WO2024066905A1

WO2024066905A1 - Automatic measurement and control system for thickness of powder-spraying film of computer case

Info

Publication number: WO2024066905A1
Application number: PCT/CN2023/116235
Authority: WO
Inventors: 李清杰; 杨铁生; 王长军; 熊立新
Original assignee: 安徽柳溪智能装备有限公司
Priority date: 2022-09-29
Filing date: 2023-08-31
Publication date: 2024-04-04
Also published as: CN115445813A; CN115445813B

Abstract

An automatic measurement and control system for the thickness of a powder-spraying film of a computer case. The system comprises an image collection module, an image analysis module, a remote control module and a loss analysis module, wherein the image collection module is used for capturing an image of laser lines that is projected on the surface of a coating film, and uploading the captured image to the image analysis module; the image analysis module is used for performing analytical processing on a received image, so as to determine the thickness of the coating film of the currently measured coating film area; the remote control module is used for sending, in combination with the image analysis module, a signal to an execution control unit in a powder spraying module, and remotely controlling the powder spraying module to perform a powder spraying operation; and the loss analysis module is used for performing loss analysis on powder coatings of the powder spraying module. The control system can improve the precision and efficiency of powder spraying.

Description

Computer case powder coating thickness automatic detection and control system

Technical Field

The invention relates to the technical field of workpiece coating, in particular to an automatic detection and control system for the thickness of powder spraying film of a computer case.

Background technique

Powder spraying uses the corona discharge phenomenon to make the powder coating adsorbed on the workpiece. The process of powder spraying is: the powder spray gun is connected to the negative pole, the workpiece is grounded (positive pole), the powder coating is sent into the spray gun by the powder supply system through compressed air, and a high voltage generated by a high-voltage electrostatic generator is added to the front end of the spray gun. Due to corona discharge, dense charges are generated near it. When the powder is sprayed from the gun nozzle, a circuit is formed to form charged coating particles. It is attracted to the workpiece with the opposite polarity due to the electrostatic force. As the amount of powder sprayed increases, the charge accumulates more. When it reaches a certain thickness, it will stop adsorbing due to the electrostatic repulsion, so that the entire workpiece obtains a certain thickness of powder coating, and then the powder is melted, leveled, and solidified through heat, that is, a hard coating is formed on the surface of the workpiece.

technical problem

In real life, most of the corrosion resistance of computer cases comes from the physical protection of the coating. The thicker the coating, the stronger its ability to protect the substrate, and the longer the service life of the computer case. However, the thicker the coating, the more paint is consumed, and the higher the production cost. Therefore, it is very important for the powder spraying unit to accurately control the thickness of the computer case coating within the target range. To this end, the present invention proposes an automatic detection and control system for the powder spraying film thickness of the computer case.

Technical Solutions

According to an embodiment of the first aspect of the present invention, a computer case powder spray film thickness automatic detection and control system is provided, comprising a powder spray module, an image acquisition module, an image analysis module, a remote control module and a loss analysis module;

The powder spraying module is used to realize powder spraying of the computer case, that is, to form a layer of coating on the surface of the computer case; the image acquisition module is used to capture the image of the laser line projected on the coating surface, and upload the captured image to the image analysis module; the image analysis module is used to analyze and process the received image, so as to determine the coating thickness of the current coating area; when the coating thickness reaches a preset thickness range, a stop signal is generated; the image analysis module is used to transmit the coating thickness and the stop signal to the remote control module; after receiving the stop signal, the remote control module controls the powder spraying module to stop powder spraying, and feeds back the corresponding coating thickness to the powder spraying module;

The loss analysis module is connected to the powder spraying module and is used to perform loss analysis on the powder coating of the powder spraying module. The specific analysis steps are as follows:

When the powder spraying module sprays powder on the computer case, record the consumption of powder coating; mark the consumption of powder coating as L1, and mark the coating thickness of the corresponding computer case as H1;

Collect various environmental factors during the powder spraying process and calculate the environmental impact coefficient HJ1; use the formula SH = (L1×b1‑H1×b2)/HJ1 to calculate the paint loss value SH of the powder spraying module; b1 and b2 are coefficient factors; if SH is greater than the preset loss threshold, it indicates that the powder spraying loss is serious and an abnormal loss signal is generated to remind the staff to inspect and repair the powder spraying unit.

