WO1991008879A1 - Procedure and apparatus for determining the ending instant of the block rounding stage in a veneer-cutting machine - Google Patents

Procedure and apparatus for determining the ending instant of the block rounding stage in a veneer-cutting machine Download PDF

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Publication number
WO1991008879A1
WO1991008879A1 PCT/FI1990/000290 FI9000290W WO9108879A1 WO 1991008879 A1 WO1991008879 A1 WO 1991008879A1 FI 9000290 W FI9000290 W FI 9000290W WO 9108879 A1 WO9108879 A1 WO 9108879A1
Authority
WO
WIPO (PCT)
Prior art keywords
rounding stage
ending
determining
cutting
instant
Prior art date
Application number
PCT/FI1990/000290
Other languages
French (fr)
Inventor
Harri Kalervo Korpela
Original Assignee
Insinööritoimisto Korpela Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Insinööritoimisto Korpela Oy filed Critical Insinööritoimisto Korpela Oy
Publication of WO1991008879A1 publication Critical patent/WO1991008879A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q15/00—Automatic control or regulation of feed movement, cutting velocity or position of tool or work
    • B23Q15/007—Automatic control or regulation of feed movement, cutting velocity or position of tool or work while the tool acts upon the workpiece
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27L—REMOVING BARK OR VESTIGES OF BRANCHES; SPLITTING WOOD; MANUFACTURE OF VENEER, WOODEN STICKS, WOOD SHAVINGS, WOOD FIBRES OR WOOD POWDER
    • B27L5/00—Manufacture of veneer ; Preparatory processing therefor
    • B27L5/02—Cutting strips from a rotating trunk or piece; Veneer lathes
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00—Program-control systems
    • G05B2219/30—Nc systems
    • G05B2219/34—Director, elements to supervisory
    • G05B2219/34388—Detect correct moment, position, advanced, delayed, then next command
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00—Program-control systems
    • G05B2219/30—Nc systems
    • G05B2219/37—Measurements
    • G05B2219/37351—Detect vibration, ultrasound
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00—Program-control systems
    • G05B2219/30—Nc systems
    • G05B2219/45—Nc applications
    • G05B2219/45037—Veneer cutting

