Workpiece surface quality on-line detection device for shot blasting derusting chamber based on optical sensing

Abstract

The present application relates to the technical fields of metal surface treatment and detection, and discloses a workpiece surface quality on-line detection device based on optical sensing in a shot blasting derusting chamber, comprising a laser roughness sensor, a fluorescent cleanliness sensor, a PLC control system and an actuator; the laser roughness sensor and the fluorescent cleanliness sensor are installed inside the shot blasting cleaning chamber, and respectively collect roughness parameters and organic pollutant fluorescence signals of the workpiece surface; the PLC control system is electrically connected with the sensors and the actuator, and outputs control instructions to adjust the shot blasting process parameters. The present application quantitatively detects the cleanliness and roughness of the workpiece surface in real time and non-contact manner during the shot blasting derusting process, and feeds back the detection data to the PLC to form a closed-loop control, thereby solving the problems of low efficiency, lack of quantitative standard and inability to dynamically adjust process parameters caused by the existing detection relying on manual off-line, and realizing on-line accurate management and control of the shot blasting derusting quality.

Description

Technical Field

[0001] This invention relates to the field of metal surface treatment and inspection technology, and in particular to an online inspection device for the surface quality of workpieces in a shot blasting and rust removal chamber based on optical sensing. Background Technology

[0002] Shot blasting is a crucial step in metal surface treatment. It involves high-speed impact of shot to remove scale, rust, and other contaminants from the workpiece surface, while simultaneously creating a surface profile with a certain degree of roughness, providing a good substrate for subsequent coating adhesion. Buoys are exposed to marine environments for extended periods, placing extremely high demands on the quality of their anti-corrosion coatings. A Sa2.5 rust removal standard and a suitable roughness range are essential conditions for ensuring coating adhesion.

[0003] Currently, the surface quality inspection process in shot blasting has the following main shortcomings: 1. Current inspection methods mainly rely on manual visual observation and offline instrument measurement. Operators must remove the workpiece from the cleaning chamber and wait for it to cool before inspection can be carried out. If quality problems are found, the workpiece must be reloaded and reworked, resulting in a lot of repetitive labor and production delays. Although some technologies use cameras to collect surface images at the exit of the shot blasting machine to achieve online monitoring, this method only provides image presentation and cannot give quantitative roughness values ​​and cleanliness indicators.

[0004] 2. Most existing shot blasting equipment adopts an open-loop control mode. Parameters such as shot blasting time, shot blasting speed, and shot flow rate are set before processing and cannot be dynamically adjusted according to the real-time status of the workpiece surface during processing. Even if some systems use PLC to realize the logic start and stop of shot blasting equipment and monitor the working current, they still lack direct online feedback on surface cleanliness and roughness, and cannot form intelligent closed-loop control, which easily leads to problems of insufficient rust removal or over-blasting. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an online workpiece surface quality inspection device based on optical sensing in a shot blasting and rust removal chamber. This solves the problems mentioned in the background technology, such as low efficiency due to reliance on manual offline inspection, lack of quantitative standards, and inability to dynamically adjust process parameters based on surface quality feedback.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An online workpiece surface quality detection device based on optical sensing in a shot blasting and rust removal chamber includes: a shot blasting chamber equipped with a conveyor roller conveyor on which workpieces are placed; at least one laser roughness sensor installed in the shot blasting chamber for online acquisition of workpiece surface roughness parameters; and at least one fluorescent cleanliness sensor installed in the shot blasting chamber for online acquisition of fluorescence signals of organic contaminants on the workpiece surface. A PLC control system is electrically connected to both the laser roughness sensor and the fluorescent cleanliness sensor. The PLC control system is used to receive data, process the data, and make judgments. An actuator is electrically connected to a PLC control system and is controlled by the PLC control system to adjust shot blasting process parameters.

[0007] Furthermore, the laser roughness sensor adopts the laser triangulation measurement principle, with a measurement range of 0.5-500μm and a resolution of 0.1μm.

