Direct drive rotary table is a type of rotary table used for continuous operation, and is many times more precise and flexible than the conventional face gear, or rack and pinion rotary tables.
Director drive rotary tables are characterized by the specialized bearing, and the highly rigid and robust nature that has a low runout of less than 0.015mm in a very compact configuration.
The high power torque motor is generally coupled with the direct drive rotary table to allow rapid and power operation. The process is often monitored by a high resolution encoder to ensure that maximum flexibility and accuracy are maintained.
Some of the key advantages of a direct drive rotary table include the repeatability, short time of indexing, flexible indexing positions, as well as the tolerability of exceptionally high axial and radial torques during rotation and stopping.
Systems based on direct drive rotary table are generally very durable, and will not require a repair until a longer period of time. Depending on the applications, the rotary table may be complemented with an internal or external clamp.
Direct drive rotary tables are very feature-rich and characterized by many key qualities. Some of these core features include:
● Direct drive rotary tables are known for their compact design and configuration, often coupled with a high torque output direct drive.
● Direct drive rotary tables are known for maximum dynamics, contributed by the use of high power torque motors.
● Direct drive rotary tables can switch between very high or low rotational speed while keeping clogging torques at the minimum.
● Direct drive rotary tables have exceptionally stability and low runout by incorporating an unique kind of bearing.
● Direct drive rotary tables feature no face gear, which lead to minimum backlash while maximizing the performance.
● Direct drive rotary tables are typically capable of reaching a high accuracy between 3 and negative 3 arc seconds.
● Direct driver rotary tables are characterized by the superb repeatability, which is often referred to as less than 0.2 arc seconds.
● Direct drive rotary tables can employ either pneumatic or hydraulic clamping system for the added rigidity of table head.
● The operation of direct drive rotary tables is both continuous and high-speed.
● Direct drive rotary tables do not consist of many mechanical parts like other machinery, which results in superior lifespan as well as low maintenance requirement.
● Direct drive rotary tables can come with customized designs.
Some of the upsides of direct drive rotary tables include:
● High Accuracy: Direct drive rotary tables are primarily known as having high accuracy because of the standard direct measuring scale feedback system incorporated.
● High Speed Rotation and Indexing: The speed can go up as high as to 1,000 RPM. The rotary table also comes with a variety of high speed options that are available based on direct drive motor selection.
● Reversal Error Free: The table is free of mechanical reversal error, making it the perfect mean for finishing. It is in fact able to provide exceptional surface finish when contouring.
● Maintenance Free: As mentioned previously, the rotary table has minimal mechanical parts, which almost completely eliminate its need for maintenance for a long period of time.
Some of the drawbacks of direct drive rotary table include:
● Low Output Torque: Large sized direct drive motor is required to accommodate heavy loads, unbalanced loads as well as heavy duty machining.
● Larger Size: The size of the table is actually larger than the standard bench tables and its popular counterpart – the worm system rotary table.
● High Thermal Deformation: The direct drive motors can generate tons of heat, which is why a coolant unit is almost always required to complement the table based on the intended applications and accuracy requirement.
● Maintenance: Although this may seem contradicting, you typically do not want the need for maintenance to happen at all because this type of rotary type is extremely difficult to adjust or repair, and the resulting crashes can be very troubling.
● Complex Tuning and Adjustment: In relation to the above, making adjustment is just as difficult. As a matter of fact, complex servo tuning and adjustment are often required for distinct applications.
The main application is to accurately position a component in desired angle in CNC machining centers to perform multi-face operation in a simple setup. Direct drive rotary tables can be interpolated as the 4th axis along with the three standard axes to enable tasks such as blade machining, cam machining, helical grooves and so on.
Fundamentally, depended on the application, you can only use the device for work holding fixture. Otherwise, other accessories may have to be used in conjunction such as revolving center tail stocks, face plate tail stocks, dead center, manual or power chucks, etc.
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