Definitions

  • the present invention relates to a procedure and an appara ⁇ tus for the determination of the ending instant of the block rounding stage in a veneer-cutting machine.
  • the ending of the rounding stage is practically based on block diameter data as measured by visual estima ⁇ tion, by means of a camera or in the centring device.
  • the methods currently used have several drawbacks. Manual ending of the rounding stage on the basis of visual obser ⁇ vation requires continuous attention. Moreover, modern machines use higher speeds of rotation as well as greater barking depths, making visual estimation more difficult.
  • the line of observation is, due to the mechanical dimensions, separated from the line of the cutting tool by a distance of about 1 - 1.5 m. There is a corresponding lag in the data concerning the phase of the rounding operation.
  • a camera e.g. a line camera
  • the operation of line camera control is based on the distinction and comparison of shades of gray, the colour differences in the veneer, caused by the wood material itself and by moisture variations, result in evaluation errors.
  • Another source of evaluation errors is the sensitivity of the line camera to changes in illumina ⁇ tion (condition and soiling of the lamps, wrong direction of light, external lights and shades, e.g. sunlight).
  • the ending instant of the rounding stage is based on block diameter data measured in the centring device, in which case the measurement can be performed using a line camera, matrix camera, laser distance measurement, ultra ⁇ sonic measurement or mechanical measurement
  • the mechanical transfer errors occurring in the centring of the block and those occurring during the positioning of the block between the mandrels cause errors and inaccuracies in the determi ⁇ nation of the ending instant of the block rounding stage.
  • the number of measuring points in the trans ⁇ verse and longitudinal sections is limited, which means that the ending of the rounding stage is based on defective data.
  • FI publication 73908 proposes a procedure for the control of the debarking and rounding of a block of wood in a veneer-cutting machine whereby the quality of the surface of the rotating block is observed by directing a beam of light at the block in its longitudinal direction and detecting the radiation reflected from the block by means of a semiconductor camera.
  • the point under observation lags behind the cutting line by about 3/4 of a turn of the block, involving a corrseponding time lag in the data regarding the phase of the rounding operation.
  • the interpretation is based on the greyness difference between the uncut block surface and the surface after the cutting, for which reason colour differ ⁇ ences in the wood material itself cause errors in the in ⁇ terpretation of the data. Due to the facts mentioned above, this procedure is sensitive to changes in illumination in the same way as when the wood sheet produced by the block rounding operation is observed by means a line camera as mentioned above.
  • the object of the present invention is to eliminate the drawbacks presented above.
  • the procedure of the invention for determining the ending instant of the block rounding stage in a veneer-cutting machine is characterized in that the sound produced by the cutting during the rounding stage is monitored by means of one or more sensors and the signal obtained from said sensors is passed to a data processing unit which, based on the cutting sound, determines the instant at which the rounding stage is to be ended and starts certain actions known in themselves for ending the rounding stage.
  • the data on the cutting sound is real-time data, providing real information on the phase of the rounding operation.
  • the data being processed is not affected by measuring, centring or transfer errors or colour differences.
  • the measured data indicates the cutting width of the cutting tool as continuous data in relation to the block length.
  • the procedure is applicable to all existing lathe types regardless of the peripherals they use, e.g. the centring device. Moreover, the costs of the procedure as compared to other systems are reasonable.
  • Fig. 1 presents a veneer-cutting machine in lateral view.
  • Fig. 2 presents a veneer-cutting machine in top view.
  • Fig. 1 shows an end frame 1 and the tool carriage 2 of a veneer-cutting machine, the tool carriage being provided with a cutting tool 3 and a counter blade 4.
  • the position of the tool carriage is monitored by means of a position sensor 5, e.g. a potentiometer.
  • the veneer sheet 8 cut from the block 7 rotating between the mandrels 6 comes out from the machine through the gap between the cutting tool and the counter blade.
  • Fig. 2 shows a top view of the tool carriage 2, lathe end frames 1 and the block 7 rotating between the mandrels 6.
  • Fig. 2 shows the main motor 9 together with a current measuring unit 10 and a tachometer generator for measuring the speed of rotation of the mandrels.
  • the determination of the end of the block rounding stage is based on the monitoring and processing of the sound produced by the cutting action.
  • the rounding stage is followed by the main cutting opera ⁇ tion in which a veneer sheet for practical utilization is produced.
  • the cutting sound is monitored by means of one or more sen ⁇ sors 12 of a suitable type (microphones), placed e.g. near the tool carriage, on one side of it.
  • the cutting sound signals obtained from the sensors are passed to a micropro ⁇ cessor 13 which processes them, performs calculations and draws conclusions.
  • the rounding stage can be ended e.g. on the basis of the intensity of the cutting sound.
  • the microprocessor 13 gives an end signal to the lathe control centre, whereupon the actions required for the ending, known in themselves, are started.
  • the number of sensors used depends on the length of the block and the accuracy aimed at.
  • the sensors may be placed on different sides of the veneer-cutting machine, depending on the mechanical structures. In practice the sensors are so located that they will easily perceive the sound and that they are mechanically protected. The sensor action may be based on the propagation of sound in air, metal or some other medium suited for the purpose. In Figs. 1 and 2, the sensors 12 are located behind the tool carriage 2.
  • the procedure makes use of the mandrel r.p.m. data in the inference process.
  • Additional auxiliary data may be obtained by monitoring the tool carriage posi ⁇ tion and the main motor load. The monitoring is continuous, and the monitoring cycle is one mandrel revolution (block revolution) . The beginning of the monitoring cycle is varied depending on the incoming sound signal.
  • the system may also provide production report data (e.g. net raw material in m 3 , average block diameters etc. ) .

