Magnetic tables, otherwise called as magnetic bases, are used for holding down metal objects for a machining process. There are two types of magnetic bases: electromagnetic bases and permanent magnet bases.
In order to understand the advantages and disadvantages between electromagnetic and permanent magnetic bases, one must first understand the difference between the two an electromagnet and a permanent magnet.
Electromagnet requires electric current to produce a magnetic field while a permanent magnet is made of a magnetized material that creates a continual magnetic field. Since permanent magnetic bases don't require electricity, they are less costly when it comes to operational cost.
However, electromagnetic also has its advantages. Electromagnetic tables allow for an operator to adjust the strength of the magnetic field according the strength required. Electromagnetic tables are often able to generate stronger magnetic fields than permanent magnet bases.
As the name says, lifting magnets are used for lifting objects which makes it easier to move or to expose hard-to-reach spots. Given how the strength is of utmost importance for lifting, most lifting magnets are electromagnetic. Electromagnets are also easier to operate since it can be control with a simple push of a button.
Metal shavings are a part of metalworking and machining. The shavings can reach hard-to-reach places and are becomes trouble to clean up. A simple permanent magnet is useful for gathering and picking up shavings so they don't get to sensitive parts of equipment in the workshop.