A 6-axis robot is one of the most widely used vertical articulated industrial robots in the field of industrial automation. It operates through six independently rotating joints that work together. The controller calculates the motion path, while servo motors drive each axis to move, allowing the end-of-arm tool to reach any position in three-dimensional space and adjust its orientation to complete various tasks.

With its high flexibility and precise motion capability, the 6-axis robot has become a core automation solution for applications such as automotive parts handling, welding, assembly, and other industrial processes.

Core Structure and Axis Functions of a 6-Axis Robot

J1 Axis (Base Rotation)

Controls the overall left and right rotation of the robotic arm and determines the horizontal working range of the robot.

J2 Axis (Lower Arm Movement)

Controls the forward and backward movement of the upper arm. It is the key joint that determines the robot’s vertical working range.

J3 Axis (Upper Arm Movement)

Works together with the J2 axis to adjust the front and rear position of the robotic arm and further expand the vertical working area.

J4 Axis (Wrist Rotation)

Allows the end tool to rotate around its own axis, enabling adjustment of the workpiece orientation.

J5 Axis (Wrist Bending)

Adjusts the tilt angle of the end tool to adapt to different working angles and surfaces.

J6 Axis (End Rotation)

Provides final orientation adjustment, allowing the end-of-arm tool to accurately align with the working position.

The first three axes are mainly responsible for positioning, determining where the end effector can reach in three-dimensional space.

The last three axes are mainly responsible for orientation adjustment, determining the angle at which the end tool performs the operation.

Motion Logic of a 6-Axis Robot

· The controller receives preset programs or external sensor signals and calculates the target position of each of the six joints through forward and inverse kinematics algorithms.

· Servo drives control the servo motors of each axis to achieve precise movement. Gear reducers are used to increase torque and improve motion accuracy.

· End-of-arm tools such as grippers, welding guns, and polishing tools are installed at the robot end to complete specific operations, including handling, welding, and assembly.

The complete system mainly consists of three core components:

1. The robotic arm body

2. The control cabinet equipped with drives and computing units

3. The teach pendant used for manual programming and debugging

3. Main Application Scenarios of 6-Axis Robots

Material Handling and Palletizing

6-axis robots are widely used for heavy-duty material handling applications, including automotive components and industrial materials. Their payload capacity can range from 5 kg to several hundred kilograms, while maintaining high repeatability and positioning accuracy.

Welding Applications

6-axis robots are commonly used in welding processes, including TIG welding and laser arc welding. They can provide consistent welding quality, stable weld formation, and continuous operation for long production cycles.

Assembly Applications

By integrating multi-dimensional force sensors, 6-axis robots can perform high-precision assembly tasks. They are widely applied in industries such as 3C electronics and automotive electronics, where accurate component positioning is required.

Cutting and Polishing Applications

The high-strength aluminum alloy structure of 6-axis robots enables them to withstand the impact generated during grinding and cutting operations. Their large working envelope allows them to handle complex surface processing tasks.

Painting Applications

With a fully enclosed stainless-steel structure and infrared sensing technology, 6-axis robots can perform automatic painting operations in explosion-proof environments.

4. How to Select a Pneumatic Gripper for a 6-Axis Robot

4.1 Selecting a Pneumatic Gripper for an ABB 6-Axis General Industrial Robot

The ABB IRB 4600-60/2.05 is a 6-axis general industrial robot developed by ABB. It is mainly used in applications including arc welding, assembly, material handling, machine loading and unloading, gluing/coating, packaging, laser cutting, laser welding, additive manufacturing, material removal, cleaning, and spraying.

The following section provides a detailed analysis of its specifications:

Environmental Specifications

Performance Characteristics Analysis

Short Cycle Time:
The ABB IRB 4600 features a compact and optimized design with lightweight construction and high acceleration performance. Compared with industry-standard robots, it can reduce cycle time by up to 25%.

Large Working Range:
With a 2.05 m reach, this robot has a relatively compact reach among robots with the same 60 kg payload class. This design provides higher payload capability and a smaller installation footprint, making it suitable for high-density production cells.

High Repeatability Accuracy:
With a position repeatability of 0.06 mm, the robot is suitable for applications requiring high precision, such as arc welding, precision assembly, and adhesive dispensing.

