The fingertips of a parallel gripper remain exactly parallel throughout their entire motion. This is different from the rotational grippers which follow a slightly curved path as they close. This is one reason that translational grippers are so good for high-precision tasks. Another reason is that Hand-E is manufactured to a very low tolerance, which contributes to its better accuracy.

One of the big advantages of such grippers is that you can easily replace the fingertips. This allows you to redesign them to perfectly suit your application needs. However, this can also be a disadvantage if it restricts their adaptability to different tasks. In the past, many translational grippers on the market came supplied with no fingertips, only an actuation block. We avoided this problem by supplying Hand-E with a pair of multi-purpose fingertips which are well-suited to many common applications.

The vast majority of translational parallel grippers on the market are pneumatically actuated. Although there were benefits to pneumatics in the past, modern electric grippers are now reaching the same levels of performance without the disadvantages of pneumatics. Hand-E is a high-performance electric gripper.

Rotational vs Translational Grippers: The Showdown

It’s time for a showdown! Let’s compare the two gripper types to see how they stack up against each other.

Here are the properties we’ll be using:

  • Stroke width: This is the distance between the gripper’s fully open and closed positions. Note that this doesn’t have to limit the maximum width of the objects as adding custom fingertips to any adaptive gripper allows you handle wider parts.
  • Clearance: This is the space needed for the gripper to enter the workspace. You can visualize it as the minimum diameter of a tube that the gripper could fit through.
    • Precision: This is the exactness with which the gripper can manipulate objects. All Robotiq grippers also come with inbuilt part detection — which allows you to detect when an object has been grasped — so this property also refers to the precision of part detection.
    • Maximum Grip Force: The maximum force which the gripper can apply on a workpiece. Note that longer custom fingertips will reduce this maximum force, so you should recalculate this for any customizations you make.
  • Environmental Conditions: The presence of dust and/or liquid in an environment is an important consideration for some applications. Some grippers have more protection from these than others.
  • Customizability: All Robotiq grippers have the option to customize them with your own fingertips. But, Hand-E is especially well suited to customization.
  • Hand Guiding: One of the major benefits of collaborative robots is that you can program them by physically moving them around. Some grippers are easier to hold onto than others, which facilitates hand-guiding.

 

Let’s look at the differences in numbers:

Rotational Gripper

Translational Gripper

Available Models

2F-85 and 2F-140

Hand-E

Stroke Width

85 — 140 mm

50 mm

Opening/Closing Speed

Fast

Medium

Clearance

148 — 202 mm

75 mm

Precision

mm+

sub-mm

Maximum Grip Force

135 — 235 N

130 N

Environmental Conditions

Some dust or drops of liquid

Lots of dust or splashes of liquid

Customizability

Several fingertip options available.

Easy to add custom fingertips

Hand guiding

Not easy to grasp

Designed for hand guiding


It’s clear that both types of gripper have different strengths. The rotational grippers have a wide stroke with high grip force, but they require a lot of clearance and are not as precise. The translational gripper has a small clearance, sub-mm precision and good environmental protection, but its grip force is not as high. Neither option seems better than the other in all categories.

Which is Best for your Application?

When considering a gripper, the question should never be “Which is Best?” Instead, the question should be “Which is best for my application?”

First, you need to be sure you are clear on the needs of your application. If you haven’t already, enter the details of the task you want to automate into Blueprints to get some clarification on what properties your application will need in a robot.

Then, ask yourself the following questions to help decide which gripper type is best for you:

  • What is the widest object the robot will pick up?
  • What is the stroke that the robot will need?
  • Is clearance an issue?
  • How precise does the gripper need to be?
  • What is the smallest dimension that the robot should be able to detect?
  • How much force should the robot be able to apply on objects?
  • How much dust or liquid will be in the environment?
  • Will custom fingertips be needed for the task?
  • Would easy hand guiding be beneficial?

Related: How to Measure ROI for Robotics Training

If you still have some questions regarding which gripper is best for you, reach out to a member of our team, post a question in the comments, or join the discussion on LinkedIn, Twitter,Facebook or the DoF professional robotics community

For more trends in robotics, visit the Robotics & AI Channel.