Temparature Control Of Vaccum Brazing Furnace Using PLC
The main objective of this project is to maintain & control temperature uniformly of the two zones in vacuum brazing furnace and braze similar or dissimilar components using certain chemicals, for the given specifications of a Brazing alloys used for brazing the components of gas turbines and aerospace applications contain nickel as the base material.
Nickel has highest affinity for oxygen. Incase if components are brazed using nickel as based filter material in air or atmosphere the braze joint will porous and braze strength is not achievable.
To avoid the presence of oxygen while brazing, either inert gas furnace or vacuum furnace can be used. Vacuum furnace is superior to inert gas controlled by furnace as only one ppm of oxygen can be present and hence it is possible to get good braze and strength. Apart from this the surface finishing of the processed components is an additional advantage.
In the second phase the control variable is temperature. The maximum temperature achievable from this furnace is 1350degree C. In this phase it includes 2 cycles-brazing cycle and post brazing cycle. In the first cycle brazing for process takes place with the temperature developed. In the second cycle uniformity of temperature in component takes place. Molybdenum heating elements are used in this furnace. Thermocouples are used as sensing elements
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