For the purpose of positioning and moving loads, precision and accuracy are the key. A vital component in this process is the roller table or motorized linear slide that is designed to provide low friction effortless movement of heavy loads.
What is a Roller Table?
Roller tables are positioning stages that are motorized linear slides with precision rail sets that support and guide loads accurately with excellent repeatability and extremely low friction. A complete range of roller table profiles that can have capacities of 2800 lbs (1270 kg) are available. Roller tables are constructed of two or more linear slide modules that are integrated into a single device.
In load positioning technology, accuracy is the most important feature and requirement. In the case of roller tables with heavy loads, this particular feature is a necessity. To meet the high standards for accuracy, roller table manufacturers produce roller tables with accuracies of 0.00008 inch up to 0.0001 inch when carrying loads in excess of 2600 lbs (1179 kg).
Roller tables are made of steel or aluminum and have three or four rail designs. In cases where there is the possibility of corrosion or rust, rails and cages can be made of stainless steel.
Roller tables can be mounted in X, XY, or XYZ configurations for multi-axis linear motion and positioning. Rubber bumpers or shock absorbers stop the slide table and can have stroke adjusters for precision positioning.
What is a Linear Slide?
The term slide implies that the table moves in a sliding motion; this is not the case. The platform is supported by ball or roller bearings that prevent friction and provide smooth motion. The slide is made up of a base and moving platform that allows it to be moved manually and secured with a locking mechanism. Roller tables have two or more slides to be able to handle the heavy loads.
Roller tables have a screw drive added between the base and the platform to create a motorized linear slide. Though the term linear gives the impression of a perfect straight line of motion, this is not true. Errors can occur where there is deviation from axial motion.
To prevent errors, air bearing slides can be used where pressurized air controls the surface tolerance between the base and the platform. In this configuration, the platform or platforms glide on a film of air and never make contact with the base, thus reducing or removing deviations. Additional technology that has been implemented to improve accuracy and remove deviations are plain bearings and rack slides.
Motorized Linear Motion Bearings
Linear motion bearings are a mechanism for carrying the load and guiding the linear movement.
- Machine Slide – Machine slides are motorized and driven by electronic, mechanical, or hydraulic mechanisms. They are heavy duty and rigid with close tolerances.
- X-Y Table – X-Y Tables are unrestricted and can move horizontally along the X and Y axis. They are motorized with bearings driven by a drive mechanism.
- Dovetail Slide – A dovetail slide is a plain linear bearing that makes direct contact with the sliding surface. They are ideal for absorbing and dampening shocks and vibrations that would damage ball or roller bearings.
- Magnetic – As the name implies, magnetic linear motion bearings use magnetic force to repel one of the components, which is kept floating. To produce the necessary magnetic field, a source for electromagnetic energy is necessary.
Roller Table Uses
Linear motion devices have been a central part of manufacturing and construction projects for centuries since the movement of objects from one location to another is a very common part of processing. The key factor is the determination of the right linear motion device to meet the needs of the project.
Roller tables are used when large loads need to be moved. They incorporate all of the factors associated with linear motion but have greater strength and stability than other linear equipment. Roller tables are engineered to meet the size, weight, space, and required motion of the application.