Machine press

06 May.,2024

 

Machine press

Machine tool that changes the shape of a work piece by the application of pressure

Click here to get more.

Manual goldsmith press General-purpose hydraulic shop press Power press with a fixed barrier guard A HACO CNC hydraulic press brake

A press brake bending a sheet of steel

A forming press, commonly shortened to press, is a machine tool that changes the shape of a work-piece by the application of pressure.[1] The operator of a forming press is known as a press-tool setter, often shortened to tool-setter.

Presses can be classified according to

Shop Press

[

edit

]

Typically consisting of a simple rectangular frame, often fabricated from C-channel or tubing, containing a bottle jack or hydraulic cylinder to apply pressure via a ram to a work-piece. Often used for general-purpose forming work in the auto mechanic shop, machine shop, garage or basement shops, etc. Typical shop presses are capable of applying between 1 and 30 tons pressure, depending on size and construction. Lighter-duty versions are often called arbor presses.

A shop press is commonly used to press interference fit parts together, such as gears onto shafts or bearings into housings.

Other presses by application

[

edit

]

  • A press brake is a special type of machine press that bends sheet metal into shape. A good example of the type of work a press brake can do is the back-plate of a computer case. Other examples include brackets, frame pieces and electronic enclosures. Some press brakes have CNC controls and can form parts with accuracy to a fraction of a millimeter. Bending forces can range up to 3,000 tons.[2][3][4]
  • A punch press is used to form holes.
  • A screw press is also known as a fly press.
  • A stamping press is a machine press used to shape or cut metal by deforming it with a die. It generally consists of a press frame, a bolster plate, and a ram.[5]
  • Capping presses form caps from rolls of aluminium foil at up to 660 per minute.

An example of peculiar press control: servo-press

[

edit

]

A servomechanism press, also known as a servo press or an 'electro-press, is a press driven by an AC servo motor. The torque produced is converted to a linear force via a ball screw. Pressure and position are controlled through a load cell and an encoder. The main advantage of a servo press is its low energy consumption; its only 10-20% of other press machines.

When stamping, it is really about maximizing energy as opposed to how the machine can deliver tonnage. Up until recently, the way to increase tonnage between the die and work-piece on a mechanical press was through bigger machines with bigger motors.[6]

Types of presses

[

edit

]

The press style used is in direct correlation to the end product. Press types are straight-side, BG (back geared), geared, gap, OBI (open back inclinable) and OBS (open back stationary). Hydraulic and mechanical presses are classified by the frame the moving elements are mounted on. The most common are the gap-frame, also known as C-frame, and the straight-side press. A straight-side press has vertical columns on either side of the machine and eliminates angular deflection. A C-frame allows easy access to the die area on three sides and require less floor space. A type of gap-frame, the OBI pivots the frame for easier scrap or part discharge. The OBS timed air blasts, devices or conveyor for scrap or part discharge.[7][8]

Comparison of various machine presses Type of press Type of frame Position of frame Action Method of actuation Type of drive Suspension Ram Bed Open-back Gap Straight-side Arch Piller Solid Tie rod Vertical Horizontal Inclinable Inclined Single Double Triple Crank Front-to-back crank Eccentric Toggle Screw Cam Rack & pinion Piston Over direct Geared, overdrive Under direct Geared, underdrive One-point Two-point Four-point Single Multiple Solid Open Adjustable Bench X X X X X X X X X X X X X X X X X Open-back inclinable X X X X X X X X X X X X X X X X X X Gap-frame X X X X X X X X X X X X X X X X X X X X X X X X Adjustable-bed horn X X X X X X X X X X X X X X X End-wheel X X X X X X X X X X X X Arch-frame X X X X X X X X X X X X Straight-side X X X X X X X X X X X X X X X X X X X X X X X X X X Reducing X X X X X X X X X X X X X X X Knuckle-lever X X X X X X X X X X X X X X X X Toggle-draw X X X X X X X X X X X X X X X X Cam-drawing X X X X X X X X X X X X X X X Two-point single-action X X X X X X X X X X X X X X X High-production X X X X X X X X X X X X X X Dieing machine X X X X X X X X X X Transfer X X X X X X X X X X X X X X X Flat-edge trimming X X X X X X X X Hydraulic X X X X X X X X X X X X X X X X X X Press brake X X X X X X X X X X X X

History

[

edit

]

Proofing press from 1941, cultural monument at the Karlsruhe Institute of Technology

Historically, metal was shaped by hand using a hammer. Later, larger hammers were constructed to press more metal at once, or to press thicker materials. Often a smith would employ a helper or apprentice to swing the hammer while the smith concentrated on positioning the work-piece. Drop hammers and trip hammers utilize a mechanism to lift the hammer, which then falls by gravity onto the work.