Furthermore, the specific calculation process of the environmental impact coefficient HJ1 is:

Mark the corresponding temperature, humidity, wind speed and air pressure as W1, M1, F1 and Y1 respectively; use the formula HJ1=W1×a1+M1×a2+F1×a3+Y1×a4 to calculate the environmental impact coefficient HJ1, where a1, a2, a3 and a4 are coefficient factors.

Furthermore, it also includes a laser line light source module, which is used to control the laser line light source to emit a laser line that falls on the coating surface of the computer case and is parallel to the cross-section of the coating, and the laser line is perpendicular to the calibration ruler; the calibration ruler is set at the leftmost and rightmost ends of the coating area photographed by the camera.

Furthermore, the specific analysis steps of the image analysis module are:

Obtain the full-scale coordinates, the leftmost zero point coordinates, and the rightmost zero point coordinates of the calibration scale displayed in the image at the current detection coating area; determine the coating width of the current detection coating area based on the leftmost zero point coordinates and the rightmost zero point coordinates;

Determine the corresponding coating coordinate position within the coating width of the currently detected coating area on the image;

According to the coating coordinate position determined in the image and the full-scale coordinates of the calibration ruler, the coating thickness of the currently detected coating area is determined.

Further, the specific steps of determining the corresponding coating coordinate position within the coating width of the currently detected coating area on the image include:

Take any point in the current detection coating area as detection point E; draw a vertical line from the detection point E to the horizontal plane where the zero point A of the calibration scale is located, intersecting it at point B, and determine the coating thickness BE of the detection point;

A parallel line drawn from the detection point E to AB intersects AF at point D; wherein AF is the height corresponding to the full-scale coordinate of the calibration ruler, and BE = AD;

Draw extension lines of the three points A, D and F on the calibration ruler and the extension lines of points E and B, and the two extension lines intersect at point G at infinity; and, determine the extension lines of the three points a, d and f on the calibration ruler in the image plane and the extension lines of points e and b, and the two extension lines intersect at point g at infinity;

On the image plane, determine the pixel height af corresponding to the calibration scale height AF on the image, the number of pixels ad of AD, the number of pixels gd of GD, and the number of pixels gf of GF;

According to the pixel height af corresponding to the calibration scale height AF on the image, the number of pixels ad of AD, the number of pixels gd of GD and the number of pixels gf of GF, the corresponding coating coordinate position within the coating width of the current detected coating area is determined.

Further, according to the coating coordinate position determined in the image and the full-scale coordinate of the calibration ruler, the coating thickness of the coating area currently being detected is determined, and the specific steps include:

Using the cross-ratio invariance principle, the pixel height af corresponding to the calibration scale height AF on the image, the number of pixels ad of AD, the number of pixels gd of GD and the number of pixels gf of GF satisfy the following relationship: (AD/AF)/(GD/GF)=(ad/af)/(gd/gf);

Let GD/GF＝1; where, at infinity, GD＝GF;

Determine the coating thickness BE(n) of any detection point n in the currently detected coating area according to the following formula: BE(n)=AD(n)=(ad(n)/af(n))/(gd(n)/gf(n))*AF; Determine the coating thickness of the currently detected coating area based on the coating thickness of each detection point n in the currently detected coating area.

Furthermore, the powder spraying module includes a powder spraying unit, an execution control unit and a signal transceiver unit; the execution control unit is used to receive the signal from the signal transceiver unit to control the powder spraying unit.

Beneficial Effects

1. The image acquisition module in the present invention is used to capture the image of the laser line projected on the coating surface, and upload the captured image to the image analysis module; the image analysis module is used to analyze and process the received image, so as to determine the coating thickness of the current detection coating area; when the coating thickness reaches a preset thickness range, a stop signal is generated; the remote control module is used to combine with the image analysis module, send a signal to the execution control unit in the powder spraying module, and remotely control the powder spraying module to perform powder spraying, thereby improving the powder spraying accuracy and efficiency;

2. The loss analysis module described in the present invention is connected to the powder spraying module, and is used to perform loss analysis on the powder coating of the powder spraying module; when the powder spraying module sprays powder on the computer case, the consumption of powder coating is recorded; the consumption of powder coating is marked as L1, and the coating thickness of the corresponding computer case is marked as H1; various environmental factors in the powder spraying process are collected to calculate the environmental impact coefficient HJ1; the coating loss value SH of the powder spraying module is calculated using the formula SH=(L1×b1‑H1×b2)/HJ1; if SH is greater than the preset loss threshold, it indicates that the powder spraying loss is serious, and a loss abnormality signal is generated to remind the staff to overhaul the powder spraying unit, improve the powder spraying efficiency, and reduce production costs.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

Figure 1 is a system block diagram of the automatic detection and control system for powder spray film thickness of computer case of the present invention.

