Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D1/00—Straightening, restoring form or removing local distortions of sheet metal or specific articles made therefrom; Stretching sheet metal combined with rolling
  • B21D1/02—Straightening, restoring form or removing local distortions of sheet metal or specific articles made therefrom; Stretching sheet metal combined with rolling by rollers

Definitions

• the subject of the invention is a method for increasing the precision of the control of the trajectory of the product in a planing machine with nested rollers and the leveling installation allowing the implementation of the process.
• a multi-roller leveler is often used comprising two leveling units each carrying a series of rollers with parallel axes and placed, respectively, above and below the strip, the rollers being offset longitudinally and vertically so as to overlap by determining an undulating path of the strip which is thus subjected to traction-bending effects in alternating directions.
• the operation of such a machine has been the subject of advanced theoretical approaches.
• the entry zone which includes the first three or four rolls, is a significant plasticization zone in which visual flatness defects such as long edges or long center, "quarter of the band" defects and any distribution are eliminated. heterogeneous cross section of longitudinal constraints.
• the exit zone which includes the last three or four rolls, has the function of reducing the gradients of the normal and transverse stresses in the thickness to assure the sheet a virtually zero residual hanger and tile.
• a leveling installation therefore generally comprises a fixed support cage, two leveling units with parallel rollers, placed respectively above and below the strip and the rollers of which are nested so as to determine a path. corrugated strip and means for adjusting and maintaining the spacing of said crews by pressing on the fixed cage for adjusting the nesting of the rollers, each leveling crew comprising a row of parallel active rollers supported on a chassis of support by means of at least one row of support rollers and mounted to rotate, at their ends, each on two bearings defining an axis of rotation perpendicular to the direction of travel, said bearings being carried, respectively, by two side parts integral with the support frame. Most often the lower leveling crew is fixed in position, the upper crew being able to move vertically for adjusting the nesting.
• the input and output actuators can be adjusted differently, which makes it possible to determine a tilting generally necessary for the realization of the two leveling effects established by the theory and exposed above.
• the actuators can also be adjusted differently from one side relative to the other by introducing a lateral tilting so as to correctly distribute the leveling effect over the width of the product to be leveled.
• the forces developed for leveling are very high, in particular when this operation is carried out on a heavy sheet after hot rolling and accelerated cooling, or else on a cold sheet.
• the deformation under stress of the different parts of the machine (also called yielding) distorts the precision of the control of the position of the leveling rollers, therefore the exact value of the curvature obtained on each roller.
• the overall yielding of the machine modifies the targeted plasticization rate, therefore there is a risk in the entry area of not completely eliminating the flatness defects, it also modifies the rate of decrease in plasticization, therefore the transition with the exit area and may not eliminate residual stresses as expected.
• the leveling module of a leveler even of robust design is of the order of 100 t / mm per column, or the leveling effort for a sheet of 3 meters in width can be from 1000 tonnes to 2500 tonnes which leads to a yield (without compensation) of 2.5 mm to 5 mm.
• the precision requested is not very high in the entry area of the machine and could accommodate a simple yield compensation, there would however be the risk of having refusal of engagement of the product in a machine set too tight as a precaution.
• the invention therefore aims to increase the precision of the control of these machines and a machine equipped with a new control device and making it possible to solve all of these problems without causing any complication or excessive cost of the devices used.
• the compensation for yielding is replaced by a real-time model for presetting the position of the leveling rollers associated with a direct measurement of the spacing of the active rollers.
• a theoretical presetting model is installed which gives at least one reference value for the presetting of nestings and at least one value of the spacing of the leveling rollers is directly measured, which is compared to the reference values and the leveling rollers are adjusted to maintain the measured values equal to the reference values so as to maintain the trajectory of the product to be leveled inside the machine in accordance with l ripple provided by the model to achieve leveling.
• two measurements are made of the value of the spacing of the leveling rollers, a first at the inlet of the machine and, respectively, a second at the outlet of the machine, which are compared each of these measurements with the reference value given by the model for the same rollers, respectively at the inlet and at the outlet of the machine and one acts on the members for adjusting the position of the leveling rollers at the inlet and respectively at the outlet of the machine for keep the measured value equal to the value of the reference so as to achieve the decrease in the rate of plasticization predicted by the model to achieve leveling.