In the mid 19th century, manual and rotary-cam hammers began to be replaced in industry by the steam hammer, which was first described in 1784 by James Watt, a British inventor and Mechanical Engineer who also contributed to the earliest steam engines and condensers, but not built until 1840 by British inventor James Nasmyth. By the late 19th century, steam hammers had increased greatly in size; in 1891 the Bethlehem Iron Company made an enhancement allowing a steam hammer to deliver a 125-ton blow.[9]

Most modern machine presses typically use a combination of electric motors and hydraulics to achieve the necessary pressure. Along with the evolution of presses came the evolution of the dies used within them.[10]

Safety

[

edit

]

Machine presses can be hazardous, so safety measures must always be taken. Bi-manual controls (controls the use of which requires both hands to be on the buttons to operate) are a very good way to prevent accidents, as are light curtains that keep the machine from working if the operator is in range of the die.

References

[

edit

]

Power Presses: Types, Applications, Benefits, and Safety

Power Presses

Please fill out the following form to submit a Request for Quote to any of the following companies listed on



Introduction

This article will take an in-depth look at power presses.

You will learn about the following topics:

  • Principle of Power Presses
  • Types of Power Presses
  • Applications, Benefits, and Safety of Power Presses
  • And Much More...

Chapter 1: Principle of Power Presses

This chapter will discuss the definition and purpose of a power press.

What is a Power Press?

A power press is a cold metal stamping machine designed to shape, cut, form, and punch metal. The different types of power presses are fast and efficient mass production pieces of equipment used for the manufacturing of metal parts and components. The two forms of power presses are hydraulically and mechanically powered.

The operating principles for power presses are mechanical, hydraulic, and servo motor. A mechanical power press changes circular motion into linear motion using a clutch, flywheel, crankshaft, and fixed and moving plungers. Hydraulic power presses use the built up pressure of hydraulic fluid to create the force to compress and shape metals. Servo power presses are powered by a servo motor that drives the eccentric gear that moves the slider of the press.

With all three forms of presses, the shape of the workpiece is determined by the meeting of the upper and lower halves of a die as they are pressed together under the force of the press.

Previously, the job of giving shape to metal sheets was done manually with great force and effort. The invention of power press machinery changed the process with the addition of mechanical force and accuracy.

Power Press Designs

The definition of a power press is related to how it supplies force. The main component of a mechanical power press is its flywheel that rotates and builds up force to drive the ram. In the case of hydraulic power presses, force is supplied by pressure created by hydraulic fluid while a servo motor power press has a motor that provides rotational motion that is converted into linear motion.

The choice of which type of power press is dependent on several factors. The concept of mechanical power presses is the oldest of the three methods with servo motors being the newest form. Hydraulic power presses, which are very widely used, were developed as replacements for mechanical power presses.

Hydraulic Power Press Design

The hydraulic press was introduced over 200 years ago by a British engineer. During the first industrial revolution, it was used for forging as a way to replace steam hammers. Over the years, the tonnage of hydraulic presses has gradually increased into the thousands of tons with the capability of mass producing a wide variety of parts and components.

A hydraulic power press uses a pump, endplates, and a piston that creates pressure in a fluid to form and shape metal parts. The main component of a hydraulic press is its pump that pumps oil under pressure into a cylinder.

Cylinder

The cylinder contains a piston that moves up and down to create the compressive force. The piston of the cylinder acts like a pump in order to produce the force. It is the part of a hydraulic press that produces the power to apply force to the workpiece.

