Professor Yongqiang Yang from South China University of Technology: Opportunities and Challenges in the Initial Industrialization of Metal 3D Printing

“3D Printing World” News/In 2012, when 3D printing was hailed by Americans and became popular around the world, Professor Yang Yongqiang from South China University of Technology recalled a seminar at the Academy of Engineering that he attended in the Great Hall of the People at that time. The purpose was to discuss Is 3D printing really a disruptive technology that will lead the third industrial revolution, as the Americans say, or is it a deceptive strategy like the arms race between the US and the Soviet Union back then?

“At the time, there were such doubts at the national level. The 3D printing industry was not large and the output value was not high. However, the United States raised it to the height of national strategy. How should we respond?” Professor Yang Yongqiang said, and the final conclusion was : 3D printing is indeed a very important process, with a good development prospect, we should develop it.

Subsequently, after two years of meticulous preparation, the Ministry of Industry and Information Technology issued the “National Additive Manufacturing Industry Development Promotion Plan (2015-2016)” and “National Additive Manufacturing Industry Development Promotion Plan (2017-2020)” which officially included 3D printing National strategy, “Made in China 2025” issued by the State Council has repeatedly emphasized 3D printing technology. Recently, the Ministry of Science and Technology has also issued key special guidelines to support additive manufacturing.

However, 3D printing is still too cutting-edge for the current manufacturing industry, and the road to industrialization has just begun…

In this issue, “3D Printing World” and Professor Yang Yongqiang, an important expert and scholar in the field of metal 3D printing in my country, discuss the opportunities and challenges in the initial stage of metal 3D printing industrialization.

Two major technical problems of metal 3D printing equipment

Tsinghua University, Beihang University, Xi’an Jiaotong University, Xi’an University of Technology, and Hua University of Science and Technology can be said to be the source of my country’s 3D printing technology. However, the first to study SLM metal 3D printing technology and successfully develop localized equipment should be South China University of Technology Mechanical and Automotive Engineering The team led by Professor Yang Yongqiang of the college. Today, Professor Yang has not only experienced the development process of the entire SLM metal 3D printing technology, but also made continuous efforts to promote the industrialization of the technology.

Beginning in 2002, the team led by Professor Yang began to study the technology that was then called rapid metal prototyping. In 2004, it cooperated with Beijing Longyuan to develop the first selective laser melting rapid prototyping machine in China. However, at that time, both foreign and domestic CO2 lasers were used as the light source, and the scanning software was not mature. Professor Yang recalled: “The first-generation machines we made did not print very well in accuracy and size. At that time Only squares or other regular shapes can be printed, but it was considered very good at the time.” Because at that time a foreign imported equipment cost four or five million, basically no university did this piece of research.

After 2005, foreign countries solved the reflection problem of fiber optic machines and finally applied fiber laser to 3D printing equipment. Professor Yang also received funding support for school discipline construction and purchased a 200W fiber laser that sold for more than 400,000 at that time. A metal 3D printing device using a fiber laser as the light source was released.

At present, Professor Yang’s team has more than a dozen patented technologies in the key powder spreading structure, and nearly 200 patent applications related to equipment. It is not only the source of technology for several domestic 3D printing companies, but also in Guangzhou in January this year. The 3D printing industrial park in Liwan District established a company—Guangzhou Leijia Additive Technology Co., Ltd. (hereinafter referred to as “Guangzhou Leijia”), which specializes in the research and development, manufacturing, sales of metal 3D printing equipment and the provision of metal 3D printing services. The metal 3D printing equipment includes DiMetal-50, DiMetal-100, DiMetal-280, DiMetal-500 series. Laseradd DiMetal-50Laseradd DiMetal-100 However, with the development of technology, these key components on domestic 3D printing equipment still rely on imports. According to Professor Yang, there are currently two major technical problems in metal 3D printing:

First, the core components of the fiber laser, scanning galvanometer, and control components on the 3D printer still use imported components. Taking the equipment developed by Professor Yang himself as an example, the fiber laser is mainly derived from IPG or SPI, and the scanning galvanometer is derived from SCANLAB in Germany or CTI in the United States. Domestic lasers and galvanometers have been very effective in the field of laser marking in the past two years, but they have not yet been fully nationalized in 3D printing equipment;

Second, although components can rely on imports, the control system and scanning software of metal 3D printing equipment have to be developed by themselves. This is the key factor that really determines the accuracy and surface quality of 3D printed parts. According to Professor Yang, Some manufacturers are not doing well in this area, and this is where the gap between domestic and imported equipment lies.