[0008] Furthermore, the fluorescent cleanliness sensor employs ultraviolet fluorescence detection technology, with an excitation wavelength of 365nm, a detection wavelength of 460nm, and output parameters as cleanliness percentage or relative fluorescence unit RFU.

[0009] Furthermore, the PLC control system adopts an Omron CJ1M-CPU12 CPU, with a user program memory capacity of 10K steps and a data memory capacity of 32K words.

[0010] Furthermore, the actuator includes at least one of a shot blasting machine frequency converter, a shot flow regulating valve, and a conveyor belt driver.

[0011] Furthermore, both the laser roughness sensor and the fluorescent cleanliness sensor are provided with an observation window between them and the shot blasting chamber. The observation window includes a mounting flange, a transparent viewing mirror, and a compressed air purging system.

[0012] Furthermore, the laser roughness sensor and the fluorescent cleanliness sensor are encapsulated in a housing.

[0013] Furthermore, the laser roughness sensor incorporates an intelligent filtering algorithm, achieving a measurement repeatability better than ±2% within a roughness range of 0.5-500μm.

[0014] Furthermore, the PLC control system has a built-in PID control algorithm or threshold comparison logic. When the cleanliness value is lower than the set threshold, the output signal increases the shot blasting time or the shot blasting speed. When the roughness value exceeds the set range, the shot flow rate or workpiece conveying speed is adjusted.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention, through the collaborative operation of a laser roughness sensor and a fluorescent cleanliness sensor, can synchronously and quantitatively detect the surface roughness and cleanliness of a workpiece in real time and without contact during shot blasting. It eliminates the need for manual inspection after machine shutdown and cooling, avoiding rework and repeated furnace loading caused by detection delays. The single processing cycle is significantly shortened, solving the problem of low efficiency caused by existing offline manual inspection.

[0016] 2. This invention uses a PLC control system to compare and calculate the real-time sensor data with preset process thresholds, and dynamically adjusts the shot blasting machine speed, shot flow rate, or workpiece conveying speed according to the deviation, forming an intelligent closed-loop control mode of "detection-feedback-adjustment-re-detection". This solves the problem of existing shot blasting equipment operating in an open loop and being unable to dynamically adjust process parameters according to surface quality, and effectively avoids insufficient rust removal or excessive shot blasting.

[0017] 3. This invention, through the integrated design of the observation window structure, compressed air purging system, and IP67 protective shell, enables the optical sensor to work stably for a long time under the harsh conditions of high dust and strong vibration in the shot blasting chamber. It solves the engineering problem that non-contact testing equipment is difficult to operate reliably in a closed shot blasting environment and fills the technical gap in online testing equipment in this field. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the online workpiece surface quality detection device based on optical sensing in the shot blasting and rust removal chamber proposed in this invention. Figure 2 This is a cross-sectional view of the sensor mounting structure of the online workpiece surface quality detection device based on optical sensing in the shot blasting and rust removal chamber proposed in this invention. Figure 3 This is an electrical schematic diagram of the PLC control system for the online workpiece surface quality detection device based on optical sensing in the shot blasting and rust removal chamber proposed in this invention. Figure 4 This is a closed-loop control flowchart of the online workpiece surface quality detection device based on optical sensing in the shot blasting and rust removal chamber proposed in this invention. Figure 5 This is a schematic diagram illustrating the working principle of the laser roughness sensor in the online workpiece surface quality detection device based on optical sensing in the shot blasting and rust removal chamber proposed in this invention. Figure 6 This is a schematic diagram illustrating the working principle of the fluorescent cleanliness sensor in the online detection device for workpiece surface quality in a shot blasting and rust removal chamber based on optical sensing, as proposed in this invention.

