RCD – Rotating dynamometers to measure cutting forces

Precise force and torque measurements

Rotating dynamometers (RCD) to measure cutting forces directly on the cutting edge

In machining processes, everything is geared to boosting productivity. A rotating dynamometer (RCD) is a diagnostic tool that is inserted directly into the machine tool's spindle. When an RCD is used, the cutting forces that act on the edge are measured directly on the rotating tool – even when the machining processes are highly complex. The cutting process can be analyzed and optimized with the help of the measured data.

Kistler's RCDs are based on piezoelectric measurement technology. This method achieves superior results as compared to other technologies, with signal quality that is unsurpassed anywhere in the world. The key characteristic: highly dynamic acquisition of the forces. The piezo technology principle makes it possible to switch measuring ranges – and in the RCDs, this advantage comes into full play when users need to select the right range. Just one single device always ensures optimum resolution of finishing processes as well as high-performance cutting processes.

Rotating dynamometers

Rotating dynamometers have the advantage of a rugged and compact design that makes handling easy. They are mounted directly via the machine spindle interface. The tool is then connected to the RCD with the help of a suitable tool holder. The RCD rotates with the spindle during operation, so the mechanical load on the tool can be quantified directly. We offer you an extensive choice of spindle adapters that open up a varied range of potential applications.

Drilling and milling with rotating dynamometers (RCD) by Kistler

Piezoelectric dynamometers display their advantages to the full in milling and drilling operations. Thanks to their high rigidity and natural frequencies, these dynamometers cope easily with high tooth passing frequencies to deliver measurement results with a level of precision that other technologies cannot match.

Optimizing machining technology

Part quality, tool life and machining time depend on different factors. Because rotating dynamometers measure the cutting forces with high precision, they provide the basis needed to assess and optimize all these factors. They include:

wear mechanisms
identification of overload situations
cooling and lubrication
material characteristics
workpiece clamping characteristics
vibrations and oscillations around the machine
no-load operation

Functionalities of the software DynoWare

As can be clearly seen, the load on one cutting edge is greater.

The reduced torque on the cutting edge (bottom left) indicates a runout error or excessive edge wear.

Comparison of torque and axial force in the direction of the spindle during thread cutting.

Tooth passing frequency during milling.

The compact model: RCD Type 9170A

The Type 9170A rotating dynamometer (RCD) is the compact member of Kistler's family of rotating systems. Designed for applications in milling and drilling processes, this model was specifically developed for high-precision machining at speeds of up to 20 000 1/min.

The RCD's integrated structural design gives it excellent rigidity, so its natural frequency is also very high. Thanks to these advantages, the Type 9170A achieves the extremely high resolution needed to measure as many as 600 cutting edge engagements per second.

Kistler offers you an extensive portfolio of standard commercial machine interfaces.

When placing your order, choose the machine interface that you need to measure the cutting forces for your type of machining. On the tool side, the ER32 collet chuck is available as standard. Please note that you cannot replace or exchange the adapters of the 9170A due to its integrated design.

Capto is a registered trade mark of the Sandvik Group

The versatile model: RCD Type 9171A

Do you operate machine tools with different spindle interfaces?

If so, we can offer you an extensive choice of spindle adapters for our Type 9171A rotating dynamometer (RCD). They can be exchanged on the tool side as well as the machine side. This range of adapters opens up a variety of options for you to adapt the RCD flexibly to each individual measurement task.

Our Type 9171A rotating cutting force measurement system (RCD) is suitable for medium to heavy machining operations in a speed range up to 12 000 1/min. Thanks to the interface for attaching tool-side adapters, you can even develop your own specific tool systems for use together with the RCD.

Capto is a registered trade mark of the Sandvik Group

PowRgrip and SecuRgrip are registered trade marks of Rego-Fix AG

MEGA New Baby Chuck is a registered trade mark of BIG DAISHOWA Group

TENDO is a registered trade mark of the Schunk Group

Flexible wireless data transmission

Transmission of measurement data and the energy supply for the rotating cutting force measurement systems are handled by wireless near-field telemetry in conjunction with a signal conditioner. The signal conditioner (compatible with both measurement systems) automatically detects which rotor is being used, and the relevant settings are also adapted automatically.

Straightforward data acquisition and evaluation

Data is acquired via hardware in combination with the DynoWare software, which makes it possible to set three different measurement ranges and low-pass filters in each case. The individual measurement ranges for axial forces and torque can also be selected independently of one another. The benefit: optimum utilization of the measurement ranges. As regards signal analysis, DynoWare offers measurement engineers real-time visualization of measurement curves as well as helpful calculation and graphics functions.