High Protection Level:
The IP67 protection rating allows the robot to operate in harsh industrial environments. The optional Foundry Plus version provides corrosion-resistant coating, rust-resistant flanges, and protection against molten metal splashes, making it suitable for demanding applications such as casting and forging.

Selecting the Pneumatic Gripper Based on Robot Payload Requirements

When selecting a pneumatic gripper for a 6-axis robot, the payload capacity of the robot is one of the most important factors to consider.

The total payload of the robot must include not only the workpiece weight but also the weight of the pneumatic gripper, mounting plate, fingers, and other end-of-arm components.

For example, if the workpiece weight is 30 kg, the remaining available payload capacity for the gripper and other accessories is 30 kg.

For FR Series pneumatic grippers with a 30 kg payload capacity:

· FR99-234-S

· FR117-270-S

· FR136

· FR175

· FR191

Considering the remaining payload limitation, only:

· FR99-234-S

· FR117-270-S

can meet the requirement.

For FZ Series pneumatic grippers with a 30 kg payload capacity:

· FZ125-200

· FZ160-250

· FZ185-292

· FZ220-352

· FZ290-430

Considering the remaining payload limitation, suitable models include:

· FZ125-200

· FZ160-250

· FZ185-292

It should be noted that some robot end-of-arm systems do not only include a gripper. They may also be equipped with additional components such as quick changers and compensation modules. The weight of these components must also be included when calculating the robot payload.

Therefore, the final gripper selection should be based on the complete end-of-arm tooling configuration and actual application requirements.

4.2 Selecting a Pneumatic Gripper for a FANUC 6-Axis General Industrial Robot

The FANUC M-710iC/70 is the highest payload model in the FANUC M-710iC series. It is positioned as a medium-sized multi-purpose industrial robot, offering high payload capability and excellent inertia performance among robots in the same class.

The following section provides a detailed analysis of its specifications:

Structure and Design Features

Compact and Lightweight Design

The FANUC M-710iC/70 adopts a slim wrist design, highly rigid arm structure, and compact footprint. It achieves lightweight construction while maintaining a high payload capacity of 70 kg.

Integrated Internal Cabling (IC Design)

Signal cables, air lines, and sensor cables are integrated inside the robot arm. This design prevents external cable wear and reduces the risk of cable interference or damage, helping to improve reliability.

Hollow Joint Structure

The reducer adopts a hollow structure, while the motors are installed on the shoulder section. This design effectively reduces cable wear and improves motor cooling performance.

Protection Level

The wrist section of the robot can achieve an IP67 protection rating, allowing it to operate in harsh environments such as casting and machining applications.

The casting protection version is available for demanding applications, with:

· Maximum operating temperature up to 70°C 

· IP67 protection for the wrist section

· IP54 protection for the robot body

Typical Application Scenarios

The FANUC M-710iC/70 is widely used in:

1. Material handling and machine loading/unloading

2. Arc welding and spot welding

3. Laser cutting and laser welding

4. Palletizing and packaging

5. Deburring, polishing, and material removal

6. Casting part removal

Pneumatic Gripper Selection Based on Payload Requirements

When considering only the robot payload capacity, the total weight of the workpiece and gripper system (including mounting plate and fingers) must be lower than the robot’s maximum payload.

For example, if the workpiece weight is 40 kg, the remaining payload capacity for the gripper and other components is 30 kg.

For FR Series pneumatic grippers with a 40 kg payload capacity:

· FR117-270-S

· FR136-320-S

· FR175

· FR191

Considering the remaining payload limitation, suitable models include:

· FR117-270-S

· FR136-320-S

For FZ Series pneumatic grippers with a 40 kg payload capacity:

· FZ160-250

· FZ185-292

· FZ220-352

· FZ290-430

Considering the remaining payload limitation, suitable models include:

· FZ160-250

· FZ185-292

(fouk customer solution)

It should be noted that some robot end-of-arm systems include not only grippers but also additional modules such as rotary units, quick changers, and compensation modules. These components also affect the robot payload calculation.

Therefore, the specific pneumatic gripper model should always be selected according to the actual application conditions and complete tooling requirements.