Reservoir

The reservoir contains the hydraulic fluid, collects contaminants from the fluid, removes air and moisture from the fluid, and sends heat into the system. The hydraulic fluid is sent from the reservoir to the cylinder through a tube.

Valve

The valve helps to relieve pressure and manages the flow of fluid from the pump to the cylinder. Additionally, the valve regulates the speed of the press and the amount of force it produces. It functions as a pressure limiter. A pressure gauge measures the pressure of the hydraulic fluid to ensure it is performing within its pressure range.

Hydraulic Pump

The hydraulic pump is the mechanical part of a hydraulic power press that moves hydraulic fluid to the reservoir and converts mechanical energy into hydraulic energy. It generates a powerful flow against the pressure at the outlet.

Plates

The press plates hold the workpiece in place and provide a platform for the press to bend, pierce, stamp, or puncture the workpiece. They are the part of the press that makes contact with the workpiece.

Hoses

The movement of the hydraulic fluid depends on a set of hoses that move the fluid from the pump to the cylinder and reservoir. The hoses are made of durable and sturdy material that is capable of withstanding the pressure and heat produced during the operation of the press. Common hose materials are thermoplastics, synthetic rubbers, and polytetrafluoroethylene (PTFE), which are materials capable of resisting corrosion and the effects of exposure to chemicals.

Ram

The ram slides within the frame and applies pressure to the die. Depending on the design of the hydraulic power press, the ram can move horizontally or vertically with some hydraulic presses having multiple rams used for the forming process.

Bed

The bed is a flat supportive surface that supports the die as force is applied by the ram.

Servo Press Design

A servo press uses precision and a servo motor to control the movement of the ram. They are popular for their accurate positioning of the ram, which is ideal for the production of parts that require precision and optimal repeatability. The servo motor is connected to a form of linear actuator, such as a ball screw, that controls the upward and downward movement of the ram.

With a servo mechanical press, the main motor, flywheel, and clutch have been removed and replaced with a servo motor that makes the ram more controllable. The elimination of the parts of a traditional mechanical press results in a servo press having fewer driving parts and a simplified structure. In a typical mechanical or hydraulic power press, the ram moves down with great force and strikes the workpiece to create the desired shape, after which it returns to its original upward position. With a servo press, the ram can be controlled to the extent that it can strike the workpiece and remain in contact for an extended period.

Servo presses are used for applications that require exceptional precision and control, such as aerospace and electronics manufacturing. They are capable of producing the stamping, punching, and forming applications of mechanical and hydraulic power presses but with greater precision.

Servo Motor

The servo motor drives the ram of a servo press and provides power and force to the servo press system. Direct drive and servo motor drive with a reducer are the types of motors used in a servo press.

Direct Drive

A direct drive motor is connected directly to the actuator and is a low speed high torque motor with a simple structure, high efficiency, and low noise. It has limited torque, which limits its use to low tonnage servo presses.

Servo Motor with a Reducer

A servo motor with a reducer allows for rapid acceleration and deceleration. It has a speed reduction ratio that matches the inertia of the motor and gearbox with the inertia of the driven load, which makes the motor run more efficiently.

Servo motors with a reducer take three different transmissions, which are deceleration with a crank connecting rod, with a crank elbow rod, or a screw elbow rod. This type of construction makes it possible for a low torque, high speed servo motor to drive high tonnage presses.

Actuator

The actuator is the part of a servo motor press that changes rotary motion into linear motion. Ball screw actuators are the most commonly used, which consist of a screw and nut assembly with ball bearings to provide smooth, even, and efficient motion. The construction of a ball screw actuator consists of a nut mounted on a grooved shaft. As the screw turns, the nut moves up and down the shaft creating linear motion and precision control.

Controller

The controller receives input from sensors, which it uses to send output signals to the servo motor. Algorithms programmed into the controller regulate the motions of the press to ensure precise operation and accurate repeatability. With hydraulic presses and mechanical presses, it is difficult to control the stroke, the pressure of the stroke, and the motion of the slider. A servo press can be programmed to control the stroke, speed, and pressure with precision allowing the press to reach the desired tonnage at a low speed.

Sensors - For the controller to perform properly, it requires data in regard to the position, force, and speed of the ram. Internal and external sensors send feedback to the controller that converts the data into command signals for the press.

