CN102179621A - Roller surface roughing laser processing system and method for irregular image roughing micro pit - Google Patents

Abstract

The invention discloses a laser processing system and method for roughening the surface of rollers with irregular image textured micro-pits, including a machine tool that drives the rotation of the roller workpiece, a laser processing device that moves along the axial direction of the roller workpiece, and irregular Image switching device. The random image switching device makes the laser output signal of the laser processing device output as a random image, and the method is to switch the laser output signal on the surface of the controllable rectangular distribution roller workpiece according to the 1, 0 information of the random black and white image. The invention has the following advantages: realizing the laser texturing of the surface of rollers with two-dimensional high-repetition-frequency irregular texturized micro-pit; the distribution of the random texturized micro-pit can be simulated and displayed through image files. At the same time, it overcomes the shortcomings of the roller surface texturing laser processing system and method that can only achieve one-dimensional high repetition frequency laser texturing in the circumferential direction and the roller surface roughening of random deflection texturing micropits. The shortcoming that the laser processing system and method can only achieve low repetition frequency laser texturing.

Description

Laser processing system and method for surface texturing of rollers with irregular image textured micropits

technical field

The invention relates to a laser processing device and a processing method for roughening the surface of rollers, in particular to a laser processing device and a processing method for roughening the surface of rollers capable of processing irregular textured pits.

Background technique

YAG laser texturing equipment is a cold roll laser processing equipment researched and developed by the Institute of Mechanics, Chinese Academy of Sciences in the 1990s, such as: Chinese patent number: ZL 92113223.9, name: "High repetition frequency modulation multi-pulse YAG laser engraving system and processing method "; Chinese patent number: ZL 94220848.X, name: "Laser processing equipment for surface roughening of rolls". Figure 1 is a schematic diagram of the overall structure of the device. The equipment uses high-power laser pulses with high repetition frequency to act on the surface of the roll, and produces countless strengthened micro-pits (texturized points) with a certain shape on the roll surface. The device is similar to a normal lathe. The working process is that the spindle motor of the machine tool drives the roll to rotate, and at the same time drives the laser head on the moving frame to translate. The acousto-optic power supply controls the laser to emit a fixed frequency laser pulse, so that a helix composed of texturized pits with equal pitch is made on the roll. Wire. Figure 4 is the topography of textured micropits on the surface of cold rolls made by this method (left and right represent the axial direction, up and down represent the circumferential direction, the same below), which is called the topography of textured micropits with uncontrollable distribution, corresponding Figure 1 is a schematic diagram of the overall structure of the laser texturing equipment with uncontrollable distribution, and the micropits are distributed in a one-dimensional controllable wave shape.

In order to increase the isotropic uniformity of the micropit distribution and adjust the isotropic elongation of the cold-rolled sheet, the Institute of Mechanics of the Chinese Academy of Sciences has developed a two-dimensional controllable distribution technology for YAG laser texturing. Such as: Chinese Patent No.: ZL00128273.5, title: "Roll Surface Texturing Laser Processing System with Controllable Distribution of Texturing Points". Figure 2 is a schematic diagram of the overall structure of the device. Fig. 5 and Fig. 6 are topography diagrams of textured pits on the surface of cold rolls punched by this method. This equipment installs a high-precision and high-resolution incremental encoder in the coaxial direction of the main shaft, and uses an industrial computer Controlling the acousto-optic power supply and the moving frame realizes the controllable distribution of the textured pits on the roller surface. Although the two-dimensional controllable distribution technology can achieve a more uniform micropit distribution than the one-dimensional controllable distribution technology, its distribution is also more regular.

The distribution of the textured pits of the above two types of textured boards has certain rules, which makes the appearance of the textured boards in all directions inconsistent and directional. Due to the regular distribution of micro pits, the laser textured board has the following disadvantages: (1) The laser textured board is prone to streaks. The regular distribution of micro-pits leads to visual differences in the distribution of micro-pits in different directions; (2) Laser textured boards are prone to light interference fringes. Light interference between two periodic regular patterns tends to produce the phenomenon of "Moiré fringes".