However, Professor Yang said that there are still many problems both at home and abroad, and further efforts are needed to improve the metal

The contradiction between materials and insufficient front-end demand

Metal materials are the cost of continuous input in the 3D printing process, and the price of imported materials is prohibitively high. In recent years, more and more scientific research institutes and material vendors engaged in thermal spraying and powder metallurgy have entered the 3D printing industry, and the quality of the powder produced has also been greatly improved. In the interview, Professor Yang denied the view that “domestic metal powder technology is not feasible”. He mentioned that a company once made 3 kilograms of powder for Professor Yang to try. The quality of the powder is very good, and it is not at all lost to foreign countries. The problem is that when 100 kilograms are needed, the quality of the powder is completely inadequate. What is the reason?

Professor Yang believes that the main problem is that 3D printing has relatively high requirements for materials. Not only the particle size of the powder must be between 10μm and 40μm, but there are also requirements in terms of oxygen content and physical and chemical properties. Therefore, this requires large investment from enterprises to ensure The milling environment meets the requirements. The above-mentioned company can carefully produce 3 kilograms of high-quality metal powder for 3D printing with previous milling technology, but when it reaches 100 kilograms, the milling environment will not meet the requirements.
However, the front-end application market for metal 3D printing has not yet risen. The demand for metal powder is relatively small, and companies are unwilling to invest huge amounts of money in this market. Therefore, my country currently does not have a very large-scale manufacturer that specializes in metal 3D printing powder.

With the lack of market demand, another problem brought to enterprises is that the more powder they sell, the greater the loss. Professor Yang gave a very practical example. For example, he bought 10 kilograms of titanium alloy powder from a certain enterprise at a price of about 2,000 yuan per kilogram. When he bought 50 kilograms of powder for the second time, the company raised the price by 3,000 yuan. Yuan per kilogram, and the other party still loses money after raising the price. Because the market demand is not enough to support the enterprise’s equipment and manpower operating costs, there has been this phenomenon that violates the laws of the market.

Biomedicine may be a breakthrough, and the permit is a long way to go

So where is the market for metal 3D printing? Professor Yang said that the two currently recognized potential markets are biomedicine and aerospace. The individual needs in biomedicine, the cost considerations of small and medium-sized batches in aerospace, and lightweight components all perfectly fit the characteristics of 3D printing technology.

Among them, the demand for high-end applications such as aerospace and aerospace is relatively small. Biomedicine may be the largest application market for 3D printing. Take dentistry as an example. Professor Yang visited a company in Chengdu not long ago. Only dental demand for 3D printing metal powder The amount can reach several tons a year.

Professor Yang’s team has worked hard in the field of biomedicine. As early as 2007, Professor Yang began to study the application of metal 3D printing in the oral cavity. In 2011, he obtained the first 3D printed medical device in China-personalized lingual orthodontics The product certification of brackets has also obtained patent authorization from the United States and Germany.

In recent years, we have not only developed special metal 3D printers for medical applications in response to the requirements of personalization, high precision, and biocompatibility of medical products, but also opened up two major medical applications, including:

Dental field: develop and manufacture dental crowns, fixed bridges, denture brackets, maxillofacial restorations, dental implants and other dental medical equipment products;
Orthopedics field: development of knee joint implants, hip joint implants, spinal implants, navigation surgery version, implant surgery guides, etc.

