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Vacuum Suction Cups: Product Overview
Vacuum cup grippers are essential end tools of various industrial robotic workholding systems. They serve as the robots’ hands allowing them to manipulate objects with safety and incredible precision. These types of grippers are widely used across several industries, including the food, automotive, and consumer electronics industries. In this article, we’ll discuss vacuum suction cups, what they are, what are the different types, and how important they are in achieving simple gripping tasks.
What Are Vacuum Suction Cups?
A vacuum suction cup is a device used by vacuum gripping systems for pick-and-place applications in automated production processes. To be able to grip and pick up various workpieces, a vacuum lifter must work in tandem with a vacuum generator or a vacuum pump. These grippers are usually made of silicone, polyurethane (PUR), chloroprene, or nitrile rubber (NBR), and they usually come in a variety of sizes and shapes, with varying holding capacities in different applications.
Types of Industrial Suction Cups
Depending on your application needs, the following types of vacuum suction cups are generally available:
Flat Vacuum Suction Cups
Flat vacuum suction cups are generally preferred for handling workpieces with a flat or a slightly curved nonporous surface. Thanks to their flat design, they’re usually recommended for universal use, as they provide high levels of stability. Flat suction cups are mostly used on flat surfaces, like glass, sheet metal, and cartons.
Oval Vacuum Suction Cups
Oval vacuum suction cups are the best choice when it comes to working with thin and elongated surfaces and long pieces, such as metal sheets. They can have a flat or a bellowed lip and are usually employed in situations that require maximum holding force.
Bellows Suction Cups
Bellows suction cups are mostly used as level compensators on uneven or rough surfaces or flexible, highly flexible workpieces. These are also ideal for delicate operations, such as placing surface-mounted electronic components and injection molded parts. Suckers with several bellows can be used to handle materials, food packages, and shrink-wrapped products.
Additional Features
There are some additional features a suction cup might require to adequately match your application needs:
· Lip Feature: A lip feature in flat suction cups prevents leakage and enables effective sealing on smooth and somewhat rough surfaces. For special applications, these might come with double-safety lips for extra protection against leakage.
· Supporting Ribs: Flat suction cups may also feature supporting ribs, which helps increase the cups’ holding force and stability.
How Does an Industrial Vacuum Suction Cup Work?
Before we dive into the working principles of suction cups, it’s important to mention pneumatic vacuum systems, which provide the cups with the necessary vacuum. These are usually vacuum generators, which operate either electrically or pneumatically. Most automation applications use pneumatic generators as this helps achieve short and rapid cycle times.
Their compact and lightweight design allows them to be directly integrated into the vacuum system and onto the automation tools. Electric vacuum generators are also used, but only when there’s no availability of compressed air.
Suction cups are two-part components: the cup itself and the connector that connects the cup with the vacuum system. They operate on the principles of differential pressure. When the vacuum generator evacuates the air between the cup and the workpiece, it creates a negative pressure. As the negative pressure increases, so does the difference between the negative and atmospheric pressure.
When the atmospheric pressure exceeds the pressure between the cup and the workpiece, the suction cup becomes attached to the workpiece, as its design prevents air from leaking inside, helping to create the vacuum. However, the resulting force must be greater than the sum of static and dynamic forces exerted upon the workpiece as it is picked up and placed during the automated production; otherwise, the cups won’t hold.
How to Choose a Suction Cup?
Source: Xiamen Better Silicone Rubber
Here are some key considerations when choosing the right suction cup for your application:
Vacuum Cup Sizing
A vacuum suction cup size is determined by applying the following formula F=P*A; where:
· F = Force = the weight of the object being grabbed in lbs/kg
· P= Pressure = the expected vacuum levels in PSI
· A= the area of the vacuum cup measured by square inches.
Considering that we are looking for the size of the suction cup, we have to rearrange the formula as follows: A=F/P. The area of the cup derived by applying this formula corresponds to the surface area of the cup or the cumulative surface areas in a multi-cup system. Also, if the resulting number turns out to be a decimal number, round it up at the next available suction diameter.
Vacuum Suction Cup Fitting
To ensure the maximum efficiency of your vacuum system, it’s important to pay close attention to the bore size of the fittings as well as the size of vacuum lines. The precise bore measurements are determined by the previously described factor.
In general, larger bore fittings are used when gripping large porous materials and uneven surfaces, as well as flexible packaging. In those cases, the bore of the fitting must be close to a 1:2 ratio to the diameter of the cup.
Vacuum Suction Cup Materials
Suction cups are made of various types of elastomers, like silicone, nitrile rubber, polyurethane, and vinyl. These have different oil, chemicals, and high-temperature properties, to better suit various applications. Vinyl, Chloroprene, and nitrile are among the most generally used materials.
Summary
Vacuum suction cups are essential components necessary for the operation of vacuum-powered automated production systems across several industries. They cover a broad specter of applications and help increase the efficiency and productivity of automated production lines.
If you’re in the market for vacuum suction cups, or parts and components for your vacuum system, don’t hesitate to visit Reid Supply — a global supplier of industrial parts and components used in machining and machine engineering. We can supply you with components such as cable carriers, check valves, vacuum switches, vacuum filters, lifting magnets, and different types of clamps. We can also source parts that we don’t keep in stock and provide technical guides and other literature.