The development of CNC (Computer Numerical Control) machine tools, which are fast, precise, complex, intelligent, open, parallel, networked, and extreme, has become a trend and direction of their development. How will these trends evolve in 2023? In which direction will machining go? Will new technologies significantly improve CNC services? We write about this below!
Increased speed in CNC machining
With the rapid development of industries such as: automotive, national defense, aviation and astronautics, as well as the use of new materials, such as aluminum alloys, the requirements in CNC machining are increasingly high. CNC machines provide in these cases:
- Spindle speed: the machine tool accepts an electric spindle (built-in spindle motor), the maximum spindle speed is 200000 rpm.
- Feed rate: the resolution is 0.01 μm, and the machine tool can achieve a maximum feed rate of 240 m/min from complex and precisely machined surfaces.
- Calculation speed: The dynamic development of microprocessors guarantees fast and precise progress of numerical control systems. As a result, processors are evolving into 32-bit and 64-bit numerical control systems, and the frequency is increasing to hundreds of megahertz and gigahertz. Thanks to calculations, the speed has significantly improved, and the feed rate of 24-240 m/min can still be achieved at a resolution of 0.1 μm and 0.01 μm.
- Tool change speed: currently, the advanced foreign tool exchange time is usually about 1 s, and the maximum can reach 0.5 s.
Better precision in CNC machining
The requirements for the accuracy of CNC machines are not limited to static geometric accuracy: more and more attention is being paid to the accuracy of machine movement, thermal deformation, vibration monitoring and compensation. New challenges in the coming year may require you to implement additional elements from a milling perspective:
- Improve CNC machining accuracy: use rapid interpolation technology to achieve continuous feeding of small program segments to enhance the CNC control unit and use high-resolution position detection devices to improve position detection accuracy.
- Adoption of error compensation technology: backlash compensation, step error, tool error, and other technologies are used to compensate for thermal deformation errors and hardware space errors. Test results show that comprehensive error compensation technology can reduce processing error from 60% to 80%.
- Predict the machining accuracy of the machine tool using simulation to ensure accuracy and repeatability of positioning. The grid is used to check and correct the accuracy of the machining center's movement trajectory. It ensures its performance is stable for a long time and can perform various processing tasks under different working conditions to ensure the quality of the processed parts.
Composite machining - CNC machining
A complex machine tool refers to the realization or production of various elements processing semi-finished products into a finished product to the greatest extent possible. From its structural features, one can distinguish process connections. These are the treatments of complex machine tools, including complex boring, milling, drilling and milling center, turning center, turning and milling, milling, boring, drilling, hybrid car processing center, etc.; complex machine tools such as multi-surface, multi-axis processing connections, complex machine tools, and twin-spindle turning centers. Processing on hybrid machines shortens the time needed for loading and unloading details, changing tools, and adjusting additional tools.
Proper supervision during CNC machining
To meet the developmental needs of flexibility and automation in production, the quality of CNC machine tools is constantly being improved. This can be seen in the following aspects:
- Adaptive process control technology: By monitoring information during processing, such as cutting force, spindle and feed motor power, current and voltage, traditional or modern recognition algorithms are used to identify tool stresses, wear and crack conditions, and the state of the machine tool in terms of whether it is stable during machining. According to these states, machining parameters (spindle speed, feed speed) and machining instructions are adjusted in real time, allowing the equipment to improve machining accuracy, reduce surface roughness, and enhance processing accuracy. Additionally, the equipment is safer to operate.
- Intelligent self-diagnosis and self-repair technology: Based on existing fault information, modern intelligent measures are used for quick and accurate fault localization.
- Intelligent error reproduction and simulation technology: It can fully record various system information, reproduce and simulate various errors and accidents occurring in CNC machines, determine the cause of errors, find problem solutions, and accumulate production experience.
- Intelligent AC Servo Drive: It can automatically identify the load and adjust the parameters of the intelligent system, including the intelligent AC spindle drive and intelligent servo drive. This type of drive device can automatically identify the motor's moment of inertia and load, automatically optimize and adjust the control system parameters, so that the drive system can achieve optimal performance.
- Intelligent 4M CNC system: In the process of production, processing, and testing, it integrates in a practical way to achieve rapid production, testing, response, measurement, modeling, processing. Four operations are integrated with the 4M system for information exchange and to facilitate the integration of measurements, modeling, processing, fixture, and handling.
