CHUAN HONG PRECISION TOOL MFG.CO, LTD. -Towards Industry 4.0 Smart Industrial Applications

The load transmission element of the planetary roller screw is a threaded roller, which is a typical line contact.

The ball screw load transmission element is a ball point connection.

Since the ball lead screw uses steel balls to undertake motion conversion, small vibrations or noises will be generated with the movement of the steel balls. When the ball screw carries a certain axial thrust, the friction coefficients of forward and reverse rotation are different, so it is not easy to achieve high-precision positioning control.

Through thread precision matching, the planetary roller screw can move in a linear manner to achieve high positioning accuracy, high repeatability, low noise and reliability.

The roller screw transmission system precisely converts rotary motion and linear motion into each other. With many years of experience and profound screw engineering design capabilities, we have developed product series that meet different requirements. Planetary motion is like a planet revolving around the sun. Even among billions of planets in the universe, the orbits of celestial bodies are exactly the same. Planetary roller screws use the movement between the screw and the precision screw to move the screw. The sliding motion is converted from screw engagement and rotary motion to linear motion of the transmission component. The smart planetary roller screw uses a high-precision screw to operate a ball screw-free steel ball return device, which performs well in applications with frequent changes in direction and high linear speed, low backlash, and low noise, creating a new aesthetic process that matches related mechanical noise reduction.

The feasibility of customizing the appearance of planetary roller screws without loop rollers is relatively improved. Since the roller screw combination consists of a large screw and 9-12 small screws, the rigid structure is relatively high, and the same specifications The diameter of the nut of the screw and roller screw is larger than that of the ball screw. If the installation space is limited, generally the nut specifications can be directly replaced with the roller screw according to the allowable space.

The minimum diameter of the planetary roller screw workpiece can reach 8m, the lead is 1.5mm, the maximum workpiece diameter can be 120mm, the lead is 50mm, the longest workpiece of the transformation grade can be 6m, and the longest length of the precision grade workpiece can be 2.2m. Functions and benefits In addition to being able to replace hydraulic cylinders and pneumatic cylinders, industrial equipment is more widely used. Chuanfeng Precision uses innovative processes to significantly reduce production costs and reduce price factors, making industry more willing to apply them. Therefore, the industry predicts that planetary rollers will Screw will become the mainstream of linear transmission components.

In line with the needs of various industries, we accept customized customization. If the length of the workpiece is within 2.2m, we can quickly provide services according to customer needs.

Planetary roller screws have the characteristics of high linear motion precision, high rigidity, large output, long life, high load, low backlash, low noise, and precise positioning. Technologies accompanying Industry 4.0 and the Industrial Internet of Things will be widely used in the machinery industry; and due to the diverse operating conditions of roller screws, sensing technology that can be mounted on a mobile carrier is required for measurement, with nuts (flanges) ) The metal strain characteristics generated by running on the screw (including overload, impact, wear, etc.). The monitoring technology developed by Chuanfeng is designed for the "roller" screw feed system. The screw is in "line" contact with the rollers and the covered nut (flange). The nut (flange) is affected by the force while the feed system is running. Force is the most direct physical reaction, which is metal deformation. Therefore, by using direct deformation measurement, the deformation amount while the roller is running can be obtained. The designed sensor can be used to lock the roller screw on the machine. The final installation can achieve the basic goals of being lightweight, highly reliable, and not affecting structural rigidity. At the same time, online monitoring of the screw can be the main development technology, and it is equipped with a high-resolution (ADC 24bit) wireless transmission signal acquisition module. All the motion processes of the planetary roller screw carrying the load, including thermal deformation, load force changes, random vibration, etc., can be collected and compared at the back end through the long-term operation of the machine and the edge computer data. Reach the comprehensive service life of diagnostic movable parts.

