A method for improving the quality of paint removal on metal sheet surface using electrostatic field

Abstract

The present invention relates to the field of laser paint removal, and discloses a method for improving the quality of paint removal on the surface of a metal plate with the assistance of an electrostatic field, comprising the following steps: Step 1, placing a metal plate on an electrostatic platform, an insulating pad is provided between the metal plate and the electrostatic platform, and the area to be processed is aligned with the laser incident area; Step 2, making an electrostatic gun contact the electrostatic platform, turning on an electrostatic generator, selecting a suitable voltage, setting the discharge mode to contact discharge, so that the surface of the electrostatic platform is full of charge and the electron density on the plate surface is increased; Step 3, turning on the laser, adjusting the laser parameters, and removing the paint layer on the surface of the sample. The present invention increases the electron density on the surface of the metal layer through the action of an electrostatic field, thereby reducing the metal's absorption rate of the laser, reducing the influence of heat input on the metal matrix during processing, and improving the quality of paint removal on the surface of the metal plate, which is of great significance to laser removal technology.

Description

Technical Field

[0001] The invention relates to the field of laser paint removal, and in particular to a method for improving the quality of paint removal on the surface of a metal plate with the assistance of an electrostatic field. Background Art

[0002] Alloy materials are widely used in modern industry due to their highly controllable properties. For protection purposes, paint is usually applied to the surface of alloy components. Paint coatings will gradually lose their protective effect on alloy components due to factors such as light, temperature, and humidity, so the paint layer needs to be removed regularly and repainted. Laser technology has been widely used in paint removal technology due to its advantages of high efficiency, greenness, and high precision.

[0003] Laser paint removal utilizes the heat and force generated inside the paint layer after it absorbs laser energy to destroy the bonding force between the paint layer and the substrate, thus separating the paint layer from the substrate. Among them, the material's absorption rate of the laser is an important factor affecting the removal quality. Only when the laser frequency is close to the natural frequency of free electrons can there be good absorption. The natural frequency of metal free electrons is generally in the ultraviolet to near-infrared band. For the most widely used infrared lasers in paint removal, the absorption rate of metal is much lower than that of the paint layer. However, due to the extremely high heat input during the laser action process, it will still cause certain damage to the substrate, seriously affecting the quality of paint removal. Therefore, there is an urgent need for a processing method to improve the quality of paint removal on the surface of metal plates. Summary of the invention

[0004] The purpose of the present invention is to provide a method for improving the quality of paint removal on the surface of a metal plate by using an electrostatic field as an aid.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for improving the quality of paint removal on the surface of a metal sheet by using an electrostatic field as an aid, comprising the following steps:

[0007] Step 1, placing a metal plate on an electrostatic platform, with an insulating pad disposed between the metal plate and the electrostatic platform, and aligning the area to be processed with the laser incident area;

[0008] Step 2, make the electrostatic gun contact the electrostatic platform, turn on the electrostatic generator, select the appropriate voltage, set the discharge mode to contact discharge, and wait for a period of time so that the surface of the electrostatic platform is fully charged and the electron density on the surface of the plate increases;

[0009] Step 3: Turn on the laser, adjust the laser parameters, and remove the paint layer on the surface of the sample.

[0010] Preferably, the laser is a CO 2 laser, Nd:YAG laser or fiber laser.

[0011] Preferably, the laser wavelength range of the CO2 laser, Nd:YAG laser or fiber laser is 1 um to 100 um.

[0012] Preferably, in step 1, the metal sheet is an aluminum alloy, a copper alloy or an alloy steel.

[0013] Preferably, in step 1, the thickness of the insulating pad is 3 mm to 10 mm.

[0014] Preferably, in step 2, the electrostatic platform is made of aluminum alloy or copper alloy, with a thickness of 5 mm to 20 mm.

[0015] Preferably, in step 2, the voltage of the electrostatic generator is set to 2KV to 10KV.

[0016] Preferably, in step 2, the waiting time is 30s to 120s.