[0019] Explanation of the labels in the diagram: Shot blasting chamber; 11. Laser roughness sensor; 111. Laser diode; 12. Collimating lens; 13. Imaging lens one; 14. High-resolution CMOS sensor; 15. Imaging lens two; 21. Fluorescent cleanliness sensor; 22. Light source; 23. Beam splitter; 24. Confocal pinhole; 25. Filter; 26. Signal processing output module; 27. Objective lens; PLC control system; Executive agency; Conveyor roller conveyor; Observation window; 61. Mounting flange; 62. Sight glass; 63. Compressed air purging system; Workpiece. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] Example 1, please refer to Figures 1 to 6 This embodiment provides an online detection device for the surface quality of workpiece 7 in a shot blasting chamber based on optical sensing. The device achieves real-time quantitative evaluation of the surface quality of workpiece 7 and adaptive adjustment of process parameters during shot blasting by using a laser roughness sensor 11 and a fluorescent cleanliness sensor 2 in collaborative detection and PLC closed-loop control.

[0022] The device consists of four main parts: a laser roughness sensor 11, a fluorescent cleanliness sensor 2, a PLC control system 3, and an actuator 4.

[0023] The laser roughness sensor 11 and the fluorescent cleanliness sensor 2 are installed inside the shot blasting chamber 1 to collect the surface roughness parameters and fluorescent signals of organic contaminants on the workpiece 7, respectively. The PLC control system 3 is located in the control cabinet outside the shot blasting chamber 1 and is electrically connected to the laser roughness sensor 11 and the fluorescent cleanliness sensor 2, respectively, to receive the data from the laser roughness sensor 11 and the fluorescent cleanliness sensor 2 and to perform data processing and judgment.

[0024] Laser triangulation principle: A linear beam emitted by laser diode 111 is collimated by collimating lens 12 and then illuminates the surface (micro-roughness profile) of workpiece 7. The reflected light produces an angular offset θ, which is then received by imaging lens 15 and imaging lens 13 and finally received by high-resolution CMOS sensor 14. FPGA sub-pixel image processing outputs Ra (arithmetic mean deviation) and Rz (maximum height).

[0025] The actuator 4 includes a shot blasting machine frequency converter, a shot flow regulating valve, and a conveyor belt driver, which are controlled by the PLC control system 3 to adjust the shot blasting process parameters. The components are interconnected through an industrial communication bus to form a complete loop from sensor data acquisition, PLC logic operation to process parameter adjustment.

[0026] The fluorescent cleanliness sensor 2 uses ultraviolet fluorescence detection technology. The UV-LED integrated inside the sensor emits ultraviolet light with a wavelength of 365 nanometers to irradiate the surface of the workpiece 7. Organic pollutants such as grease and lubricant on the surface generate fluorescent radiation with a wavelength of 460 nanometers under ultraviolet light excitation. The fluorescence intensity is proportional to the thickness of the contamination layer. The photodiode inside the fluorescent cleanliness sensor 2 receives the fluorescence signal and converts it into a cleanliness value.

[0027] The fluorescence cleanliness sensor 2 adopts a confocal optical path design. The ultraviolet light emitted by the light source 21 is focused onto the surface of the workpiece 7 to be measured by the objective lens 26. The fluorescence generated on the surface returns through the same optical path and passes through the beam splitter 22, the confocal pinhole 23, and the filter 24 before being guided to the photodetector. Finally, the signal is output by the signal processing output module 25. This confocal structure can effectively suppress the interference of ambient stray light. The measurement result is expressed in relative fluorescence units or cleanliness percentage. The lower the relative fluorescence unit, the cleaner the surface. The resolution of the sensor reaches 0.1 relative fluorescence units or 0.1 percent. The measurement point diameter is about 1 mm, the measurement distance is about 4 to 5 mm, and the sampling frequency can reach up to 100 Hz.

[0028] The calibration method of the fluorescent cleanliness sensor 2 is as follows: it is calibrated to be 100% clean by using a standard part that has achieved the ideal cleanliness, and the critical value is calibrated by a contaminated sample that is known to cause surface defects. Based on this, a reliable cleanliness judgment threshold is established. The sensor transmits the cleanliness value to the PLC control system 3 through the RS-485 interface.