Best Mode for Carrying Out the Invention

As shown in FIG1 , the computer case powder coating thickness automatic detection and control system includes a powder coating module, a laser line light source module, an image acquisition module, an image analysis module, a remote control module, a loss analysis module, and an alarm module;

The powder spraying module is used to realize powder spraying of the computer case, that is, to form a layer of coating on the surface of the computer case; the powder spraying module includes a powder spraying unit, an execution control unit and a signal transceiver unit; the execution control unit is used to receive the signal of the signal transceiver unit to control the powder spraying unit;

The laser line light source module is used to control the laser line light source to emit a laser line that falls on the coating surface of the computer case and is parallel to the cross section of the coating. The laser line is perpendicular to the calibration ruler.

The image acquisition module includes a camera for capturing images of the laser line projected on the coating surface and uploading the captured images to the image analysis module; the calibration scale is set at the leftmost and rightmost ends of the coating area captured by the camera;

The image analysis module is used to analyze and process the received image to determine the coating thickness of the current coating area. The specific analysis steps are as follows:

Step 1: Obtain the full-scale coordinates, the leftmost zero point coordinates, and the rightmost zero point coordinates of the calibration scale displayed in the image at the current detection coating area; determine the coating width of the current detection coating area based on the leftmost zero point coordinates and the rightmost zero point coordinates;

Step 2: Determine the corresponding coating coordinate position within the coating width of the current detection coating area on the image, specifically:

Take any point within the current detection coating area as detection point E;

Draw a vertical line from the test point E to the horizontal plane where the zero point A of the calibration scale is located, intersecting it at point B, and determine the coating thickness BE at the test point;

Draw a parallel line from the detection point E to AB, which intersects AF at point D; AF is the height corresponding to the full-scale coordinate of the calibration ruler, and BE = AD;

According to the pixel height af corresponding to the calibration ruler height AF on the image, the number of pixels ad of AD, the number of pixels gd of GD and the number of pixels gf of GF, the corresponding coating coordinate position within the coating width of the current detection coating area is determined;

Step 3: Determine the coating thickness of the current detection coating area based on the coating coordinate position determined in the image and the full-scale coordinate of the calibration ruler; specifically:

Let GD/GF＝1; where, at infinity, GD＝GF;

According to the following formula, determine the coating thickness BE(n) of any detection point n in the current detection coating area:

BE(n)＝AD(n)＝(ad(n)/af(n))/(gd(n)/gf(n))*AF;

According to the coating thickness of each detection point n in the current detection coating area, the coating thickness of the current detection coating area is determined; when the coating thickness reaches the preset thickness range, a stop signal is generated; the image analysis module is used to transmit the coating thickness and the stop signal to the remote control module;

After receiving the stop signal, the remote control module controls the powder spraying module to stop spraying and feeds back the corresponding coating thickness to the powder spraying module; wherein, the remote control module is used to combine with the image analysis module to send a signal to the execution control unit in the powder spraying module and remotely control the powder spraying module to perform powder spraying, thereby improving the powder spraying accuracy and efficiency;

Collect various environmental factors during the powder spraying process, including temperature, humidity, wind speed and air pressure; mark the corresponding temperature, humidity, wind speed and air pressure as W1, M1, F1 and Y1 respectively; use the formula HJ1＝W1×a1+M1×a2+F1×a3+Y1×a4 to calculate the environmental impact coefficient HJ1, where a1, a2, a3 and a4 are all coefficient factors; Normalize the consumption of powder coating, coating thickness and environmental impact coefficient HJ1 and take their values; use the formula SH＝(L1×b1‑H1×b2)/HJ1 to calculate the coating loss value SH of the powder spraying module; where b1 and b2 are all coefficient factors;

Compare the paint loss value SH with the preset loss threshold; if SH is greater than the preset loss threshold, it indicates that the powder spraying loss is serious and a loss abnormality signal is generated;

The loss analysis module is used to transmit the abnormal loss signal to the remote control module; after receiving the abnormal loss signal, the remote control module drives the alarm module to sound an alarm to remind the staff to inspect and repair the powder spraying unit, improve the powder spraying efficiency and reduce production costs.

