HYDRAULIC PRESS

Aim: To make mosquito coil stand/washer/lid using Hydraulic press.

Equipment: Hydraulic Press, Compound Die, Progressive Die, Deep-Drawing Die.

Raw Material: Mild Steel

Description of the equipment: Presses are classified in various ways. They may be classified according to

i. Source of power

ii. Method of actuation of the rams (slides)

iii. Number of slides

iv. Types of frames

v. The type of work for which the press has been designed.

Source of power: Two kinds of sources of power supply to the ram: Mechanical and hydraulic.

Mechanical presses, the energy of flywheel is utilized which is transmitted to the work piece by gears, cranks, eccentrics or levers.

The flywheel rotates freely on the crankshaft and is driven from an electric motor through gears or v- belts.

The motors runs continuously and stores energy in the flywheel. When the operator presses a foot treadle or actuates a button, the clutch gets engages and the flywheel is connected to the crankshaft. (Driveshaft).

Starts rotating and the stored up energy in the flywheel is transmitted to the ram on its downward stroke. The clutch to engage and disengaged the flywheel to the drive shaft can be; a Jaw clutch and the air operated clutch or an electro magnetic clutch. In manually operated mechanical presses, the clutch is disengaged to each cycle. But in automatic presses in which the metal strip is fed to the die automatically, there is no need of single stroke clutch. Disengaging mechanism and the ram moves up and down continuously. These presses can be classified as plain and geared press, the flywheel is carried on a auxiliary shaft which is connected to the main shaft. Through one or more gear reduction, depending upon size and energy needed.

In this arrangement, the flywheel stores considerably more energy than the plain as its speed is higher than the main drive shaft.

In Hydraulic press, the ram is actuated by oil pressure on a piston in a cylinder.

Mechanical presses have following advantages over the hydraulic presses.

1. Run faster

2. Lower maintenance cost

3. Lower capital cost.

Advantages of hydraulic presses are

1. More versatile and easier to operate

2. Tonnage adjustable to zero to maximum

3. Constant pressure can be maintained through out the stroke

4. Force and speed can be adjusted through out the stroke.

5. Safe as it will stop at a pressure setting.

6. The main disadvantages of hydraulic press is that it is slower than a mechanical press.

A press is rated in tones of force; it is able to apply with out undue strain. To keep the deflections small, it is a usual practice to choose a press rated 50 to 100 percent higher than the force required for an operation.

Procedure:

1. Set the compound die or progressive die or deep drawing die in the required position.

2. Switch on the motor to start the machine.

3. Pass the MS sheet in to the progressive die/compound die. In case of deep drawing

4. Apply injection pressure using direction control valve.

5. The plunger punches the sheet into the mosquito coil stand/washer lid shape.

6. Release injection pressure.

7. Take out the finished product from the die.

8. Switch off the motor.

Precautions:

1. Do not apply too high injection pressure

2. Proper lubrication must be done between moving parts of die and press

3. Operate the hydraulic press carefully.