[0029] The PLC control system 3 uses an Omron CJ1M-CPU12 CPU module, supporting up to 320 I / O points, a user program memory capacity of 10K steps, a data memory capacity of 32K words, and a basic instruction execution speed of 0.10 microseconds. This PLC achieves integrated detection and control through the following methods: In terms of data acquisition, the laser roughness sensor 11 transmits roughness parameters to the PLC control system 3 via an RS-485 interface. The fluorescent cleanliness sensor 2 also transmits cleanliness values ​​to the PLC control system 3 via an RS-485 interface. After receiving these data, the PLC control system 3 stores them in the data memory and calls the built-in judgment program to compare them with the preset threshold. The CPU module is equipped with a standard RS-232C serial port and communicates with the sensor via an RS-485 interface extended by an adapter.

[0030] In terms of logic control, the PLC control system 3 outputs control commands through threshold comparison logic based on the real-time detection results fed back by the laser roughness sensor 11 and the fluorescent cleanliness sensor 2. When the cleanliness value is lower than the set threshold, the PLC control system 3 outputs a signal to increase the shot blasting time or increase the shot blasting speed. When the roughness value exceeds the set range, the PLC adjusts the shot flow rate or the conveying speed of the workpiece 7. When the detection value meets the standard, the PLC control system 3 issues a process completion signal, allowing the workpiece 7 to be discharged or enter the next process.

[0031] The closed-loop control process is as follows: Workpiece 7 enters shot blasting chamber 1, and PLC control system 3 starts the shot blaster to begin operation; during shot blasting, laser roughness sensor 11 and fluorescent cleanliness sensor 2 continuously collect roughness and cleanliness data of the workpiece 7 surface at a frequency of five times per second and upload them to PLC control system 3; PLC control system 3 compares and calculates the real-time values ​​with preset process standards; when the detected value does not meet the standard, PLC control system 3 dynamically adjusts the shot blasting process parameters to form a negative feedback closed loop; when the detected value meets the standard for a certain period of time, PLC control system 3 determines that the process is completed, issues an audible and visual prompt, and instructs the material to be discharged; before discharge, PLC control system 3 stores the complete detection data of this processing in the data storage device and uploads it to the upper management system.

[0032] Considering the high concentration of dust and strong vibration environment inside the shot blasting chamber 1, the laser roughness sensor 11 and the fluorescent cleanliness sensor 2 adopt a special installation and protection structure.

[0033] A sensor mounting flange 61 interface is reserved on the wall panel of the shot blasting chamber 1. A pressure-resistant, dustproof, and transparent sight glass 62 is installed on the mounting flange 61. The sight glass 62 is made of high light transmittance and shot impact resistant optical glass, and the surface is coated with a dustproof and hydrophobic coating. The laser roughness sensor 11 and the fluorescent cleanliness sensor 2 are both installed in the sealed cavity outside the sight glass 62. Non-contact measurement is performed on the internal workpiece 7 through the sight glass 62. The laser roughness sensor 11 maintains a measurement distance of about 50 mm from the surface of the workpiece 7, and the fluorescent cleanliness sensor 2 maintains a measurement distance of about 4 to 5 mm.

[0034] A compressed air purging system 63 is installed at the installation position of the transparent sight glass 62. The PLC control system 3 controls the nozzle of the compressed air purging system 63 to blow air at regular intervals. Each purging lasts for 2 seconds, with an interval of 60 seconds, to prevent dust from adhering to the surface of the transparent sight glass 62 and affecting the measurement accuracy. The laser roughness sensor 11 and the fluorescent cleanliness sensor 2 are each encapsulated in a stainless steel housing with an IP67 protection rating, and can operate normally in extreme environments ranging from -20 degrees Celsius to 60 degrees Celsius. The cables of the laser roughness sensor 11 and the fluorescent cleanliness sensor 2 are led out of the cleaning chamber through a sealed conduit and connected to the control cabinet of the PLC control system 3.

[0035] Work process The float to be processed is loaded into the conveyor roller 5 in the shot blasting chamber 1 and the equipment is started. The laser roughness sensor 11 and the fluorescent cleanliness sensor 2 continuously collect surface data of the workpiece 7 at a frequency of five times per second and upload it to the PLC control system 3. The PLC control system 3 records and displays the roughness value and cleanliness value in real time.

