Industrial Parallel Robot Grippers Help Manufacturers Get More Done

Universal Robots provides a wide range of UR certified grippers through UR+ –a global ecosystem of components, software, and application kits that have been validated and certified to be mechanically, electrically and digitally compatible with cobots from Universal Robots.

At first, the sheer variety of grippers available can seem daunting, especially if you’re new to automation. There are electric grippers, pneumatic grippers, soft grippers and vacuum grippers. There are 2-finger and 3-finger grippers, magnetic grippers, mechanical grippers and adaptive grippers, and each gripper provides unique advantages in support of your machine tending, material handling and assembly applications.

This article is about parallel grippers, so if you’re at a more preliminary stage in your gripper journey and you’re wondering ‘What are the types of grippers?’ try reading this article first. (If you are looking for an overview of some of the differences between grippers and want to know how vacuum grippers and pneumatic grippers work, for example, check out this article.)  

What is a parallel gripper?

Parallel grippers are a type of industrial robot gripper featuring two fingers that remain parallel when they open and close. In operation, the fingers close onto the workpiece, grip it for the duration of the task and release the object when required. The robot gripper mechanism found in parallel grippers makes them a great fit for handling parts with predictable shapes and they are often chosen for machine tending and pick & place type applications. Parallel grippers are one of the most popular gripper types in the UR+ ecosystem due to their ease of use.

Parallel grippers can be powered by electricity or pneumatics. Electric parallel grippers use electricity to power motors. The motors are linked to the gripper’s fingers in such a way that the circular motion of the motor is translated into a linear motion. Meanwhile, pneumatically-powered parallel grippers use air pressure to open and close the gripper’s fingers.

Parallel grippers are also found in ‘mechanical gripper’ and ‘adaptive gripper’ forms. The term ‘mechanical gripper’ refers to any industrial gripper that uses movable levers (or ‘fingers’) to grasp objects. Mechanical grippers offer reliable performance in all sorts of manufacturing applications from machine tending to assembly, but adaptive grippers are more versatile, since they enable your robot to pick up a wide variety of different objects without the end-user having to step in and change the gripper.

Parallel grippers should not be confused with 3-finger or angled grippers. 3-finger grippers have a more complex mechanism that grasp the workpiece with three fingers that are offset by 120°. In operation, the fingers slide the workpiece to the gripper's centre to safely grasp the object. Meanwhile, angled grippers are so-called because they use fingers that approach the gripper from a variety of angles (e.g. 80° or 30°). For some applications, such as when there isn’t space for a parallel gripper to open and close successfully, angled grippers may be the better choice.

Now that we’ve covered some of the basics, let’s take a look at some of the UR certified parallel grippers available through UR+.

Robotiq's Hand-E gripper provides a 50-mm parallel stroke, which makes it ideal for precision assembly tasks. The gripper's sealed design is rugged enough to ensure reliability in the toughest manufacturing conditions, including CNC machining. Available in both dual and single configurations and specially designed for use with collaborative robots, Hand-E also provides adjustable force, rounded edges, self-locking functionalities, and other features that make it safe to use in close proximity to humans. The Hand-E is truly adaptive, which means that it is able to autonomously adjust to many different types of products of different sizes and shapes.

Fusion OEM is a U.S. Company that specializes in part machining. Fusion's high-mix, low-volume production facility is home to 14 CNC machines. The company wanted to free its workers from repetitive loading and unloading tasks, so they deployed UR5e and UR10e cobots fitted with Hand-E grippers in order to automate this task. The gripper first picks parts presented to it on a nesting system. Then it opens the CNC machine's door and inserts it into the chucking system. The gripper then closes the door and sends a signal to the machine to start the cycle. “We’re able to connect the grippers directly to the robot’s wrist, get feedback on position and force, and know if there’s a part where there should be one and if it’s the right part,” said R&D manager Stephen Milchuck.

The Hiwin X-Series is an electric parallel gripper with a gripping force of 25~50 N, a moving speed of 1~60 mm/s and a repeatability of ±0.01 mm. This end-user friendly gripper comes in 3 different models offering strokes of 16mm, 32mm and 64mm. URCap software provides a handshake between the gripper and the UR cobot and allows you to easily change parameters for gripping stroke speed and force directly from the UR cobot’s teach pendant. The Hinwin X-Series is especially suited to workpieces that are fragile or elastic, including electrical components and glass materials.

The GRIPKIT-CR-EASY-L from WEISS ROBOTICS is a compact, plug & play, servo-electric 2-finger parallel gripper that comes with an integrated controller, URCAP software on a USB Key and part detection features. The gripper’s integrated smart sensorless gripping part detection is designed to ensure consistently high levels of performance with robots from Universal Robots. The GRIPKIT-CR-EASY-L has a 30mm stroke and a gripping force of 75-200N.

New Scale Robotics’ Precision Gripper/Caliper NSR-PG-10-20-URe is designed to help you automate small part measurement, inspection, sorting and gauging tasks. Built to provide high precision for intricate part handling, measurement and assembly applications, this small, lightweight parallel gripper provides fast movements, with accuracy. This precision parallel gripper also transforms traditional pick & place tasks into pick-measure-record & place operations making it a popular choice for quality applications.

The NSR-PG Gripper/Caliper provides a measurement resolution of 2.5 µm (0.1 inches/1000) and comes with URCap software that’s fully integrated with your UR teach pendant. The gripper –three of which can be mounted onto a single cobot-- is included in the Q-Span Workstation Application Kit.

As we noted above, some parallel grippers are powered by pneumatic systems rather than electric motors. For example, Lupeon’s GPN Series are lightweight, pneumatic parallel grippers designed for use with Universal Robots. Based on industrial pneumatic gripping modules with high reliability, the GPN Series requires just one airline, providing an easy way to get started on pneumatically powered collaborative applications. GPN Series grippers provide a gripping force of 55 - 190N and integrates a 5/2 valve that enables control of the gripper module without the need for any additional hardware.

The Zimmer Group offers both electric parallel grippers and pneumatic parallel grippers through the UR+ platform.

The parallel gripper series HRC-01, for example, is electrically-driven and comes with a host of features including servo technology for maximum flexibility, self-locking and Safe Torque Off functionality and LED status information.

The HRC-04 gripper provides a pneumatic IO-LINK, integrated sensor and valve technology and easy integration with the cobots from Universal Robots.. It comes with embedded URCaps software enabling easy deployment and operation, including parameter changes. The HRC-04 gripper provides maximum gripping forces from 90N to a massive 950N.

From systems designed to handle small and delicate parts for quality and inspection to powerful pneumatically driven systems designed to handle demanding payloads, parallel grippers are well suited to wide range of industrial and manufacturing tasks. But are they the right fit for your application?

Choosing the right gripper is a decision that depends on many factors, from the size, shape and weight of the item(s) to be gripped to environmental conditions and your budget. Contact one of our experts today to begin your gripping adventure!