Aomate are exported all over the world and different industries with quality first. Our belief is to provide our customers with more and better high value-added products. Let's create a better future together.

Human Machine Interface (HMI) - The HMI connects operators to the servo press and allows them to monitor, adjust, and change aspects of servo press operations, such as speed, force, and positioning. A necessary component of servo presses is a user friendly interface with graphics that are displayed in real time on the HMI, which can be programmed to the needs of the part being manufactured.

For complex systems of HMIs, a supervisory control and data acquisition (SCADA) system is used to interface HMIs in a factory or facility. Information and commands can be sent to a specific HMI or several HMIs using the SCADA system.

Mechanical Power Press Design

The major components for power transmission on a mechanical power press are the clutch, crankshaft, flywheel, moving ram, and stationary ram. The slide is joined to a crankshaft with connecting rods (“pitmans”).


The crankshaft is coupled with the flywheel, which is constantly rotating while the motor is running. A clutch connects the spinning flywheel with the crankshaft. The crankshaft converts the flywheel’s rotational motion to the upward and downward motions of the press slide.

Ram

The ram is the primary operating component of a mechanical power press, which operates directly during the reforming of a workpiece. The ram moves to and fro within its guides, which prescribe a stroke length and power. The transferred stroke length and power can be adjusted according to the requirements of the operation. The lower end of the ram carries the punch to process the workpiece.

Flywheel

A driven pulley or driven gear is made in the shape of a flywheel (which is used to store the energy reserve) in order to maintain a constant ram speed when the punch is pressed onto the workpiece. The flywheel is fixed at the driving shaft’s edge and is attached to it via a clutch.


The energy stores up in the flywheel when it is idle. If the machine has insufficient flywheel energy, it will come to a halt and won’t be able to finish the operation. Essentially, by employing a flywheel, the motor can work with less capacity. At the same time, maximum tonnage is supplied at the required need of the operation.

For a bigger working space (in case of a drawing process) and for quicker processing (in case of an automatic piercing or blanking process), more power and energy must be provided.

In the blanking process, the work is finished in a very short portion of the stroke. So in this, energy is to be taken from the flywheel, which then instantly provides all the energy needed for operation. The same applies to the remaining cycle period. The drawing process takes a significant portion of the cycle. Since time is adequate, excess energy can be tapped from the motor and lacking energy provided by the flywheel.

Allowable Speed Reduction of Flywheel:

Its value for discontinuous operation = 20%

For continuous operation = 10%

  • E = energy
  • D = flywheel diameter
  • W = flywheel weight.
  • N = speed, R = gyration radius.

From operation E = P x K x L

  • P = average force, L = stroke length.
  • K is friction loss (constant).

If the energy of the flywheel is lower than P x K x L, the speed N must be increased.

Clutch

The mechanical clutch is used to connect and disconnect the driving shaft from the flywheel when it is essential to stop or start the movement of the ram. A clutch moves the torque generated by the flywheel and drives to the gear shaft. Two different kinds of clutches are used on power presses: full revolution and part-revolution clutches.


Full Revolution Clutch

As defined by OSHA, a full revolution clutch is a type of clutch that, when tripped, can’t be disengaged till the crankshaft has nearly done a complete revolution and the press slide a complete stroke. Presses with full revolution clutches are generally older and more dangerous because of their cycling operation.

Part-revolution Clutch

A part-revolution clutch, also defined by OSHA, is a type of clutch that can be disengaged at any time before the crankshaft has done a complete revolution and the press slide has done a complete stroke. The majority of part revolution power presses are air clutch and brake. When air is trapped and compressed in compartments, the clutch engages and the brake disengages. To stop the pressing, the reverse takes place.

Brakes

The brakes are utilized to stop the motion of the driving shaft promptly after it disconnects from the flywheel.


Brakes are very crucial in any mobile system. Commonly, two types of brakes are used. The first type is a normal brake that can stop the driven shaft quickly after disengaging from the flywheel. The other is an emergency brake which is offered as a foot brake to any power press machine. These brakes have a power-off switch with normal strong braking to bring all movements to rest quickly.

