Pneumatic motor can be assembled according to process and material specifications, which allow them to be used without lubrication.
This has several advantages:
No need to check the oil in the FRL
No exhaust particles
These benefits are highly appreciated in industries such as food, pharmacy, fine chemistry, and nuclear. In fact, in these industries there are often clean, and even sterile environments, within which operations must be carried out in the utmost cleanliness.
Be aware, however, that using a non-lubricated motor requires usage precautions and has some limitations you shouldn’t neglect!
Using a non-lubricated motor requires particular constraints for the treatment of the air. Often non-lubricated motors are used in environments that are already very clean, even in “cleanrooms”. In a more “common”, or “difficult” atmosphere (with dust or moisture), their sensitivity may constitute a major inconvenience and they involve taking a lot of precautions (filters, storage, etc.).
A lubricated motor is more durable to use than a non-lubricated motor, because it accepts air that is not perfectly clean. Lubrication makes it more resistant to very small particles that may potentially be in the air, even after filtering. A motor used without lubrication may seize up, become damaged, or break when it comes in contact with air containing particles, even very small particles.
A non-lubricated motor requires more frequent maintenance than a lubricated motor. All the time you think you’re “saving” by not having to check the oil or the FRL will be lost with more regular and consistent maintenance.
Because they use more expensive materials (bearings, blades, and treatment of the mobile parts), the final parts of the motor will be more expensive and therefore the maintenance costs will be higher too.
In conclusion, you can’t consider a non-lubricated motor as a solution of convenience. Using them corresponds perfectly to specific environments or special cases with specific constraints, but they are not intended to replace lubricated engines that are more durable.