Press Comparison Guide: Mechanical vs. Servo Press Technology

Selecting the best press machine for your metal stamping operations is a very critical undertaking, which involves a great deal of understanding regarding the types of machines you choose to invest in. Some press types are better suited for certain production needs. In this article, we hope to give you a foundational understanding of the pros and cons of mechanical and servo presses, so you can be confident in choosing the proper press type for your next project or production expansion.

Mechanical Press Technology

The mechanical press machine has a long history in metal stamping seeing as how it was among the first kinematic mechanisms used in modern metal stamping. Mechanical presses are complex machines with multiple variations of the same machine type and have a wide range of applications and capabilities.

Overview - Mechanical Stamping Presses

A mechanical press machine is a type of press that can exert extreme amounts of force driven by mechanical means which involves a flywheel, crankshaft, and clutch-brake mechanism. Mechanical presses are fundamental machines in various metal forming operations due to their reliability, efficiency, and capability to produce a high volume of parts with consistent quality. One of the more common variations of a mechanical press is within the frame which we compare in another article here: C frame vs straight side presses.

Working Principle & Applications - Mechanical Presses

The fundamental working principle of a mechanical press involves the conversion of rotational energy into linear motion. This is accomplished by the flywheel storing rotational energy and releasing a controlled portion of said energy to drive the ram of the press. The ram then uses the force applied to shape the material based on the composition of the tool and die. This entire process is done with a great deal of speed and precision which is one of the many reasons why mechanical press machines are essential in high volume production environments.

Mechanical Presses are versatile machines and are suited for several common metal stamping applications such as:

• Blanking
• Coining
• Drawing
• Shearing
• Embossing
• Bending
• Punching

Advantages - Mechanical Presses

Speed & Efficiency
Mechanical Stamping Presses excel in operating at higher speeds than servo press machines. This can be particularly advantageous for large-scale operations where every second of production matters. The continuous & rapid cycles of a mechanical press ensure a high output making them an ideal choice for repetitive high-volume production tasks.

Reliability & Durability
Mechanical Presses offer unmatched robustness & dependability. They are constructed with technology that has been proven and refined over decades. Their sturdy construction helps reduce unexpected breakdowns and maintenance leading to continual operation and minimized downtime.

Power
These press models are known for the power that they can provide to a given operation. Mechanical presses can produce extreme amounts of force which makes them suitable for heavy-duty tasks and applications that use thicker more resistant materials, or processes with significant material deformation like deep drawing.

Cost Effectiveness
When looking at costs mechanical presses often have an advantage over servo press machines. Mechanical options typically require less upfront investment, which can benefit businesses operating with budget constraints. Another area where these presses have an edge is when considering maintenance costs. Costs associated with maintenance are often more straightforward and inexpensive leading to a lower total cost of ownership.

Limitations - Mechanical Presses

Flexibility
One of the primary limitations of mechanical presses is the reduced flexibility of the stroke length and profile. Unlike servo presses, which can adjust these parameters mechanical presses often have fixed stroke lengths and speeds.

Energy Consumption
Mechanical presses can be more energy-intensive. The flywheel, which is a key component in these machines, needs to continuously operate throughout the press cycle. This constant motion leads to a steady draw of power, which can result in higher energy consumption, especially in comparison to servo presses that use energy only when in motion. 

Noise Levels
Noise is another factor to consider with mechanical presses. They tend to operate at higher noise levels due to the nature of their mechanical operations. This could require additional noise reduction measures in the workplace, such as sound enclosures or protective gear to ensure a safe work environment for operators.

One way to counteract the limitations of a mechanical press is by utilizing the adjustable stroke technology that we incorporate into our presses. When an adjustable stroke is paired with a variable frequency drive you can expect servo-like flexibility with the speed, consistency, and simplicity of a mechanical press.

Servo Press Technology

What makes a servo press stand out in terms of press technology is its incorporation of servo motors, which distinguishes it from traditional mechanical presses. These machines leverage the control of servo motors to drive the press ram mechanism, offering a high degree of accuracy and flexibility. Unique for their programmability, servo presses allow users to control the slide position, speed, and pressure with precision. Their adaptability makes them suitable for complex and varied stamping tasks.

Working Principle & Applications - Servo Presses

At the heart of a servo press is the servo motor, which directly controls the press’s ram movement. Unlike mechanical presses that operate on a fixed cycle determined by the flywheel, a servo press can adjust its stroke and speed in real time based on the task at hand. This is made possible by software that controls the servo motor, allowing adjustments to be made on the fly  This results in a highly adaptable press, which can be tailored to specific production requirements.