• a measurement is made of the value of the spacing of each of the leveling rollers which is compared to each reference value given by the model and action is taken on the individual adjustment members of the position of each of the leveling rollers to maintain the measured value equal to the value of the reference so as to achieve the undulation and the decrease in the rate of plasticization predicted by the model for achieving leveling.
• position control requires ensuring that at uniform positions of the leveling rollers, given by position sensors, identical leveling forces correspond.
• a kind of calibration must first be carried out so as not to depend on the mounting mode of the sensors in the machine and the position of their 'zero' reference.
• a calibration is carried out, called equalization of the active rollers on a flat machined sheet of known thickness by differentially modifying the position of the active rollers by lateral tilting from one side to the other. so as to obtain equal leveling forces on both sides of the machine measured by the measuring devices.
• the leveling is carried out on a moving sheet by differentially modifying the position of the active rollers by a lateral tilting from one side to the other and which is carried out. equalization of the averages of the forces recorded by the measuring devices on each side during said scrolling.
• a device allowing direct measurement of the value of the spacing of the leveling rollers at at least one point so as to know the exact value of the nesting by direct measurement.
• the installation also includes, and still according to the invention, an electronic device making it possible to control the measured spacing of the leveling rollers to the theoretical value given by the model by acting on the devices for adjusting the nesting.
• the nesting adjustment devices are hydraulically operated.
• the installation is provided with a device allowing the direct measurement of the value of the spacing of the leveling rollers at at least two points, one located in the machine entry area and the other located in the exit area.
• the electronic device makes it possible to control the measured spacing of the leveling rollers situated in the entry zone of the machine and respectively in the exit zone at the theoretical value given by the model for the spacing of the situated rollers. in the entry zone of the machine and respectively in the exit zone by acting independently on the devices for adjusting the nesting of the rollers of each of the entry and exit zones respectively.
• These devices are preferably hydraulically operated.
• independent devices allow the direct measurement of the value of the spacing of each pair of active leveling rollers separately.
• the leveling installation with parallel rollers comprises a means for individually adjusting the position of each leveling roller and an electronic device making it possible to control the measured spacing of each of the leveling rollers to the theoretical value given by the model for the 'spacing of each of these rollers by acting independently on their nesting adjustment device.
• the leveling installation advantageously comprises a device for adjusting the nesting of each roller with hydraulic control.
• the electronic devices making it possible to control the measured spacing of the leveling rollers to the theoretical value given by the model include a differential adjustment device making it possible to adjust a lateral tilting of the rollers d 'one side with respect to the other and with respect to the set value, to allow the device to be tared by a leveling process on a flat machined sheet of known thickness.
• a differential adjustment device making it possible to adjust a lateral tilting of the rollers d 'one side with respect to the other and with respect to the set value, to allow the device to be tared by a leveling process on a flat machined sheet of known thickness.
• Figure 1 there is shown the mechanical part of the assembly of an installation according to the invention comprising, in general, a support cage 1, an upper leveling equipment 2 and a lower leveling equipment 2 ' multi-roll.
• the fixed support cage 1 comprises a lower bed base 11, two lateral uprights placed on either side of a longitudinal median plane P of travel of the strip 10 to be leveled and an upper bed base 14.
• Each lateral upright consists of a pair of spaced apart columns 12, 12 ', 13 (in the figures, only three columns are visible).
• These columns and the upper base generally forming a rigid slab, are equipped with various devices known in themselves and widely described in the prior art which can cooperate to allow vertical sliding of the base 14 along the four columns 12, 12 ' , 13.
• each cylinder consists of a body 31 fixed to the base 14 and a piston 32 secured to the column.
• the lower base 11 being fixed, the upper base 14 can therefore move, under the action of the four jacks 3, the pistons of the jacks remaining at the same level.
• the jacks 3 are positioned to adjust the desirable nesting of the rollers relative to the thickness of the sheet to be planed so as to achieve the corrugation determined by the theoretical model. They exert the leveling force during the passage of the product.
• Each leveling device 2, 2 ′ comprises a row of active rollers 4, 4 ′ associated with a row of support rollers 5, 5 ′, the whole being carried by a chassis.
• Each active roller 4, 4 ' is rotatably mounted on two bearings defining its axis of rotation, it is supported on a support roller 5, 5' rotatably mounted on two end bearings.
