EP3774136A1

EP3774136A1 - Calibration method

Info

Publication number: EP3774136A1
Application number: EP19709412.1A
Authority: EP
Inventors: Christian Müller
Original assignee: DORST Technologies GmbH and Co KG
Current assignee: DORST Technologies GmbH and Co KG
Priority date: 2018-03-29
Filing date: 2019-02-28
Publication date: 2021-02-17
Also published as: US20210008626A1; WO2019185286A1; JP2021517207A; DE102018107637A1; JP7359778B2

Abstract

The invention relates to a method for calibrating, in particular, sintered press parts, wherein a calibration method of each individual press part is controlled as a function of at least one specific press part parameter of the respective press part, which has been measured before calibration, and/or as a function of at least one production parameter of a preceding pressing and/or sintering step of the respective press part.

Description

calibration

description

The invention relates to a method for calibrating in particular sintered pressed parts, a method for producing a calibrated pressed part, a control device for controlling a calibration of in particular sintered pressed parts, a sizing press device and a system for producing calibrated, in particular sintered pressed parts.

Calibration is understood to mean the recompression and reshaping of, in particular, sintered pressed parts (by a further pressing operation) to improve the dimensional accuracy and / or surface quality and / or increase the density of the pressed part. In currently known sizing presses, a defined calibration sequence is usually run unchanged, until required the press is stopped and manual changes are made.

DE 10 2010 009 800 B3 describes a high-precision calibration of a component. DE 10 2015 201 966 A1 describes the control of a powder press.

EP 1 964 664 B1 describes automatic control and correction of a punch stroke. For this purpose, the dimensions of a manufactured molding are recorded. In DE 103 01 224 Al a method for hydraulic calibration or powder presses for final position control of the respective press for dimensionally accurate shaped body is described. During the pressing process becomes a characteristic

Press value (eg the position of the press ram) in dependence on another characteristic press value (eg pressing force) and the

End position of the already advanced, in pressing position located punch corrected as a function of the measurement. Thereby, a desired thickness of a pressing part, for example, in a calibration, be set with high accuracy. However, the process according to DE 103 01 224 A1 is considered to be comparatively complicated overall.

It is an object of the present invention to propose a method for calibrating in particular sintered pressed parts, in which in a simple manner the lowest possible manufacturing tolerance of the pressed part after the

Calibration can be maintained.

It is another object of the invention to provide a corresponding method for

Production of a calibrated pressed part, a corresponding one

Control device for controlling a calibration of particular sintered pressed parts to propose a corresponding sizing press device and a corresponding system for producing calibrated, in particular sintered, pressed parts.

In particular, the object is achieved by a method for calibrating

(Presumably sintered) pressing parts solved, wherein a calibration process of each individual pressing part in dependence of at least one before calibration measured, specific pressing part parameter of the respective pressing part and / or controlled depending on at least one production parameter of a preceding pressing and / or sintering step of the respective pressing part (if necessary regulated).

A key idea of the invention is to measure and / or to measure a specific molding parameter prior to calibrating each individual molding

To detect production parameters of a preceding pressing and / or sintering step of each individual pressing part and depending on the

measured / recorded values to control (in particular to regulate) the calibration process of each individual pressed part. In contrast to the prior art, therefore, in particular the parameters of the preceding process steps (pressing, in particular powder pressing or sintering) and (alternatively or additionally) compression-specific properties of the individual pressed part before calibration (eg geometric dimensions, weight and / or density - considered as such) during calibration. The fact that (at least in one alternative) the specific pressing part parameters of the respective pressing part are used as such, a comparatively simple method is achieved (in particular compared to DE 103 01 224 Al, where tried various Pressteildicken by balancing a pressing force and pressing position in the calibrated pressing part compensate).

In particular, a clear relationship between a pressed part weight and press part height after calibration could be found in calibration experiments carried out, even if the pressed parts examined had approximately identical geometric properties prior to calibration. Furthermore, it has been recognized that by means of a calibration sequence (in particular a press-part-specific force / position control) adapted to the press-part-specific parameters or previous process steps, significantly closer press-die tolerances can be maintained after calibration if, for each (individual) press part, one or more specific parameters precede the Calibration are known (for example, a pressing part height, a pressing part width, a segment height, a weight, a density, a pressing force during (powder) pressing and / or a pressing position in (powder) pressing) and in the calibration process and the

resulting calibration positions are considered accordingly.

