The advantages are obvious
Leak testing has undoubted advantages. These advantages have an impact on various areas: Quality control, production, finance, sales, marketing and development. Some of these benefits are:
Increased sales: it is obvious that products intended for the storage of liquids, including gases, must be leak-proof as part of their specification. Their tightness then becomes a selling feature or advantage. Since there is no such thing as a leakproof product, leakproofness gradually becomes a quality feature. It is therefore obvious that during the production and quality control phases, regular checks must be made to ensure that certain tightness standards are met.
Products that leak less are more attractive than those of competitors.
Improved reputation: If customer complaints are the norm, the company that produces products that have fewer complaints than comparable products will benefit from a better reputation in the market.
Lower costs: High reject rates do not offer profit-optimising potential! Every product has its manufacturing costs: material, labour, overhead, etc. If it is not possible to reduce scrap, a lot of money is lost. More precise control in production allows process adjustment and a reduction in scrap rates, resulting in lower overall costs.
Modern leak testing methods are non-destructive. The tested product that passes the test is returned to production.
Reproducible leak testing: Automatic leak testing is not operator dependent. Each test is highly reproducible and accurate.
Improved working environment: Leak testing with compressed air, vacuum, flow measurement and trace gases is clean and dry. There are no dirty dyes or water to spill on floors or equipment, reducing the safety risk.
High test throughput: Leak tests with compressed air take only a few seconds. Unlike immersion tests, which require operators to wait for bubbles to appear (which can take up to 30 minutes or more), air leak testing provides a clear result in a fraction of the time: pass or fail. The method is dry (see above), i.e. no drying time is required.
Advantages of the leak test
Case study
The production of car radiators is a complicated process. Companies are under enormous pressure from their automotive customers. High quality and competitive prices are essential. Losing a single customer due to quality or price issues can be disastrous.
Uson put the radiators through two tests at one customer's site. The first was the core test, which was carried out before the header tanks were fitted to both ends of the core (cooler). The reason for doing two tests, with the core test being done first, was so that the core could be repaired if there was a leak between the tube and the header.
Core testing under water was done with positive pressure and was very time consuming, subjective and required the operator to observe the entire test with extreme care.
Good cores were then passed to the next stage where the collectors were installed. The cooler assembly was then subjected to another underwater test with similar problems. The floor in the test rooms was covered with water and oil, and the testers' gloves were filled with water.
Coolers that passed this "test" were then placed in an oven to dry. Running the oven added costs to the manufacturing process and was time consuming.
The relationship between the air leakage rates and the water leakage rate was determined empirically. Several coolers were fitted with holes of different sizes and subjected to an air pressure test, with the results noted. Each cooler was then filled with a water/glycol mixture and brought to normal operating temperature and pressure. Each cooler was checked for fluid leakage; the smallest hole through which water appeared on the surface was one that leaked 22 cc/min of air. A specification of 4 cm³/min of air was chosen to ensure a comfortable safety factor.