Page 134 - CITS - Fitter - Trade Theory

FITTER - CITS

Applications:
• Metal Stamping: Power presses are commonly used in the automotive, aerospace, appliance, and electronics
industries for stamping metal components such as panels, brackets, and connectors.
• Forming and Bending: They are employed for bending, folding, and forming sheet metal into desired shapes
and configurations, often using specialized tooling and dies.
• Blanking and Piercing: Power presses are utilized for cutting or piercing sheet metal blanks to create parts
with specific geometries and features.
Advantages:
• High Force: Power presses can exert high levels of force, making them suitable for heavy-duty metalworking
tasks and mass production.

• Efficiency: Motorized operation enables faster production rates compared to manual presses, leading to in-
creased productivity and throughput.
• Precision: Power presses offer precise control over force, speed, and stroke length, allowing for consistent
and accurate results in metalworking operations.
Disadvantages:
• Complexity: Power presses require electrical, hydraulic, or pneumatic systems for operation, adding complexity
compared to manual presses.
• Maintenance: Power presses may require regular maintenance and servicing of motors, hydraulic pumps, and
control systems to ensure optimal performance and safety.
• Initial Cost: Power presses typically have higher initial costs compared to manual presses due to the inclusion
of power sources and control systems.

Types of Driving Mechanism used in Power Press
Power presses use various driving mechanisms to generate the force required for metalworking operations. The
driving mechanism determines how the force is applied to the press tool and ultimately to the workpiece. Here are
some common types of driving mechanisms used in power presses:
1 Mechanical Drive:
• Mechanical power presses use a mechanical linkage system to convert rotational motion into linear motion,
which is then transmitted to the press tool.
• Mechanical drives typically consist of a motor, flywheel, crankshaft, connecting rods, and a ram or slide.
• The motor drives the flywheel, which stores kinetic energy. When the press is activated, the flywheel’s
rotational energy is transferred to the crankshaft, causing it to rotate. The crankshaft’s movement is then
transmitted to the ram or slide through connecting rods, producing the required force.
2 Hydraulic Drive:
• Hydraulic power presses use hydraulic fluid pressure to generate force for metalworking operations.

• A hydraulic system consists of a hydraulic pump, hydraulic fluid reservoir, valves, cylinders, and actuators.
• When the press is activated, the hydraulic pump pressurizes hydraulic fluid, which is then directed to one
or more hydraulic cylinders. The pressure exerted by the fluid causes the cylinders to extend, driving the
ram or slide downward with considerable force.
3 Screw Drive:
• In a press machine with a screw drive, the force is generated by a threaded screw mechanism.
• The screw drive system typically consists of a threaded screw shaft and a nut or follower that travels along
the length of the screw.
• When the screw shaft rotates, it causes the nut or follower to move along the screw, translating rotational
motion into linear motion.
• The linear motion of the nut or follower is then used to drive the ram or slide of the press machine, exerting
force on the workpiece.

119

CITS : CG & M - Fitter - Lesson 21 CITS : CG & M - Fitter - Lesson 21