There are quite a lot of textured boards in the project that require the irregular distribution of micro pits. In order to improve the appearance quality of the laser textured board, the Institute of Mechanics, Chinese Academy of Sciences developed a controllable random distribution technology based on the two-dimensional controllable distribution technology. Such as: Chinese patent number: ZL 200510117158.8, title: "Laser processing system and method for surface texturing of rollers with irregular texturing points on the circumference". The laser processing system includes a machine tool that drives the roll workpiece to rotate, a laser processing device that moves axially along the roll workpiece, and a pseudo-random delay device. The method is that the pseudo-random time-delay device causes the laser output signal emitted to the surface of the roll-like workpiece to generate a random time-delay within a specified time range. Fig. 9 is a schematic diagram of the distribution of rectangular irregular time-delayed textured micro-pits, and Fig. 10 is a schematic diagram of the distribution of diamond-shaped irregular time-delayed texturized micro-pits. Its advantages are fast response speed and high texture frequency (up to tens of thousands of times). Its disadvantage is that it can only achieve one-dimensional random distribution in the circumferential direction.

Another example: Chinese patent number: ZL 200510116750.6, title: "Laser processing system and method for surface texturing of rollers with random deflection of texturing points". The laser processing system includes a machine tool that drives a roll workpiece to rotate, a laser processing device that moves axially along the roll workpiece, and a pseudo-random deflection device. The method is that the pseudo-random deflection device makes the laser output signal emitted to the surface of the roll workpiece generate random deflection within a specified space range. Fig. 10 is a schematic diagram of distribution of rectangular random deflection textured micropits, and Fig. 11 is a schematic diagram of distribution of diamond-shaped random deflection texturized micropits. Its advantage is that two-dimensional random distribution in the circumferential and axial directions can be realized. Its disadvantages are slow response speed and low texture frequency (up to several thousand times).

Contents of the invention

In order to solve the problems existing in the prior art, the present invention provides a laser processing system and method for surface texturing of rollers with irregular image textured micropits, which overcomes the surface roughening of rollers with irregularly textured micropits The laser processing system and method can only achieve the disadvantage of one-dimensional high repetition frequency laser texturing in the circumferential direction, and overcome the surface texturing of rollers with irregular deflection texturing micropit. The laser processing system and method can only realize low repetition frequency laser texturing. It is a more ideal laser processing equipment and method capable of processing two-dimensional random textured pits on the surface of rollers.

The roller surface roughening laser processing system for irregular image texture micropit of the present invention includes a machine tool that drives the roller workpiece to rotate, and a laser processing device that moves along the axial direction of the roller workpiece, and is characterized in that: it also includes There is a random image switching device for controlling the laser output signal of the laser processing device; the random image switching device receives and processes image files with random point distribution, and replaces them with corresponding control signals, and then drives the laser processing The device processes the surface of the roller workpiece, thereby forming two-dimensional irregularly distributed textured pits on the surface of the roller workpiece corresponding to images distributed in random dots.

Further, the random image switch device includes a single-board computer with PC functions and an image switch interface, and the image switch interface further includes an input interface, an image switch, and an output interface connected in sequence; wherein, the single-board computer passes through The PC/104 bus is connected with the image switch, and the single-board computer processes the image file of the input random point distribution, the position of the point forms a control signal 1, and the position without a point forms a control signal 0, and the The formed control signal is transmitted to the image switch; the input interface is used for level conversion of the input signal, the image switch is turned on or off according to the 1, 0 control signal, and the output interface is used according to the state of the image switch Driving the laser processing device.

Further, the roller-type surface texturization laser processing system for irregular image texturization micropit of the present invention may also have the following characteristics: the laser processing device includes a laser power supply, a laser, an industrial computer, a controllable distribution interface card, The acousto-optic power supply, the acousto-optic box, the input signal interface of the random image switch device is connected to the or control distribution interface card, the output signal interface of the random image switch device is connected to the signal input terminal connected to the acousto-optic power supply, RS232C The interface is connected with the industrial computer.

