Lightweight Machine Tool: High Energy Efficiency Combined with Light Structure

The main long-term goal of machine tool manufacturing technology has been to focus on improving productivity and processing quality. However, in recent years, with the increasing awareness of environmental protection and the increasing shortage of natural resources, the effective use of energy and resources and the reduction of pollution in the production process have played an increasingly important role in the design concept of machine tools.

Lightweight is the technical direction
In order to achieve the goals of economy and environmental protection, light machine technology came into being. Light technology is especially used to meet the stiffness requirements of the corresponding processing technology, and lightweight construction technology plays a crucial role.

Perhaps precisely because of this consideration, the Institute of Machine Tools of the University of Stuttgart, USA, and the new department of the Fraunhofer Institute for Production Technology and Automation, the Ministry of Light Structure Technology, have a precise cooperation, and will carry out basic research and production application research and teaching activities. Want to combine, to better promote the innovation of industrial production and teaching content with the times.

At the 3rd China-Germany Advanced Manufacturing Technology Forum, the participating experts believed that the combination of the implementation of the new sustainable production method and the application of the new plant structure and organizational management structure determines the success or failure of the industrial manufacturing enterprise in the global large-scale market. .

Part of the new sustainable production method is the development of so-called lightweight materials, which will be expanded into new areas, followed by development of the necessary production and processing processes that are compatible with product manufacturing.

Taking the structural chain as a clue, the light structure is firstly concerned with the issue of raw materials, followed by the challenges faced by new materials in the subsequent processing, such as the evaluation methods of processing quality due to different machining processes, colleagues, and processing technologies. The cutter is also a new perspective and direction.

The specific load characteristics and wear characteristics of the light structures during processing and the tool design concepts derived therefrom are also of interest.

Finally, the connection process necessary for the construction of structural materials from lightweight materials is also a challenge, because in addition to the use of matching fasteners, there is the possibility of using adhesives and particle beams.

Industry sources said that from the energy point of view, the quality-strength ratio of lightweight materials has obvious advantages, which also makes its application areas continue to expand.

For a long time, fiber composite materials have been fully used in the fields of aerospace technology and wind power equipment. It can be foreseen in the future that fiber composite materials will surely shine in the automotive manufacturing industry.

This means that the current single or small-scale production model (mostly manual production) on the market is bound to change through automated material production and processing to achieve the goal of mass production.

Lightweight automotive applications have been applied in batches

"Not saving energy, the product will not sell." This situation was more prominent in 2012. Especially in Japan, after the Great East Japan Earthquake in 2011, topics related to energy shortages continued to heat up, and consumers’ awareness of energy conservation continued to increase. Under this background, the processing technology that can achieve light weight has gained more attention than ever. Among them, it is the automotive industry that promotes related development.

At present, the main contents of automotive lightweighting include the combination of lightweight materials, lightweight design, and lightweight construction.

The lightweighting of the material means that the vehicle body can be lightened by using steel substitute materials or light metal materials. The substitute material is a high-strength steel plate to replace the ordinary low-carbon cold-rolled steel plate, to improve the strength and rigidity of the components, and to reduce the thickness or section size of the steel plate to reduce the weight. .

In recent years, domestic automobile manufacturers have gradually adopted high-strength steels. For example, the proportion of DP340 high-strength steel used by Chery in its newly-developed models has reached 45%, and some models have reached 50%. Dongfeng Motor Co., Ltd. uses a 700MPa class high strength steel for the commercial vehicle frame instead of a 510MPa grade tensile material, and achieves a weight reduction of 38kg for the main beam, a 170kg weight reduction for the reinforced beam, and a total weight loss of 208kg in the carriage. In terms of lightweight, 700MPa grade high-strength steel plate was used instead of Q235 production standard car trunk, achieving a weight reduction of 20% to 37%.

Because lighter weight contributes to improving fuel efficiency, more and more automakers have proposed numerical targets for component manufacturers, such as a 10% weight reduction. In this case, there have been significant examples of lightweighting. For example, Japan's KOIWAI company continued to obtain orders by using the “KOIWAI Law” as a weapon for lamination mold casting technology. The company has produced 45% less auto aluminum alloy subframes than the current Steel Products, and 40% less motorcycle tank frames, gaining great attention from automakers.

It is reported that by using the rapid prototyping (RP) technology to manufacture a core and combining it with a low-temperature mold, a sub-frame with a thin and hollow integral structure is cast.

In fact, material technology and low level of design also affect the development of lightweight products.

The members of the China Engineering Society’s Strategic Alliance for Lightweight Technology Innovation believe that vehicle lightweighting technology does not rely solely on materials, and that vehicle lightweighting is a project that integrates design, manufacturing, and material technology. For example, Dongfeng tractors have a weight reduction of 1,400 kilograms, of which structural optimization accounts for 19%, functional configuration optimization accounts for 40%, both account for 59% of the total, and real new materials and new technologies only account for 41%.

If we only consider lightweighting as a material supply problem, it will hinder one of the major technological bottlenecks in the improvement of China's lighter weight.

It is reported that the goal of lightweighting domestic automobiles is to reduce the weight of fuel cars by 5% to 8% and the weight of hybrid buses by 10% in 2013 target models. At the same time, seven technologies need to be overcome to establish design and evaluation methods, including high-strength steels. Advanced molding technology of parts, module design and application technology of fiber-reinforced plastics, development and manufacturing of deformable aluminum alloys, integration of multi-objective lightweight technologies, and construction of common technology platforms.

The domestic academia is also exploring in many ways. For example, Harbin Institute of Technology in China uses internal pressure forming theory to replace traditional stamped butt welded parts. This method has the advantages of light weight, stiffness, and light fatigue. Therefore, it is lightweight in the manufacture of automobiles. The area has played an important role.

According to reports, high pressure forming through the role of high-pressure liquid plastic deformation of the pipe, the required pressure is often as high as 200 to 400 MPa, hence the name.

However, the higher the pressure, the greater the required equipment tonnage, the higher the pressure requirements for the mold, the structural reliability of the seals, and the pressure of the high pressure source, leading to increased product costs. For example, a pipe with a diameter of 100 mm is formed at 200 MPa. If the total length reaches 2000 mm, a clamping force of 4000 t is required. Therefore, by improving the process and reducing the internal pressure forming pressure, it is an important way to reduce the threshold of the internal high pressure forming technology, reduce equipment investment and improve product competitiveness.

It was precisely because of the advent of new materials and new structural parts such as automobiles, aerospace, etc. that it was necessary to make adjustments to the machine tools as soon as possible. For example, in addition to plastic materials, the US foreign auto industry is trying The application of titanium-magnesium alloys is a new challenge and an attempt for machine tools.

However, it is worth noting that the needs of the user industry are not only to meet its processing requirements, but also that additional requirements can improve productivity and economic efficiency while ensuring the quality of processing, and can further reduce costs.

All of these require machine tool companies to make innovative changes to adapt to the constant demands of the user industry. After all, change on demand is the survival of the machine tool manufacturing industry.