Streamlined, high precision measurement of household refrigerators

Founded in 1945, Sub-Zero is a leading player in the home appliances market. Over the decades, the company has developed a range of innovative products in refrigeration, wine storage, and outdoor kitchen appliances. For the new design of its Pro48/36 refrigerators, Sub-Zero innovated its fitting check process with Hexagon’s CALIPRI C14, increasing the quality and reliability of its products.  

Precise gap and flush is a crucial element of refrigerator manufacturing. Fit and finish has a direct effect on the overall aesthetic, energy consumption, and functionality of the product. To maximise the quality of its high-end refrigerators, Sub-Zero performs 100% inspection at final assembly to ensure perfect fit and finish. This makes flush and gap inspection a potentially time-consuming process, and that’s before factoring in the level of customisation that can occur, such as size differences and additional options like glass doors. 

Before adopting CALIPRI C14, Sub-Zero used manual gauges to check gaps and flushes on the Pro product line. In order to measure the individual characteristics of gap and flush correctly, two different gauges were needed. But throughput takes a central role in home appliance production, and Sub-Zero looked to the CALIPRI C14 non-contact profile and surface measurement solution to save time and money with faster and more accurate inspection.
“There are five parameters with which we value measurement devices: throughput, accuracy, reliability, non-contact measurement and ease-of-use. Each one of these parameters has a direct influence on our manufacturing process”, says Brett Grunwald Senior, Quality Engineer at Sub-Zero.

Sub-Zero has a rigorous qualification process for any metrology device introduced to its production, and the team was very pleased with the reliability and usability of CALIPRI C14. “We put the device to the test by having untrained personnel measure 30 gap points in the Sub-Zero facility,” says Grunwald. “Happily, we were able to prove that the device is truly reliable in the hands of different operators, averaging a range of 0.06mm among the three operators.

After being trained to use CALIPRI C14 and the reliability it demonstrated, we were able to implement the tighter tolerance scheme our new design demanded and with that increase our overall product quality/reliability before reaching our customers.”

Seamlessly driving greater product quality

As high-end products, the aesthetic of Sub-Zero’s refrigerators is highly important. Scratches on the surface are an absolute no-go. A significant problem with manual gauges is they require contact measurement. CALIPRI C14 again met a key need for Sub-Zero. “Non-contact measurement, especially at the final assembly stage is a main requirement for us,” says Grunwald. “Being able to measure the appliance without any risk of scratching eliminates one vital variable in our process.”

The CALIPRI C14 works as an integrated part of the production line at Sub-Zero. The measured results are exported to the company quality software for further analysis. The operator then gets an immediate decision from the software to confirm that the unit has passed the quality check. Another major plus for Sub-Zero is portability, adaptability, and real-time insights offered by CALIPRI C14. “We needed a solution that allows to us use the device in a seamless way for the entire shift,” says Grunwald. “The operator feedback is very positive. The CALIPRI C14 is easy to hold and they see the results immediately meaning they know what has to be adjusted and can make the necessary changes right away.”

For Sub-Zero the combination of contactless measurement, high precision and usability was key to choosing CALIPRI C14, and these qualities have helped make manufacturing even smarter for this industry leader.