The output and input signals of the random image switch device are both pulse signals, and the output signal is triggered by the rising edge of the input signal and output after the image switch.

The laser processing method for roughening the surface of rollers with irregular image textured micropits of the present invention is to make the roller workpiece rotate along its own axis, make the laser beam move at a uniform speed along the axial direction of the roller workpiece, and pass through the random image switch The device receives and processes image files with irregular point distribution, and replaces them with corresponding control signals, and then drives the laser processing device to process the surface of the roller workpiece, thereby forming irregular point distribution on the surface of the roller workpiece. The image corresponds to the two-dimensional random distribution of textured micropits.

The present invention adds an irregular image switching device to the existing roller surface texturing laser processing equipment - controllable distribution laser texturing equipment, so that the textured micro pits are distributed randomly in two dimensions.

Compared with prior art equipment and processing methods, the present invention has the following advantages:

1. Realize the laser texturing of the surface of rollers with two-dimensional high repetition frequency irregular texturing pits;

2. The distribution of irregular textured dimension pits can be simulated and displayed through image files.

Description of drawings

Figure 1 is a schematic diagram of the overall structure of the uncontrollable distributed YAG laser texturing equipment;

Figure 2 is a schematic diagram of the overall structure of the controllable distribution YAG laser texturing equipment;

Fig. 3 is a schematic diagram of the connection between the incremental encoder and the main shaft described in the embodiment of the present invention;

Figure 4 is the topography of uncontrollable distribution of textured micropit;

Fig. 5 is a topography diagram of textured micropit with rectangular distribution;

Fig. 6 is a topography diagram of diamond-shaped distribution textured micropit;

Fig. 7 is a schematic structural diagram of an irregular image switching device;

Fig. 8 is a flow chart of the program of the random image switching device;

Fig. 9 is a schematic diagram of irregular time-delay textured micropit with diamond distribution;

Fig. 10 is a schematic diagram of diamond-shaped distributed irregularly deflected textured micropit;

Fig. 11 is a schematic diagram of random image textured micropits according to an embodiment of the present invention;

Fig. 12 is a schematic diagram of an algorithm for generating random image files according to an embodiment of the present invention;

Fig. 13 is a block diagram of the laser texturing equipment control system of the present invention;

Fig. 14 is a schematic diagram of the optical path on the upper layer of the mobile frame of the machine tool.

Explanation of the drawings: 1-roller to be processed; 2-optical path shield; 3-air path; 4-laser; 5-machine head; 6-monitor; 7, 20-machine guide rail; 9-laser head; 10-light rod; 11-end of machine bed; 12-two-dimensional mobile frame; 13-sound and light power supply; 14-top seat; 15-longitudinal servo motor; 16-ball screw; 18-control cabinet; 19-industrial computer; 21-incremental encoder; 22-elastic coupling; 23-incremental encoder mounting sleeve; 24-machine tool spindle gearbox; 25-machine tool spindle sleeve; 26-machine tool Main shaft; 27-transverse movement adjustment mechanism; 28-focusing lens; 29-beam expander; 30-mirror; 31-optical path switching device; ; 35-A sound and light box; 36, 37-light protective cover.

Detailed ways

The present invention is described in detail below in conjunction with accompanying drawing:

In order to realize the irregular distribution of laser texturing, the scheme proposed in this embodiment is shown in Fig. 2, Fig. 3, Fig. 7, Fig. 12 and Fig. 13 . The roughening processing of the random roughened micropit on the surface of the roller is realized by the random image switch device. That is to say, an irregular image switching device is added to the controllable distribution laser texturing equipment, so that the textured micropits are distributed randomly in two dimensions.