The above formulas are all calculated by removing dimensions and taking their numerical values. The formula is a formula that is closest to the actual situation obtained by collecting a large amount of data and performing software simulation. The preset parameters and preset thresholds in the formula are set by technical personnel in this field according to actual conditions or obtained by simulating a large amount of data.

Embodiments of the present invention

The automatic detection and control system for the film thickness of powder spraying of computer cases, when working, the powder spraying module is used to realize the powder spraying of computer cases, that is, to form a layer of coating on the surface of the computer case; the laser line light source module is used to control the laser line light source to emit a laser line that falls on the coating surface of the computer case and is parallel to the cross section of the coating; the image acquisition module is used to capture the image of the laser line projected on the coating surface, and upload the captured image to the image analysis module; the image analysis module is used to analyze and process the received image, so as to determine the coating thickness of the current detection coating area; when the coating thickness reaches the preset thickness range, a shutdown signal is generated; the remote control module is used to combine with the image analysis module, send a signal to the execution control unit in the powder spraying module, and remotely control the powder spraying module to perform powder spraying, so as to improve the powder spraying accuracy and efficiency;

The loss analysis module is connected to the powder spraying module and is used to perform loss analysis on the powder coating of the powder spraying module. When the powder spraying module sprays powder on the computer case, the consumption of powder coating is recorded. The consumption of powder coating is marked as L1, and the coating thickness of the corresponding computer case is marked as H1. Various environmental factors in the powder spraying process are collected to calculate the environmental impact coefficient HJ1. The paint loss value SH of the powder spraying module is calculated using the formula SH = (L1×b1‑H1×b2)/HJ1. If SH is greater than the preset loss threshold, it indicates that the powder spraying loss is serious and an abnormal loss signal is generated to remind the staff to overhaul the powder spraying unit, improve the powder spraying efficiency and reduce production costs.

Industrial Applicability

The automatic detection and control system for the film thickness of powder spraying of computer cases, when working, the powder spraying module is used to realize the powder spraying of computer cases, that is, to form a layer of coating on the surface of the computer cases; the laser line light source module is used to control the laser line light source to emit a laser line that falls on the coating surface of the computer cases and is parallel to the cross section of the coating; the image acquisition module is used to capture the image of the laser line projected on the coating surface, and upload the captured image to the image analysis module; the image analysis module is used to analyze and process the received image, so as to determine the coating thickness of the current detection coating area; when the coating thickness reaches the preset thickness range, a shutdown signal is generated; the remote control module is used to combine with the image analysis module, send a signal to the execution control unit in the powder spraying module, and remotely control the powder spraying module to perform powder spraying, so as to improve the powder spraying accuracy and efficiency;

Claims

The computer case powder spray film thickness automatic detection and control system is characterized by comprising a powder spray module, an image acquisition module, an image analysis module, a remote control module and a loss analysis module;

The powder spraying module is used to realize powder spraying of the computer case, that is, to form a coating layer on the surface of the computer case; the image acquisition module is used to capture the image of the laser line projected on the coating surface, and upload the captured image to the image analysis module; the image analysis module is used to analyze and process the received image, so as to determine the coating thickness of the current detection coating area;

When the coating thickness reaches a preset thickness range, a stop signal is generated; the image analysis module is used to transmit the coating thickness and the stop signal to the remote control module; after receiving the stop signal, the remote control module controls the powder spraying module to stop powder spraying, and feeds back the corresponding coating thickness to the powder spraying module;

The loss analysis module is connected to the powder spraying module and is used to perform loss analysis on the powder coating of the powder spraying module. The specific analysis steps are as follows:

When the powder spraying module sprays powder on the computer case, the consumption of the powder coating is recorded; the consumption of the powder coating is marked as L1, and the coating thickness of the corresponding computer case is marked as H1;