Abstract

Procedure and apparatus for determining the ending instant of the block rounding stage in a veneer-cutting machine, in which procedure the sound produced by the cutting during the rounding stage is monitored by means of a sensor (12). The signal obtained the sensor is passed to a data processing unit (13) which, based on the cutting sound and making use of the mandrel r.p.m., determines the instant at which the rounding stage is to be ended and starts certain actions known in themselves for ending the rounding stage.

Description

PROCEDURE AND APPARATUS FOR DETERMINING THE ENDING INSTANT OF THE BLOCK ROUNDING STAGE IN A VENEER-CUTTING MACHINE
The present invention relates to a procedure and an appara¬ tus for the determination of the ending instant of the block rounding stage in a veneer-cutting machine.
At present, the ending of the rounding stage is practically based on block diameter data as measured by visual estima¬ tion, by means of a camera or in the centring device. The methods currently used have several drawbacks. Manual ending of the rounding stage on the basis of visual obser¬ vation requires continuous attention. Moreover, modern machines use higher speeds of rotation as well as greater barking depths, making visual estimation more difficult.
When the sheet of wood produced by the rounding operation is observed using a camera (e.g. a line camera) placed after the tool carriage, the line of observation is, due to the mechanical dimensions, separated from the line of the cutting tool by a distance of about 1 - 1.5 m. There is a corresponding lag in the data concerning the phase of the rounding operation. As the operation of line camera control is based on the distinction and comparison of shades of gray, the colour differences in the veneer, caused by the wood material itself and by moisture variations, result in evaluation errors. Another source of evaluation errors is the sensitivity of the line camera to changes in illumina¬ tion (condition and soiling of the lamps, wrong direction of light, external lights and shades, e.g. sunlight).
When the ending instant of the rounding stage is based on block diameter data measured in the centring device, in which case the measurement can be performed using a line camera, matrix camera, laser distance measurement, ultra¬ sonic measurement or mechanical measurement, the mechanical transfer errors occurring in the centring of the block and those occurring during the positioning of the block between the mandrels cause errors and inaccuracies in the determi¬ nation of the ending instant of the block rounding stage. Furthermore, the number of measuring points in the trans¬ verse and longitudinal sections is limited, which means that the ending of the rounding stage is based on defective data.
FI publication 73908 proposes a procedure for the control of the debarking and rounding of a block of wood in a veneer-cutting machine whereby the quality of the surface of the rotating block is observed by directing a beam of light at the block in its longitudinal direction and detecting the radiation reflected from the block by means of a semiconductor camera. However, due to the mechanical structures, the point under observation lags behind the cutting line by about 3/4 of a turn of the block, involving a corrseponding time lag in the data regarding the phase of the rounding operation. The interpretation is based on the greyness difference between the uncut block surface and the surface after the cutting, for which reason colour differ¬ ences in the wood material itself cause errors in the in¬ terpretation of the data. Due to the facts mentioned above, this procedure is sensitive to changes in illumination in the same way as when the wood sheet produced by the block rounding operation is observed by means a line camera as mentioned above.
The object of the present invention is to eliminate the drawbacks presented above. The procedure of the invention for determining the ending instant of the block rounding stage in a veneer-cutting machine is characterized in that the sound produced by the cutting during the rounding stage is monitored by means of one or more sensors and the signal obtained from said sensors is passed to a data processing unit which, based on the cutting sound, determines the instant at which the rounding stage is to be ended and starts certain actions known in themselves for ending the rounding stage.