Most of the applications that apply to a mechanical press can also be performed with a servo press.

Advantages - Servo Presses

Precision & Control
Some of the standout aspects of servo press technology lie in the amount of precision and control that it provides users. Unlike a mechanical press which operates on a fixed cycle, a servo press has a highly programmable stroke profile. This allows the user to adjust the motion, speed, and position of the slide at any point in the stroke. Servo presses can pause or slow down during certain points in the stroke to ensure proper time for feeds or transfer systems to complete their function. This makes very intricate or complex forming processes much more viable in applications where gradual or variable force is needed to guarantee sufficient part quality.

Energy Efficiency 
Servo press machines contribute to energy-efficient manufacturing thanks to the press only consuming power during the stamping process whereas with a mechanical press energy consumption is constant when the machine is powered on. Another way servo presses contribute to energy efficiency is by optimizing the stroke profile for specific jobs.

Versatility
Thanks to the programmability of the stroke profile the servo press can offer a great deal of versatility for metal stamping operations. They can adapt to different materials, thicknesses, and forming requirements without the need for physical or manual adjustments to the press. The versatility of the servo press makes it a quality choice for operations that tend to see a high mix of parts that vary in requirements.

Reduced Set-Up Times 
With the right controls that offer tool/program storage capabilities, these presses can recall and adjust to the different programs that have been stored with ease. This helps drastically reduce setup and changeover times for operators which can be a huge factor for high-mix, low-volume stamping operations.

Limitations - Servo Presses

Initial Investment
Due to the advanced controls, programmable features, and other components a servo-driven press comes at a much higher initial cost compared to traditional mechanical presses. This type of upfront capital requirement may serve as a barrier to entry for smaller operations, or those with limited budgets.

Maintenance
Since servo presses rely on sophisticated software and controls, this makes the maintenance of these machines more complex than that of their mechanical counterparts. The requirement of specialized knowledge for both the mechanical and software aspects necessitates a higher level of technical expertise. Operations may encounter increased maintenance costs from training their existing operators and personnel. These factors and the need for specialized diagnostics, updates, and system checks may lead to a higher total cost of ownership.

Operator Training 
The complexity and programmability of these presses demand a higher level of operator training and understanding. Maintaining skilled personnel is essential to fully leveraging the capabilities, and maintaining efficiency. This can be challenging in times and areas where skilled labor is scarce or for companies that place less value on developing and educating their personnel.

Comparing Mechanical and Servo Presses

Performance
Mechanical presses lead the pack in terms of raw speed and simplicity, making them more suitable for high-volume job requirements. Servo presses, however, offer much more programmability and flexibility making them a great option for applications that require control and adaptability.

Efficiency
Servo presses are often more energy-efficient, as they consume power on demand as opposed to running continuously. This efficiency can lead to cost savings in the long term.

Precision
Servo-driven presses when utilized properly can provide exceptional precision in operation thanks to the control and programmability. Mechanical presses serve as a consistent option and precision can be determined by the quality and condition of the press.

Flexibility
Typically servo presses offer more flexibility, but for the tradeoff of less operational speeds. This makes them an ideal candidate for high-mix, low-to-mid-volume operations. Traditional mechanical presses tend to lack the flexibility to run multiple jobs optimally. This is one of the reasons the adjustable stroke feature is standard on a Sangiacomo press, so you can tune the stroke of the press to the application at hand which ensures efficient production. Also as mentioned earlier when you pair an adjustable stroke press with a variable speed option you can obtain similar flexibility to that of a servo press without giving up operational speed.

Operational Implications
Whether you are a seasoned metal stamper or a beginner looking to bring part production in-house it is important to know what will be required of your business to run a stamping operation successfully. This includes having skilled operators and maintenance personnel that can run the press and keep it running optimally, also you must invest time and money into ensuring that operators who run the press have the knowledge and skill to do so properly. This can be quite a challenge for those who are new to stamping, and servo presses present unique challenges in terms of programming the profile of the stroke. With mechanical presses the operation can be significantly simpler, so keep that in mind when considering your options for purchasing a press. If you are not going to be committed to investing in the proper support and training required to run the press you can run into significant issues down the road.

The choice between mechanical and servo presses should be informed by the specific needs, operational requirements, and future objectives of your metal stamping operation. Mechanical presses, with their speed, reliability, and cost-effectiveness, are ideally suited for high-volume production tasks where the simplicity and robustness of the machine can translate into operational efficiency and reduced downtime. On the other hand, servo presses offer precision, control, and versatility, making them perfect for complex stamping applications.