• the end bearings 51 of the upper leveling equipment 2 are supported on the upper base by means of a support member 52.
• this support member may include an adjustment device which makes it possible to individually modify for each active roller its nesting, the overall value of which is given by the positioning of the bed base of the upper leveling crew 2 using the jacks 3
• These adjustment devices can be mechanical, such as for example a wedge system, or can be constituted by a row of hydraulic cylinders as in patent FR 2 732 913. In this case it will be possible, in addition to the individual adjustment of the nesting, to obtain by the differential adjustment of the cylinders of the same row, a cambering effect of the active cylinders so as to better distribute the leveling effect over the width of the band to hover.
• the at least one sensor 6 making it possible to continuously measure the absolute value of the spacing of the active cylinders 4, 4 ′, independently of the deformation of the columns and of the whole of the machine, installed for example between the upper 2 and lower 2 ′ leveling crews.
• two sensors 6 and 6 ′ are shown, one at the inlet of the machine and the other in the outlet area so as to be able to more precisely control the variation in the plasticization rate as well as this has been described in the general description of the problem.
• the sensors can be of any type, and for example of the LVDT type
• FIG. 2 represents all of the associated mechanical and electrical devices to constitute a leveling machine according to the invention.
• the mechanical part of the machine is shown schematically in a cross section.
• the sensor (s) 6 are mounted on one side of the machine, the hydraulic cylinders 3 are fitted with sensors 35 allowing the measurement of the overall leveling forces.
• These jacks are supplied by a conventional pump and accumulator device 8 via two servo valves or two groups of servo valves 71, 72 supplying each side of the machine.
• These servo valves are controlled by at least one electronic control circuit, which is broken down into two electronic circuits, each controlling a servo valve or a group of servo valves.
• a closed loop is produced of the measured value of the spacing of the active rollers 4, 4 ′ on the reference position introduced into the electronic circuit for controlling the servo valves.
• These electronic circuits (91, 92) which can be analog or else digital computers comprise summing circuits and conventional circuits of proportional, integral and differential control called 'PID'.
• the reference values corresponding to the desirable nesting of the active rollers are developed by a leveling model 110 implemented in a process computer 100, they are introduced into the electronic circuits for controlling the servo valves. (91, 92) via a summing / differentiating stage 93, 94 which makes it possible to introduce a command for tilting the machine from one side relative to the other.
• the force sensors 35 are connected to the computer 100 in which a tilting instruction will be developed, this is added to the nesting reference in circuit 94 to be sent as a control signal for one side of the machine, it is differentiated from the same signal in circuit 93 to be sent as a control signal to the other side of the machine.
• the computer 100 is connected to operator interface devices such as screen and control console 101, printer and recorder 102 so as to be able to control the operation of the machine and manage its production.
• operator interface devices such as screen and control console 101, printer and recorder 102
• printer and recorder 102 so as to be able to control the operation of the machine and manage its production.
• the same type of circuit will be used.
• the jacks 3 located on the inlet side and those on the outlet side are supplied separately by servo valves and all the electronic circuits 9 described above are doubled for independent control of each zone; of course it is the same computer 100 which prepares all the references and distributes them over all of the electronic control circuits.
• the support members 52 of each upper support roller 5 are adjustment members and make it possible to control each upper active roller 4 individually, a separate and individual embodiment is carried out. measurement of the spacing between each of the upper and lower active rollers and a control device similar to that described is installed for each pair of active cylinders.
• a control device (9) of the type described above is produced for each pair of active cylinders.
• the computer 100 is used to draw up all the instructions and to distribute them on all the electronic control circuits 9. In this case the main jacks 3 are no longer used for these functions and are used to regulate the general opening and closing of the machine depending on the thickness of the sheet to hover.
• the exact undulation desired is obtained by adjusting the individual nesting of each roller 4 by means of the adjustment devices 52.
• the spacing of the active rollers 4,4 ' is measured, compared to the reference setpoint developed using the leveling model and the necessary correction is introduced so as to cancel the error resulting from the deformations of the machine under the leveling force by acting on the means for adjusting the nesting .
• the absolute measurement of the deviation of the active cylinders is obtained using the sensors 6, this value is compared with the reference in circuits 91 and 92 and the resulting signal is used to control the servo valve 7 which makes it possible to move the jacks 3 controlling the movement of the leveling equipment.
