Thermal Shock Test Chambers are no strangers to manufacturers in the semiconductor industry, electronic components, and LED lighting products. The purpose of a thermal shock chamber is to test the ability of a product to withstand continuous exposure to extremely high and low temperatures in an instant, enabling product screening and improving quality control. Daily maintenance can extend the service life of the thermal shock chamber and significantly reduce the probability of equipment failure that prevents normal operation. Proper operation and good maintenance can also save businesses considerable operating expenses. So, how can thermal shock test chambers be properly maintained during use?
01. Maintenance of Electrical Components
Clean the circuit system at least once every four months to prevent airborne dust from accumulating on the machine’s cold components, especially accessories like condensers and evaporators.
Regularly clean and inspect the distribution panel. Dust can affect the heat dissipation and electrical insulation of components; loose contacts and connections can put the entire equipment in a dangerous working state, potentially burning out components or even causing fire. When cleaning the distribution panel, simply use a vacuum cleaner to remove dust from the panel. After inspecting component contacts and connections, use the appropriate tools to tighten them.
Check high-current contactors and circuit breakers (controlling compressors and fans) for discoloration or burn marks, and replace them promptly if found.
02. Maintenance of Water Circuit and Refrigeration Unit
The cooling unit’s radiator (condenser) should be maintained regularly to keep it clean. Dust adhering to the condenser can cause poor compressor heat dissipation, leading to false alarms from the high-pressure switch tripping. The condenser should be maintained monthly. Use a vacuum cleaner to remove dust attached to the condenser’s cooling fins, or after shutdown, use a stiff brush or high-pressure air nozzle to clean the dust off.
The refrigeration system is the core of the thermal shock test chamber. All copper pipes must be inspected annually for refrigerant leaks, checking each flared joint and weld. If any oil stains are found leaking externally, address the issue immediately. Inspect copper pipes, flared joints, and welds monthly. If any abnormalities are found, contact KOMEG’s after-sales professionals for assistance.
If the equipment is not used for an extended period, start the compressor once every two weeks, running it for no less than one hour each time.
Water Circuit System: Regularly check (at least once a month) to ensure no leaks or blockages in the pipes, and that each water level control cup has no leaks and maintains a normal water level. Regularly clean pipes and water level control cups of dirt or sediment. Strictly use a water source that meets quality requirements to ensure the long-term smooth operation of the water circuit system.
For wet-bulb/dry-bulb type test chambers, frequently check the wet-bulb gauze. Replace it promptly when the gauze hardens or becomes dirty; replacement every three months is recommended.
The water stored in the humidifier should be replaced monthly to ensure water quality remains clean and water flow is smooth.
03. Chamber Maintenance and Cleaning
Chamber Cleaning: Clean the interior of the chamber at least once every six months. When cleaning, use a vacuum cleaner to remove dust or use compressed air to blow it out. Clean the exterior chamber casing monthly. When cleaning, wipe it with rust-proof oil; never use corrosive liquids.
Regularly check whether the two gas-type temperature protection switches inside the high/low-temperature compartments are functional. The temperature setpoints are the default factory settings. Attempt to manually adjust them to the current workspace temperature; under normal circumstances, the machine should alarm, indicating the temperature protection switch is effective.
After each test using the equipment, promptly remove any possible debris remaining inside the workspace to keep it clean. This prevents debris from being drawn into the air duct and contaminating the workspace. Additionally, operational precautions are also part of the daily maintenance of thermal shock test chambers, which we share with you in this dedicated topic.
04. Operational Precautions
Avoid frequently starting and stopping the thermal shock chamber (try not to restart it within five minutes of stopping) to prevent increasing the mechanical load on the refrigeration system’s compressor, which affects the unit’s service life.
It is strictly forbidden to test flammable, explosive, volatile, or corrosive items in the thermal shock chamber, as this could lead to accidents, causing machine damage or invalid test results.
The placement of test items should not impede the airflow balance and smoothness within the workspace; otherwise, it will affect the chamber’s performance and the validity of the test. On any cross-section perpendicular to the direction of the internal circulation airflow, the total area of test items should not exceed 1/3 of the chamber’s cross-sectional area in that direction.
Before operating the thermal shock chamber, the chamber door must be closed tightly. Failure to do so will cause gas leakage from the workspace, and the test will not meet performance requirements.
The thermal shock chamber should be operated by professional personnel to avoid unnecessary damage caused by non-standard operation.
When the thermal shock chamber is operating for low-temperature tests below 0°C, try to avoid opening the chamber door. Opening the door during low-temperature tests can easily cause frost formation on the refrigeration system’s evaporator and other parts, especially at lower test temperatures. If opening the door is necessary, minimize the duration it is open.
After completing a low-temperature test run with the thermal shock chamber, be sure to set the test conditions to 30°C for a drying process for about half an hour (returning to normal temperature; the temperature controller can set this automatic function) before shutting down and opening the chamber door to retrieve test items. This avoids affecting the test performance of the next operational condition. Failure to perform the 30°C drying process may cause machine malfunction.
When the thermal shock chamber is operating under high temperature and high humidity, it is strictly forbidden to open the chamber door, as this may lead to the following adverse consequences:
High-temperature gas rushing out of the chamber can easily cause burns to personnel.
The inner side of the door, the test area, and the surface of the test item remain at high temperatures, easily burning hands.
The hot air may trigger fire alarms, causing false activations.
Thermal Shock Chamber Door Opening Operation: When opening the door, the operator must move backward away from the chamber door in the direction it opens to prevent being injured by the large amount of hot air that may surge out immediately after a high-temperature test.
During the operation of the thermal shock test chamber, do not touch the machine’s system components with your hands to avoid electric shock or injury from motors. Therefore, always stop the machine operation and turn off the power before inspecting.