What are vacuum suction cups?
Vacuum suction cups, also known as suction cups or vacuum cups, are devices that use negative pressure or vacuum to adhere to a surface and hold objects. They typically consist of a flexible cup-shaped body made of materials such as rubber or silicone, and a connector or fitting for attachment to a vacuum pump or other vacuum source.
The suction cups work by creating a vacuum between the cup and the surface to which it is attached. This vacuum creates a strong seal that can hold objects securely in place, even when subjected to various forces such as gravity or vibration.
How do vacuum suction cups work?
Vacuum suction cups work by creating a vacuum between the cup and the surface to which it is attached. When the vacuum is created, the surrounding atmospheric pressure pushes the suction cups against the surface, creating a seal that can hold objects in place.
The process of creating a vacuum typically involves a vacuum pump or other vacuum source that is connected to the suction cups via a hose or tubing. When the pump is activated, it draws air out of the cup and the space between the cup and the surface, creating a negative pressure or vacuum.
As air is removed from the space between the cup and the surface, the atmospheric pressure outside the cup pushes the cup against the surface, creating a strong seal. The suction cups can then hold objects securely in place, even when subjected to various forces such as gravity or vibration.
To release the suction cups, the vacuum source is turned off or disconnected, allowing air to flow back into the space between the cup and the surface. This breaks the seal and releases the suction cup from the surface.
Overall, the vacuum suction cup works by utilizing the principles of atmospheric pressure and vacuum to create a secure and reliable attachment between the cup and a surface.
What are vacuum suction cups used for?
Vacuum suction cups are commonly used in various sectors, including manufacturing, secondary packaging industry, and transportation, for tasks such as lifting and moving heavy objects, handling fragile workpieces such as glass plates or glass panels, and holding materials in place during processing. They are also commonly used in household applications such as attaching showerheads and other bathroom accessories to smooth surfaces.
When shouldn't we use vacuum suction cups?
While vacuum suction cups can be useful in many applications, there are certain situations where they may not be the best choice. Here are some examples:
Rough or porous workpieces: Vacuum suction cups work best on smooth, non-porous surfaces such as glass industry or polished metal. Rough or porous surfaces, such as wood or concrete, may not provide a strong enough seal for the suction cup holder.
High-temperature environments: Suction vacuum cups can become less effective at high temperatures, as the heat can cause the seal to break down or the cup to deform. In such cases, other types of fasteners or clamps may be more appropriate.
Extremely heavy loads: While vacuum suction cups can be used to lift and move heavy objects, such as wood handling, there are limits to their weight capacity. It's important to carefully evaluate the load and select a suction cup with an appropriate weight capacity to avoid accidents or damage.
Hazardous materials: Vacuum suction cups should not be used to handle hazardous materials or substances that could contaminate the cup or the vacuum system.
Moving objects: Vacuum suction cups are designed for use on stationary objects. They may not be suitable for applications where the object is moving or subject to significant vibration, as this can cause the suction cup to lose its seal.
Overall, it's important to carefully consider the specific application and requirements before selecting a vacuum suction cup. It's recommended to use suctions cups
Operating principle of a suction cup
When air is evacuated from the suction cup, a pressure difference is created with atmospheric air. As atmospheric pressure is higher, the workpiece is pressed against the suction cup.
Selection criteria for suction cups
When choosing a suction cup, not only the mass of the object to be gripped by the suction cup is important, but also other factors.
Material selection for suction cups
Suction cups are available in different materials. The choice of material depends on the application or industries. Suction cups (the plastic body) are available in a wide variety of materials such as Perbunan (rubber), Polyurethane, Silicone, Viton and anti-static Perbunan (rubber). They are of high quality and optimised for different application areas such as foodstuffs, oily products, etc.
The shape of industrial suction cups
An optimal shape of the suction cup guarantees high suction power despite its small size. Therefore, using a smooth surface and a good shape is very important for the right suction cup:
- Standard flat suction cups for gripping flat or slightly undulating surfaces, such as sheet steel or cardboard.
- Extra hollow suction cups for gripping round or very curved shapes.
- Bellows suction gripper for gripping angled, curved, round, large and deformable products or fragile objects such as glass bottles. In addition, this design offers advantageous height compensation.
- Oval suction pads for gripping narrow, elongated objects, e.g. profiles and tubes.
Between venturi and vacuum suction cups
Depending on the application, we place some additional devices between the vacuum suction cups and the gripper to increase the efficiency of the suction cups.
To know the operation of the suction cups and ensure that objects are gripped properly by the suction cups, the vacuum (level) at the suction cups must be measured and monitored. Pressure sensors monitor the correct vacuum and give the PLC the information needed to control the machine. There are different types of vacuum sensors.
The vacuum switch
In these components, an electrical contact is activated when a certain vacuum is reached. The pressure at which the contact switches can be set or not, depending on the type of switch.
The vacuum sensor
This vacuum sensor is more compact than the vacuum switch and is also protected against short circuits. Depending on the type, we find vacuum sensors offer the following advantages
- Introduction of a limit value via a button (teach-in method) instead of a complicated setting via a set screw.
- Introduction of different detection thresholds.
- Hysteresis adjustment of switching points and travel of the workpiece.
- The possibility of mounting the sensor directly in the compressed air hose or venturi.
- An LCD display on which all useful values can be read and which also allows for simplified manual adjustment of the sensor.
Care must be taken to ensure that contaminants drawn from the air do not reach the ejector. If filters are used in combination with vacuum sensors, it is advisable to place the sensor between the filter and the workpiece. If a vacuum sensor is placed between the filter and the venturi, the sensor can switch in case of insufficient vacuum at the suction cups due to a dirty filter.
The vacuum leakage limiter
The vacuum leak limiter reduces vacuum leaks resulting from a poorly sealed suction cup. The vacuum leak limiter consists of a check valve held open by a spring and a fixed throttling valve.
Vacuum and energy consumption
Creating a vacuum in the ventures requires airflow, and therefore energy. Energy means cost. To reduce costs, we should try to optimize two aspects when using vacuum generators:
- Place the vacuum generator as close as possible to the suction cups.
- Minimize the time needed to generate the vacuum, possibly by applying an energy-saving function.