Measuring systems for tool monitoring

Systems for tool monitoring, machine monitoring and process monitoring for machine tools

High productivity combined with low production costs and high workpiece quality are the essential prerequisites for cost-efficiency, competitiveness and sustainability in the machining industry. Requirements for machining are extremely strict across different industry sectors and can vary greatly depending on the production process or workpiece.

Challenges in micro-machining

Micro-machining on Swiss-type turning machines involves the strictest precision requirements in terms of the workpiece, machine and tool. When machining turned micro-parts, such as watch components or medical components like bone screws, even the tiniest micro-chipping in a range of just a few µm on the tool’s cutting edge can cause increased cutting force and vibrations. This, in turn, can result in unwanted displacement of the workpiece as well as irregularities in the workpiece surface and, ultimately, scrap costs.

Challenges in rough machining

During rough machining of workpieces with larger diameters, the risk of displacement of the workpiece is significantly reduced; however, the cutting forces are much greater. In this case, tool wear determines the cost-effectiveness. Once again, monitoring of the cutting force provides relevant information and identifies trends that make it possible to indirectly monitor chip removal and tool life in order to optimally utilize the tool lifetime.

Detecting tool wear and avoiding tool breakage

Since machines today often operate unmanned and around the clock, and since there are multiple influencing variables that impact machining processes, these processes must be monitored continuously. Cutting force monitoring offers the advantage that it takes place where the action happens, so both tool-side and workpiece-side anomalies stand out.

Continuous monitoring of machining processes, cutting tools and machine tools provides valuable real-time data and establishes the basis for predictable, productive and reproducible production processes. Ideally, this monitoring allows users to react immediately to deviations in the process: identifying tool wear early on and preventing tool breakage in order to entirely avoid time-consuming and costly consequences like unplanned machine downtime, damage to machines, quality loss and scrap.

Realization of autonomous, high-precision and competitive machining processes featuring maximum process reliability and long tool life – whether on Swiss-type turning, single-purpose or CNC machine centers with tool turrets.

Advantages of measuring systems from Kistler for tool monitoring, process monitoring and machine monitoring: greater cost-efficiency, sustainability and competitiveness

Better machine utilization (increase in overall equipment efficiency (OEE))
Optimal use of tool lifetimes (thanks to tool status monitoring)
Higher workpiece quality (thanks to optimized cutting parameters)
More efficient quality assurance (material batch comparison, separation of scrap during production)
Higher productivity

Less unexpected machine downtime (thanks to less tool breakage)
Lower tool costs
Prevention of consequential damage
Less scrap and less follow-up work
Conservation of scarce resources (e.g. working hours, energy, materials)
Low production and unit costs

We deliver application-specific, easy-to-integrate measurement systems that enable the retrieval of reliable process data in machining operations. These systems serve as the foundation for monitoring and optimizing your machining processes.

Our solution for tool monitoring, process monitoring and machine monitoring

As experts with many years of experience in dynamic measurement technology, we offer practical, tailored and sustainable solutions for a variety of different machine tools and machining applications. Our systems for tool, process and machine monitoring rely on highly sensitive piezoelectric sensors that, integrated either into the tool or the machine structure, make it possible to measure complex machining processes in real time.

Benefit from our wide-ranging application expertise. We are your partner for machining – from retrofitting equipment in existing machinery pools all the way to collaborative development of a new system with integrated sensor technology. Discover the application-specific solutions Kistler has developed for industry.

Systems for tool monitoring in micro-machining on Swiss-type turning machines

Detecting tool wear, avoiding tool breakage

The integration of highly sensitive piezoelectric force sensors directly into the tool holder of Swiss-type turning machines for micro-machining – close to the tool’s cutting edge, where the acting force is the greatest – allows for precise, high-resolution indirect measurement of cutting forces throughout the machining process, from roughing all the way to finishing.

Our application-specific solution for micro-machining relies on the “linear unit” of the quick-change system of the Piezo Tool System (PTS linear), which was developed in collaboration with Paul Horn GmbH. The clever positioning of the sensors between the machine interface and the baseplate retains the advantages of quick tool changes. At the same time, the sensors can monitor a variety of different tool holders.

Real-time measurement of extremely small cutting forces in micro-machining generates critical, high-resolution cutting force data. It makes it possible to capture even the smallest force variations and vibrations, which can indicate deviations in the machining process as the result of tool wear. Cutting force measurement with the PTS enables plant operators to intervene in good time (machine stop) before damage can result from tool wear or tool breakage.

Advantages of process monitoring and tool monitoring in micro-machining:

Optimal utilization of tool lifetimes
Minimum scrap thanks to high product quality
Creation of a basis of high-resolution data for important cutting parameters (feed rate, cut depth, spindle speed) for optimal programming of CNC lathes

Material batch comparison and monitoring
Separation of potential scrap parts
Stoppage of further processing of a part in the event of anomalies

PTS linear unit with integrated force sensors

PTS linear (from Horn) with force sensor for monitoring in Swiss-type turning processes. Available for various machines (Citizen, Star, Tornos, etc.) and tool-holder systems

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PTS linear unit with integrated force sensors

PTS linear (from Horn) with force sensor for monitoring in Swiss-type turning processes. Available for various machines (Citizen, Star, Tornos, etc.) and tool-holder systems

Learn more

Systems for tool monitoring in CNC machining centers with tool turrets

Detecting tool wear, avoiding tool breakage

Our application-specific solution for tool monitoring of highly automated CNC lathes or multi-spindle lathes with rotating tool systems is based on the Piezo Tool System (PTS) tool holders developed by Paul Horn GmbH developed by Paul Horn GmbH with an integrated Kistler piezoelectric force sensor. In rotating systems, a telemetric measuring system (TMS) transmits signals from the rotating machine element.

