A method for applying coating to metal parts without local coating

Abstract

This invention relates to the field of paraffin technology, and more specifically, to a method for coating metal parts with partial uncoated areas. The method includes the following steps: Step 1: Pre-treating the metal part; Step 2: Loading the pre-treated metal part into a furnace, and applying paraffin material to the metal part through a deposition process to obtain a coated metal part; Step 3: Performing partial uncoating treatment on the coated metal part. The coating accuracy of this application is as follows: The coating thickness is uniform and controllable, within ±10%; Product appearance: The coating layer is undamaged in the coating area, the location of the local uncoated area is accurate, the film boundary is controlled within 0.5mm, there is no residual film layer in the uncoated area, and the product is undamaged. Automated operation is possible; Product flatness variation: The product tolerance and flatness variation are small, basically preserving the dimensional accuracy of the product itself; Voltage withstand test: Stable voltage withstand performance; Adhesion test: Good film adhesion, adhesion ≥4B.

Description

Technical Field

[0001] This invention relates to the field of paraffin technology, particularly to the field of IPC B05D 3 / 12, and more specifically, to a method for coating metal parts with partial non-coating. Background Technology

[0002] Parallelon coating is a process that applies a polymer coating to the surface of a substrate. In this process, the polymer coating can be in liquid, powder, or film form, and is typically applied by spraying, brushing, printing, or dipping. This process provides the substrate with properties such as abrasion resistance, corrosion resistance, water resistance, and heat insulation, while also improving the substrate's appearance and surface quality. Parallelon coating is widely used in various industries, including automotive, construction, aerospace, and electronics. Through precise coating techniques, it can achieve both protection and functional enhancement of the substrate. It is an important coating technology that is providing higher-quality products and solutions to various industries. However, current coating precision and flatness are not ideal, especially when applied to localized areas, as voltage resistance and adhesion are affected.

[0003] CN 117900096 A discloses a mandrel coating method and its application, comprising the following steps: S1, sandblasting: sandblasting the mandrel with sandblasting material; S2, cleaning: first cleaning the surface with diluted acid, then rinsing with deionized water; S3, pretreatment: soaking in a silane coupling agent; S4, coating: depositing parylene on the mandrel surface. The mandrel coating method described in this invention can simultaneously achieve mandrel lubrication performance and meet biocompatibility requirements; the lubrication friction coefficient is <0.25, but this invention does not involve a coating method for areas without coating. Summary of the Invention

[0004] This invention provides a method for applying a coating to a metal part without localized coating, comprising the following steps:

[0005] Step 1: Pre-treat the metal parts;

[0006] Step 2: Load the pre-treated metal parts into the furnace, and apply the paraffin material to the metal parts through a deposition process to obtain the coated metal parts;

[0007] Step 3: Perform localized uncoating treatment on the coated metal parts.

[0008] The pretreatment process includes, in sequence, grinding, sandblasting, cleaning, and bonding promotion treatment.

[0009] The grinding process uses grinding stones and rust-preventive oil, with the volume ratio of the grinding stones, rust-preventive oil, and metal parts being (10-30):(0.5-3):1.

[0010] The grinding stone includes at least one of brown corundum grinding stone, resin grinding stone, ceramic grinding stone, high-alumina ceramic grinding stone, and high-frequency ceramic grinding stone.

[0011] Preferably, the grinding stone includes at least one of brown fused alumina grinding stone and resin grinding stone.

[0012] The shape of the grinding stone includes at least one of the following: equilateral triangle, oblique triangle, oblique triangular shape, cone, cylinder, oblique cylinder, and sphere.

[0013] Preferably, the shape of the grinding stone includes at least one of an equilateral triangle, an oblique triangle, and a cone.

[0014] The grinding method includes one of rolling grinding, centrifugal grinding, and vortex grinding.

[0015] Preferably, the grinding method includes one of rolling grinding and vortex grinding.