After completing the sensor design to be lightweight, highly reliable, not affecting structural rigidity, and capturing flange strain signals with high resolution, the first thing to do is to ensure the accuracy of the signal source. If the signal source cannot be correctly classified and labeled, it will end up being just one. There is a lot of incomprehensible noise, and the traditional industry is not like the technology semiconductor industry. All machine and equipment operations are controlled and monitored by the central control room and work orders are issued uniformly. In contrast, in the traditional industry, only on-site paper and pen records are maintained by the operators. We can rely on the memory and experience of the master. As the times change, the problems also arise: a low birthrate (shifts are more dependent on foreign workers), a high turnover rate (few skilled workers can perform maintenance, etc.), and the traceability of usage history (responding to Aerospace industry)...etc. In order to ensure stable signal quality and build a reliable monitoring system, and at the same time solve the above problems for users, Figure 3, the pre-built function items of the monitoring system include: 1. Operation information input item, on-site personnel operation is targeted at production and Maintenance creates digital information and is designed with the concept of reducing human errors. During production, you only need to scan the work order barcode (barcode or QR code) and the program will obtain the number from the database and automatically bring out the information (product name, materials used, and desired production quantity). ) and upload it; conversely, maintenance also requires scanning the barcode and selecting the cause of damage code. This not only replaces handwritten records with digital records, but also completes the identification of signal sources and anomaly labeling. 2. It has TCP/IP communication protocol data transmission and integrates digital real-time information. The system is connected to the front-end analog sensor signal source for wireless transmission. Although analog signals are often interfered by noise in the factory environment, they are less affected than digital signals. Noise means that the analog signal is damaged and cannot be reconstructed to make it more reliable. In the signal acquisition unit, the analog signal first passes through the signal processor (signal condition) and then is converted to analog-to-digital by the ADC chip. The wireless transmission enters the monitoring system program and is presented. Our team's monitoring system has highly flexible customized functional screen design, machine utilization management based on mainstream needs, early warning management of monitoring needs, and online operation estimation and judgment of artificial intelligence models are also its focus. 3. Connect to the cloud database SQL system. The database can be connected to the ERP (Enterprise Resource Planning) system through permission control. Data can be transferred for machine operation information, such as the production name, product materials, etc. corresponding to the work order number. Pre-production quantity, as well as front and rear station information, and the operating status diagnosis results of the roller screw can also be sent back and stored. Data can be connected in series without affecting the operation of the enterprise's ERP. It also makes the health diagnosis system more flexible to use, regardless of the future. Regardless of the brand of ERP system, as long as it is connected to the database, it can combine the real-time information and the highly flexible operation of the system.

The intelligent planetary roller screw end calculates and predicts the comprehensive life of the movable parts through long-term machine operation and data collection. Automatic detection of life can replace the screw before it wears out, reducing the cost of repairing parts due to damage. In order to achieve the goal of online edge computing, our team uses supervised learning to build a diagnostic model. The user marks the abnormal time interval through the monitoring system as the target of the model training output, and the input signal The source is the strain generated by the nut flange during operation. The signal will be pre-processed in the time domain to automatically select key signal segments to reduce noise that affects the signal authenticity, and then proceed to feature extraction and feature annotation. During the extraction process, the signal will be disassembled into multiple groups of sub-signals and frequency ranges, and enter the feature labeling stage. This stage is to further find out the correlation between excessive features to reduce the future calculation dimension. The decoupled sub-signals are classified into similar features through regular operations, thereby forming clustering of features, and the clustering results are output for comparison with the user's annotations. At the same time, cross-comparisons are performed in this stage of the process. Yes, the sub-signal for training will not be output until the comparison result reaches 90% similarity with the target marked by the user.

Finally, a planetary roller screw diagnostic model was constructed based on this highly relevant feature, which was used to evaluate the following four operating states:

• Real-time monitoring of moving load
  Adopts direct pressure sensing to monitor the load carried by the screw when it moves to avoid damage to the roller screw due to long-term exceeding the load-bearing weight.
• Assessment of unbalanced load status
  By installing the sensor in parallel on the flange to sense the load, you can evaluate whether the screw is operating in a balanced manner and avoid thread damage to the roller screw due to long-term unbalanced load.
• Predictive maintenance
  Set abnormal load warning and unbalanced load thresholds to perform maintenance in advance before a fault occurs.
• Fault Diagnosis
  Integrate two load monitoring data to construct a model to diagnose fault factors to improve maintenance efficiency.
  With the addition of smart components, the smart roller screw has functions such as real-time monitoring of transferred loads, assessment of unbalanced load status, predictive maintenance and fault diagnosis, etc. It can also reduce faults, maintenance schedules and even eliminate the need for industrial applications. Quality products are produced and checked. In recent years, in response to the machining accuracy requirements of the machine tool industry and forming machines, planetary roller screws do not require a reflow device and can achieve faster rotation speeds, more precise positioning accuracy, a larger output range, and lower noise levels than ball screws. , has been widely used in the precision machinery industry, including: all-electric plastic injection machines, servo punches, folding machines, broaching machines, 3D printing and other high-speed, high-load, high-precision mechanism applications, etc.