What is a Plain Press? Basic Introduction

In today's industrial field, plain press, as the most commonly used and economically efficient punching equipment, occupy a pivotal position in the metal processing industry. It has become the preferred equipment for mass production of metal parts due to its simple structure, convenient operation, and high production efficiency.

This article will take you through a comprehensive understanding of plain press, from their core definition and working principles, to their mechanical structure and components, to their outstanding advantages and wide application fields, providing you with a complete cognitive guide.

1、 What is a plain press? Core concepts and positioning

A plain press is essentially a stamping press, belonging to a type of metal plastic forming equipment. In national production, stamping technology has become increasingly widely used due to its advantages over traditional mechanical processing, such as saving materials and energy, high efficiency, and lower technical requirements for operators.
The term 'ordinary' is mainly used to distinguish it from more complex and expensive hydraulic presses, high-speed presses, or servo presses. It usually refers to a traditional punch press that uses mechanical drive to achieve reciprocating motion of the slider through a crankshaft or eccentric gear structure.
This type of punch press is mainly used for processing sheet metal. By equipping specific molds, it can complete various cold stamping processes such as cutting, punching, forming, deep drawing, and trimming, thus producing a variety of parts from simple gaskets to complex electrical casings.

Many items we come into contact with in our daily lives, such as switches, sockets, cups, computer cases, and even numerous accessories on cars and airplanes, cannot be separated from the manufacturing process of plain press.

2、 The working principle of plain press: from circular motion to linear punching

The core design principle of a plain press is to convert circular motion into linear motion.
This sports system starts with the main electric motor, which drives the flywheel to rotate and store energy. Subsequently, the rotational power is transmitted to the gears, crankshaft (or eccentric gear) through the clutch, thereby driving the connecting rod to operate.
The connection point between the connecting rod and the slider is the key to achieving motion form conversion. This transfer point usually adopts two mechanism designs: one is a spherical structure, and the other is a pin type (cylindrical) structure.
It is through this mechanism that the circular motion of rotation is smoothly converted into the linear motion of the slider up and down.
During stamping processing, the material is placed between a set of molds (the upper mold is fixed on the slider, and the lower mold is fixed on the workbench). When the slider moves downwards with the upper mold, it exerts tremendous pressure on the material, causing it to undergo plastic deformation or separation, thereby achieving the required shape and accuracy in the design.

The enormous reaction force generated throughout the entire process is absorbed and carried by the highly rigid and high-strength frame body of the punch press, ensuring stable and precise processing.

3、 The core components of the mechanical structure of a plain press

The performance and stability of an plain press cannot be achieved without the collaborative work of its key mechanical components.
Rack: As the "skeleton" of the punch press, it is usually welded from high-quality steel plates and subjected to heat treatment to eliminate internal stress, ensuring that the equipment does not deform under long-term high-intensity work and has high rigidity and stability.
Crankshaft and connecting rod: This is the "heart" that achieves motion conversion. The crankshaft converts rotational power into reciprocating motion of the connecting rod, and its manufacturing accuracy and wear resistance directly determine the motion accuracy of the slider.
Sliding block: As the "arm" that performs stamping actions, the sliding block is driven up and down in a straight line by a connecting rod, and an upper mold is installed on it. The slider usually has an adjustment mechanism that allows manual or electric fine-tuning of its height to adapt to molds with different closing heights, with an accuracy of up to 0.1mm.
Clutch and brake: These are the "nerve centers" that ensure the safe operation of equipment. Modern plain presss often use high-sensitivity clutch/brake combination devices, coupled with dual electromagnetic control valves, to ensure that the slider can move at high speed and stop accurately and reliably, greatly improving operational safety.

Mold: Although not part of the punching machine body, it is an indispensable "sharp edge" in stamping processing. Molds are divided into upper and lower molds, and their cavities and cutting edges directly determine the final shape of the workpiece, which is the specific executor of the stamping process.

4、 The prominent features and advantages of plain presss

The popularity of plain presss in many industrial fields is due to a series of significant characteristics and advantages.
1. High rigidity and high precision: The sturdy frame structure and core components (such as crankshafts and gears) that have undergone hardening heat treatment and precision grinding ensure that the equipment maintains stable high precision for a long time, meeting the needs of precision stamping.
2. Reliability and safety of operation: Thanks to advanced clutch/brake combinations, dual electromagnetic control valves, and overload protection devices, the operation of the punch press is more convenient and accurate in positioning, while ensuring safety during high-speed movement and stopping.
3. Extremely high production efficiency: The number of strokes of the punch press is fixed, enabling continuous and rapid stamping production. When paired with corresponding automatic feeding devices, fully automated production can be achieved with low cost and extremely high efficiency.
4. Energy saving, environmental protection and low noise: Compared with some heavy-duty forging equipment, modern plain presss pay more attention to environmental protection in their design, adopting advanced technology to reduce noise, energy consumption and pollution.

5. Strong universality and easy maintenance: The relatively simple structure and mature technology make plain presss very versatile. At the same time, its maintenance and upkeep are relatively convenient, reducing later operating costs and maintenance difficulties.

5、 The main classification methods of plain press

Although they are collectively referred to as "plain presss", there are also multiple classification methods within them to meet different processing needs.
According to the driving force, it can be divided into mechanical punching machines and hydraulic punching machines. The plain press we usually refer to mostly refers to mechanical punch presses, which transmit power through mechanical transmission mechanisms; Hydraulic punch presses rely on hydraulic cylinders to generate pressure and are often used in situations that require significant nominal pressure or deep drawing.
Divided by slider drive mechanism: This is a more detailed classification of the internal structure of mechanical punching machines.
Crankshaft punch press: This is the most common type, with a simple structure, fixed stroke, and wide applicability, suitable for almost all plain press processing such as punching, bending, and stretching.
Eccentric gear punch press (without crankshaft): This type of punch press structure is superior to the crankshaft type in terms of shaft rigidity, lubrication, and maintenance, but it is more expensive and more suitable for processing longer strokes.
Elbow punch press: Its characteristic is that the slider moves very slowly near the bottom dead center, providing continuous clamping force, especially suitable for compression molding processes such as embossing and finishing.

In addition, it can be divided into C-type (open type) and gantry type (closed type) according to the body structure. The C-type body is open on three sides, with an open operating space for easy loading, unloading, and observation, making it a common form of small and medium-sized punch press.

6、 The wide application fields of plain presss

The application fields of plain presss almost cover all aspects of modern manufacturing, and their "ordinary" name precisely reflects their wide popularity.
1. Electronic and electrical industry: producing switches and sockets, computer cases, various connectors, heat sinks, etc.
2. Automotive and transportation manufacturing industry: used for manufacturing various hardware components on automobiles, motorcycles, and bicycles, such as brake pads, brackets, gaskets, etc.
3. Household appliances and furniture industry: Metal panels for refrigerators, washing machines, air conditioners, as well as metal connectors and hinges on furniture, all rely on stamping processing.
4. Daily hardware and instruments: From the cups and tableware we use to precision instrument parts, punching machines can efficiently shape them.
By using different molds, plain presss can complete various processes such as cutting, punching, bending, stretching, shaping, riveting, etc., demonstrating their strong process adaptability and productivity.
The core competitiveness of plain presss lies in their extremely reliable mechanical structure, which converts simple rotational movements into precise and efficient linear punching actions. This enduring design philosophy has enabled it to firmly occupy a key position on modern factory production lines in today's rapidly iterating technology.
For the large-scale production of metal parts that pursue stability, high efficiency, and low cost, investing in a high-performance plain press is undoubtedly a wise choice that has been proven over time.