[0016] The applicant's research found that the grinding process using grinding stones and rust-preventive oil, with a volume ratio of grinding stones, rust-preventive oil, and metal parts of (10-30):(0.5-3):1, not only removes sharp burrs generated during metal part processing but also maintains the dimensional accuracy of the product. This is likely due to the addition of rust-preventive oil during the grinding process, creating a wet lubrication state and preventing excessive wear of the metal parts caused by heat generated during grinding. Simultaneously, the specific amount of rust-preventive oil added maintains the contact area between the grinding stone and the metal parts, improving grinding efficiency. Further research revealed that by limiting the type and shape of the grinding stones and the grinding method, coating adhesion can be further improved, ensuring the coating's insulation performance. This may be due to improved matching of parameters such as hardness between the grinding stones and the metal parts, increasing the surface uniformity of the metal parts. Furthermore, the specific grinding method maintains a certain porosity, which is beneficial for improving the bonding force between the pararay material and the metal parts.

[0017] The sandblasting pressure is 0.8-5 MPa, and the sandblasting type is one of direct spraying, oblique spraying, or rotary spraying.

[0018] Preferably, the sandblasting pressure is 1-3 MPa, and the sandblasting type is rotary sandblasting.

[0019] More preferably, the sandblasting material is brown fused alumina with a mesh size of 80-120.

[0020] This research found that the sandblasting material is brown fused alumina with a mesh size of 80-120, and the sandblasting pressure is 1-3 MPa. This can further improve the adhesion between the sandblasting material and the coating. It is possible that the specific mesh size of the sandblasting material and the pressure are matched with the micropores on the surface of the ground metal part, achieving the effect of fixing the sandblasting material and thus improving the stability of the product. However, if the mesh size of the sandblasting material is too high, the surface roughness will be too large. If the mesh size is too low, the surface roughness will be insufficient, affecting the adhesion between the product and the coating. If the sandblasting pressure is too low, the surface roughness will be insufficient; if the sandblasting pressure is too high, it will easily cause product deformation.

[0021] The cleaning process uses a solvent-based cleaning solution, which includes one of alcohol solvents and hydrocarbon cleaning solutions.

[0022] The alcohol solvent includes at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, and ethylene glycol.

[0023] Preferably, the alcohol solvent includes at least one of ethanol, n-propanol, isopropanol, and ethylene glycol.

[0024] The hydrocarbon cleaning solution includes isoparaffin hydrocarbons.

[0025] Preferably, the isoalkane hydrocarbons include C8-C10 isoalkanes.

[0026] After cleaning, the surface tension of the metal parts is 38-44 dyn / cm.

[0027] Preferably, the surface tension of the metal part after cleaning is 42-44 dyn / cm.

[0028] The bonding-promoting treatment process includes plasma treatment and silane coupling agent immersion treatment.

[0029] The gases used in the plasma treatment include at least one of argon, nitrogen, oxygen, an argon-oxygen mixture, and hydrogen.

[0030] Preferably, the gas used in the plasma treatment includes at least one of argon, nitrogen, and an argon-oxygen mixture.

[0031] More preferably, the gas used in the plasma treatment includes argon, nitrogen, and an argon-oxygen mixture.

[0032] Preferably, the plasma power is 400-700W and the duration is 10-300s.

[0033] The silane coupling agent contains at least one of the following functional groups: acryloyloxy, allyl, vinyl, and alkoxysilane.

[0034] The alkoxysilane functional group includes at least one of methoxysilane, ethoxysilane, and isopropoxysilane.

[0035] Preferably, the silane coupling agent includes at least one of A174, A151, and KH570.

[0036] The parallax material includes at least one of unsubstituted diparaxylene (N type), dichlorosubstituted diparaxylene (C type), 4,7,12,15-tetrachlorosubstituted diparaxylene (D type), 3,4,11,12-tetrachlorosubstituted diparaxylene, 4,5,12,13-tetrachlorosubstituted diparaxylene, 4,5,12,13-tetrabromosubstituted diparaxylene, 1,1,2,2,9,9,10,10-octafluoro[2,2]diparaxylene (AF type), and 4,5,7,8,12,13,15,16-octafluorosubstituted diparaxylene.

[0037] Preferably, the parallax material includes at least one of dimeric p-xylene (N-type) and dichloro-substituted dimeric p-xylene (C-type).