Base

The base is the supporting structure of the press and offers arrangements for clamping and tilting the frame in an inclined press. It supports the workpiece holding dies and various controlling tools of the press. The table size limits the size of the workpiece that can be processed on the power press.

Drive Mechanism

Different kinds of driving mechanisms are applied in various types of presses, such as piston and cylinder configuration in a hydraulic press, eccentric and crankshaft configuration in a mechanical press, etc. These mechanisms are utilized to drive the ram by moving power from the motor to the ram.

Control Mechanism

Controlling mechanisms are utilized to run a press under pre-programmed, controlled conditions. Normally, two parameters are configured by controlling mechanisms: the power of the stroke and the length of stroke of the ram. Transferring of power can be cut off with the help of a clutch offered with driving mechanisms as per requirement. In many power presses, controlling mechanisms are inherent to the driving mechanisms. Nowadays, computer-controlled presses are used where control is guided by a microprocessor. These power presses provide accurate and reliable control with automation.

Bolster Plate

This is a thick plate fixed onto the base or bed of the press. It is utilized to clamp the die assemblage rigidly to support the workpiece. The die used in press working might have more than one component, which is why the name “die assembly” is being used in place of the die.

Manually fed presses are cycled by either foot or by two hand controls or trips. With foot control, the press is triggered by pressing down on a foot pedal or switch.


It leaves the hands free while cycling the press. This free hand movement puts operators using foot control at a higher risk of getting an injury while operating. About twice as many press injuries come from foot-controlled presses. With two hand controls or trips, when a workpiece is positioned on the press, both hands should be removed from the operation point to depress the buttons.

How a Power Press Functions

Power press machines work on the principle of reshaping the metal sheets by applying the necessary force. The main parts used are a ram, bed, flywheel, clutch, and crankshaft. The ram and bed are furnished with a combination of dies that enable a metal sheet to be shaped into a particular form. The rotational motion of a flywheel is powered by an electric motor. The rotating flywheel is joined to the crankshaft by a clutch. Upper and lower dies are joined to the ram, one workpiece on the bed is fed into the machine, and the process is initiated. As a result of the rotational motion of the flywheel, pressing and shaping jobs are done when the upper and lower dies apply a force together. Once the process is done, the formed workpiece is detached and replaced by a new workpiece, and the same process is repeated.

How to Calculate the Size of a Power Press

To properly calculate the size of a power press, the tonnage needed, the size of the worktable, and the press opening height must be defined.

  • The tonnage is determined according to the type and thickness of the material to be processed and the shape and size of the press tool.
  • To define the size of the worktable, it is enough to know the maximum size of the materials that need to be handled.
  • To select the opening height for a press, the choice must be based on the stamping extent and the height needed to clear the workpiece.
  • Working speed is an important aspect to consider, particularly for serial production.

Considerations When Choosing a Power Press

When choosing a power press, its purpose must be clearly understood. However, the operating methods and the working of the press are very difficult to understand. The wrong choice of a power press will lead to poor efficiency of the press and can lead to waste of equipment investment. Below are factors to consider.

Correctly Determining Processing and Operating Method

Correctly Determine Operation Method and Engineering

There are different methods for stamping that are sometimes combined with cutting. When choosing a punch, the desired processing method should be checked. If the processing method is chosen, the punch type required is roughly determined.

Degree of Production

If a batch is over 3000-5000 pieces, it is more beneficial to utilize automatic feeding. When there are numerous projects and a huge production amount, it is important to consider using continuous and transfer processing.

Material Shape and Size

This should be known with regards to processing method, usage rate, and material usage rate.

Supplying materials, Taking out Products, and Disposing of Waste

These are collectively called material handling. In a production plant, material handling accounts for a huge proportion of the work.

Frequency of Die Buffer Use

During the extension operation, extra die buffers must be considered in the single-action punch. Due to the die buffer’s high performance, it is conceivable to do difficult drawing processes without using a double-action punch.

Selecting the Suitable Processing Punching Capacity

Calculate the Processing Pressure and Stroke Curve

The maximum pressure needed during processing should be calculated. For multi-engineering processing, the pressure stroke curve for each project must be attained, and the combined pressure stroke curve must be attained by overlapping. These must be determined to determine the pressure capacity that should be selected.