The overall structural schematic diagram of this embodiment is the same as that shown in Figure 2. The equipment consists of three parts: the head of the machine tool, the bed of the machine tool and the control cabinet. The head of the machine tool 5 includes a frequency converter (model VFD-220B43A), a machine tool spindle drive variable frequency motor (model YP-50-22-4B3), a machine tool spindle gearbox 24 (a reduction ratio of 3.75), a machine tool spindle 26 and a machine tool spindle Cover 25, high-precision and high-resolution incremental encoder 21 (the model is ALFA-2500BM-G10L, 100,000 lines per revolution) and incremental encoder installation cover 23, chuck and lubricating system, etc. The frequency converter is installed at the bottom of the head of the machine tool 5, and it is electrically connected with the main shaft drive frequency conversion motor; One side fixes the main shaft sleeve 25, the main shaft sleeve 25 (with the shaft head) is threadedly connected with the machine tool main shaft 26, and the main shaft sleeve 25 is connected with the incremental encoder 21 shaft through the elastic sheet coupling 22 (to ensure that the incremental encoder is mounted on the machine tool Main shaft 26 coaxial direction); Incremental encoder 21 end faces are fixed incremental encoder mounting sleeve 23 and link to each other with machine tool spindle gearbox 24 through mounting sleeve. The lubrication system includes lubrication pumps, oil tanks and oil pipes, etc. The lubrication system is used to lubricate the machine tool spindle gearbox. The D/A interface card in the industrial computer 19 sends a signal to the frequency converter, and the frequency converter drives the spindle motor of the machine tool to rotate together with the roller, and the speed is steplessly adjustable. When the main shaft motor rotates together with the roller, the incremental encoder outputs a pulse signal reflecting the rotational position of the roller, and the pulse signal is sent to the controllable distribution interface card in the industrial computer 19, after being processed by the computer, it controls the irregular image switch device and the longitudinal servo driver. The random image switch device controls the acousto-optic power supply 13 . The longitudinal servo driver drives the longitudinal servo motor 15, and drives the machine tool moving frame 12 to move left and right on the machine tool guide rail 20 through the ball screw 16.

The bed includes a machine tool guide rail 20, a machine tool two-dimensional mobile frame 12, a longitudinal servo motor 15, a ball screw 16, a top seat 14, and the like. Described servomotor 15 (used model is MDMA152A1A) is directly connected with ball screw 16, and servomotor 15 drives ball screw 16 to drive movable frame 12 to slide and cooperate with guide rail through screw nut, and moves left and right on guide rail 20, and speed Steplessly adjustable. The mobile frame 12 is divided into upper and lower parts. The lower part is equipped with one or two acousto-optic power sources 13 and laser power source 17. The upper part is equipped with A-channel lasers, A-channel acousto-optic boxes, B-channel lasers and B-channel acousto-optic boxes. , Optical path switching device, laser beam expander, beam reflector, lateral movement adjustment mechanism, laser head and optical path protective cover.

Fig. 14 is a schematic diagram of the optical path on the upper layer of the mobile frame of the machine tool. The optical path switching device is composed of a low-speed synchronous motor, a lead screw, a guide rail, a slide seat and a full reflection mirror on the slide seat. The low-speed synchronous motor is directly connected with the lead screw, and the lead screw, guide rail and slide seat form a transmission pair. The function of the optical path switching device is to turn the optical path so that the laser beam emitted by the B-path laser enters the laser beam expander. The laser beam expander includes a diverging mirror and a focusing mirror. It is composed of multiple mirrors and has the function of collimating the laser beam. The total reflection mirror is used to bend the transmission direction of the beam. The lateral movement adjustment mechanism is composed of a lateral servo motor (model MSMA042A1A), a ball screw, a guide rail and a sliding seat. The driver and the position PID regulator constitute the distance automatic tracker, and the tracking distance can be set by the D/A interface card in the industrial computer. The focus lens includes a laser focus lens, a protective lens, and an auxiliary gas injection device. The protective lens is installed in front of the focus lens, and its function is to block the channel between the laser focus lens and the point of action of the laser on the roller surface, so that the laser focus lens is free from pollution. . The auxiliary gas injection device is a double gas path structure. In the process of laser texturing, the metal on the surface of the roll is melted and partially gasified under the action of the laser. In order to make the roll and the rolled metal plate reach a certain roughness, it is necessary to make the surface of the roll not only form pits but also form pits. There should also be a boss around the metal, which is formed by the solidification of the molten metal flowing out of the pit. For this reason, one of the gas paths of the auxiliary gas injection device is designed to form an included angle with the optical axis, the range of change is 30°-75°, and the molten metal at the laser action point is blown to one side. The other gas path of the auxiliary gas injection device is coaxial with the converging laser beam. The air flow is introduced before the protective mirror. The air flow ejected from the nozzle of the gas path is used to block the dust and splashes caused by the laser and metal to protect the mirror from contamination. The laser focusing mirror is a group of combined lenses, which not only focus the laser beam on the surface of the workpiece, but also eliminate optical aberration and reduce the dispersion of the laser beam. The A-channel laser is equipped with an A-channel acousto-optic box, and the B-channel laser is equipped with a B-channel acousto-optic box. The optical path protective sleeve is used to prevent dust in the optical path, and it has two structures. The optical path protective sleeve 36 is composed of two or more fixed-length metal sleeves, its function is to connect the optical path between the beam reflector and the focusing lens, and its characteristic is that the length of the protective sleeve can be adjusted with the lateral movement of the mechanism changes with forward and backward movement. Optical path protective sleeve 37 is a finely adjustable corrugated metal tube or plastic tube, which is used for the optical path connection between the A-path laser, the B-path laser, the optical path switching device, the laser beam expander and the reflector; In order to supply power to the laser and ensure a constant supply current, the acousto-optic power supply controls the light pulses emitted by the laser by sending ultrasonic signals to the acousto-optic box.