[0038] More preferably, the pararayon material comprises dimeric p-xylene (N-type).

[0039] The furnace loading method includes either the threaded rod method or the wire rope method.

[0040] Preferably, the furnace loading tooling is pre-sandblasted before use.

[0041] Preferably, the furnace loading fixture includes a semi-enclosed square fixture.

[0042] The pyrolysis temperature in the deposition process is 630-670℃, the deposition pressure is 20-90 mtorr, and the center value of the deposition thickness is 10-100 μm.

[0043] Preferably, the deposition pressure includes a pre-deposition pressure and a post-deposition pressure, wherein the pre-deposition pressure is 20-60 mtorr and the post-deposition pressure is 60-90 mtorr.

[0044] The applicant's research found that the deposition pressure includes pre-deposition pressure and post-deposition pressure. The pre-deposition pressure is 20-60 mtorr, and the post-deposition pressure is 60-90 mtorr. This can improve the uniformity of film thickness and further improve voltage withstand performance. This may be to avoid excessively rapid voltage rise in the early stage. However, when the deposition pressure is high, the collision frequency between molecules increases, and the free path of evaporating molecules in the vacuum chamber is shortened, which leads to an increase in the film deposition rate on the substrate surface, resulting in uncontrollable deposition areas and problems such as uneven film thickness.

[0045] Further research by the applicant revealed that the partial non-coating method employs a laser method, in which the laser is rotated while the product is fixed. The relative angle between the coated metal part and the laser light source is 15-75°, ensuring precise control of the film boundary, which can be kept within 0.5mm. No residual film layer is found in the removal area, and the product remains undamaged. This method is particularly suitable for coated products containing internal holes. It is possible that the laser rotation angle is matched with specific tooling and furnace loading methods, further improving the automation of the coating process.

[0046] The method for controlling the deposition thickness includes one of the following: thickness center value control method, raw material control method, and online thickness measurement method.

[0047] Preferably, the method for controlling the deposition thickness includes online thickness measurement.

[0048] The ratio of the measured value to the controlled median thickness using the online thickness measurement method is fixed, with batch differences within 3%.

[0049] The method for treating areas without coating includes one of the following: plasma method, laser method, and sandblasting method.

[0050] Preferably, the method for treating the uncoated areas includes laser treatment.

[0051] The laser used in the laser method includes one of ultraviolet lasers and carbon dioxide lasers.

[0052] Preferably, the laser used in the laser method includes an ultraviolet laser.

[0053] The power of the ultraviolet laser is 5-100W; preferably, the power of the ultraviolet laser is 10-50W.

[0054] Preferably, the laser is rotated while the product is fixed, and the relative angle between the coated metal part and the laser light source is 15-75°.

[0055] The coating thickness error of the coating method is no higher than 10%.

[0056] The adhesion of the film obtained by the coating method is not less than 4B.

[0057] Beneficial effects:

[0058] 1. The grinding process uses grinding stones and rust-preventive oil, and the volume ratio of the grinding stones, rust-preventive oil and metal parts is (10-30):(0.5-3):1, which not only removes the sharp burrs generated during the processing of metal parts, but also maintains the dimensional accuracy of the product.

[0059] 2. The sandblasting material is brown corundum with a mesh size of 80-120, and the sandblasting pressure is 1-3 MPa, which can further improve the adhesion between the coating and the coating.

[0060] 3. The deposition pressure includes pre-deposition pressure and post-deposition pressure. The pre-deposition pressure is 20-60 mtorr, and the post-deposition pressure is 60-90 mtorr, which can improve the uniformity of film thickness and further improve voltage resistance.

[0061] 4. The partial non-coating method uses laser technology. The laser is rotated while the product is fixed. The relative angle between the coated metal part and the laser light source is 15-75°. The film boundary is accurately controlled and can be controlled within 0.5mm. There is no residual film layer in the film removal area and the product is undamaged. It is especially suitable for coated products with internal holes.

[0062] 5. The method for controlling the deposition thickness includes online thickness measurement, wherein the ratio of the measured value to the controlled median thickness is fixed, and the batch difference is within 3%.