The preferred embodiments of the invention are presented in the other claims.
As compared to previously known systems, the invention provides the following advantages: The data on the cutting sound is real-time data, providing real information on the phase of the rounding operation. The data being processed is not affected by measuring, centring or transfer errors or colour differences. The measured data indicates the cutting width of the cutting tool as continuous data in relation to the block length. The procedure is applicable to all existing lathe types regardless of the peripherals they use, e.g. the centring device. Moreover, the costs of the procedure as compared to other systems are reasonable.
In the following, the invention is described in detail by the aid of examples by referring to the attached drawing, in which
Fig. 1 presents a veneer-cutting machine in lateral view.
Fig. 2 presents a veneer-cutting machine in top view.
Fig. 1 shows an end frame 1 and the tool carriage 2 of a veneer-cutting machine, the tool carriage being provided with a cutting tool 3 and a counter blade 4. The position of the tool carriage is monitored by means of a position sensor 5, e.g. a potentiometer. The veneer sheet 8 cut from the block 7 rotating between the mandrels 6 comes out from the machine through the gap between the cutting tool and the counter blade. Fig. 2 shows a top view of the tool carriage 2, lathe end frames 1 and the block 7 rotating between the mandrels 6. Moreover, Fig. 2 shows the main motor 9 together with a current measuring unit 10 and a tachometer generator for measuring the speed of rotation of the mandrels.
In the procedure of the invention, the determination of the end of the block rounding stage is based on the monitoring and processing of the sound produced by the cutting action. The rounding stage is followed by the main cutting opera¬ tion in which a veneer sheet for practical utilization is produced.
The cutting sound is monitored by means of one or more sen¬ sors 12 of a suitable type (microphones), placed e.g. near the tool carriage, on one side of it. The cutting sound signals obtained from the sensors are passed to a micropro¬ cessor 13 which processes them, performs calculations and draws conclusions. The rounding stage can be ended e.g. on the basis of the intensity of the cutting sound. To end the rounding stage, the microprocessor 13 gives an end signal to the lathe control centre, whereupon the actions required for the ending, known in themselves, are started.
The number of sensors used depends on the length of the block and the accuracy aimed at. The sensors may be placed on different sides of the veneer-cutting machine, depending on the mechanical structures. In practice the sensors are so located that they will easily perceive the sound and that they are mechanically protected. The sensor action may be based on the propagation of sound in air, metal or some other medium suited for the purpose. In Figs. 1 and 2, the sensors 12 are located behind the tool carriage 2.
In addition to the data obtained from the sensors measuring the cutting sound, the procedure makes use of the mandrel r.p.m. data in the inference process. Additional auxiliary data may be obtained by monitoring the tool carriage posi¬ tion and the main motor load. The monitoring is continuous, and the monitoring cycle is one mandrel revolution (block revolution) . The beginning of the monitoring cycle is varied depending on the incoming sound signal.
Besides the cutting sound, it is possible to monitor and analyze the power or current consumed by the mandrel actua¬ tor, or some other quantity proportional to the load. If necessary, the system may also provide production report data (e.g. net raw material in m3, average block diameters etc. ) .
It is obvious to a person skilled in the art that different embodiments of the invention are not restricted to the examples presented above, but that they may be varied within the scope of the following claims.