The control cabinet 18 includes an industrial computer 19 (the model is AWS-8259), a longitudinal servo driver (the model is MSDA153A1A), a horizontal servo driver (the model is MSDA043A1A), a cooling system and other relay control circuits, etc. Fig. 12 is a block diagram of the control system of the laser texturing equipment of the present invention. A controllable distribution interface card and two electrically isolated dual-way D/A interface cards (model PCL-728) are installed on the AT bus in the industrial computer. When the main shaft motor rotates together with the roller, the incremental encoder outputs a pulse signal reflecting the rotational position of the roller, and the pulse signal is sent to the controllable distribution interface card in the industrial computer 19, after being processed by the computer, it controls the irregular image switch device and the longitudinal servo driver. The random image switch device controls the acousto-optic power supply 13 . The longitudinal servo driver drives the longitudinal servo motor 15, and drives the machine tool moving frame 12 to move left and right on the machine tool guide rail 20 through the ball screw 16. A D/A interface card in the industrial computer 19 sends two-way signals to the laser power supply 17 to control the A-way laser 34 and the B-way laser 32 . Another D/A interface card in the industrial computer 19 sends a signal to the frequency converter, and the frequency converter drives the spindle motor of the machine tool to rotate together with the roller, and the speed is steplessly adjustable; the D/A interface card sends another signal to the position PID regulator . The automatic tracker for the distance between the laser and the roller surface is composed of an industrial computer 19, a position PID regulator, an inductive non-contact displacement sensor (the model used is ST-1), a horizontal servo drive, a servo motor, and a ball screw transmission pair. It is a closed-loop control system. The industrial computer 19 sets the size of the distance, the displacement sensor detects the actual distance, and the servo drive works in the speed control mode. The industrial computer 19 is connected with the random image switching device through one RS232C, and is used for transmitting irregular image files. The cooling system consists of a water tank, a water pump and a temperature controller for cooling the laser.

The schematic diagram of the random image switching device is shown in Fig. 7 . The device contains a single-board computer and a PC/104 image switch interface card. Single-board computer (using PC/104 module) provides all the functions of a complete PC. PC/104 image switch interface card is composed of input interface, image switch and output interface. The single-board computer processes the input image file with irregular dot distribution, the position of the dot forms a control signal 1, and the position without a dot forms a control signal 0, and transmits the formed control signal to the image switch. The input interface is used for level conversion of the input signal, and the image switch of the control signal is turned on or off according to 1 and 0. The output interface drives the laser processing device according to the state of the image switch. The PC/104 image switch interface card is installed on the PC/104 expansion bus of the single board computer.