[0063] 6. The coating method for metal parts in this application has a uniform and controllable coating thickness, and the error can be controlled within 10%. Detailed Implementation

[0064] Example 1

[0065] A method for applying a coating to a metal part that is not partially coated comprises the following steps:

[0066] Step 1: Pre-treat the metal parts;

[0067] Step 2: Load the pre-treated metal parts into the furnace, and apply the paraffin material to the metal parts through a deposition process to obtain the coated metal parts;

[0068] Step 3: Perform localized uncoating treatment on the coated metal parts.

[0069] The pretreatment process consists of the following steps: grinding, sandblasting, cleaning, and bonding promotion treatment.

[0070] The grinding process uses grinding stones and rust-preventive oil, with the volume ratio of the grinding stones, rust-preventive oil, and metal parts being 20:1.5:1.

[0071] The grinding stone is a brown corundum grinding stone; the shape of the grinding stone is an equilateral triangle.

[0072] The grinding method is rolling grinding.

[0073] The sandblasting pressure is 2 MPa, and the sandblasting type is rotary sandblasting.

[0074] The material used for sandblasting is brown corundum with a mesh size of 100.

[0075] The cleaning process uses a solvent-based cleaning solution, which is an alcohol-based solvent, specifically ethanol.

[0076] The bonding-promoting treatment process involves immersion in a silane coupling agent; the silane coupling agent is A174.

[0077] The para-xylene material is dimeric p-xylene (N-type).

[0078] The furnace loading method is a threaded rod method, and the furnace loading tooling is pre-sandblasted before use.

[0079] The furnace loading fixture is a semi-enclosed square fixture.

[0080] The pyrolysis temperature in the deposition process is 650℃, the pressure before deposition is 50 mtorr, the pressure after deposition is 80 mtorr, and the center value of the deposition thickness is 40 μm.

[0081] The method for controlling the deposition thickness is online thickness measurement.

[0082] Online thickness measurement: Through online thickness monitoring at fixed locations, under stable environmental and process conditions, the ratio of the online thickness measurement value to the controlled median thickness is fixed.

[0083] The method for treating the uncoated areas is a laser method; the laser used in the laser method is an ultraviolet laser; the power of the ultraviolet laser is 30W. The laser is rotatable, and the relative angle between the coated metal part and the laser light source is 15-75°.

[0084] Example 2

[0085] The specific implementation method is the same as in Example 1; the difference is that in Example 2, the bonding promotion treatment process is plasma treatment and silane coupling agent immersion treatment (60 min); the gas used in the plasma treatment is argon.

[0086] The plasma has a power of 500W and a duration of 200s.

[0087] The silane coupling agent is A174.

[0088] Example 3

[0089] The specific implementation method is the same as in Example 1; the difference is that in Example 3, the pretreatment process is as follows: cleaning and adhesion promotion treatment.

[0090] The cleaning process uses a solvent-based cleaning solution, which is an alcohol-based solvent, specifically ethanol.

[0091] The bonding-promoting treatment process involves immersion in a silane coupling agent; the silane coupling agent is A174.

[0092] Example 4

[0093] The specific implementation method is the same as in Example 1; the difference is that in Example 4, the pretreatment process is as follows: cleaning and adhesion promotion treatment.

[0094] The cleaning process uses a solvent-based cleaning solution, which is an alcohol-based solvent, specifically ethanol.

[0095] The bonding-promoting treatment process consists of plasma treatment and silane coupling agent immersion treatment; the gas used in the plasma treatment is argon, nitrogen and argon-oxygen mixture.

[0096] The plasma has a power of 500W and a duration of 200s.

[0097] The silane coupling agent is A174.

[0098] Example 5

[0099] The specific implementation method is the same as in Example 1; the difference is that in Example 5, the pretreatment process is as follows: sandblasting, cleaning and bonding promotion treatment.

[0100] The sandblasting pressure is 2 MPa, and the sandblasting type is rotary sandblasting.

[0101] The material used for sandblasting is brown corundum with a mesh size of 100.

[0102] The cleaning process uses a solvent-based cleaning solution, which is an alcohol-based solvent, specifically ethanol.

