Difficulties and Solutions in CNC Machining Technology for Joint Components of Humanoid Robots

Joint components can be regarded as the "motion core" of humanoid robots. It is like a human joint, responsible for transmitting power and adjusting posture. Its processing quality not only directly affects the flexibility and stability of robot motion, but also is a key factor determining the robot's load capacity. This type of component covers various types such as gears, shafts, shells, swing arms, etc. Most of them have complex structures, strict precision requirements, and special materials, which bring many technical challenges to CNC machining. The following text will combine the practical experience of Huiwen Zhizao to analyze in detail the core difficulties of CNC machining of joint components, and provide practical solutions to provide reference for industry enterprises.

1、 The CNC machining of joint components in humanoid robots mainly faces four major difficulties

1. Difficulty in processing complex structures

These structures not only have irregular shapes, but also need to ensure the accuracy of the connection between various parts. Traditional three-axis machining methods are difficult to achieve all-round coverage processing, and multiple clamping can easily produce positioning errors, which cannot meet the processing requirements of complex structures.

2. The precision requirements are extremely strict

The dimensional error of joint components should be controlled within ± 0.005 millimeters, and the surface of the parts should have sufficient smoothness, with a roughness of Ra0.8 microns. Any small precision deviation can lead to joint jamming, unstable operation, and even affect the overall service life of the robot.

3. High difficulty in material cutting

To balance the lightweight and durability of robots, joint components are often made of materials such as aluminum alloy and high-strength stainless steel. This type of material generally has the characteristics of high hardness and strong toughness. During the cutting process, a large amount of heat is easily generated, which not only causes thermal deformation of the parts, but also causes serious tool wear, sticking and other problems, greatly reducing processing efficiency and product qualification rate.

4. Processing deformation is difficult to control

Some joint components are thin-walled structures with a wall thickness of less than 2 millimeters. These parts have poor rigidity and are prone to deformation under the action of cutting forces and cutting heat. Even if subsequent modifications are made, it is difficult to restore the design accuracy, becoming the core pain point in the processing of thin-walled joint components.

2、 The solution to the problem of complex structure processing

The core solution for the processing pain points of complex structures of joint components is to use five axis CNC machining equipment, accompanied by specially designed fixtures. Huiwen Zhizao has introduced over 200 five axis CNC machining centers,

It can simultaneously drive the X, Y, and Z linear axes and the A and C rotational axes to operate in linkage. Whether it is complex surfaces or irregular structures, it can achieve multi angle and all-round machining, avoiding positioning errors caused by multiple clamping parts.

Meanwhile, design specialized fixtures and jigs based on the specific structure of the joint components. For example, for gear and shaft parts, an integrated fixture can be used to complete multiple processes in one clamping, reducing the number of clamping times and balancing processing efficiency and accuracy.

In addition, Huiwen utilizes CAD/CAM software to plan machining paths and optimizes tool motion trajectories using contour cutting, spiral cutting, and other methods to ensure precise machining of complex structures.

3、 Response strategies for ultra-high precision requirements

At the equipment level, Huiwen Zhizao not only uses German imported Demage five axis CNC machine tools, but also collaborates with top of the line testing equipment such as Zeiss coordinate measuring instruments and laser interferometers to regularly calibrate the machine tool accuracy, ensuring that the processing equipment is always in the best condition and providing hardware support for high-precision processing.

At the process level, the engineering team of Huiwen Zhizao customizes and optimizes the entire cutting process parameters based on the characteristics of humanoid robot joint components, using high-speed cutting technology (cutting speed not less than 3000 revolutions per minute) to reduce the impact of cutting force and cutting heat on accuracy. At the same time, using high-precision tools such as diamond coated tools and PCD tools can improve cutting accuracy and extend tool life.

At the inspection level, Huiwen uses a Zeiss coordinate measuring instrument to conduct full-scale inspection of the parts, and combines it with a laser interferometer to test the accuracy of the machine tool itself, ensuring that the dimensional errors, form and position errors, and surface roughness of the processed parts meet the design requirements.

4、 Processing plan for difficult to cut materials

The key is to choose the right tool and match it with appropriate cutting parameters. When processing aluminum alloy joint components, it is suitable to use hard alloy cutting tools, with a cutting speed controlled at 2000-3000 revolutions per minute and a feed rate controlled at 0.1-0.2 millimeters per revolution. At the same time, emulsion cooling is used to reduce cutting heat generation. When processing titanium alloy joint components, PCD tools or hard alloy tools can be used. The cutting speed should be appropriately reduced (500-800 revolutions per minute), the feed rate should be increased, and high-pressure cooling technology should be used to timely remove cutting heat and reduce tool wear.

In addition, coating tools with TiN, TiAlN and other coatings can improve their hardness and wear resistance, and extend their service life.

5、 Control measures for processing deformation

Optimization is needed from both the clamping method and the process flow. In the clamping process, flexible clamping or additional auxiliary support is used. For example, when processing thin-walled shell parts, vacuum suction cups are used for clamping, combined with elastic support blocks to reduce part deformation caused by clamping force.

In terms of process flow, a staged machining mode of "rough machining semi precision machining precision machining" is adopted. After rough machining, the parts are subjected to aging treatment to eliminate internal stress, and then semi precision machining and precision machining are carried out, which can effectively reduce machining deformation. At the same time, in the precision machining stage, a cutting strategy of small cutting amount and high speed is adopted to reduce the impact of cutting force on the parts and avoid deformation problems.

Through the above solution, the technical difficulties of CNC machining of humanoid robot joint components can be effectively overcome, improving machining accuracy and efficiency, and providing technical support for mass production of joint components. With the rapid development of the humanoid robot industry, the structure of joint components will become increasingly complex, and precision requirements will continue to increase. In the future, CNC machining technology needs to continue to innovate, combining digital and intelligent technologies to optimize machining processes and support the high-quality development of the humanoid robot industry.