Precautions for operating a customized laboratory rotary furnace

The operation of customized laboratory rotary furnaces must strictly follow safety regulations and process requirements, combined with their dynamic heating, atmosphere control, and other characteristics. Special attention should be paid to equipment start-up, operation, shutdown, and maintenance. The following are specific operational precautions:

1. Preparation before operation
Equipment inspection
Mechanical structure: Check whether the rotating parts of the furnace body (such as gears, bearings, and drive belts) are loose or worn, ensuring smooth rotation without any jamming.
Electrical system: Confirm that the power cord, heating element (resistance wire, induction coil), and temperature sensor (thermocouple, thermistor) are securely connected without damage or aging.
Atmosphere control system: Check whether the gas pipeline, valves, and flow meters are leaking, whether the oil level of the vacuum pump (if equipped) is normal, and whether the seals are intact.
Safety device: Verify whether the functions of explosion-proof valve, over temperature alarm, emergency stop button, etc. are normal, and ensure that the exhaust gas treatment device (such as activated carbon adsorption tank) is installed and available.
Confirmation of process parameters
Temperature curve: Set the heating rate, insulation temperature and time, and cooling rate according to experimental requirements to avoid substrate cracking or film detachment caused by sudden temperature changes.
Atmosphere conditions: Clearly define the type of gas to be introduced (such as N ₂, H ₂, O ₂, NH ∝), flow rate and pressure, or vacuum requirements (such as ≤ 10 ⁻ Pa), to ensure compatibility with the coating process.
Substrate compatibility: Confirm that the substrate material (such as metal, ceramic, polymer) is compatible with the furnace tube material (quartz, corundum, silicon carbide) to avoid chemical reactions or contamination.
Environment and Protection
Ventilation requirements: Ensure good ventilation in the laboratory to avoid the accumulation of flammable gases (such as H ₂) that may cause explosions.
Personal protection: Operators are required to wear protective goggles, heat-resistant gloves, gas masks (if handling toxic gases), and anti-static work clothes.
Warning signs: Set up warning signs such as “high temperature”, “high pressure”, “toxic gas” around the equipment, and prohibit unrelated personnel from approaching.

2. Operation process specification
Device startup
Preheating stage: Preheat the furnace body to 100-200 ℃ with low power (such as 50% rated power) first, eliminate moisture in the furnace, and avoid water evaporation at high temperatures that may cause furnace tube rupture.
Atmosphere replacement: If an inert atmosphere (such as N ₂) is required, first introduce gas for 5-10 minutes to replace the air inside the furnace and prevent substrate oxidation; If a vacuum environment is required, first start the vacuum pump to the target vacuum level.
Rotation test: Rotate the furnace body without load at low temperatures (such as ≤ 200 ℃) to observe whether the operation is smooth, without abnormal vibration or noise.
Heating and Coating
Segmented heating: Gradually heat up according to the preset temperature curve, and hold for 10-15 minutes after each stage of heating to ensure uniform temperature inside the furnace.
Dynamic monitoring: Real time monitoring of temperature distribution inside the furnace through temperature sensors. If local overheating (temperature difference>10 ℃) is found, the heating power or rotation speed should be adjusted immediately.
Dynamic atmosphere adjustment: Adjust the gas flow rate or switch the atmosphere type in real time according to the coating stage (such as pretreatment, deposition, post-treatment) to avoid cross contamination.
Observation of substrate condition: Regularly check the substrate movement and film deposition through observation windows or sampling ports to prevent adhesion or accumulation.
Safety Control
Overtemperature protection: If the temperature exceeds the set value ± 5 ℃, an alarm will be triggered immediately and the power will be automatically cut off. Manual coverage of the protection function is prohibited.
Gas leakage treatment: If you smell an irritating odor or detect a gas leak, immediately turn off the gas source, turn on the ventilation system, and evacuate personnel to a safe area.
Emergency stop: In case of furnace jamming, abnormal noise or fire, immediately press the emergency stop button, cut off the power and gas supply, and use a fire extinguisher (such as CO ₂ fire extinguisher) to extinguish the fire.

3. Shutdown and post-processing
Cooling control
Natural cooling: After the experiment, turn off the heating power first, keep the furnace rotating and the atmosphere circulating until the furnace temperature drops to ≤ 200 ℃.
Forced cooling: If rapid cooling is required, cooling gas (such as N ₂) can be introduced or the water cooling system can be started, but the cooling rate should be controlled (≤ 50 ℃/min) to avoid thermal stress causing furnace tube rupture.
Atmosphere maintenance: During the cooling process, inert gas is continuously introduced or vacuum is maintained to prevent substrate oxidation or moisture absorption.
Substrate removal
Protective measures: After the furnace temperature drops to ≤ 50 ℃, wear heat-resistant gloves and gas masks to remove the substrate and avoid burns or inhaling harmful gases.
Substrate treatment: Clean (such as ultrasonic cleaning), dry, and perform performance testing (such as thickness, adhesion, hardness) on the coated substrate, and record experimental data.
Equipment cleaning
Furnace tube cleaning: Use a soft bristled brush or vacuum cleaner to remove residual powder or particles inside the furnace tube, avoiding blockage or scratching of the furnace tube.
Gas pipeline cleaning: For pipelines that are filled with corrosive gases (such as Cl ₂, HF), rinse them with deionized water or alcohol to prevent pipeline corrosion.
Seal inspection: Replace aging or damaged sealing rings and O-rings to ensure the sealing of the atmosphere in the next experiment.

4. Maintenance and upkeep
Routine maintenance
Lubrication and maintenance: Add high-temperature resistant grease (such as molybdenum disulfide) to rotating components (such as bearings and gears) every week to reduce wear.
Electrical inspection: Check the power cord and heating element connections for looseness every month, and use a megohmmeter to measure insulation resistance (≥ 1M Ω) to prevent leakage.
Atmosphere system calibration: Calibrate flow meters and pressure gauges with standard gases every quarter to ensure gas flow control accuracy (± 1% FS).
Regular maintenance
Furnace tube replacement: If there are cracks, deformations, or thinning (≥ 20%) in the furnace tube, it should be replaced immediately to avoid rupture during the experiment.
Temperature sensor calibration: Send thermocouples or thermal resistors to the metrology department for calibration every year to ensure that the temperature measurement error is ≤ ± 1 ℃.
Vacuum pump maintenance: For rotary furnaces equipped with vacuum pumps, replace the vacuum pump oil every 500 hours, clean the oil circuit and filter element, and maintain the stability of the vacuum degree.
Record and Trace
Operation log: Record the temperature curve, atmosphere conditions, substrate type, and experimental results of each experiment for process optimization and problem tracing.
Fault record: Detailed recording of equipment faults (such as abnormal heating and rotation jamming), including time, phenomenon, and handling measures, to provide a basis for maintenance.