How to choose a salt spray test chamber?

How should you choose a salt spray test chamber? Dongguan Zhongzhi Times Testing Equipment Co., Ltd. recommends considering the following aspects when selecting a salt spray tester:
- Test Requirements:
- Test Type: Identify the type of salt spray test you need to conduct, such as the neutral salt spray test (NSS), acetic acid salt spray test (ASS), or copper-accelerated acetic acid salt spray test (CASS). Different test types have different tester requirements. Ensure that the selected tester meets the requirements of the corresponding test method.
- Sample Size and Quantity: Select a tester with appropriate working dimensions based on the size and quantity of the samples to be tested. The working space must be large enough to accommodate the samples, with sufficient spacing between samples to ensure uniform contact of the salt spray on the sample surfaces. Generally, manufacturers offer a variety of tester models and sizes.
- Technical Specifications:
- Temperature Range: Salt spray tests are typically conducted under specific temperature conditions, typically ranging from room temperature to approximately 55°C. To ensure the accuracy and stability of the tester’s temperature control, temperature uniformity should be within ±2°C, and temperature fluctuation should be within ±0.5°C to guarantee the accuracy of the test results.
- Salt spray deposition: Salt spray deposition is a key indicator of tester performance and should meet the national standard of 1-2 ml/80 cm²·h. Uniformity of salt spray deposition is also crucial; otherwise, samples in different locations will be exposed to varying degrees of salt spray erosion.
- Spraying method: Continuous spray and periodic spray are available. The desired spraying method is determined based on the test requirements. For example, some products may require long-term, continuous salt spray exposure, while others may require periodic salt spray exposure.
- Chamber Material:
- PVC board: It has a certain degree of corrosion resistance and is commonly used in neutral salt spray tests. However, PVC board has relatively poor high-temperature resistance and should not be used at temperatures exceeding 50°C for long periods of time. It may also become brittle at low temperatures. However, it is relatively inexpensive and suitable for applications with less demanding testing requirements.
- PP sheet: More heat-resistant and corrosion-resistant than PVC sheet, it can be used in a variety of salt spray tests, including acid salt spray tests. PP sheet also has high strength and a relatively long service life, making it a commonly used material for salt spray tester enclosures.
- Titanium sheet: Featuring excellent corrosion resistance, high-temperature resistance, and high strength, it is suitable for a variety of complex test environments and applications requiring high test precision. However, titanium sheet is relatively expensive, which can increase the cost of the tester.
- Spray System:
- Nozzle: The quality of the nozzle directly affects the spray quality and uniformity of the salt spray. Choose a sturdy, corrosion-resistant, and uniform glass nozzle or other high-quality nozzle. Also, pay attention to the nozzle replacement cycle and maintenance methods. Generally, glass nozzles may need to be replaced after 5,000 hours of use.
- Atomizer: The atomizer must be corrosion-resistant, wear-resistant, and non-deformable to ensure stable salt spray generation during the salt spray test. Prolonged exposure to excessively salty or acidic environments may corrode the atomizer, affecting its performance.
- Air-water separator: A properly designed air-water separator prevents excessive pressure inside the chamber, ensuring uniform salt spray application and improving the accuracy of test results. When selecting a testing machine, pay attention to the proper design of the air-water separator.
- Safety Features:
- Overtemperature Protection: The testing machine should have an overtemperature protection function. When the chamber temperature exceeds the set safety level, it automatically shuts off the heating power to prevent hazards. The saturation tank should also have overtemperature protection to protect the equipment and test specimens.
- Short-circuit and Water-Outage Protection: Short-circuit protection immediately shuts off power in the event of a short circuit, preventing equipment damage and safety accidents. Water-outage protection automatically stops the test if the salt water supply is insufficient or the water level is too low, preventing dry-burning of the equipment.
- Brand and After-Sales Service:
- Brand: Choose a salt spray tester from a reputable brand for greater assurance of product quality and after-sales service. You can learn about the reputation and quality of different brands through online searches, industry reviews, and peer recommendations.
- After-sales service: Good after-sales service is an important guarantee for the normal operation of equipment. Understand the manufacturer’s after-sales service system, including after-sales response speed, timeliness of repair services, and whether regular equipment maintenance and servicing are provided.