Table of contents:
- Sensitive material creates problems
- Looking for a solution
- Monitoring including analysis tools
- Increase productivity efficiency
- Book tip
Video: How A Piezo Force Sensor Helps With Tool Monitoring
2023 Author: Hannah Pearcy | [email protected]. Last modified: 2023-06-01 01:49
Where raw forces prevail: During machining, high surface forces act on the workpiece and cutting tool. This limits the life of the inserts and varies depending on the material and application. The service life varies enormously, especially in the micro range and for materials that are difficult to machine.
Sensitive material creates problems
The production employees at Kistler in Winterthur also struggled with this problem. The expert for measurement technology produces adapter sleeves and membranes for sensitive pressure sensors with wall thicknesses of only 0.06 mm. A nickel-iron alloy is used for this - it is very difficult to machine. The material deforms immediately on strong contact, which often causes tool breaks.
In addition, tool life is very short and varies widely. “The extremely varied downtimes were very tedious for our production employees,” says Severin Hosmann, group leader at Kistler, “They had to keep an eye on every single machine. That was very inefficient and required a system to optimize this process in the long run.”
Looking for a solution
Measures such as adjusting the geometry of the cutting edge brought no improvement. The monitoring of the drive power of the main spindle motor was also ruled out due to the excessive mass of the machine spindle and the friction losses in the spindle. The measurement of structure-borne noise, in turn, did not provide constant results due to the low mass inertia for small workpieces.
When looking for a solution, the specialists at Kistler remembered their core competence in sensor technology: In close cooperation with the tool manufacturer Paul Horn GmbH, a solution was developed for real-time tool monitoring of micro turning operations - the Piezo Tool System (PTS).
Monitoring including analysis tools
The system consists of a high-resolution slim-line force sensor from Kistler and analysis software including a connection to a machine control system for evaluating the processing data recorded with the sensor. The software runs on a standard industrial PC under the Windows operating system from version 7.
The PTS measures the cutting force and the tool load during operation. The data obtained provide information about the expected service life of the tool or the cutting inserts. Faulty materials and cutting materials or even a broken tool are recognized immediately, which minimizes rejects.
Increase productivity efficiency
With PTS tool monitoring, cutting forces are continuously recorded. By evaluating this data, customers receive a trend analysis of the service life of the cutting tool. This enables the downtimes to be extended and thus increases efficiency in production. At the same time, machines no longer have to be continuously monitored, but can sometimes produce unmanned.
"Our tests have shown that usually only the critical tool in a manufacturing process needs to be equipped with PTS," says Gunnar Keitzel, Head of Cutting Force. “This not only massively extends the service life of the Kistler Group, it also means that the workforce can be used more efficiently. A single employee has an overview of all processes and can take care of several machines at the same time."
The book industrial sensors describes the development and practical application of the most important sensors. Through application-related error analysis of measuring systems, sensors and sensor systems, each supplemented by many detailed, fully calculated application examples, the book is not only suitable for students, but also for engineers and technicians from various disciplines.
The new Piezo Tool System is compatible with the standard rotary holders from Horn. It does not require any intervention in the CNC control and can therefore be used independently of the machine. The sensors can be replaced quickly and easily. Existing tools can also be reworked and equipped with PTS.
When monitoring non-rotating cutting edges, Kistler works exclusively with Horn. Due to the good experience with the Piezo Tool System, the measurement technology specialist is already working on solutions for other tools, such as solutions for multi-spindle machines.