Claims

1. Procedure for determining the ending instant of the block rounding stage in a veneer-cutting machine, c h a r a c t e r i z e d in that the sound produced by the cutting during the rounding stage is monitored by means of one or more sensors (12) and the signal obtained from said sensors is passed to a data processing unit (13) which, based on the cutting sound, determines the instant at which the rounding stage is to be ended and starts certain actions known in themselves for ending the rounding stage.
2. Procedure according to claim 1, c h a r a c t e r ¬ i z e d in that it makes use of the r.p.m. of the lathe mandrels in determining the ending instant of the block rounding stage.
3. Procedure according to claim 1 or 2, c h a r a c ¬ t e r i z e d in that the position of the tool carriage and the load of the mandrel actuator (9) of the veneer- cutting machine are used in addition as auxiliary data in determining the ending instant of the block rounding stage.
4. Procedure according to any one of the preceding claims, c h a r a c t e r i z e d in that the action of the sensors is based on the propagation of sound in air, metal or some other medium suited for the purpose.
5. Procedure according to any one of the preceding claims, c h a r a c t e r i z e d in that the monitoring is con¬ tinuous, that the monitoring cycle is one mandrel revolu¬ tion, and that the beginning of the monitoring cycle is varied depending on the incoming sound signal.
6. Procedure according to any one of the preceding claims, c h a r a c t e r i z e d in that the power, current or some other quantity proportional to the load, consumed by the mandrel actuator (9), is monitored and analyzed.
7. Procedure according to any one of the preceding claims, c h a r a c t e r i z e d in that, based on the data it receives, the data processing unit performs calculations for production reports.
8. Apparatus according to claim 1 for determining the ending instant of the block rounding stage in a veneer- cutting machine, c h a r a c t e r i z e d in that, to allow monitoring of the sound produced by the cutting action during the rounding stage, the apparatus is provided with one or more sensors (12), and that the signal obtained from said sensors is passed to a data processing unit (13) which, based on the cutting sound, determines the instant at which the rounding stage is to be ended and starts certain actions known in themselves for ending the rounding stage.
9. Apparatus according to claim 8, c h a r a c t e r ¬ i z e in that it is provided with a unit (11) for meas¬ uring the r.p.m. of the mandrels, the signal obtained from said unit being utilized in the determining of the ending instant of the rounding stage.
10. Apparatus according to claim 8 or 9, c h a r a c ¬ t e r i z e d in that it is provided with a position sen¬ sor (5) for determining the position of the tool carriage, and with a device (10) for measuring the load of the man¬ drel actuator (9), the data obtained from said devices being utilized in the determining of the ending instant of the rounding stage.
11. Apparatus according to claim 8, 9 or 10, c h a r a c ¬ t e r i z e d in that the sensors can be placed on differ¬ ent sides of the cutting tool.
PCT/FI1990/000290 1989-12-08 1990-12-05 Procedure and apparatus for determining the ending instant of the block rounding stage in a veneer-cutting machine WO1991008879A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI895880A FI84148C (en) 1989-12-08 1989-12-08 FOERFARANDE OCH ANORDNING FOER BESTAEMNING AV SLUTTIDPUNKTEN FOER AVRUNDNINGSSKEDET AV ETT BLOCK I EN FANERSVARV.
FI895880 1989-12-08

Publications (1)

Publication Number Publication Date
WO1991008879A1 true WO1991008879A1 (en) 1991-06-27

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5490548A (en) * 1994-01-18 1996-02-13 Durand-Raute Industries Ltd. Method and apparatus for controlling veneer lathe knife clearance angle

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4356850A (en) * 1980-09-29 1982-11-02 Black Clawson, Inc. Veneer lathe scanning system
SE428540B (en) * 1981-04-13 1983-07-11 Wibra Kb SET AND DEVICE FOR MONITORING OF THE TOOL STATUS IN A TOOL MACHINE WITH CYCLE PROCESSING
FI66555B (en) * 1982-02-19 1984-07-31 Eero Kalervo Sampo FOERFARANDE FOER STYRNING AV MANUELL BEARBETNINGSMASKIN
EP0165482A2 (en) * 1984-05-18 1985-12-27 Omron Tateisi Electronics Co. Tool monitoring system
WO1989012528A1 (en) * 1988-06-17 1989-12-28 Regents Of The University Of Minnesota Integral acoustic emission sensor for manufacturing processes and mechanical components

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4356850A (en) * 1980-09-29 1982-11-02 Black Clawson, Inc. Veneer lathe scanning system
SE428540B (en) * 1981-04-13 1983-07-11 Wibra Kb SET AND DEVICE FOR MONITORING OF THE TOOL STATUS IN A TOOL MACHINE WITH CYCLE PROCESSING
FI66555B (en) * 1982-02-19 1984-07-31 Eero Kalervo Sampo FOERFARANDE FOER STYRNING AV MANUELL BEARBETNINGSMASKIN
EP0165482A2 (en) * 1984-05-18 1985-12-27 Omron Tateisi Electronics Co. Tool monitoring system
WO1989012528A1 (en) * 1988-06-17 1989-12-28 Regents Of The University Of Minnesota Integral acoustic emission sensor for manufacturing processes and mechanical components

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5490548A (en) * 1994-01-18 1996-02-13 Durand-Raute Industries Ltd. Method and apparatus for controlling veneer lathe knife clearance angle

Also Published As

Publication number Publication date
FI84148C (en) 1991-10-25
FI895880A (en) 1991-06-09
FI84148B (en) 1991-07-15
FI895880A0 (en) 1989-12-08

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