Mechanical Press vs. Hydraulic Press

Posted on Jun 8, 2021

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Mechanical Press

A press is a machine that shapes and forms a variety of materials. It can perform many metalworking tasks, including forging, stamping, and die cutting. There are two main types of presses today –  the mechanical press and the hydraulic press. Although both serve the same purpose, it’s important that we understand their key differences.

Generally, a mechanical press features high production speed, while a hydraulic press offers higher flexibility for more complex forming processes. In this article, we'll discuss how they differ in terms of the mechanism and applications.


The Working Principle of the Mechanical Press

Figure 1. Mechanical Press

As the name implies, a mechanical press generates its power mechanically. Its main motor is connected to a crankshaft that cycles the ram and to a flywheel. In simple mechanical presses, a clutch controls the motor directly. In bigger and more complex press machines, the flywheel activates in motion pinion gear system that rotates the crankshaft.

As the motor powers the main system, the flywheels store this kinetic energy and convey it to the rest of the machine. Flywheels with bigger mass will yield a higher level of energy. This allows mechanical presses to achieve highest production speeds and forces. Especially when working with relatively flat and simple work pieces. 

The simple setup and operation requirements translate to fast and repeatable results. Mechanical presses are also less prone to leakage as they do not require hydraulic fluid to power itself. That being said, they do suffer from the lack of variable stroke lengths, which in turn limits their applications.
 

→ Read more: What Makes Mechanical Press Machines So Impressive?
 

The Working Principle of the Hydraulic Press

A hydraulic press exerts force on a fluid that in turn generates power. It mainly consists of a piston, a hollow cylinder, and a power unit/pump. The pump moves the piston which increases the internal fluid pressure. The cylinder then moves along the axis of the piston. This generates a linear momentum which forces the ram onto the workpiece.


Unlike mechanical presses, how much force a hydraulic machine can generate is subject to the operating pressure and cylinder bore size. The power unit also plays an important role in determining the ram speed. Overall, hydraulic presses are more versatile thanks to the variable stroke lengths. 

Despite the advantages, hydraulic presses are often susceptible to leakage owing to the fluid mechanism. Some types of hydraulic fluids can even catch fire. Also, it has a relatively low operational speed.
 


   Figure 2. A heavy-duty mechanical press for processing automotive parts
 

Differences in Applications

The major applications of mechanical and hydraulic presses are as follows:

 
  Mechanical Press Hydraulic Press
Function

Sheet metal blanking

Forming

Shaping

Deep Drawing

Piercing

Glassmaking

Sheet metal blanking

Forming

Shaping

Deep Drawing

Punching

Forging

Industry

Automotive

✓ Electronics

✓ Communications

✓ Household Appliances

✓ Furniture

Automotive

✓ Oil & Gas

✓ Marine Transport

✓ Commercial Transport

✓ Aerospace

Figure 3. Applications and Industries of Mechanical and Hydraulic Press


As you can see, while both machines perform similar functions, hydraulic presses are more versatile. This is because they can create very intricate shapes and are more economical to maintain. The automotive industry uses hydraulic presses especially often to process a wide spectrum of car parts. Mechanical presses, on the other hand, are used in applications where speed and production output are the primary concerns. 

 

Mechanical vs Hydraulic - Benefits and Drawbacks

So let us summarize the advantages and disadvantages of the two press types. When should you go for a mechanical and when for a hydraulic press?
 

Mechanical Press Advantages +  

  • High production efficiency: This is attributed to the higher level of control and operation speed, making mechanical presses suitable for fast and high-volume production.
  • Simple setup: The simpler setup and operation requirements lead to reduced upfront and operational cost. 
  • Environmentally-friendly: The use of hydraulic fluid is not required, which prevents adverse environmental impacts due to leakage and spillage. 
 

Mechanical Press Drawbacks −

  • Limited capacity: The fixed stroke length makes mechanical presses unsuitable for applications that require variable stroke lengths, such as open die forging.
  • High maintenance cost: Components such as the crankshafts, flywheels, and brake systems are all very expensive to replace and often require custom fabrication.
 

Hydraulic Press Advantages +

  • Full tonnage through strokes: The most notable advantage of a hydraulic press is that it can generate full pressing force anywhere during a stroke. This gives operators a high level of control over various operation parameters such as pressure, travel distance, etc.
  • Economical components and maintenance: Although relatively more complex to set up, the standard components of a hydraulic press are relatively cheaper than those of a mechanical press. Repair and replacement are cheaper, too
  • Flexible design: Hydraulic presses come with different designs and sizes to accommodate various applications. This includes the placement of power systems, tonnage requirements, etc. It also allows a high degree of customization.
 

Hydraulic Press Drawbacks −

  • Leakage: The hydraulic fluid can enter the environment from spills and leakage. There is even a risk that it contaminates the soil and even the groundwater below a factory.  
  • Low Speed: Unlike mechanical presses, hydraulic presses are not high-speed machines. The cylinder motion and fluid mechanism are not designed for rapid production.
 

Final Thoughts - Mechanical or Hydraulic?

Despite the differences between a mechanical press and a hydraulic press, both machines have their own advantages. Much like choosing between hydraulic and mechanical brakes, you are going to face a series of trade-offs. Therefore, review your metalworking requirements in terms of flexibility, speed, output, cost, etc. before buying your press machine.

 

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