The external signal of the irregular image switch device has three routes: input, output and RS232C interface. Both input and output signals are pulse signals. The output signal is triggered by the rising edge of the input signal and output after the image switch.

Fig. 8 is a flow chart of the program of the random image switching device. The program first downloads the random image file from the industrial computer to the memory through the RS232C interface, then waits for the input signal, and controls the pulse output of the output signal according to the 1, 0 information of the corresponding pixel of the random black and white image file, and so on. When the corresponding pixel is 1, the output signal has a pulse output, and the laser emits a laser beam to generate micro pits at the corresponding position on the roller surface, otherwise the output signal has no pulse output, and no micro pits are generated at the corresponding position on the roller surface. In this way, a two-dimensional random dimple distribution corresponding to the random image can be processed on the roller surface.

The random image switching device is inserted behind the signal of the existing roller surface roughening laser processing equipment to control the laser output. Refer to Figure 13.

There are many ways to generate two-dimensional random image files, which can be pre-generated image files with two-dimensional random point distribution. is a schematic diagram of the random image file generation algorithm described in the embodiment of the present invention. The algorithm is: the data file is generated in order from left to right and from top to bottom. In one of the four directions of the schematic diagram 12, the continuous pixel is 0, and the pixel is 1; otherwise, the pixel is 1 or 0 with a probability of 0.5.

The present invention does not limit the laser wavelength. The random image switching device can be used for various types of lasers used for laser texturing that use electric pulses to control light pulses, such as acousto-optic control continuous YAG lasers, radio frequency carbon dioxide lasers.

Claims (5)

1. A roller type surface roughening laser processing system of irregular image texture micropit, it comprises the machine tool equipment that drives the roller type workpiece to rotate, the laser processing device that moves along the axial direction of the roll type workpiece, it is characterized in that: It includes a random image switching device that controls the laser output signal of the laser processing device; the random image switching device receives and processes image files with random point distribution, and replaces them with corresponding control signals, and then drives the laser The processing device processes the surface of the roll-like workpiece, thereby forming two-dimensional random-distributed textured pits on the surface of the roll-like workpiece corresponding to images distributed in random dots. 2. the roller class surface roughening laser processing system of irregular image roughening dimples as claimed in claim 1, is characterized in that, described random image switch device comprises single-board computer and image switch interface with PC function, The image switch interface further includes an input interface, an image switch, and an output interface connected in sequence; wherein, The single-board computer is connected with the image switch through the PC/104 bus, and the single-board computer processes the input image files with irregular point distribution, and the positions with dots form control signal 1, and the positions without dots form control signal 1. The control signal is 0, and the formed control signal is transmitted to the image switch; the input interface is used for level conversion of the input signal, and the image switch is turned on or off according to the 1, 0 control signal, and the output interface is based on The state of the image switch drives the laser processing device. 3. The roller-type surface texturization laser processing system of random image texture micro-pit as claimed in claim 1 or 2, characterized in that: the laser processing device includes a laser power supply, a laser, an industrial computer, a controllable distribution Interface card, acousto-optic power supply, acousto-optic box, the input signal interface of the random image switch device is plugged with the controllable distribution interface card, and the output signal interface of the random image switch device is connected to the signal of the acousto-optic power supply The input terminals are connected, and the RS232C interface is connected with the industrial computer. 4. The roller-type surface texturing laser processing system of random image textured micro-pit as claimed in claim 3, characterized in that: the output and input signals of the random image switching device are pulse signals, and the output signal Triggered by the rising edge of the input signal. 5. The laser processing method for roughening the surface of rollers with irregular image textured micro-pit, which is to make the roller workpiece rotate along its own axis, make the laser beam move at a uniform speed along the axial direction of the roller workpiece, and pass through the irregular image switching device Receive and process the image files with irregular point distribution, replace them with corresponding control signals, and then drive the laser processing device to process the surface of the roller workpiece, so as to form an image with irregular point distribution on the surface of the roller workpiece The corresponding two-dimensional random distribution of textured micropit.

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