Hybridization of CNC production with additive technologies
Subtractive CNC machining and additive 3D printing are two separate processes. A CNC machine removes material from the workpiece. 3D printing involves building three-dimensional objects one layer at a time. Even when reversing the principles of operation, both processes can be effectively combined. Many machine designers have adopted "hybrid production", combining CNC milling and turning with additive manufacturing methods. More and more companies are wondering how to combine CNC machines and 3D printers to speed up project implementation. Tolerances less than 0.01 mm can be achieved with CNC machines, making them ideal for applications where precision is crucial. However, 3D printers have an accuracy of up to 0.1 mm, which is one of the reasons why additive manufacturing is widely used in prototyping. Prototypes can be printed on a 3D printer. Then the CNC machine will be able to finish the product.
On-demand production and instant quotation
Production strategies known as "on-demand production" or "cloud production" have evolved. This began to disrupt the supply chain sector and was clearly accelerated by the coronavirus, the war in Ukraine, and supply problems from China. The term "on-demand production" describes a production method in which products are produced exactly when they are needed and in the necessary quantities. Traditional production, on the other hand, requires costly own production machines, mass production of goods, or reliance on local production partners. On-demand production reduces capital investment, increases delivery speed, and improves resilience.
Several other factors, such as reduced cost of CNC machined parts and quick ordering through instant quote software, have contributed to the widespread acceptance of on-demand production. Custom enclosures are reliable for companies of all sizes. Consumers, businesses, and the environment can benefit from the program. Here are three key benefits that companies can gain from on-demand production:
- reduction of production costs
- agile operation due to faster purchases and greater availability of various production technologies
- easy access to global production resources
Improving CNC machining with the use of digital twins
Digital twins are used for a deeper understanding of the operation of hardware and processes. In most cases, a digital twin is an exact copy of its physical counterpart. Moreover, while simulations often show only one feature, digital twins are more complex. They can simultaneously provide information about many different processes. Digital twins in CNC production can be implemented in process planning, machining, model building, and feedback loops. Based on various input parameters, such as feed rate, tool material, clamping force, a surface roughness prediction model can be implemented using support vector machines, generating tool paths, experimenting, and inputting results into its model (SVM), Gaussian process (GPR), and fully connected deep neural network (FCDNN). Digital twin technologies enhance the decision-making capabilities of process planners and machine operators to control machining parameters during process planning and machining.
Larger investments in automation
Automation also affects the CNC machining process in many different ways. Its importance has increased in recent years and this trend will continue in the future. Automation, on the other hand, focuses on individual processing. For example - the cooperation between Mitsubishi and AIST led to the development of solutions for CNC machines that integrate artificial intelligence and automated processes. This is an error correction method that uses artificial intelligence to estimate the difference between the current position of the CNC machine and its set value. According to test results, the strategy achieved a 51% improvement in accuracy compared to a solution without artificial intelligence. The technology can also be improved during dynamic machining, which saves time while maintaining high quality. The trend is to automate the entire factory. The benefits of this action are straightforward: labor cost savings, increased productivity and consistency. Starting with camera-controlled robots for automatic loading or unloading of CNC machines, factories will build additional workstations to manage marking, measurements and packaging to take advantage of the capabilities of autonomous factories. When developing an automated factory, several questions should be asked:
- Is the current mix of parts suitable for automated production?
- Are there appropriate machine functions, tools, and control systems that allow factories to operate without lighting?
- How to obtain automation-friendly flexible tools and workpiece holders?
- How will remote monitoring, maintenance, and troubleshooting be ensured?
- How to automatically detect errors such as machine downtime, tool failure, or software failure?
A well-implemented machining workshop has enormous potential to revolutionize the way machining is done, but workshops must be willing to invest and improve their processes. Of course, this high degree of automation is only suitable for the production of repeatable parts on a large scale, it does not work very well for prototyping and small-scale production, which requires optimization from the human side, creativity, and practicality.
Developing environmentally sustainable solutions
CNC manufacturers will need to start tracking and reducing the carbon footprint of their production processes and supply chains to meet the growing customer demand for more eco-friendly products. New or redoubled efforts to reduce carbon dioxide emissions through CNC machining services will continue to satisfy consumer demand, support corporate responsibility, and comply with government agency regulations. Manufacturing companies will need to utilize more readily available production and supply chain data to conduct more accurate assessments of the carbon footprint of their products and discover new ways to produce and ship their products in a more environmentally friendly manner.
Development of production as a service
MaaS (Manufacturing as a Service) has only recently entered the CNC machining industry. However, it can be expected that it will gain popularity over time. In short, MaaS utilizes network resources for manufacturing operations and makes them available through digital interfaces. MaaS can provide companies with greater flexibility, increased productivity, greater agility, and cost savings with less effort. As the effects of the pandemic continue to persist, it can be confidently said that companies looking to cut expenses and operating on tight budgets will at least consider the idea of commissioning CNC-based MaaS services, as it can help save materials and improve the work of every milling machine.