What Is a Direct Drive Rotary Table?
The Direct Drive Rotary Table is one of the most versatile and popular forms of wood working tables available today. In many ways, the Direct Drive Rotary Table is better suited to many forms of artistic expression than the more traditional rotary models. The Direct Drive Rotary Table is built with two circular steel cocks that run parallel to each other, with each set perpendicular to the other. When the two cocks are moved in tandem, the mechanical force of the rotary shaft mounted on the outer ring of the rotary wheel creates a counter-clockwise spinning motion inside the inner steel cage.
The DVR-series direct-drive rotary table features a rotary hammering system and is made from heavy-duty forged aluminum. The rotational motion is caused by a high-speed fan located above the work surface. This fan can be manually or electronically controlled. Tilting mechanisms are available to alter the length of the stroke, which in turn can alter the amount of damping. This system has both free cooling and manual damping control.
High-speed direct drive rotary tables are designed for rapid application and precise timing of torque. The high-speed engines use both clockwise and anti-clockwise rotation speeds, resulting in a high-torque rating. The inherent high-speed and large torques are necessary to support both large-scale and small production applications. Standard features include fully adjustable leg room and high-temperature dielectric cooling options. Other features to look for are high-speed throttling and an automatic timing lock.
With direct drive rotary tables having higher gear-driven motors, they require more accuracy than gear-driven machines. The result is that precision is more difficult to obtain, resulting in less consistent timing and delivery of parts. Some manufacturers use a variety of methods to reduce this effect including variable gear-driven motors and self-adjusting gear boxes. High-speed electric motor designs are sometimes preferred because of their accuracy, although many other manufacturers have adopted this technology where higher RPM is preferred.
There are three types of direct drive (DR) rotary tables available – two-piece, three-piece, and four-piece. Two-piece designs use one gear in a lower case direction. Three-piece designs have a gear in each direction, with both pieces powered by the same shaft and gear unit. Four-piece designs use a gear in each direction and also combine the shaft and gear units, providing a symmetrical assembly.
While high-speed DDT table designs provide high torque and high-torque capabilities, they are typically used in applications requiring relatively low RPMs or high torque. A benefit of these designs is that they require lower RPMs for optimal performance. For many consumers, the cost-effectiveness of DR designs is worth the higher cost of acquisition. Precision and economy are advantages that can be had with any of the top rated DDT products. In many cases, the purchase price of the machine outweighs the cost of ownership.