In particular, a length of the (entire) pressed part in the axial direction or pressing direction (during a calibration

preceding pressing step). A segment height is understood in particular to mean a height of a segment of the pressed part in the axial direction or pressing direction (during a pressing step preceding the calibration). Under a press part width is in particular a (maximum)

Extension of a radial section of a pressing part or a cross section of the pressing part perpendicular to the pressing direction (during a pre-calibrating pressing step) to understand. Preferably, each individual pressing part is calibrated as a function of a (previously measured) parameter inherent in the pressing part, in particular a weight and / or a geometrical dimension, preferably a height, in particular pressing part height and / or segment height, and / or a volume, and / or a Density of the pressed part (as respective specific

Pressing part parameters or as respective specific pressing part parameters).

Particularly in the case of the control (regulation) as a function of a weight and / or a density of the pressed part, press-on part heights can be achieved with a low manufacturing tolerance.

In general, a specific pressing part parameter of the respective pressing part is to be understood as a parameter which is inherent in the pressing part, that is to say defines its structural-physical form. In contrast, a production parameter is a parameter which is not inherent to the respective pressing part but is linked thereto, in particular by a (the calibration step) preceding production step, preferably (powder) pressing step and / or sintering step of the respective pressing part. In this respect, a production parameter can be understood to mean a "pressing and / or sintering parameter", unless otherwise stated or nothing else arises from the context.

In a preferred alternative embodiment, the calibration of each individual pressing part is controlled (or regulated) as a function of a (previously determined or transmitted) pressing position (a pressing path) and / or a pressing force of a preceding (powder) pressing process (as a production parameter). The pressing position or pressing force can be determined within a method for producing a calibrated pressed part, in particular measured or

be provided as input within the calibration procedure itself (to be transmitted).

Under pressing position (Pressweg) is preferably the position (path), z. B.

End position to understand a particular punch (which is used for calibration or previous (powder) pressing). Under pressing force is preferably used by the respective press ram (which is used for calibrating or preceding (powder) pressing) applied during pressing force. The control of the calibration sequence preferably comprises a

Control (regulation) of a force and / or a position (of a path or stamp path) during calibration. According to the embodiment, the pressing force during calibration is not (directly) dependent on the pressing position (or vice versa), but is set as a function of the previously determined pressing part parameter and / or production parameter. However, it may also be possible additionally to control (control) the pressing force during calibration as a function of the pressing position during calibration.

A sizing press is preferably not stopped during the calibration of the pressed parts (ie it is in particular a continuous process in which individual or sintered pressed parts are arranged continuously or successively in the sizing press and then calibrated according to the method described above). Under a stop is

in particular, to understand stopping the sizing press after completion of a single calibration (of a single press part) (which, for example, is done in the prior art in order to be able to change the calibration settings manually).

A calibrating press device is preferably not stopped during the calibration of a single pressing part (a punching speed during the calibrating pressing is therefore always greater than zero during the pressing of the individual pressing part until a punching end position is reached). This allows a simple yet accurate calibration can be achieved.

The method of calibrating may include calibrating a plurality of

(sintered) pressed parts, for example at least 10 or

at least 100 or at least 1000 pressed parts, being a single one

Calibrating a single one of the plurality of pressed parts for a time of preferably less than 30 seconds, more preferably less than

10 seconds.

In particular, the above-mentioned object is achieved by a method for producing a calibrated pressed part, comprising the steps: - Pressing a starting material, in particular powder, to a

Press part,

preferably sintering of the pressed part,

- Calibrating the (sintered) pressed part as described above

Method.

The above object is further achieved by a

Control device for controlling (in particular control) of calibrating pressed parts (preferably sintered), preferably in accordance with the method described above, wherein the control device is configured to calibrate each individual pressing part as a function of at least one specific pressing part parameter of the respective pressing part measured before calibration or (depending on at least one production parameter of a preceding pressing and / or sintering step of the respective pressing part to control (in particular to regulate).

