What is a 4-finger robot gripper?

A 4-finger gripper, as the name suggests, has four individually actuated fingers that can grab and manipulate objects with a high degree of accuracy and dexterity. 

These grippers are perfect for handling delicate or irregularly shaped items that would be extremely hard for a simple 2-finger gripper.

These robots offer plenty of benefits over their counterparts. 4-finger grippers provide more contact points, so they can grab objects with more stability and with greater precision. They also have adaptive grasping, for non-uniform shapes. 

With their four skilled fingers, these grippers can perform complex tasks like unscrewing bottle caps or plugging in USB cables.

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What should you look for in a 4-finger robot gripper?

Before you buy your new robot gripper, there are plenty of things to pay attention to. 

Answer these questions thoroughly first: 

• What’s the actuation method? 4-finger grippers are commonly actuated using electric servomotors, pneumatics, or even shape memory alloys. Electric grippers tend to be more compact, while pneumatic models typically offer an increased grasping force.
•  Shape memory alloy-based grippers are best for applications where electrical interference is an issue.

• What are the jaw materials? 4-finger gripper jaws, or “fingers,” are available in hard materials like aluminum or soft, pliant materials like silicone rubber. The hard jaws provide rigidity for high-precision grasping, while softer jaws can conform to irregular shapes and are safe for handling fragile objects. Some grippers offer interchangeable jaw sets with different materials.
• Is your 4-finger gripper compatible? You'll also want to think about how the gripper attaches to your robot. Does it have a standard connector like M4 or M8 that will plug right in? Or will it require some custom integration? Check with the gripper and robot manufacturers to make sure you’ve got the right fit. 
• How much does the gripper weigh? Pay attention to the gripper's weight and size. You want one that, when combined with your robot's payload, won't be too heavy to maneuver effectively. A more compact gripper will also give your robot more maneuverability. 
• What about the signals? Think about how you will provide control signals to the gripper. 4-finger grippers may require more advanced control systems and robot programming to operate well. 

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How do you integrate a 4-finger robot gripper with your robot?

Integrating a 4-finger gripper with your robot requires some serious thought because you'll need to determine how you'll provide power to the gripper and connect its control signals to your robot arm. 

For power, the easiest options are:

• Use the same power supply as your robot if it can handle the additional load. But, make sure the voltage and current ratings match the gripper's requirements.
• Add an additional power supply just for the gripper. But remember to connect the ground lines of the power supplies to ensure a common ground.

For control signals, you have a few choices:

• If your robot controller has spare digital outputs, you can connect directly to those. You'll need at least one pin for the gripper's open/close control – and possibly more for position control or force sensing.
• You can use a serial interface like RS-232 or CAN bus and connect to your robot's controller. This keeps wiring neat but requires some configuring of the serial communication.
• Or, use a gripper-specific interface board that provides connectors for power, control signals, and feedback sensors. The board then connects to your robot controller through a standard bus or cable. These boards can simplify setup but add to the overall cost.
• For the most integrated solution, choose a gripper from the same manufacturer as your robot. Grippers and robot arms that are made to work together will connect seamlessly and can be programmed using the same software interface.

Now, once you determine the best connectivity method for your needs, installation typically involves:

1. Mounting the gripper to your robot's end-of-arm tooling plate.
2. Plugging in the power and control cables.
3. Configuring your robot software with the gripper parameters and programming the tool change sequence.
4. Finally, testing and calibrating the gripper to make sure you’ve got proper functionality before deploying your robot.

The top 4-finger robot gripper on the market in 2024

We’ve done our homework (so you don’t have to), and here are the results - the best 4-finger robot grippers for your robot. 

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Check them out: 

SoftGripper 4-Finger Centric Gripper

• An excellent pneumatic-driven elastic gripper for simple, robust, and sensitive handling.
• It has adaptable soft surfaces to handle objects of varying shapes and sizes without damage.
• Its food-grade silicone construction allows for use with food items.
• Payload capacity: up to a whopping 400 kg. 
• Weight: 0.5 kg.
• Price: $1,890. 