And Professor Yang has achieved quite a bit in industrialization and practical application:

In terms of industrialization, Guangzhou Ruitong Biotechnology Co., Ltd. was established in cooperation with Guangzhou Ruitong Laser Technology Co., Ltd. for the “Personalized Lingual Orthodontic Brackets” project; the 3D printing knee joint project and Peking University Third Hospital are cooperating to establish a company company. Personalized Knee Joint Prosthesis For the application of personalized bone plates for pelvic and acetabular fractures, we cooperated with Guangzhou Army General Hospital to develop intervertebral disc fusion cages for the spine, and cooperated with the Third Hospital of Southern Medical University for hip and hip bone plates.

But whether it is biomedical or aerospace, one of the biggest problems facing the industry is the need to obtain certification.

Take the hip and hip bone plates currently done by Professor Yang as an example. In the past, five or six bone plates were used for comminuted fractures of the hips. 3D printing can be used to design a complete bone plate directly connected. The effect after the application of the Third Hospital of Southern Medical University is very good. At present, 10 clinical cases have been done. Although many patients came here to want to perform such operations, the hospital refused to do more because they did not have a license.

“If there is no license, no matter how good these devices are, it is a so-called counterfeit and inferior. Once a certain link goes wrong, the hospital needs to take a greater risk.” Professor Yang said that to get this license would require thousands of investments. Wan, currently Professor Yang is also seeking investors.

According to a rough estimate, a doctor of Southern Medical University will do more than 100 such cases a year, and the fee for a bone plate is about tens of thousands. From a national perspective, it is also a relatively large market. This is just a small example in the field of life medicine. You can see how many treasures there are in the entire biomedical market to be discovered by 3D printing, and the important stepping stone is to obtain a license.

The ultimate opportunity lies in industry, and design thinking needs to be changed

But in the end, the widespread application of metal 3D printing should exist in the industry. 3D printing is used to directly make industrial components, parts and molds. Professor Yang further stated that at present, 3D printing has the industry in the manufacture of molds and complex parts. Larger advantage, but its main competitor CNC is still insurmountable like a mountain.

“Metal 3D printing has not yet reached the level that can compete with CNC. They are not on the same level. Metal 3D printing is still in a period of development.”

After years of development, CNC is an advanced manufacturing method that integrates computer, material, control and other technologies. It has created a glorious history in the process of industrial development and fixed the current general design thinking. It is based on subtractive manufacturing. The starting point for the design of industrial products is the processing method rather than the functionality of the component. Because in the past, if the product could not be made by subtractive manufacturing, this design was unsuccessful. This kind of geometrically described things have very regular shapes, and some functions are sacrificed.

But whether it is in the human body or in the natural world, things are irregular shapes to meet functional requirements. Therefore, in the future, when the industry pays more and more attention to lightweight and functionality, CNC will begin to decline, 3D The advantages of printing will be highlighted.

But before, Professor Yang emphasized, “If you don’t change the design thinking, 3D printing will have no way out, or it can only be a corner.” For this reason, he wrote a book called “Manufacturing Change Design” in 2014. Design perspective to change everyone’s understanding of 3D printing. The most important thing is to establish a new industry standard

Whether it is obtaining a medical license or changing industrial design thinking, the ultimate basis is the establishment of new industry standards. “Now in the entire 3D printing industry, many people are studying standards, but there is no clear standard system yet.” Professor Yang said.

On October 12, 2017, the inaugural meeting of the Guangdong Provincial 3D Printing Standardization Technical Committee was held in Zhuhai, with Professor Yang Yongqiang serving as the chairman. Similar efforts are also being carried out all over the country. For example, the Special Processing Branch of the China Mechanical Engineering Association has formulated standards for rapid prototyping around 1988 and 1989. Last year, the China Mechanical Engineering Society established a new Additive Manufacturing Branch. There is also a standardization committee. At present, the National Standards Committee and the standards committees of various provinces are also formulating relevant standards, and even some companies are beginning to customize corporate standards.

In general, we are in such a historical transition period. As a very important manufacturing technology, 3D printing will have a revolutionary impact in the future. However, in the early stages of industrialization, the return of huge investments may be slow, but Under the guidance of the country’s policies, we still need to accumulate in the early stage, and once it breaks out, we will not fall behind.