Eccentric Load

When one punch press is utilized with more than two dies or a continuous die is utilized, there is an eccentric load, yet many of the punching operations also have an eccentric load. Therefore, for the processing of eccentric load, punching capacity with adequate margin must be selected.

Calculate the Reduction of Effective Die Buffer Capacity

The buffer capacity is generally 1/6 of the minimal punch press capacity. When necessary, it’s better to use a double-acting punch.

Defining the Dimensional Accuracy of Processed Products

Dimensional accuracy is the measurement of tolerance, which defines the plus or minus limits of acceptable errors. When choosing a power press, accuracy or tolerance can be defined by the type of power press that is selected with mechanical presses, hydraulic presses, and servo presses each having different capabilities. When exceptionally accurate and precision performance is necessary, servo presses are the best choice due to their highly efficient control mechanism.

Fully Understanding the Function of the Punch

Fully Investigate the Specifications

Catalog specifications specify the main abilities and dimensions of punch presses and are the core for choosing the punch presses.

Selecting Attachments for Punch

Proper use of accessories will increase productivity, so different accessory devices must also be fully reviewed.

Choosing a Reliable, Easy-to-Maintain Punch

Security

Pressing operations have a high disaster risk, hence full consideration must be given to safety measures. One with safety equipment function must be selected.

Noise and vibration

These are prohibited by laws and regulations because of pollution problems. Therefore, it is important to include noise and vibration measures into the pressing equipment.

Chapter 2: Types of Power Presses

There are different methods of classifying power presses, such as by mainframe type, drive mechanism type, or job operation (mechanism).

Types of Frames

All types of power presses can be defined as C-Frame type or H-Frame type, regardless of the type of power. The type of frame can also define the tonnage of a power press.

C-Frame Power Press

The frame is C-shaped and is used for small presses up to 250 tons. Due to the C shape, the press frame has angular and longitudinal deflection bigger than other frame types; hence, this frame has a drawback when high accuracy is needed. C-frame power presses are more frequently used with presses up to 100 Tons.


They are utilized for bulk production in cold-working of ductile metals like mild steel, with spinning flywheels operating as energy storehouses to operate the ram to hit onto the workpiece. It is utilized to operate different functions with plate, bed, bolster and ram. The knockout mechanism is used to remove the finished workpiece from the power press.

Proper cushioning should be provided beneath the bolster if heavy impact is applied to the workpiece. The C-type is designed to provide continuous production with high accuracy. The frames are made from solid steel fabricated with appropriate cross ribbing. The clutch offers continuous stroking for mass production. The crankshaft is made from special steel alloy and furnished with gun metal bushes to smoothen work and provide longer life. Table and ram are seamlessly aligned to each other to achieve highly precise power press execution.

H-Frame or Straight Frame

The box-type H-shaped design offers more rigidity and has zero deflection and lasting smooth and precise task operations. This frame has four box-type pillars and can only be operated in front of the press. Job size is according to available windows. H-Frame design will improve tool life and precision in job operation. It is more expensive than the C-Frame Power Press and Ring Frame Press.


Generally, this design is utilized for 100-ton to 800-ton power presses with two-point or single-point suspension. For tonnage capacity higher than 400 tons, it’s hard to handle the power press inside the factory floor since the frame will be too big. Therefore, this type of frame is recommended for up to 400 tons.

Hybrid Frame or Ring Frame

Ring frames are a hybrid or combination of H-frame and C-type frame designs. In this design, the C-type Frame Press offers support in the front. The open size increases rigidity and makes it resistant to deflection. It is useful for 110-ton to 250-ton power presses. H-Frame designs will improve tool life and job operation precision.


H Frames/Straight Side Frames with Tie Rods

These are also Box Type Pillar Frames, but their frame bodies are divided into four parts: Pillar 1, Pillar 2, Crown, and Base or Bed. All these four parts are furnished with Hydraulic Tie Rods. These bear all the forces generated during the stroke, and it makes these press frames design very rigid, secure, precise, and non-deflecting. Commonly, these frames may be used for heavy piece sheet metal forming and utilized with progressive tools.


