When you see the phrase speeds and feeds, it may be referred to as a pair, but it actually refers to two separate measurements in machining: Cutting speed and feed rate. The combined effect on the cutting process is remarkable. Cutting speed, or surface speed is the speed difference between the cutting tool and the surface of the workpiece. Feed rate or federate is the relative velocity at which the cutter is advance along the workpiece. Feed Units, or feeds, enhance speeds in drilling and tapping, reaming, and thread rolling applications.
Feed Unit Basics
A feed unit is an automated self-contained modular machining unit. Feed units can do everything from drilling and tapping to drill/reaming, reaming and thread rolling. The feed mechanism usually extends from the spindle in a quill. Today, feed units can be driven mechanically, but are typically driven hydraulically or pneumatically. These units can perform both rapid advance and controlled feed. Position feedback is provided through limit sensors or through feedback for integration into machine control.
When a feed unit is being retrofit, the existing tools will affect which type of feed unit will be most efficient, with the smoothest operation and highest production levels. Zagar Inc. is a manufacturer and distributor of a range of workholding solutions, multi-spindle drill and tap heads, feed units and robotic end effectors. With machine expertise in industries such as automotive, electrical, medical and more, Zagar offers hydraulic, pneumatic and high-production drilling and tapping solutions.
Ballscrew Feed Units
Ballscrew Feed Unit technology has become vital to feed unit capability, offering flexibility, programmable controls, power, and precision. Zagar’s ballscrew unit provides the feed through transmission, such as a coupling, belt and pulleys, or gears from the feed motor (usually a servomotor). Some feed units have the quill attached directly to the ballscrew nut, while others have the ballscrew nut attached to the quill by a connection device. In the latter type, the ballscrew is offset from the centerline access of the spindle and quill. A direct coupling to the ballscrew nut provides high-efficiency thrust on the tool’s centerline axis. This also results in reduced deflection, a major consideration in precision tooling.
Pneumatic Feed Units
Air powered spindle and quill make the pneumatic feed unit the most popular type of Zagar Feed Unit. On most pneumatic feeds, a piston style quill advances and retracts the spindle via air power. Other units employ a spring-loaded return rather than an air-powered return. Still other feed unit spindles are powered by an electric motor, and use pulley combinations to vary the speed.
Hydraulic Feed Units
A hydraulic feed unit is powered using hydraulic fluid. It can reach much higher thrust levels than a similarly sized pneumatic unit. However, hydraulic feed units used in large groups may require extra hydraulic tanks. Zagar self-feed units are engineered for for high volume drilling, tapping, screw driving and nutrunning, and feature a self-lubricating cylinder.
Determining Your Feed Unit Needs
When you are trying to figure out the most effective unit for your application, speaking with a Zagar professional can shed light on which choice would be the best option for your specific needs. Knowing how many consecutive hours daily that your feed unit needs to operate, can help you and your Zagar professional determine which type of Feed Unit can deliver the performance you need. Call ZAGAR today at (216) 731-0500 or click the Zagar link for specific application questions and concerns.