Vacuum Grippers for Smartphone Production

What is it that characterizes a smartphone? The answer: perfection. Its glass and metal exterior is sleek and smooth, the control buttons discreetly embedded in the housing. When switched on, it dazzles the user with brilliant colors and undreamed-of functions. Manufacturers invest a considerable amount of effort into developing this look and feel and performance, and make the highest demands on the production process. Schmalz has just the solutions to meet these tough demands – be it for handling the thin glass display, assembling the battery or positioning the sensitive printed-circuit board.

Schematic diagram of the main smartphone components, which are handled with vacuum grippers.
The area gripper STGG handles displays and sensitive glass gentle, non-marking and highly dynamic.
Flow grippers SCG compensates height differences on the PCB and prevents damage due to mechanical load.
The contact surface of the FM area gripper is a soft, flexible foam, which holds and handles the lithium ion cells damage free and secure.
Vacuum suction pads made of Elastodur are wear-, abrasion- and dust- resistant and offer optimum grip in highly dynamic handling processes.

More than 1.4 billion smartphones are sold worldwide every year. In Germany, as in the rest of the world, the number of smartphone users continues to grow steadily and expectations are great for the high-tech product. While the innovative leaps may be smaller nowadays, manufacturers are constantly finding ways to generate hype with each new smartphone release. Not only the camera, but also the display, battery and processor performance in particular are consistently being optimized. Production is labor intensive and requires considerable sensitivity. The assembly process must be carried out with extreme precision in order to maintain the high quality standards.

Sensitive Layer

The display is a crucial element of the phone's appearance. Most phones feature a capacitive touch screen, which consists of a glass substrate coated with metal oxide. The corners of the display are fitted with electrodes that generate an electric field by means of alternating voltage. Upon skin contact, this field is broken, whereupon the controller translates the finger movements into control commands. The coating is essential for operation of the smartphone, which is why – just like the glass itself – it must not be damaged during handling.

For the production of the glass, which is just a few hundred microns thick, Schmalz has developed the thin glass gripper STGG. In order to grip the glass and display modules quickly and then handle them safely and precisely at high acceleration speeds, the STGG is equipped with a large suction area with suction openings placed closely together. This ensures that the gripper can produce a high suction force with low vacuum levels and keep the surface pressure low. The contact surface of the thin glass gripper is made of contamination-free PEEK to prevent any kind of contamination both before or after the display is coated. The production process also uses individually shaped suction cups made of HT1 high-temperature-resistant material, which leaves few marks. These suction cups are also suitable for cleanroom applications.

Full Charge

As is the case with the display, precision and speed are also extremely important when handling the battery. Schmalz uses special area grippers to handle the extremely thin, sensitive electrodes dynamically, yet without causing displacement and damage. The concept of decentralized vacuum generation with a high flow rate directly in the gripper itself enables quick and safe suction power. The battery gripper also features an integrated exhaust duct: The air for generating the vacuum is diverted to ensure that dirt particles cannot enter the process room – an important function for applications in cleanrooms. In order to grip the sensitive electrodes without causing any contamination, the special material PEEK is also used for the suction areas on the battery gripper. The grippers must not cause any mechanical, chemical or visual damage and must prevent uncontrolled electrostatic discharge (ESD) of the battery components. Schmalz has developed special spring plungers, grippers and suction cup materials in order to construct ESD-compliant gripping systems. Changing battery designs also require appropriate handling: The integration of additional function modules, such as dual cameras, into smartphones means that their batteries need to be increasingly compact, while at the same time having even more power to handle the new functions. New battery shapes, for example, L-shaped batteries, also have to be accommodated. The area grippers in the FM series have integrated valves, enabling them to handle parts reliably even when only part of the gripper is occupied. The contact surface is made of a soft, flexible foam that grips and holds the lithium-ion cells without causing any damage.

Voltage-free Zone

Specialist knowledge regarding ESD-sensitive objects is also very important when handling printed-circuit boards (PCBs). PCBs are becoming smaller and smaller and the conducting paths increasingly sensitive, thereby multiplying the risk of damage due to rapid unloading. A compliant suction cup material combined with conductive spring plungers for flexible height adjustment enables gripping solutions in the ESD resistance range.

The requirements for vacuum technology are also high when it comes to assembling the printed circuit boards: Various components with different geometries and properties have to be positioned precisely in the shortest possible time. Handling the assembled printed circuit board is equally challenging: The height differences of the individual components on the printed circuit board must be compensated for, while at the same time preventing damage due to mechanical load. Schmalz's solution for this process step is the flow gripper SCG, which generates a high flow rate for reliable and gentle handling. The vacuum is generated quickly, which allows for very short handling cycles. The SCG moves the components reliably even in the case of low coverage of the suction area, for example, with printed circuit boards that have recesses due to the geometry.

The suction cup on the flow gripper is made from Perbunan nitrile rubber: This material is ESD compliant and dissipates potential electrical charges that could damage sensitive electronic components in a controlled manner.

Hard Shell

While precision and speed are the main priorities when producing the interior components, production of the housing is focused on different requirements: Aside from short cycle times, it is essential that the suction cups are robust and the vacuum generators resistant to dust. At the same time, it is important to keep energy consumption low. Schmalz responds to the durability requirements with suction cups that are made of Elastodur and Vulkollan. The vacuum expert achieves short suction and depositing times with minimum energy use with the compact ejector SCPS with integrated suction and blow-off functions. The integrated automatic air-saving function means that the ejector is only activated when vacuum is needed. The ejector's small size allows it to be positioned close to the suction cup, thus facilitating short evacuation times.

The requirements within the smartphone production process are extremely varied, and as a vacuum expert and handling specialist, Schmalz provides customized solutions for the individual process steps. Every single smartphone component places its own specific demands on the grippers and vacuum generators: Sensitive materials have to be gripped, moved and positioned with a high level of speed and precision. Schmalz also focuses on special features such as ESD protection, chemical resistance and use in cleanrooms. Added to this, the solutions from Glatten-based company are also smart-factory-ready: Using IO-Link, all process steps can be recorded, controlled and monitored centrally. The interface brings digitization to the sensor level and makes the vacuum components visible right up to the higher control levels. This allows them to be installed and configured quickly, and ensures reliable operation thanks to the predictive maintenance and condition monitoring function. Near-field communication, or NFC for short, means that data can be exchanged in a contactless manner and new parameters can be loaded directly.


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