[0036] In the initial stage of shot blasting, cleanliness and roughness increase rapidly. In the middle stage, the PLC control system 3 dynamically adjusts the shot blasting parameters based on the detected values. When the cleanliness value is lower than the set threshold, the PLC control system 3 outputs a signal to increase the shot blasting time or increase the blasting speed. When the roughness value exceeds the set range, the PLC control system 3 adjusts the shot flow rate or the workpiece 7 conveying speed. After about 15 to 20 seconds, the cleanliness and roughness stabilize within the target range and continue to meet the standards. The PLC control system 3 automatically judges that the process is completed, issues an audible and visual prompt, stops the shot blaster, and stores the complete detection data in the memory. Throughout the process, the operator does not need to enter the shot blasting chamber or open the chamber for observation. All quality inspection data can be monitored in real time and historically reviewed on the control console.

[0037] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. An online workpiece surface quality inspection device based on optical sensing in a shot blasting and rust removal chamber, characterized in that, include: A shot blasting chamber (1) is provided with a conveyor roller (5) on which a workpiece (7) is placed. At least one laser roughness sensor (11) is provided in the shot blasting chamber (1) for online acquisition of the surface roughness parameters of the workpiece (7). At least one fluorescent cleanliness sensor (2) is provided in the shot blasting chamber (1) for online acquisition of the fluorescent signals of organic pollutants on the surface of the workpiece (7). The PLC control system (3) is electrically connected to the laser roughness sensor (11) and the fluorescent cleanliness sensor (2) respectively. The PLC control system (3) is used to receive data and perform data processing and judgment. as well as The actuator (4) is electrically connected to the PLC control system (3) and is controlled by the PLC control system (3) to adjust the shot blasting process parameters.

2. The device for on-line detection of workpiece surface quality in a shot blasting chamber based on optical sensing according to claim 1, characterized in that, The laser roughness sensor (11) adopts the laser triangulation measurement principle, and its measurement range is 0.5-500μm with a resolution of 0.1μm.

3. The online workpiece surface quality detection device based on optical sensing in a shot blasting and rust removal chamber according to claim 1, characterized in that, The fluorescent cleanliness sensor (2) uses ultraviolet fluorescence detection technology. Its excitation wavelength is 365nm, its detection wavelength is 460nm, and its output parameters are cleanliness percentage or relative fluorescence unit RFU.

4. The online workpiece surface quality detection device based on optical sensing in a shot blasting and rust removal chamber according to claim 1, characterized in that, The PLC control system (3) adopts an Omron CJ1M-CPU12 CPU with a user program memory capacity of 10K steps and a data memory capacity of 32K words.

5. The device according to claim 1, wherein, The actuator (4) includes at least one of the following: shot blasting machine frequency converter, shot flow regulating valve and conveyor belt drive.

6. The device for on-line detection of workpiece surface quality in a shot blasting chamber based on optical sensing according to any one of claims 1 to 5, characterized in that, The laser roughness sensor (11) and the fluorescent cleanliness sensor (2) are both provided with an observation window (6) between them and the shot blasting chamber (1). The observation window (6) includes a mounting flange (61), a light-transmitting sight glass (62), and a compressed air purging system (63).

7. The device according to claim 6, wherein the device is characterized by: The laser roughness sensor (11) and the fluorescence cleanliness sensor (2) are encapsulated in a housing. 8.The device according to claim 1, wherein, The laser roughness sensor (11) has a built-in intelligent filtering algorithm, and its measurement repeatability is better than ±2% in the roughness range of 0.5-500μm. 9.The device according to claim 1, wherein, The PLC control system (3) has a built-in PID control algorithm or threshold comparison logic. When the cleanliness value is lower than the set threshold, the output signal increases the shot blasting time or increases the shot blasting speed. When the roughness value exceeds the set range, the shot flow rate or the workpiece (7) conveying speed is adjusted.

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