Labeling machines in the mechanical industry can be classified into various categories based on their functions and features. 

One common classification is based on the type of labels they can apply, such as pressure-sensitive labels, sleeve labels, or wrap-around labels. Another classification criterion is the method of labeling, including automatic, semi-automatic, and manual labeling machines.

Additionally, labeling machines can also be categorized according to their speed and capacity, with high-speed labeling machines designed for mass production and smaller capacity machines suitable for smaller scale operations.

Overall, labeling machines play a crucial role in the efficiency and accuracy of labeling processes in the mechanical industry, and there are a variety of options available to suit different production needs and requirements.