[0103] The bonding-promoting treatment process consists of plasma treatment and silane coupling agent immersion treatment; the gas used in the plasma treatment is argon, nitrogen and argon-oxygen mixture.

[0104] The plasma has a power of 500W and a duration of 200s.

[0105] The silane coupling agent is A174.

[0106] Example 6

[0107] The specific implementation method is the same as in Example 1; the difference is that in Example 6, the pretreatment process is as follows: sandblasting, cleaning and bonding promotion treatment.

[0108] The sandblasting pressure is 2 MPa, and the sandblasting type is rotary sandblasting.

[0109] The material used for sandblasting is brown corundum with a mesh size of 100.

[0110] The cleaning process uses a solvent-based cleaning solution, which is an alcohol-based solvent, specifically ethanol.

[0111] The bonding-promoting treatment process involves immersion in a silane coupling agent; the silane coupling agent is A174.

[0112] Example 7

[0113] The specific implementation method is the same as in Example 1; the difference is that in Example 7, the furnace loading method is hook loading (single products are loaded using hooks), and the furnace loading tooling is not pre-sandblasted before use.

[0114] Example 8

[0115] The specific implementation method is the same as in Example 1; the difference is that in Example 8, the furnace loading method is a smooth rod mounting (using a smooth gold plastic rod mounting), and the furnace loading tool is not pre-sandblasted before use.

[0116] Example 9

[0117] The specific implementation method is the same as in Example 1; the difference is that in Example 9, the furnace loading method is steel rope loading (using multi-strand wound steel wire rope loading), and the furnace loading tooling is not pre-sandblasted before use.

[0118] Example 10

[0119] The specific implementation method is the same as in Example 1; the difference is that in Example 10, the furnace loading method is the threaded rod method, and the furnace loading tool is not pre-sandblasted before use.

[0120] Example 11

[0121] The specific implementation method is the same as in Example 1; the difference is that in Example 11, the furnace loading fixture is a circular parallel furnace loading fixture, an open fixture.

[0122] Example 12

[0123] The specific implementation method is the same as in Example 1; the difference is that in Example 12, the furnace loading fixture is a ring-shaped furnace loading fixture, an open fixture.

[0124] Example 13

[0125] The specific implementation method is the same as in Example 1; the difference is that in Example 13, the furnace loading fixture is a square furnace loading fixture, an open fixture.

[0126] Example 14

[0127] The specific implementation method is the same as in Example 1; the difference is that in Example 14, the method for controlling the deposition thickness is the raw material control calculation method.

[0128] Specifically: Raw material control calculation method = (tooling material coefficient + coating cavity material coefficient + product material coefficient) * coating thickness control median coefficient.

[0129] Example 15

[0130] The specific implementation method is the same as in Example 1; the difference is that in Example 15, the pyrolysis temperature in the deposition process is 650°C, the deposition pressure is 85 mtorr, and the center value of the deposition thickness is 41 μm.

[0131] Example 16

[0132] The specific implementation method is the same as in Example 1; the difference is that in Example 16, the method for treating the local uncoated areas is a method of removing the mask after applying a jig mask.

[0133] Example 17

[0134] The specific implementation method is the same as in Example 1; the difference is that in Example 17, the laser is a fixed angle laser with both front and back sides.

[0135] Example 18

[0136] The specific implementation method is the same as in Example 1; the difference is that in Example 18, the laser is fixed at an angle and the product is rotated.

[0137] Example 19

[0138] The specific implementation method is the same as in Example 1; the difference is that in Example 19: a carbon dioxide laser, the laser is fixed at an angle, and the product is rotated.

[0139] Performance testing methods

[0140] The performance of the partially uncoated metal parts prepared in the examples was tested, and the test data are listed in Tables 1-7.