RobotDigg Flexible Adaptive Gripper

• Flexible, adaptable, and available in configurations with 2, 4, or 6 fingers with different lengths and strokes. 
• They come with a silicone rubber layer for improved gripping of small friction items.
• Weight: Approximately 1.5 kg for the 4-finger model.
• Price: Starts at around $309.00.

SFG-FNC4-N3025 Pneumatic Gripper by Soft Robot Tech 

• A flexible, pneumatic, soft 4-jaw gripper.
• This gripper is designed to imitate human grasping and starfish design, and it’s capable of bending deformation to adaptively cover and grip objects.
• Grip Strength: 8 N - 8 N.
• Stroke: 6 mm - 10 mm.
• Applications: Particularly suitable for Collaborative robots, it can handle a variety of objects, including those in the food industry, pharmaceuticals, and other delicate items.
• Price and weight: Contact the manufacturer. 

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FAQs

How much payload can a 4-finger gripper lift?

The payload capacity depends on the specific gripper model and can range quite a bit. In general, you can expect medium-duty grippers to handle 1.5/6, while heavy-duty models are built for 7.5 kg and up. The gripper’s payload should be taken into account along with the payload of your robot arm to make sure that it can lift and maneuver the total weight.

What kinds of items can a 4-finger gripper grab?

4-finger grippers are extremely versatile and can grab a wide variety of objects. Their anthropomorphic design allows them to pick up items in a similar way to a human hand. They work well for grasping boxes, cans, bottles, and other containers. With soft, flexible jaws, they can also handle delicate or irregularly shaped items without breaking them. Certain grippers even have interchangeable jaw sets for different applications.

How are 4-finger grippers actuated and powered?

Most 4-finger grippers are electrically powered, either by a motor, pneumatic or hydraulic actuator. Electric grippers are popular for their precision, control, and easy integration. They use servo motors to open and close the jaws, while pneumatic grippers are driven by air pressure and hydraulic grippers use fluid pressure. These tend to be used for high-force applications. In any case, the gripper will need a power source, wiring, tubing or hoses to function.

What types of tool changers are compatible with 4-finger grippers?

Many 4-finger grippers are designed to work with the standard robot tool changers, such as the ISO 9409-1-50-4-M8 and ISO 9409-1-31.5-4-M5. These have four M8 or M5 threaded mounting holes in a square pattern. On the other hand, some grippers also offer side or bottom mounting options for different tool changers. 

Are 4-finger grippers hard to control and program?

4-finger grippers are designed to be easy to integrate and control. Most work with a simple open/close command and many provide position feedback for precise control and sensing. Programming and control are usually done through your robot controller's software. Also, many grippers offer sample code to help you get started. 

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Summing up

There are several options for 4-finger robots out there, so it’s a good thing you’ve got this guide to help you make an informed choice.

Now, remember: It’s all about checking out your gripper’s actuation method, payload, materials, and compatibility before you make a choice. Then, it’s just a matter of programming and watching it go! 

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Next steps

Looking for a robot arm that works well with a 4-finger gripper and can handle a huge variety of tasks? RO1 from Standard Bots is what you’re after.

It has universal M8 connectors and is fully compatible with OnRobot's range of end-effectors, offering maximum versatility for both large and small workshops.

• Cost-effectiveness: RO1 is an economical choice in its class, offering prices 50% lower than its closest competitors, with lease rates beginning at just $5 per hour.
• Sophisticated vision capabilities: Equipped with advanced vision systems, RO1 excels in performing tasks with its intuitive, no-code programming. This is especially beneficial for detecting small defects and irregularities.
• Emphasis on safety and collaboration: RO1 prioritizes safety, featuring built-in safety sensors and collision detection technology, guaranteeing safe operation in all areas of your workshop.

Contact our expert team today for a free, 30-day on-site trial. Our professionals are prepared to offer thorough support and insights on integrating your first robot efficiently.

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