The control device preferably comprises at least one device (in particular comprising one or more sensors) for determining a weight and / or a density and / or a geometrical dimension, in particular a height, preferably pressing part height and / or pressing part width and / or segment height and / or a volume and / or a density of the pressed part (as a specific pressing part parameter or specific

Press Part parameter).

The control device may comprise at least one device for detecting a pressing position and / or a pressing force of a preceding (powder)

Pressing process (as a production parameter) include.

Furthermore, the control device can be configured to control (regulate) a pressing force and / or a pressing position (of a stamp) during calibration.

The above object is further achieved, in particular, by a calibrating press device comprising the above control device. The above object is further achieved in particular by a system for producing calibrated (sintered) pressed parts, comprising:

a press device for pressing a starting material,

especially powder, to a pressed part,

- Preferably, a sintering device for sintering the pressing part and

- A sizing press device of the type mentioned above.

Preferably, the system comprises at least one device for determining (measuring) a pressing force and / or pressing position during pressing of the

Starting material (powder).

In embodiments, after calibrating (a respective pressing part) at least one calibration pressing part parameter can be detected, for example a weight and / or a density and / or a geometrical dimension, in particular a height, preferably pressed part height and / or segment height, and / or a volume , and / or a density of the pressed part. This at least one calibration pressing part parameter can be used (in particular in combination with at least one pressing part parameter of a subsequent pressing part and / or at least one production parameter of the following pressing part) for continuous optimization (readjustment) of the calibration of a subsequent pressing part.

Further embodiments emerge from the subclaims.

The invention will be described with reference to embodiments, which are explained in more detail with reference to the figures. Hereby show:

Fig. 1 is a schematic view of a system for the production of

calibrated, sintered pressed parts;

Fig. 2 is a diagram for explaining an inventive

Calibration. In the following description, the same reference numerals are used for identical and equivalent parts.

Fig. 1 shows a schematic view of a system according to the invention for the production of calibrated sintered pressed parts.

The system comprises a powder press device 10, a sintering device 11, a calibrating press device 12 and a control device 13.

In the powder press device 10, a pressed part is produced from a raw material (powder).

In particular, a device 14 for determining (measuring) a pressing position (of a punch path) and / or a pressing force can be provided in the powder press device 10. For example, a (total) punch path and / or an initial position of the punch (before pressing) and / or an end position of the punch can be determined. If necessary, the

Stamp position can also be measured as a function of time (in particular continuously). Alternatively or additionally, a stamping force,

for example, in time dependence during pressing, are measured. In this case, in particular, a dependence of the pressing position on the pressing force (and / or vice versa) can be determined.

Corresponding production parameters (in particular pressing position and / or pressing force) can then be transmitted to the control device 13. For this purpose, the control device 13 has, in particular, a device 15 for receiving (detecting) the one or more production parameters (s) from the device 14 for determining a pressing position and / or pressing force of the powder press device 10.

Furthermore, a parameter of the sintering device 11 (for example, a sintering temperature or sintering temperature profile) can optionally be recorded (detected) by the control device 13 or its device 15 for recording a production parameter. The control device 13 furthermore comprises a device 16 for determining at least one pressing part parameter (for example, weight and / or density and / or a geometrical dimension, in particular height, preferably pressing part height and / or pressing part width and / or segment height and / or a volume). The device 16 for determining a pressing part parameter can be an integral part of the control device 13 or be connected to it (so that it is possible to communicate between device 16 and control device 13).

Depending on manufacturing parameters that are determined by the powder press device 10 (or its device 14 for determining at least one

Production parameters) and / or the sintering device 11 and / or data provided by the device 16 for determining at least one pressing part parameter (and optionally to the control device 13

transmitted), the control device 13 now controls the calibrating press device 12, in particular with regard to a pressing position and / or a pressing force.

The control device 13 can be an integral part of the calibrating press device 12 or be designed as a separate component (and communicate with the calibrating press device 12 wirelessly or by wire). The device 16 for determining at least one pressing part parameter may also be an integral part of the calibrating press device or designed as a separate component.

