Eccentric Press For Sale — 851

Eccentric Press

What is an Eccentric Press?

The mechanical press is defined as a forging press with an inertia flywheel, a crank and clutch, or other mechanical device to operate the ram. A mechanical press in which an eccentric, instead of a crankshaft, is used to move the ram is known as eccentric press. Whereas the eccentric is the offset portion of the driveshaft that governs the stroke or distance the crosshead moves on a mechanical or manual shear. The most commonmechanical pressesuse an eccentric drive to move the press's ram. The nature of drive system determines the force progression during the ram's stroke. Mechanical presses have a press force progression towards the bottom dead centre depending on the drive and hinge system. Mechanical presses therefore can reach higher cycles per unit of time and are usually more common in industrial press shops.

Eccentric type of press and drive is used where a very long stroke is required normally in excess of 24 inches. All of the features of a double-geared press apply to this drive design however, accuracy is not as good as an eccentric-shaft press because of the clearance with the arrangement of the gear train and the additional clearance needed in the slide guiding gib adjustment.

Construction and Working of an Eccentric Press

The model Eccentric press simulates a mechanical press designed as a portal frame machine, as used for example in metal forming industries. The eccentric press consists of the mechanical press, a store and a pusher to insert and withdraw parts automatically.The eccentric press uses a motor to drive an eccentric shaft, rotating in a connecting rod. The connecting rod moves a ram in a slider joint one dimensionally. The eccentric shaft itself is round, therefore it may completely rotate within the connecting rod. The centre of the drive is not the centre of the overall shaft. As the motor rotates, the centre of the drive remains stable but the overall centre of the shaft changes. This causes the shaft to change position, providing motion. The actual working principle of an eccentric press is very similar to a crank press.

A slider crank mechanism is used to transfer the energy of flywheel through the crank, the connecting rod and finally the slide to the workpiece. A slight variation of the eccentric press is the crank press, where a crank is used instead of an eccentric shaft. The presses are sometimes differentiated by the fact that the total stroke of crank press cannot be changed whereas the total stroke of eccentric press is adjustable. These presses are recommended for short working stroke or for high speed operation. The use of the eccentric shaft reduces the effect of bending on the main shaft thus making the shaft stiffer.

The basis of the machine is a welded frame with longitudinally placed crankshaft and two connecting rods which the slide is suspended on. A change of the length of stroke is provided by adjustable eccentric bushes located in connecting rods. This solution enables optimum utilization of the press with high numbers of the slide strokes. The press drive is provided by an asynchronous motor with a frequency converter driving a flywheel over V-belts. The flywheel together with the clutch/brake and epicyclic gear form a unit fixed to the frame and connected with the crankshaft.

Advantages of Eccentric Press

A few advantages of eccentric presses when compared to their other mechanical counterparts which make them more preferable are:

• As the mechanical press is driven by electric motors and not by a hydraulic motor, energy loss in the machine is limited and the output in relation to power consumption is thus optimum.
• A mechanical press has considerably longer lifetime than a hydraulic press. In the long run the mechanical press gives a much better return on investment than a hydraulic press.
• High production rates
• Low machining time and lower costs for maintenance
• Moving bolsters ensure short changeover times

• Minimal slide deflection under off-centre loading
• Modular design of the press series permits cost-effective, customer-specific solutions
• Numerous options such as drawing cushions, etc. are available to custom-tailor the line to the customer's needs

Applications of Eccentric Press

Eccentric Presses have a very wide range of applications. The main applications cover the following operations of manufacturing:

• Punching,
• Bending,
• Cutting,
• Deburring,
• Stamping,
• Machining of Progressive Dies.

Manufacturers of Eccentric Presses

FAGOR, SCHULER, Knuth Machine Tools, MOSSINI, Minster, GERMAK Makina, Pressix, Colombo Agostino, MECOLPRESS, Coperion, Hesse and Dirinler Machinery are some of the well-known industries involved in the production of eccentric presses.