Collect various environmental factors during the powder spraying process and calculate the environmental impact coefficient HJ1; use the formula SH = (L1×b1-H1×b2)/HJ1 to calculate the paint loss value SH of the powder spraying module; b1 and b2 are coefficient factors; if SH is greater than the preset loss threshold, it indicates that the powder spraying loss is serious and an abnormal loss signal is generated to remind the staff to overhaul the powder spraying unit.
The computer case powder coating thickness automatic detection and control system according to claim 1 is characterized in that the specific calculation process of the environmental impact coefficient HJ1 is: the corresponding temperature, humidity, wind speed and air pressure are marked as W1, M1, F1 and Y1 in sequence; the environmental impact coefficient HJ1 is calculated using the formula HJ1=W1×a1+M1×a2+F1×a3+Y1×a4, wherein a1, a2, a3, and a4 are all coefficient factors.
The computer case powder spray film thickness automatic detection and control system according to claim 1 is characterized in that it also includes a laser line light source module, which is used to control the laser line light source to emit a laser line that falls on the coating surface of the computer case and is parallel to the cross-section of the coating, and the laser line is perpendicular to the calibration ruler; the calibration ruler is set at the leftmost and rightmost ends of the coating area photographed by the camera.
The computer case powder coating thickness automatic detection and control system according to claim 1 is characterized in that the specific analysis steps of the image analysis module are:

Obtain the full-scale coordinates, the leftmost zero point coordinates, and the rightmost zero point coordinates of the calibration scale displayed in the image at the current detection coating area; determine the coating width of the current detection coating area based on the leftmost zero point coordinates and the rightmost zero point coordinates;

Determine the coating coordinate position corresponding to the coating width of the currently detected coating area on the image; determine the coating thickness of the currently detected coating area based on the coating coordinate position determined in the image and the full-scale coordinates of the calibration ruler.
The computer case powder coating thickness automatic detection and control system according to claim 4 is characterized in that, wherein, determining the coating coordinate position corresponding to the coating width of the current detection coating area on the image, the specific steps include: taking any point in the current detection coating area as the detection point E; drawing a vertical line from the detection point E to the horizontal plane where the zero point A of the calibration scale is located, intersecting at point B, and determining the coating thickness BE of the detection point;

A parallel line drawn from the detection point E to AB intersects AF at point D; wherein AF is the height corresponding to the full-scale coordinate of the calibration ruler, and BE = AD;

Draw extension lines of three points A, D and F on the calibration ruler and extension lines of points E and B, the two extension lines intersect at point G at infinity; and determine the extension lines of three points a, d and f on the calibration ruler and extension lines of points e and b in the image plane, the two extension lines intersect at point g at infinity;

On the image plane, determine the pixel height af corresponding to the calibration ruler height AF on the image, the number of pixels ad of AD, the number of pixels gd of GD, and the number of pixels gf of GF;

According to the pixel height af corresponding to the calibration ruler height AF on the image, the number of pixels ad of AD, the number of pixels gd of GD and the number of pixels gf of GF, the corresponding coating coordinate position within the coating width of the current detection coating area is determined.
The computer case powder coating thickness automatic detection and control system according to claim 5 is characterized in that the coating thickness of the currently detected coating area is determined according to the coating coordinate position determined in the image and the full-scale coordinate of the calibration ruler, and the specific steps include:

Using the cross-ratio invariance principle, the pixel height af corresponding to the calibration ruler height AF on the image, the number of pixels ad of AD, the number of pixels gd of GD and the number of pixels gf of GF satisfy the following relationship: (AD/AF)/(GD/GF)=(ad/af)/(gd/gf);

Let GD/GF = 1; where, at infinity, GD = GF;

According to the following formula, the coating thickness BE(n) of any detection point n in the current detection coating area is determined:

BE(n)=AD(n)=(ad(n)/af(n))/(gd(n)/gf(n))*AF;

The coating thickness of the currently detected coating area is determined according to the coating thickness of each detection point n in the currently detected coating area.
The computer case powder spray film thickness automatic detection and control system according to claim 1 is characterized in that the powder spray module includes a powder spray unit, an execution control unit and a signal transceiver unit; the execution control unit is used to receive the signal of the signal transceiver unit to control the powder spray unit.