Cutting machine comprising a force transducer, use of such a cutting machine and process of calibrating the force transducer of such a cutting machine

Patent metadata

Field	Value
Publication number	US-12420372-B2
Application number	US-202117909014-A
Country	US
Kind code	B2
Filing date	Jan 21, 2021
Priority date	Mar 19, 2020
Publication date	Sep 23, 2025
Grant date	Sep 23, 2025

Abstract

A cutting machine configured for the chip-removing machining of a workpiece includes a plurality of required tools. Each tool can exert a tool force onto the workpiece. The cutting machine includes a tool holder for simultaneously holding all of the tools required for operating on the workpiece. A tool slide moves the tool holder to successively align one of the tools to operate on the workpiece, and the tool and the workpiece are movable for chip-removing machining in each manufacturing step. The tool holder includes at least two single-component force transducers. Each single-component force transducer measures a tool force exerted by one of the tools during the chip-removing machining of the workpiece in a force main connection.

First claim

The invention claimed is:

1. A cutting machine for the chip-removing machining of a workpiece, which chip-removing machining takes place in a chronological sequence of manufacturing steps by using several required tools; wherein in each manufacturing step a required tool can exert a tool force onto the workpiece in a force main direction; the cutting machine comprising:
a tool holder configured for holding the required tools all at the same time, wherein the tool holder defines a plurality of recesses and at least one cavity;
a plurality of signal lines and a signal socket connected to the tool holder,
a tool slide configured for moving the tool holder so that one of the required tools can be aligned with a workpiece and the required tool and the workpiece can be moved with respect to each other for chip-removing machining in each manufacturing step;
wherein the tool holder includes a first fastening means and a second fastening means;
wherein the tool holder is fastened to the tool slide via the first fastening means and via the second fastening means;
wherein the tool holder fastened to the tool slide is spaced apart from the tool slide by a gap proximate the plurality of recesses;
wherein the tool holder includes at least two single-component force transducers;
wherein each of the at least two single-component force transducers is configured to measure a tool force exerted by one of the required tools during the chip-removing machining of a workpiece in the force main direction;
wherein each of the single-component force transducers is inserted into a respective one of the plurality of recesses;
wherein each of the single-component force transducers is electrically connected to the signal socket via a respective one of the plurality of signal lines;
wherein the plurality of signal lines is introduced into the cavity;
wherein the tool holder defines a plurality of first housing end faces and a plurality of second housing end faces; and
wherein the single-component force transducers inserted into the plurality of recesses are in planar contact to the tool slide via the second housing end faces proximate the recesses.

2. The cutting machine according to claim 1 , wherein the tool holder fastened to the tool slide is in planar contact to the tool slide via a contact surface that is disposed proximate the second fastening means; and wherein the cavity of the tool holder fastened to the tool slide is sealed by the tool slide.

3. The cutting machine according to claim 2 , wherein a sum of the second housing end faces of the single-component force transducers is larger than the contact surface of the tool holder.

4. The cutting machine according to claim 1 , wherein each of the at least two single-component force transducers measures a respective different force component of the tool force.

5. The cutting machine according to claim 1 , wherein each of the at least two single-component force transducers is configured to measure the tool force independently of each of the other at least two single-component force transducers; and wherein each of the at least two single-component force transducers generates analog measurement signals that correspond to a main cutting force exerted on the workpiece.

6. The cutting machine according to claim 5 , wherein the tool holder is configured to hold the required tools in a plurality of different positions during the chip-removing machining; and wherein each of the at least two single-component force transducers is configured to measure the tool force in each of the plurality of different positions.

7. The cutting machine according to claim 6 , further comprising at least one converter unit that is configured to convert analog measurement signals for each manufacturing step performed by a required tool into digital measurement signals; and at least one computer that is configured to sum up the digital measurement signals for each manufacturing step to obtain a position-specifically averaged measurement signal.

8. The cutting machine according to claim 7 , wherein the computer is configured to store reference signals for a material of the workpiece and for a cutting material of a required tool; wherein the computer is configured to read out a reference signal for each manufacturing step; wherein the computer is configured to store calibration factors for a position of a required tool relative to each respective one of the at least two single-component force transducers; wherein the computer is configured to import a calibration factor for each manufacturing step; wherein the computer is configured to multiply the position-specifically averaged measurement signal by a read out calibration factor for each manufacturing step; and wherein the computer is configured to calculate a difference of the position-specifically averaged measurement signal multiplied by a read out calibration factor and the read out reference signal for each manufacturing step.

9. The cutting machine according to claim 7 , wherein the computer is configured to store predefined tolerance values; wherein the computer is configured to read out a predefined tolerance value for each manufacturing step; wherein for each manufacturing step the computer is configured to compare a difference to the predefined tolerance value; and wherein the computer is configured to determine that the required tool is not abraded to a degree warranting replacement of the required tool so long as the difference is not greater than the predefined tolerance value.

10. The cutting machine according to claim 9 , wherein the computer is configured so that upon determining that the difference exceeds the predefined tolerance value, then the computer signals that the required tool is to be replaced.

11. A cutting machine for the chip-removing machining of a workpiece, which chip-removing machining takes place in a chronological sequence of manufacturing steps by using several required tools, wherein in each manufacturing step a required tool can exert a tool force onto the workpiece in a force main direction, the cutting machine comprising:
a tool holder configured for holding the required tools all at the same time, wherein the tool holder defines a plurality of recesses and at least one cavity:
a plurality of signal lines introduced into the cavity and connected to the tool holder;
wherein the tool holder includes at least two single-component force transducers;
wherein each of the single-component force transducers is inserted into a respective one of the plurality of recesses;
a tool slide configured for moving the tool holder so that one of the required tools can be aligned with a workpiece and the required tool and the workpiece can be moved with respect to each other for chip-removing machining in each manufacturing step;
wherein each of the at least two single-component force transducers is configured to measure a tool force exerted by one of the required tools during the chip-removing machining of a workpiece in the force main direction;
a signal socket connected to the tool holder;
wherein each of the single-component force transducers is electrically connected to the signal socket via a respective one of the plurality of signal lines;
wherein the tool holder includes a first fastening means and a second fastening means;
wherein the tool holder is fastened to the tool slide via the first fastening means and via the second fastening means; and
wherein the first fastening means, by fastening the tool holder to the tool slide, mechanically biases the single-component force transducers inserted into the plurality of recesses.

12. A method for calibrating single-component force transducers

Assignees

• Kistler Holding Ag

Inventors

• Keitzel Gunnar
• Kohler Denis

Classifications

• B23Q2717/003

  in lathes · CPC title

• B23B29/26

  Tool holders in fixed position · CPC title

• B23Q17/0966 Primary

  by measuring a force on parts of the machine other than a motor · CPC title