Everyone is concerned with cycle time. We work in a highly competitive industry where everyone wants improved cycle times.
You are often asked, "How fast can you make this part?"
"Well, we can make the part in 45 sec!"
Your competition may say, "We can make the part in 40 sec."
Someone with a multi-spindle screw machine would have them all beat: "I can make that part in 10 sec!"
This is not an "in your dreams" cycle time. It is reality with today's multi-spindle machines. By the time a standard CNC lathe has turned on the spindle and indexed to the first tool station, the multi-spindle machine tool has nearly completed making the part.
The key to such extraordinarily fast cycle times is simultaneous machining. Multi-spindle turning machines--aka screw machines--are complex machine tools with the ability to work 4, 6, or 8 parts at one time. Actuated by means of cams and levers, tool slides are mechanically advanced by means of a cam follower riding on a profiled cam disc. The material is bar-fed into the machine in numerous stations where separate tooling types work on the stock at the same time.
Similar to an assembly line, each tooling station performs a specific operation before the spindle carriage rotates to another station. There are 4, 6, or 8 individual spindles. These machines are normally designed to accept 12-ft bar stock material. Chucker-type machines are also available for parts manufactured from diameters that are too large to bar feed. The 6-spindle machine is very popular for many applications. This machine type can have six cross slides and six end-working stations. Each tooling station performs a distinct segment of the machining process.
To produce specific part diameters, a dovetail form tool is typically applied. Standard tools produce drilled, tapped, and reamed holes.
Multi-spindle machines have been around for more than 100 years and are not typically controlled by CNC. There is no computer or control to tell the tool stations or the stock how and where to move. Cams typically control the main slide movement. Newer multi-spindle machines (such as the Euroturn 6/32 Multi-Spindle Automatic shown above) operate with a PLC unit (Programmable Logic Controller). PLC units replace some of the cams used to actuate machine movements. This PLC unit can fire a slide forward until an electrical proximity switch is actuated at...