Machine tool manufacturer's push for precision

NANCHANG - It took Zhang Jun and his colleagues three months to solve the influence of temperature on machining accuracy, considered a "hard bone" in the machine tool industry.

While operating, the spindle of the machine tool generates a large amount of heat. Due to thermal expansion, the metal spindle stretches when it is heated, affecting the accuracy of the machined parts, said Zhang, chief of research and development (R&D) with Jiangxi JUST Numerical Control Technology Co Ltd, a machine tool manufacturer in Nanchang, capital of East China's Jiangxi province.

Machining accuracy is a key indicator for measuring the performance of machine tools. With 15 years of machine tools experience under his belt, Zhang knows the importance of component accuracy in high-grade, precision and advanced products.

Leveraging technology including position sensors and algorithms to measure the spindle's elongation, Zhang's team finally solved the problem.

"Compared with developed countries, China's machine tool industry is a relative newcomer. Domestically-produced machine tools are mainly mid-to-low-end, and we have to import most of the high-precision computer numerical control (CNC) machine tools," said Liu Hua, chairman of the company.

Realizing the necessity of developing high-precision CNC machine tools in China, in 2017, Liu led the company to develop a machine tool with one-micron accuracy, reaching the level of developed countries. In 2019, the more advanced one with 0.5-micron accuracy was developed.

At present, the company's machine tools have been used for high-precision component processing in aerospace, new energy vehicles and industrial robots, among others.

Among the machined components displayed in the company's exhibition hall, the thinnest one boasts an accuracy error not exceeding one percent of a hair's diameter.

"When we initially brought our high-performance machine tools to the market in 2017, the clients didn't trust our products," said Bai Yu, executive deputy general manager of the company.

Responding to the misgivings, the company set up an R&D application center in Dongguan, a manufacturing powerhouse in South China's Guangdong province, to show the clients samples of the machined components.

"Our products have now gained the recognition of more and more clients," said Bai.

"We will continue to ramp up efforts in R&D and foster new quality productive forces, to meet the diversified needs of the high-end manufacturing industry," said Liu.