[0017] The method of the present invention can also be applied to the laser removal of the oxide layer on the surface of aluminum alloy and the laser removal of the rust on the surface of steel material.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The method of the present invention increases the electron density on the surface of the metal plate through the action of the electrostatic field, reduces the absorptivity of the substrate to the far-infrared wavelength laser, reduces the influence of heat input on the metal substrate during processing, and improves the paint removal quality without reducing the paint removal efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0021] Figure 1 The present invention relates to a cleaning process for improving the quality of paint removal on the surface of a metal plate with the aid of an electrostatic field;

[0022] Figure 2 This is a macroscopic comparison of the removal results with and without an electrostatic field when the laser parameters in Example 1 are used to remove the paint layer on the surface of an aluminum alloy;

[0023] Figure 3 This is a macroscopic comparison of the removal results with and without an electrostatic field when the laser parameters in Example 2 are used to remove the paint layer on the surface of an aluminum alloy;

[0024] Figure 4 This is a macroscopic comparison of the removal results with and without an electrostatic field when the laser parameters in Example 3 are used to remove the paint layer on the surface of the copper alloy;

[0025] Markings in the figure: 1 is laser pulse beam, 2 is paint coating, 3 is metal plate, 4 is insulating pad, 5 is electrostatic platform, and 6 is electrostatic gun. DETAILED DESCRIPTION

[0026] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0027] Example 1

[0028] A method for removing paint from a metal plate surface by using an electrostatic field to improve the quality of the paint removal, the steps are as follows:

[0029] Step 1, such as Figure 1 As shown, the aluminum alloy plate with the paint layer 2 on the surface is cut to a suitable size, the sample to be processed is fixed on an insulating pad, and the side covered with the paint layer 2 is aligned with the laser cleaning head;

[0030] Step 2, make the electrostatic gun 6 contact with the electrostatic platform made of aluminum alloy, turn on the electrostatic generator, set the voltage to 3KV, set the discharge mode to contact discharge, wait for 60 seconds, so that the surface of the electrostatic platform is full of charge and the electron density on the surface of the plate increases;

[0031] Step 3, turn on the laser, use an Nd:YAG laser with an average power of 100W to remove the surface paint layer 2, the laser wavelength used is 1064nm, the laser spot is circular, the diameter is 50um, the laser output power is 90%, the pulse frequency is 1000kHz, the pulse width is 100ns, the bow scanning is used, and the pulse overlap rate is 80%;

[0032] After the operation is completed, turn off the laser, clean the waste remaining on the surface of the sample, and take out the sample.

[0033] Figure 2 This is a macroscopic comparison of the removal results with and without an electrostatic field when the laser parameters in this embodiment are used to remove the paint layer on the surface of an aluminum alloy.

[0034] Example 2

[0035] A method for removing paint from a metal plate surface by using an electrostatic field to improve the quality of the paint removal, the steps are as follows:

[0036] Step 1, cutting the aluminum alloy plate with the paint layer 2 on the surface into a suitable size, fixing the sample to be processed on an insulating pad, and aligning the side covered with the paint layer 2 with the laser cleaning head;

[0037] Step 2, make the electrostatic gun contact with the electrostatic platform made of aluminum alloy, turn on the electrostatic generator, set the voltage to 5KV, set the discharge mode to contact discharge, wait for 120 seconds, so that the surface of the electrostatic platform is full of charge and the electron density on the surface of the plate increases;

[0038] Step 3: Turn on the laser and use an average power of 200W CO 2 The surface paint layer 2 is removed by laser, the laser wavelength used is 10.6um, the laser spot is circular with a diameter of 100um, the laser output power is 60%, the pulse frequency is 500kHz, the pulse width is 80ns, unidirectional scanning is adopted, and the pulse overlap rate is 60%;

[0039] After the operation is completed, turn off the laser, clean the waste remaining on the surface of the sample, and take out the sample.

[0040] Figure 3 This is a macroscopic comparison of the removal results with and without an electrostatic field when the laser parameters in this embodiment are used to remove the paint layer on the surface of an aluminum alloy.

