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Number of SAT Thermocouples Required
According to paragraph 3.4.1.2. of AMS2750G: "The SAT shall be performed on all control and recording systems required by the applicable instrumentation type, as well as any additional recording systems used for parts and raw material acceptance in each control zone of each piece of thermal processiRead more
According to paragraph 3.4.1.2. of AMS2750G:
“The SAT shall be performed on all control and recording systems required by the applicable instrumentation type, as well as any additional recording systems used for parts and raw material acceptance in each control zone of each piece of thermal processing equipment used for production heat treatments.”
That means you should perform SAT on all control temperatures as well as any other temperature measurement system which are required by instrumentation type. For example Load thermocouples for instrumentation type A and B.
SAT is not required for overtemp systems (if overtemp protection is the only function of that system).
Each of those ‘systems’ (Thermocouple, TC wires, feedthroughs, and measuring/recording instrument) should be within SAT tolerance (which is 2F for class 1 equipment) to their SAT sensor.
See lessBurn in cycle for new hot zone
Furnace burn out (a.k.a. thermal cleaning) cycles are important part of vacuum furnace maintenance. It is meant to reduce and outgas contaminants inside the heating zone and within the insulation. For new hot zone it is more related to drying, conditioning and outgassing the remaining resin from insRead more
Furnace burn out (a.k.a. thermal cleaning) cycles are important part of vacuum furnace maintenance. It is meant to reduce and outgas contaminants inside the heating zone and within the insulation.
For new hot zone it is more related to drying, conditioning and outgassing the remaining resin from insulation manufacturing processes. Every new furnace should be burned out at it’s nominal temperature and I’d say this rule should also apply to any hot zone replacement. Your hot zone supplier should be able to tell you the nominal temperature of the hot zone.
Duration of burnout should be at least 2 hours at the temperature, however you may keep it longer if you see continuous improvement of furnace vacuum level.
Slow cooling is recommended after burnout.
IMPORTANT: The burn-out cycle is always performed with empty furnace. any tooling / fixturing and other equipment must be removed otherwise serious damage of furnace and tooling may occur.
See lessFor your own safety you should follow the OEM manuals.