Green Ecological Machine Knowledge

What is a green ecological machine tool?

In the process of use, machine tools not only consume energy, but also produce solid, liquid, and gaseous waste, causing direct or indirect contamination of the work environment and the natural environment. From the perspective of the entire machine tool life cycle, how to reduce the environmental impact of green ecological machine tools has become a hot topic of current research. Green ecological machine tools should have the following characteristics:

1) The main parts of the machine tool are made of recycled materials.

2) The weight and volume of the machine tool is reduced by more than 50%.

3) The power consumption is reduced by 30 to 40% by means of measures such as lightening of the moving mass and reduction of the idle operating power.

4) Reduce 50 to 60% of various wastes from the use process and ensure that there is no pollution in the work environment.

5) The material of the machine tool after retirement is 100% recyclable.

2.1 Weight loss and energy conservation According to statistics, the power used to remove metal during the use of the machine tool only accounts for about 25% of the total loss. The first measure of the green ecological machine tool is to construct an eco-efficient machine by significantly reducing the weight of the machine and reducing the power required. Green ecological machine tool puts forward a brand-new concept: Reduce the weight of the machine tool greatly, save the material; Reduce the energy consumption while using the machine at the same time.

The traditional machine tool design concept is "only enough rigidity can guarantee the processing precision, and the stiffness must increase the weight of the machine tool". Therefore, 80% of the weight of the existing machine tool is used to "guarantee" the rigidity of the machine tool, and only 20% is used to satisfy the kinematics of the machine tool. Therefore, there is a lot of room for optimization of the machine structure. The way to achieve this goal is through adoption of new structures and new materials.

2.2 MQL emission reduction Lubricating coolant in the use of machine tools is a harmful emission, especially the emulsion used in grinding is very harmful to the environment and the health of workers. Therefore, a significant reduction in the use and emissions of coolant is a basic feature of green ecological machine tools. There are two ways to achieve this goal:

1) Dry cutting, no coolant is used. The machine is required to have sufficient rigidity and sharp cutting tools. It is only suitable for machining certain relatively simple milling and turning operations.

2) Minimal lubrication (MQL). MQL has a wide range of applications and can be used in various processing methods, but it requires special equipment to provide aerosol or low-temperature air (cold air), as well as specialized lubricants.

2.3 Tool efficiency The productivity of the machine tool is reached at the tool tip. The use of advanced tools, the selection of a reasonable tool geometry and cutting parameters, can greatly improve the efficiency of cutting, reduce the power required for the cutting process, extend the life of the tool, so as to achieve greater output with less resource consumption the goal of.

2.4 Value-Added Reuse of Metal Cutting Machining chips are the main solid wastes in the use of machine tools. The traditional method is to sell it as a waste product to the waste recycling unit and enter the social waste recycling. Yangli Group of Jiangsu Province will use thousands of tons of iron scraps and steel scraps per year to sort, crush, mix, and melt cast high-quality ductile iron castings. This will turn waste into treasure and make crankshafts such as presses. And other key parts.

3. Smart processing system If the vision of the eco-machine is eco-friendly, the goal of the smart machine is user-friendliness. The meaning of “user-friendly” is to greatly increase work efficiency and work more comfortable and safe. This requires the machine tool to manage itself, be able to automatically identify processing tasks and processing status, with little or no manual intervention, and be able to communicate with the operator in a timely manner, become "smart", and open up a new era of CNC machine tools.

The machine tool inevitably produces various errors in the process of machining. Modern monitoring and compensation techniques are needed to further improve the performance and communication capabilities of the machine tool. In 2005, the National Institute of Standards and Technology of the United States proposed a research plan for the Smart Machining System.

The five goals of a smart processing system are:

1) System dynamic optimization. The related process and equipment knowledge are integrated and modeled to optimize the dynamic performance of the system.

2) Equipment characterization. Develops characteristic measurement methods, models, and standards, and measures and communicates machine tool performance under operating conditions.

3) Adopt the next-generation CNC system. The interface and data format compatible with STEP-NC allow the CAD model-based machine control to run seamlessly.

4) Condition monitoring and reliability, developing measurement, sensing and analysis methods.

5) Direct measurement of tool wear and workpiece accuracy during machining.

The essence of a smart processing system is the intelligence and networking of the manufacturing system.

3.1 Advanced Process Control System The connotation of Advanced Process System is to monitor the working status of the electric spindle. Because the spindle is the heart of a CNC machine tool, its state is directly related to machining accuracy and machining efficiency. The principle is that an acceleration sensor is installed near the front bearing in the motor spindle housing so that the vibration generated during the milling process can be displayed in the form of an acceleration “g load” value.

3.2 Intelligent temperature control system Machine tool thermal deformation is one of the main factors affecting the machining accuracy. There are many factors that cause thermal deformation, mainly from the working environment of the machine tool and the thermal effects inside the machine tool:

1) Environmental impact. Such as the temperature distribution and temperature changes of the workshop and the convection of air; the influence of heat sources such as sunlight, heating, and adjacent machine tools; and heat conduction from the machine tool base.

2) The internal influence of the machine. Such as machine parts heat (bearings, screw, rails, motors, gears, hydraulic systems, etc.), the heat generated by the cutting process and the heat generated by the cooling system.

The above-mentioned thermal influence is a complex heat input to the machine tool structure. It changes with time and the working state of the machine tool. It is unpredictable, and ultimately the size and location of the thermal deformation of the machine tool also depend on the thermal properties of the machine structural material. It is the thermal expansion coefficient, thermal conductivity and heat capacity of the material and the structural design of the machine tool, ie the shape, quality and heat source distribution of the components.

4. When e-machine tools machine complex 3D contours at high speeds, they often encounter how to optimize the three interrelated values: speed, accuracy and surface finish. For example, when roughing a mold, speed should be taken into consideration first; precision is the most important when precision-manufacturing small precision electrodes; while in finishing, the surface finish is pursued. How to properly configure and optimize the performance of the machine tool to achieve the target in different situations is a complicated issue. Because it involves hundreds of CNC parameters, such as motion control algorithms, servo loop gain, feedforward, smoothing filters, and so on.