A wide range of PTS tool-holder systems for a variety of turning applications enables the measurement of cutting forces and detection of the smallest force variations that may indicate deviations in the machining process as a result of tool wear. Real-time cutting force measurement with the PTS makes it possible to intervene (machine stop) in ongoing turning processes on CNC machining centers in good time before damage occurs as a result of tool wear or tool breakage – from the roughing process to the finishing process.

Advantages of process monitoring and tool monitoring in CNC machining centers with tool turrets:

Optimal utilization of tool lifetimes
Creation of a basis of high-resolution data for important cutting parameters (feed rate, cut depth, spindle speed) for optimal programming of CNC lathes

Minimization of machine downtime
Machine stoppage in the case of process deviations
Material batch comparison and monitoring
Separation of potential scrap parts

PTS linear unit and force sensor

PTS linear units (Paul Horn GmbH) and our force sensor are available for various machines and tool-holder systems

PTS linear unit and force sensor

PTS linear units (Paul Horn GmbH) and our force sensor are available for various machines and tool-holder systems

Systems for tool monitoring during rough machining on CNC machines with tool turrets

Detecting tool wear, avoiding tool breakage

Changing tools during rough machining of workpieces on CNC machines with tool turrets is a rapid process involving high cutting forces. Tool wear is significant and increases the risk of tool breakage. Excessive cutting forces damage the material and can result in thermal deformations, cracks and rough surfaces, which can cause damage to tools and necessitate reworking. Once again, monitoring of cutting forces is the means of choice to check for rapid tool wear and prevent tool breakage.

Cost-efficient solution from Kistler:

For this purpose, we integrate a piezoelectric force sensor directly under the bolt that secures the turret housing on the slide in order to measure the moment transferred to the bolt by the cutting forces. This system is especially suitable for rough machining processes, where the cutting forces are high enough to be transferred within the machine structure and measured relatively by the sensor. The precision of this kind of measurement is mainly dependent on the stiffness of the structure and the magnitude of the cutting forces. Thanks to the highly sensitive piezo technology, even the smallest changes in the process can be recorded.

Advantages of process monitoring and tool monitoring in CNC machining centers with tool turrets through the integration of piezoelectric force sensors:

Reduction of tool costs thanks to optimized tool lifetimes
Less scrap and higher, more uniform quality of workpieces
Minimization of machine downtime

Force sensor

Force sensors with different sizes and force-measuring ranges for integration underneath machine fastening elements

Explore force sensors

Force sensors

Force sensors with different sizes and force-measuring ranges for integration under the bolt that secures the turret housing onto the slide

Explore force sensors

Systems for machine monitoring and tool monitoring in single-purpose machines for turning, drilling, and milling

Detecting tool wear, avoiding tool breakage

One method for monitoring the tool status in single-purpose machines is the integration of piezoelectric strain sensors and force sensors into the machine structure. Cutting forces cause strain in the machine structure. Depending on the positioning and how the forces acting on the machining point are transferred to the machine structure, this strain can be monitored very well in relative terms via highly dynamic measurement using piezoelectric sensors. An increase in cutting forces results in greater strain in the structure of the machine. This, in turn, allows us to draw conclusions about the degree of tool wear or anomalies in the machining process. The system is easy to retrofit on existing systems.

Advantages of machine monitoring and tool monitoring in single-purpose machines through the integration of strain and force sensors:

Extension of tool lifetimes
Minimization of machine downtime
Machine stoppage in the case of process deviations
Material batch comparison and monitoring
Separation of potential scrap parts

Force sensor / strain sensor

Force sensors and strain sensors with different sizes and force-measuring ranges for integration into or onto machine structures

Explore force sensors

Explore strain sensors

Force sensor / strain sensor

Force sensors and strain sensors with different sizes and force-measuring ranges for integration into or onto machine structures

Explore force sensors

Explore strain sensors

Measurement technology for tool monitoring and process monitoring for manufacturers of machine tools – collaborative partnership with Kistler

Detecting tool wear, preventing tool breakage with integrated measurement solutions ex works – added value for end customers

When it comes to procuring a new machine tool for end customers, the ideal solution for monitoring the machining process and the tools themselves is often a fully integrated monitoring solution that requires no additional installation work and which displays measurement data directly in the machine control. Many machine tool manufacturers already offer corresponding solutions that tend to observe machining processes via active current monitoring of machine spindles.

These kinds of systems are sufficient for a broad spectrum of applications. However, when it comes to workpieces with extremely small diameters and therefore the smallest force-measuring ranges, these solutions often reach their technological limits. As an expert development and technology partner, this is where we come in: with piezoelectric measurement solutions for machine tools – from early concept development to prototype testing all the way to market launch.

Advantages of a collaboration to develop monitoring solutions in machine tools:

Benefit from Kistler’s expertise and core competency in the field of piezoelectric measurement technology
Draw on an extensive product range of generic sensors, load amplifiers and integration possibilities in machines