Drive Mechanism Types

Although all power presses are dependent on slider Crank Mechanisms, the crank may be of 3 types. These are eccentric gear, crankshaft, and eccentric shaft. Additionally, instead of utilizing a simple crank drive, a link drive mechanism can be used, for example, a Knuckle Joint and 6 link Mechanism. Link Mechanisms change the movement on the slide, making the movement slow when falling during the forming process and going back swiftly to save idle time.

Eccentric Gear Crank Mechanism

Gear and crank parts are combined. It is a robust system that is utilized for power presses over 250 to 400 tons and stoves over 10 in (250 mm).

Crankshaft Mechanism

It is utilized for small power presses of up to 250 tons (at times up to 400 tons). It is not suitable for high stoves.

Eccentric Shaft Crank Mechanism

It is basic and robust for high speeds and very low stroke power presses. It is utilized for tonnage reaching 630 tons and strokes of 4 to 4.7 inches (100-120mm) or less.

Job Operation Basis (Mechanism)

The basic job operations of power presses include:

Blanking Power Press


The blanking press is utilized in notching and punching applications. These are found in 4-column types and C-type frame designs with high-speed processing to fit individual production requirements. Different capacities are available up to 100 tons as well as power units matching requirements. They are robust in construction and highly reliable through high-end electronics and hydraulics.

High Speed Stamping Power Press

The high-speed stamping press is suitable for economical production of precise pieces with high cutting accuracy. These fast and robust machines guarantee high production rates and low costs per piece and are found in the range of 630 kN to 1,250 kN. They are available in H-frame or C-frame. Capacity is in the range of 35 to 500 tons.


Stamping Power Press

A stamping power press is a piece of metalworking machinery utilized to cut or shape metal using a die. It is simply another form of the modern-day hammer and anvil. The variance is that a stamping power press utilizes precision-made female and male dies to order the shape of the end product.


Leading Manufacturers and Suppliers

    Chapter 3: Applications, Benefits, and Safety of Power Press

    This chapter will discuss the applications, benefits, and safety measures of power presses.

    Applications of Power Presses

    Power presses are used for various applications like curling, bending, piercing, and deep drawing. Automation makes power pressing much faster, which is currently a major requirement for the production industry. This saves money and time. Research and development are currently being carried out for these heavy machines in order to streamline their efficiency, high production, and low wastage of raw material. Power presses are easily operated, with top-notch protection guards to protect the operator’s life and technical enhancements such as power press speed and width of the material.

    Below, the major applications of power presses are explained in more detail.

    Assembly

    Fastening of two or more pieces together. Examples include shafts, bearings, electrical switches, rear axle assembly, water pumps, munitions assembly, fuel injection sensors, windshield wiper blades, gear assemblies, and medical instrument assembly.

    Deep draw

    The deep drawing operation is a metal forming operation that happens under a combination of compressive and tensile conditions utilizing a compression power press. To be considered a deep-drawn part, the case height is usually about two times the diameter. Some examples include oil cans, fire extinguishers fan, aerospace ductwork, and housings.

    Coining

    A squeezing process, usually done cold inside a closed die, where the material is forced to flow in the profile and shape of the dies. Due to the high weight requirements of cold working processes, customized power presses are preferred in this application. Coining may be used for high voltage power lugs and resizing powdered metal pieces.

    Forming

    Using a custom power press to change the shape of a material part without deliberately reducing the material thickness. Examples include electrical housings, journal bearing for trains, medical batteries or device cases, ranges, appliances like dishwashers and refrigerators (and formed and stamped panels for these products), flattening exhausts for mounting, HVAC parts, windshield wiper blades, and jewelry.

    Embossing

    An operation using a custom power press that creates imprinted designs on sheet metal by means of female and male dies, theoretically without change in material thickness. Examples include structural stiffening and lettering sheet metal pieces.

    Piercing

    Punching or cutting an opening, like a hole in a metal sheet, plate, or different parts, with a power C-frame floor press. Examples include high-power electrical connectors and automotive exhaust systems.