• the reference is obtained by combining the dimension developed by the leveling model 110 and the tilting instruction.
• the two quantities are added in circuit 94 to be applied on one side of the machine, they are subtracted in circuit 93 to be applied on the other side of the machine, so as to achieve a balanced tilting and distributed by side by compared to the value of the theoretical nesting necessary to obtain the undulation defined by the model.
• an absolute measurement is made of the distance between the active cylinders 4, 4 ′ in the entry zone of the machine, and another in the exit zone.
• the nesting references developed by the leveling model 110 are added to a tilting instruction to control one side of the machine, and subtracted to control the other side; so as to carry out a balanced tilting and distributed by side compared to the value of the theoretical nesting necessary to obtain the undulation defined by the model.
• the means for individual adjustment of the nesting of the active cylinders 52 are constituted by a row of hydraulic cylinders, it will be advantageous to superimpose the adjustment of the nesting of the row of cylinders, an individual differential adjustment of each cylinder making it possible to achieve a cambering effect on the active roller so as to obtain a better distribution of the leveling effect over the width of the product to be leveled.
• the tilting instructions are established during a leveling phase on a flat machined product of known thickness serving as gauge. This product or size is introduced into the machine and a slight nesting is ordered to cause the active rollers to be clamped on the product or size.
• the leveling forces induced on each side of the machine are then measured, for example using the force sensors 35 installed on the jacks 3 when one is in the presence of a machine of the type described in FIG. 2.
• a tilting is then controlled so as to balance the forces on one side and the other of the machine, if they are not at the start, by tightening the side of the machine which generates the smallest effort, and we note the value of the tilting which makes it possible to obtain equal efforts on each side.
• This entire sequence is managed by the computer 100 which makes it possible to store the values of the forces and those of the tiltings produced.
• This leveling process is, according to the invention, used with all of the embodiments of the process described, that is to say that it can be implemented by the two groups of jacks 3 (one group for each side of the machine) in the case where there is only one sensor for measuring the spacing of the active rollers, but it can also be implemented by performing a simultaneous but independent equalization of the cylinders 3 of the area entry and those of the exit zone in the case where there is a measurement in each of these zones.
• each upper active roller 4 is a device consisting of a row of hydraulic cylinders, as well as an absolute gauge measurement for each pair of active rollers.
• the procedure is the same and consists in ordering a tilting of each pair of active rollers until the efforts applied at their end are equal, and using this tilting value as a setpoint for all subsequent operation. of the machine.
• the leveling is carried out on a moving strip.
• Such a model calculates the behavior of the product to be leveled and the leveler from the geometric and mechanical characteristics of the sheet to be leveled and the leveler (for example: thickness and width of the sheet, elastic limit at the leveling temperature of the metal of which it is made, possibly amplitude and nature of the defects; number of planer rollers, distance between rollers of the same equipment, diameter of the rollers). It allows, by methods that a person skilled in the art will know how to determine, an optimal adjustment of the leveler, and thus to determine tightening instructions in particular at the entry and exit of the leveler.
• the adjustment instructions can be supplemented by balancing instructions between the two sides of the leveler, determined by the leveling operation.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Straightening Metal Sheet-Like Bodies (AREA)
• Press Drives And Press Lines (AREA)
• Rolls And Other Rotary Bodies (AREA)
• Machine Tool Units (AREA)
• Road Paving Machines (AREA)

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• 2003
  • 2003-10-13 FR FR0312012A patent/FR2860738B1/fr not_active Expired - Fee Related
• 2004
  • 2004-09-28 US US10/574,701 patent/US7475581B2/en not_active Expired - Lifetime
  • 2004-09-28 DE DE602004010293T patent/DE602004010293T2/de not_active Expired - Lifetime
  • 2004-09-28 WO PCT/FR2004/002457 patent/WO2005046899A1/fr active IP Right Grant
  • 2004-09-28 JP JP2006530403A patent/JP2007508148A/ja active Pending
  • 2004-09-28 EP EP04787476A patent/EP1673181B1/de not_active Expired - Lifetime
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  • 2004-09-28 BR BRPI0414749A patent/BRPI0414749B1/pt not_active IP Right Cessation
  • 2004-09-28 CN CNB2004800278702A patent/CN100364681C/zh not_active Expired - Fee Related

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