters ) to deburr metallic and non-metallic workpieces by igniting a gas mixture at high temperatures in a so-called deburring chamber . The particular benefit of this process is that even hard-to-reach places - e.g. overlapping of two bores in the component - can be deburred.

A mixture of oxygen and hydrogen , natural gas or methane is fed into the hermetically sealed deburring chamber and then ignited electrically ( oxyhydrogen reaction ). The resulting temperatures of 2500 to 3500 ° C initiate combustion of the burr with the remaining oxygen. Since the burr surface is very high in relation to the burr volume, the heat introduced can only poorly be dissipated into the workpiece interior. The temperature of the material required for combustion is reached and only affects the burrs. For work safety, the workpieces must be free from layers of grease and oil. In connection with pure oxygen, they develop flammable vapors, which can heat up to the ignition temperature at the high filling pressures in the chamber of up to 23 bar. The reaction pressure in a combustion chamber is many times higher.

The deburring process is influenced by the mixing ratio of the gases, the filling pressure, the component geometry and, to a large extent, the thermal conductivity of the material. The disadvantage of this deburring process is that burrs that lie close to the component give off heat to the component and are so difficult to oxidize. Large quantities of chips should also be removed before thermal deburring, as in the worst case they will melt into a lump and stick to the component. With most types of steel, slag beads can remain and have to be further oxidized in a second deburring process, while aluminum and plastic workpieces do not require any further treatment.