    Trimming

    Generally, a secondary shearing or cutting process on a previously drawn, formed, or forged part. The aim is to “trim” all surplus metals off of the edges and bring the piece to the required shape and size. Examples include dishwasher baskets, automotive carpets and dashboards, die-cast trimming, plastic parts, and truck body panels.

    Press fitting

    Joining pieces with an interference fit.

    Advantages of Power Presses

    The multi-functionality of power presses has led to different advantages:

    • Previously, the job of shaping and pressing was done manually; this machinery has resulted in a big saving of labor and effort.
    • Presses are designed so that workpieces do not need to be arranged over and over on the machine.
    • Power presses are very easy to work with, in contrast to manual presses.
    • The design and adaptability of the machines give users the benefit of moving them freely around the workplace.
    • Power presses can trim, straighten, press, assemble, and disassemble parts into different shapes.
    • Power presses are classified as sturdy, robust, and energy-efficient.
    • They have low initial costs and are user-friendly machines.
    • These highly reliable machines with excellent punching, pressing, and clasping techniques do not need lofty maintenance.
    • The compact size of these machines makes them remain steady for longer terms.

    Disadvantages of Power Presses

    Just like all machinery, power presses have their own drawbacks discussed below.

    • Overheating – power press machines can easily overheat. The higher forces required and faster speeds are at the cost of having to be careful not to overload the machine.
    • Higher Power Consumption – A power press machine uses more electrical energy than most types of presses, which is another unexpected result of generating more energy than the alternatives.

    Safety Measures of Power Presses

    Power press machines fall into the class of heavy machinery; hence, it is very important to follow a few guidelines when utilizing power press machinery at a workshop or factory.

    • First and foremost, the employee responsible for operating the power press must be given adequate training.
    • The working principle of the machine should be explained to all persons responsible for any type of task on a power press machine.
    • Due maintenance activity must be done in the workshop or factory as per the requirements. This includes an examination by a technical person of major parts responsible for malfunctioning to evade unwanted consequences.
    • When not being used, the power of the power press machine must be switched off.
    • Working instructions that need to be followed must be either pasted on the power press machinery or handed to the operator.
    • A suitable record of power press maintenance action must be upheld to schedule maintenance actions on time.

    Maintenance of Power Presses

    Power press maintenance and inspection are very important to keep it safely operating and prolong its working life. Therefore, maintenance and inspection before operation should be carefully carried out.

    • Pipelines – No leakages on lubrication, air, and hydraulic pipelines
    • Circuits – Not damaged and well connected.
    • Air pressure – The air pressure is close to 0.5Mpa
    • Seeper – No water inside pneumatic dual part, mist catcher, or filter relief valve
    • Oil – Adequate oil in gear casing, ball coupling between link and ram, hydraulic overload protection, and lubrication pump
    • Direction of flywheel – For mechanical power presses, start the primary motor to check if the flywheel runs according to the arrow marked there.
    • Emergency stop – Press the emergency stop button to ensure the primary motor will immediately stop. Press and hold the emergency stop button while performing other actions; the motion should not be completed.
    • Guideway – the guideway surface should be completely lubricated five minutes later and with no thermal hazards.
    • Opto-electronic – Stop immediately to shield the beam in operation. After an opto-electronic emergency stop, the machine can’t be started without first resetting the module.

    Hazards Associated with Power Presses

    Workers operating power presses without appropriate safeguards can suffer amputations, crushed bones, and even fatalities. General point of operation safeguards for power presses include the following:

    • Barrier guards
    • Presence sensing devices
    • Two-hand controls
    • Foot controls
    • Restraints
    • Pushbacks/Pull-outs
    • Type “A” or “B” gates

    Conclusion

    Power press machines are highly advantageous and expedient workshop machines wielded for bending, cutting, pressing, and forming metal sheets into different sizes, shapes, and dimensions along with multitasking tools. Power press machines are majorly applied in manufacturing industries for preparing the casing for appliances. Due to their multi-functional features, they are utilized in all factories and industrial workplaces. There are different power press types available in the market, C-frame type and H-frame type, for metal sheet machining work used in the manufacturing industry. A combination of both types is also available.

    Leading Manufacturers and Suppliers

      Contact us to discuss your requirements of crank press machine. Our experienced sales team can help you identify the options that best suit your needs.