Referring now to Figure 2, there is shown a schematic process for making a single calibrated sintered compact. In a step 1, a pressed part is first pressed from a powder (starting material). This is then sintered in a step 2. Thereafter, in a step 3 at least one

Manufacturing parameters (which may have been measured during step 1 and / or 2) recorded (detected) and / or at least one pressing part parameter determined (detected), in particular measured. Then it is done

actual calibration in step 4 (ie pressing the sintered pressed part to the final product, namely the calibrated, sintered pressed part) below

Consideration of the production parameter and / or pressing part parameter.

Unless otherwise stated in the context in question, a "pressing part" is to be understood as meaning a part (product) which results from pressing in a (powder) press device, and a part under "sintered pressed part" (Product) which is pressed and sintered; and under a "calibrated, sintered pressed part" a part (end product) which has passed through the calibration step and (possibly with a small amount)

Post-processing steps) is ready for use.

It should be noted at this point that all parts described above, taken alone and in any combination, especially in the

Drawings shown details are claimed as essential to the invention. Variations thereof are familiar to the person skilled in the art.

reference numeral

1 process step "pressing"

2 process step "sintering"

3 method step "determination of parameters"

4 "calibration" step

10 (powder) press device

11 sintering device

12 Calibration press device

13 control device

14 Device for determining at least one production parameter

15 device for receiving at least one production parameter

16 device for determining at least one pressing part parameter

Claims

claims

1. A method for calibrating in particular sintered pressed parts, wherein a calibration process of each individual pressing part as a function of at least one measured before calibration, specific

Pressteilparameters the respective pressing part and / or in dependence of at least one production parameter of a preceding pressing and / or sintering step of the respective pressing part is controlled.

2. The method according to claim 1,

d a d e d e r c e n ts i c h n et that

calibrating each individual pressing part as a function of a weight and / or a density and / or a geometrical dimension,

in particular a height, preferably pressed part height and / or

Segment height, and / or a volume, and / or a density of the pressing member is controlled.

3. The method according to claim 1 or 2,

d a d u rc h e g e n s i n s that

calibrating each individual pressing part as a function of one

Pressing position and / or pressing force of a preceding (powder)

Pressing process is controlled.

4. The method according to any one of the preceding claims,

d a d u rc h e n d i n s i n s that

the control of the calibration process comprises a control of a pressing force and / or a pressing position during calibration.

5. The method according to any one of the preceding claims,

d a d u rch e ke n ze i c h n et that

a calibrating press device (12) is not stopped during the calibration of a plurality of pressed parts and / or a calibrating press device (12) is not stopped during the calibration of a single pressing part.

6. A method of making a calibrated compact, comprising the steps of:

Pressing a starting material, in particular powder, into a pressed part,

preferably sintering of the pressed part,

Calibrating the sintered pressed part according to one of

previous claims.

7. Control device (13) for controlling a calibration of

in particular sintered pressed parts, preferably according to one of claims 1 to 5, wherein the control device (13) is configured to calibrate each individual pressing part as a function of at least one specific pressing part parameter of the respective pressing part measured before calibration and / or as a function of at least one production parameter of one preceding pressing and / or sintering step of the respective pressing member to control.

8. Control device according to claim 7,

marked by

at least one device (16) for determining a weight and / or a geometrical dimension, in particular a height, preferably pressed part height and / or segment height, and / or one Volume, and / or a density of the pressed part.

9. Control device according to 7 or 8,

marked by

at least one device (15) for detecting a pressing position and / or a pressing force of a preceding pressing operation.

10. Control device according to one of claims 7 to 9,

d a d e d u rch e n d e s c h n et that

the control device (13) is configured to control a pressing force and / or a pressing position during calibration.

11. Calibration press device (12), comprising a control device (13) according to one of claims 7 to 10.

12. System for producing calibrated sintered in particular

Pressed parts, comprising:

a press device (10) for pressing a starting material, in particular powder, into a pressed part,

- Preferably, a sintering device (11) for sintering the pressing part and

- A calibration press device (12) according to claim 11.

13. System according to claim 1,

marked by

at least one device (14) for determining a pressing force and / or pressing position during pressing of the starting material.