Gentle and Intelligent—A Robot Gripper Made for Sensitive Tasks

Some industrial robots are used to move components from one point to another or to insert components into other assemblies. To perform these tasks, the robot must be outfitted with an end effector that grips the components without leaving marks.

Most of the time, this is an easy task, but some components are delicate and require special grippers so that the component is not damaged during the gripping process. In response to this challenge, Schunk, a global leader in robotic grippers, released the smart EGK gripper.

 

Schunk’s new EGK smart gripper. Image used courtesy of Schunk

 

Smart Robot Gripper

The EGK smart gripper is an electrically powered gripper, which is slightly different from Schunk’s other line grippers which are pneumatic. Inside the EGK is a spur gear with pinion and rack assembly. This gear train provides constant gripping force along the entire finger length, and with the gripper being electric, the finger position is retained during an emergency stop situation. Unlike pneumatic grippers, the EGK smart gripper has an internal, high-resolution absolute encoder. This design allows the control system to know exactly where the gripper fingers are at all times.

 

An inside look of the smart EGK gripper. Image used courtesy of Schunk

 

Pneumatic Gripper vs Electric Gripper

When components are small or made from delicate materials, it is important to control the gripping force. With pneumatic grippers, this is typically done with an air regulator, which is not very accurate and is prone to integration issues. With the EGK gripper being electric, the gripping force, along with the stroke, can be programmed and is continuously adjustable. The EGK can apply a gripping force of 20 to 300 N. There are even special gripping modes for ultra-delicate work pieces called the ”SoftGrip” mode.

 

The EGK gripper is available cleanroom ready. Image used courtesy of Schunk

 

IP67 Rated and Cleanroom Ready

Some robots are used in cleanrooms which are areas that have tightly controlled specifications as to the type of material, type of lubrication that can be used, and air quality. The EGK gripper comes in many variants, some of which are cleanroom ready. They use a food-compliant H1 greasing and have three-state sealing to protect the internal gear train. The electronics are fully integrated and sealed to support an IP67 rating, making these grippers an excellent choice for food handling.

 

EGK gripper software for PLC integration. Image used courtesy of Schunk

 

Connectivity and Commissioning 

Schunk doesn’t call the EGK gripper smart for nothing. This gripper has an integrated fieldbus connection that expands the programming capability. All the major industrial protocols are supported: Ethernet/IP, ProfiNet, EtherCat, IO-Link, and Modbus RTU. By using industrial protocols, Schunk has greatly reduced the need for special encoder interface cards and reduced the number of inputs and outputs. The gripper's speed and position, along with force, can all be controlled easily from the PLC or robot controller. To reduce the integration phase even further, Schunk also offers pre-programmed function modules that can be used in a PLC or robot controller of the user's choice. 

 

A Flexible Gripper

Choosing the right robot gripper can be a daunting task, especially when a gripper that is fully controllable and is able to grip small delicate components is needed. Schunk’s EGK gripper solves these problems by being an electric gripper that comes in three different sizes and 10 variants. This style of gripper works very well in the pharmaceutical industry when compressed air is a concern because of cleanroom requirements. The food and beverage industry sometimes needs to handle food that is easily crushed in a typical gripper, so being able to accurately control the gripper is very important.