The type that mounts female screw into upper part of gantry typed slide and raising the female screw with male screw to ascend the slide for stamping. It has been well used for bolt forging based on the advantage of long stroke length possibility and adjustability for material protrusion and knockout structure. Up to now, most of the type had cone shape of friction wheel and flywheel to eliminate slippage from peripheral velocity difference since flywheel doesn?ft have up and downward movements. Recently, however, it became flat type to allow easy clutch lining manufacturing and replacement. Whole stamping pressure is absorbed within the slide and that reduces frame workload. It has unique structure to compare with other type of screw presses.

The type has a male screw with its upper and lower part threaded in CW and CCW respectively, and total two female screws are attached to the frame and the slide. During one rotation of the flywheel and the male screw, the slide moves two more times and this makes high-speed specification available as well as smaller friction disc diameter with compact machine header profile.

Enomoto Irons Co., Ltd. (Former company of current Enomoto Machine Co., Ltd.) developed the machine.

In conventional friction type machine, the friction disc pushes the flywheel from one side resulted in increase of friction resistor because the increase of clutch operational pressure produces side pressure in screw bushes. Thus there was a limitation to shorten clutch start acceleration time. In this model, two friction discs are driven in opposite direction and sandwich the flywheel driven the clutch for descending to solve the above problems for the purpose of higher speed. The maximum ram speed reaches to the level of 1000mm/sec. Also, energy efficiency is getting better since less of friction loss from no side pressure on screw bush.

One more friction disc for slide ascending was also added making total of four discs. Enomoto Machine Co., Ltd. also designed the machine.

None of friction disc. Large capacity flywheel is always driven with motor and clutch installed between the flywheel and the male screw descends the slide. Ascending is made with cylinder (such as hydraulic) to pull the slide compulsorily when the clutch is released. This has the advantage of extremely high speed pressing with no need of accelerating period since the flywheel rotates at a constant speed from the beginning.

While the flywheel energy is consumed from the beginning of forging and has to cut the clutch off at the time of flywheel revolution down to a certain percentage by clutch cut-off signal. Or clutch will be cut off by the position of adjusted slide lower position. However, processing for clutch off timing is extremely short and the problem of excessive overload occurs due to only a slight deviance of clutch-off timing which actually brought a lot of machine breakdown by the overload, so some manufactures have to quit the production.

Another negative point is that flywheel energy can?ft be fully used for stamping operation as other screw press (Basically, the flywheel is unable to be stopped.)

The type that the hydraulic motor directly drives flywheel. Energy control can be made with hydraulic oil flow control. Starting response is quite high because of no friction transmission mechanism.

Two major category: Ultra large machine that is impossible

Classification of the Screw Press for the machine with friction transmission mechanism and small machine that can cover several other machines?f capacity ranges with this model. Small machine furnishes with one unit of motor while large machine does with several motors coupled with gears of flywheel outer surface.

The type that the servomotor torque is transferred to screw axis directly or after amplified. The slide combined with the screw axis is controlled with forming speed, position and torque to have drawing operation for sheet metal. Forming capability is similar to hydraulic press machine. The machines ranging from several 10kN up to several 1000KN are produced. Two marketing possibility:

Mechanical press manufacturers develop it for their intention of controllability in forming condition. The other is hydraulic and pneumatic press manufacturers try to replace from current hydraulic and pneumatic mechanism. Attempting is made to put a general name, Servo-Press, summing up presses equipped with a servomotor including a mechanical press in which a servomotor is connected directly to a crank shaft.

The type that the servomotor controls the flywheel revolution and the slide position eliminating friction disc of the friction screw press. Detailed in latter part. Enomoto Machine Co., Ltd. developed it.