Hydraulic Shaper by Er. Abhisek Bhattacharjee

Hydraulic liquid is pumped by a constant discharge pump into the direction control valve. It has four ports and three stages. If the pressure goes beyond desired limits, the same is released by the pressure relief valve. The liquid reaches the right side of the cylinder through the inlet E and outlet A of the valve. Due to the pressure of the liquid, the piston moves towards left. The tool head moves forward to perform the forward cutting stroke. The liquid on the left side of the piston is sent back to the reservoir through B and P. Due to the change of position of plunger inside the valve, the liquid reaches the left side of the cylinder through the inlet E and outlet B. Piston moves towards right. The tool head moves in the opposite direction and this movement is known as the return stroke. The liquid on the right side of the piston is sent back to the reservoir through A and P.

Quick Return of the Ram

Due to the change of stroke volume of the cylinder during forward and return stroke, the piston returns at a faster rate. The stroke volume of the cylinder during return stroke is comparatively smaller than during forward stroke due to the presence of the piston rod. So, the pressure increases automatically to push the piston and the tool head at a faster speed during return stroke.

Parts of Hydraulic shaper machine:

• Fixed Double Acting Cylinder, – Fixed in RAM of Machine 
• spool-type DC valve,
• spool shaft stroke adjusting lever,
• pump,
• pressure relief valve or Relief valve
• return line with filter,
• oil reservoir.

Advantages of Hydraulic Shaping machine

1. Does not make any noise and operates very quietly
2. Ability to stall against an obstruction without damage to the tool or the
3. Ability to change length and position of stroke or speed while the machine is running
4. The cutting and return speeds are practically constant throughout the stroke. This permits the cutting tool to work uniformly during the cutting stroke.
5. The reversal of the ram is obtained quickly without any shock as the oil on the other end of the cylinder provides a cushioning effect.
6. Offers great flexibility of speed and feed
7. Relief Valve ensures proper pressure supply hence machine overloading is avoided.
8. More strokes per minute can be achieved by consuming less time for reversal and return stroke.

Disadvantages of Hydraulic Shaping Machine: 

• Hydraulic shaper machine is more costlier than mechanical shaper
• The stopping point of the cutting stroke in a hydraulic shaper can vary depending upon the assistance offered to cutting by the work material.
• Leakage of oil poses a major problem in machine tools. When the amount of leakage increases the capacity of the unit reduces and the efficiency goes down.

Application Hydraulic Shaper machine : 

• To generate straight and flat surfaces
• To smooth rough surfaces
• To make internal splines
• To make gear teeth
• To make dovetail slides
• To make keyways in pullies or gears