[0141] 1. Pre-processing efficiency:

[0142]

[0143] 2. Adhesion:

[0144]

[0145] 3. Withstand voltage performance:

[0146]

[0147] 4. Mounting efficiency:

[0148]

[0149] 5. Removal efficiency:

[0150]

[0151] 6. Product Appearance (Film Appearance)

[0152]

[0153] 7. Thickness uniformity:

[0154]

[0155] 8. Thickness accuracy:

[0156]

[0157]

[0158] 9. Thickness repeatability:

[0159]

[0160] 10. Coating efficiency:

[0161]

[0162] 11. Degree of automation:

[0163]

[0164] 12. Membrane interface dimensions:

[0165]

[0166] Performance test data

[0167] Table 1

[0168] Example 1 Example 2 Preprocessing efficiency ★★★ ★★ Adhesion ★★★★★ ★★★★★ withstand voltage performance ★★★★★ ★★★★★ racking efficiency ★★★★ ★★★★ Removal efficiency ★★★★ ★★★★ Product Appearance ★★★★★ ★★★★★ Thickness uniformity ★★★★★ ★★★★★ Thickness accuracy ★★★★★ ★★★★★ Thickness repeatability ★★★★★ ★★★★★ Application efficiency ★★★★★ ★★★★★ Automation level ★★★★★ ★★★★★ Membrane interface size ★★★★★ ★★★★★

[0169] Table 2

[0170] Preprocessing efficiency Adhesion withstand voltage performance Example 3 ★★★★★ ★★ ★★ Example 4 ★★★★ ★★★ ★★★ Example 5 ★★★ ★★★★ ★★★★ Example 6 ★★★★ ★★★★★ ★★★★

[0171] Table 3

[0172] racking efficiency Removal efficiency Product Appearance Example 7 ★ ★ ★★ Example 8 ★★★★ ★★★★★ ★★★ Example 9 ★★★ ★★★★★ ★★★★★ Example 10 ★★★★ ★★★★ ★★★★

[0173] Table 4

[0174]

[0175]

[0176] Table 5

[0177] Thickness accuracy Thickness repeatability Application efficiency Example 14 ★★★ ★★★ ★★★

[0178] Table 6

[0179] Thickness uniformity Product Appearance withstand voltage performance Example 15 ★★★ ★★★ ★★★★

[0180] Table 7

[0181] Automation level Membrane interface size Product Appearance Example 16 ★ ★ ★ Example 17 ★★ ★★★★★ ★ Example 18 ★★★★★ ★★★★★ ★★★★ Example 19 ★★★★★ ★★★ ★★★

Claims

1. A method for applying a coating to a metal part without localized coating, characterized in that, Includes the following steps: Step 1: Pre-treat the metal parts; Step 2: Load the pre-treated metal parts into the furnace, and apply the paraffin material to the metal parts through a deposition process to obtain coated metal parts; Step 3: Perform localized uncoating treatment on the coated metal parts; The pretreatment process includes, in sequence: grinding, sandblasting, cleaning and bonding promotion treatment; the grinding uses grinding stones and rust-preventive oil, and the volume ratio of the grinding stones, rust-preventive oil and metal parts is (10-30):(0.5-3):1; The sandblasting pressure is 1-3 MPa, and the sandblasting material is brown corundum with a mesh size of 80-120 mesh. The furnace loading method includes either the threaded rod method or the wire rope method.

2. The method for coating partially uncoated metal parts according to claim 1, characterized in that, The bonding-promoting treatment process includes plasma treatment and silane coupling agent immersion treatment.

3. The method for coating partially uncoated metal parts according to claim 2, characterized in that, The pyrolysis temperature in the deposition process is 630-670℃, the deposition pressure is 20-90 mtorr, and the center value of the deposition thickness is 10-100 μm.

4. The method for coating partially uncoated metal parts according to claim 3, characterized in that, The method for controlling the deposition thickness includes one of the following: thickness center value control method, raw material control method, and online thickness measurement method.

5. The method for coating partially uncoated metal parts according to claim 4, characterized in that, The method for treating areas without coating includes one of the following: plasma method, laser method, and sandblasting method.

6. The method for coating partially uncoated metal parts according to claim 1 or 5, characterized in that, The coating thickness error of the coating method is no higher than 10%.

7. The method for coating partially uncoated metal parts according to any one of claims 1-6, characterized in that, The adhesion of the film obtained by the coating method is not less than 4B.

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