[0041] Example 3

[0042] A method for removing paint from a metal plate surface by using an electrostatic field to improve the quality of the paint removal, the steps are as follows:

[0043] Step 1, cutting the copper alloy plate coated with a paint layer 2 on the surface to a suitable size, fixing the sample to be processed on an insulating pad, and aligning the side covered with the paint layer 2 with the laser cleaning head;

[0044] Step 2, make the electrostatic gun contact with the electrostatic platform made of copper alloy, turn on the electrostatic generator, set the voltage to 4KV, set the discharge mode to contact discharge, wait for 90 seconds, so that the surface of the electrostatic platform is full of charge and the electron density on the surface of the plate increases;

[0045] Step 3, turn on the laser, use an optical fiber laser with an average power of 500W to remove the surface paint layer 2, the laser wavelength used is 2100nm, the laser spot is circular, the diameter is 50um, the laser output power is 20%, the pulse frequency is 600kHz, the pulse width is 100ns, circular scanning is used, and the pulse overlap rate is 90%;

[0046] After the operation is completed, turn off the laser, clean the waste remaining on the surface of the sample, and take out the sample.

[0047] Figure 4 This is a macroscopic comparison of the removal results with and without an electrostatic field when the laser parameters in this embodiment are used to remove the paint layer on the surface of the copper alloy.

[0048] Example 4

[0049] A method for removing paint from a metal plate surface by using an electrostatic field to improve the quality of the paint removal, the steps are as follows:

[0050] Step 1, cutting the stainless steel plate with the paint layer 2 on the surface into a suitable size, fixing the sample to be processed on an insulating pad, and aligning the side covered with the paint layer 2 with the laser cleaning head;

[0051] Step 2, make the electrostatic gun contact with the electrostatic platform made of copper alloy, turn on the electrostatic generator, set the voltage to 10KV, set the discharge mode to contact discharge, wait for 30 seconds, so that the surface of the electrostatic platform is full of charge and the electron density on the surface of the plate increases;

[0052] Step 3, turn on the laser, use an optical fiber laser with an average power of 100W to remove the surface paint layer 2, the laser wavelength used is 2100nm, the laser spot is circular, the diameter is 50um, the laser output power is 50%, the pulse frequency is 800kHz, the pulse width is 200ns, bidirectional scanning is used, and the pulse overlap rate is 50%;

[0053] After the operation is completed, turn off the laser, clean the waste remaining on the surface of the sample, and take out the sample.

[0054] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for improving the quality of paint removal on the surface of a metal sheet using an electrostatic field, characterized in that: The steps include: Step 1, placing a metal plate on an electrostatic platform, with an insulating pad disposed between the metal plate and the electrostatic platform, and aligning the area to be processed with the laser incident area; Step 2: Make the electrostatic gun contact the electrostatic platform, turn on the electrostatic generator, select a suitable voltage, set the discharge mode to contact discharge, wait for a while, so that the surface of the electrostatic platform is full of charge and the electron density on the surface of the plate increases, the electrostatic generator voltage is set to 2KV~10KV, and the waiting time is 30s~120s; Step 3: Turn on the laser, adjust the laser parameters, and remove the paint layer on the surface of the sample.

2. The method for improving the quality of paint removal on the surface of metal sheet using electrostatic field as aid according to claim 1, characterized in that: The laser is a CO2 laser, a Nd:YAG laser or a fiber laser.

3. The method for improving the quality of paint removal on the surface of metal sheet using electrostatic field as aid according to claim 2, characterized in that: The laser wavelength range of the CO2 laser, Nd:YAG laser or fiber laser is 1um~100um.

4. The method for improving the quality of paint removal on the surface of metal sheet using electrostatic field as aid according to claim 1, characterized in that: In step 1, the metal plate is aluminum alloy, copper alloy or alloy steel.

5. The method for improving the quality of paint removal on the surface of metal sheet using electrostatic field as aid according to claim 1, characterized in that: In step 1, the thickness of the insulating pad is 3 mm to 10 mm.

6. The method for improving the quality of paint removal on the surface of metal sheet using electrostatic field as aid according to claim 1, characterized in that: In step 2, the electrostatic platform is made of aluminum alloy or copper alloy with a thickness of 5 mm to 20 mm.

7. The method for improving the quality of paint removal on the surface of a metal sheet with the aid of an electrostatic field according to any one of claims 1 to 5, characterized in that: It can also be used for laser removal of oxide layers on the surface of aluminum alloys and laser removal of rust on the surface of steel materials.

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