A method of calibrating a curved surface coating thickness measurement
By machining arc segments and fabricating calibration plates on the calibration device, and combining them with a digital thickness gauge, the problems of accuracy and efficiency in measuring the thickness of coatings on curved surfaces were solved, enabling efficient and accurate measurement of complex curved surfaces.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LANDING GEAR ADVANCED MFG
- Filing Date
- 2025-12-03
- Publication Date
- 2026-08-04
AI Technical Summary
Existing technologies are insufficient for accurately measuring the thickness of coatings on curved surfaces, and traditional methods are prone to damaging the coating or having large errors, failing to meet the measurement requirements for complex curved surfaces.
By combining a dedicated calibration device with a digital thickness gauge, and by machining an arc segment on the calibration device and making a calibration piece, an application program is established to perform multi-point measurements and calibrations to ensure that the readings are within the set range, thus achieving accurate measurement of the coating thickness.
It improves the accuracy and efficiency of coating thickness measurement on curved surfaces, avoids coating damage, is suitable for measuring complex curved surfaces, and features simple operation and high precision.
Smart Images
Figure CN121452985B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of machining technology, and in particular to a calibration method for measuring the thickness of a curved surface coating. Background Technology
[0002] Controlling the coating thickness is crucial to product performance. For example, with cadmium-plated parts, if the coating is too thin, the parts will have poor corrosion resistance; if the coating is too thick, the parts will have poor adhesion, reduced fatigue performance, and may even lead to hydrogen embrittlement fracture. Therefore, it is necessary to strictly control the coating thickness.
[0003] There are two main methods for measuring the thickness of coatings on curved surfaces: I. Indirect Measurement Method: This method involves using inside and outside micrometers to measure the dimensions of internal holes and external circles before and after plating, and then calculating the plating thickness. This method is labor-intensive, time-consuming, and prone to damaging the plating. Furthermore, the measurement points before and after plating cannot be guaranteed to be in the same location, leading to significant errors in the calculated plating thickness and a high rework rate. Additionally, the indirect method cannot be used to measure the thickness of some irregular, non-mating curved surfaces. II. Direct Measurement Method: This method uses a digital thickness gauge. It is accurate and does not easily damage the coating. The standard calibration block provided with the thickness gauge is generally a flat plate. This calibration block is more accurate for readings on flat surfaces, but the error is larger when measuring curved surfaces. Summary of the Invention
[0004] The purpose of this invention is to provide a calibration method for measuring the thickness of curved surface coatings, thereby improving the accuracy of curved surface coating thickness measurement.
[0005] The technical solution of this invention is: a calibration method for measuring the thickness of a curved surface coating, comprising: Step 1: Machining a calibration device, wherein the calibration device has at least one arc segment with a certain diameter; Step 2: Process calibration pieces according to the coating thickness; Step 3: Create at least one application package on the thickness gauge; Step 4: Perform multiple measurements on a circular arc segment of a certain diameter using the thickness gauge probe, and reset the measurement value at each point to zero to complete the application setup. Step 5: Open the application created in Step 3. Place the calibration piece at a certain position on the arc segment surface from Step 3. Then, bring the probe into contact with the calibration piece to obtain a reading. If the reading is not within the set measurement thickness range, adjust the application until the reading is within the set measurement thickness range. Then, place the calibration piece at the next position on the arc segment surface and obtain a second reading, ensuring that this reading is within the measurement thickness range. Repeat the above steps to obtain multiple readings. The calibration of the application is now complete. Step six: Retrieve the calibrated application to measure the curved surfaces on the part.
[0006] Preferably, two calibration plates are processed, wherein the difference between the reading obtained by the first calibration plate and the upper limit of the set measurement thickness value is ≤15%, and the difference between the reading obtained by the second calibration plate and the lower limit of the set measurement thickness value is ≤15%.
[0007] Preferably, multiple calibration pieces are processed according to the range of coating thickness values, and the multiple calibration pieces are calibrated in order from thinnest to thickest.
[0008] Preferably, during measurement, the probe is perpendicular to the contact surface of the arc segment; and the probe is lifted vertically before measuring the next point.
[0009] Preferably, the material, shape, and size of each arc segment on the calibration device are the same as the corresponding part being measured.
[0010] Compared with related technologies, the beneficial effects of the present invention are as follows: I. This invention forms a curved surface by creating a special calibration device with an arc segment. When used in conjunction with a thickness gauge, it can quickly complete the calibration and thickness measurement of inner holes, convex curved surfaces, and concave curved surfaces of different sizes. This can improve the accuracy of coating thickness measurement on curved surfaces and improve the measurement precision and efficiency of coating thickness on curved surfaces. II. This invention combines a digital thickness gauge with a rapid calibration device to solve the problems of easy damage to the coating surface and large measurement errors and low efficiency when using measuring tools such as inside micrometers and inside gauges to measure the thickness of coatings on complex curved surfaces. This invention has the characteristics of simple structure, easy manufacturing and strong versatility. The calibration method has the characteristics of simple operation, high efficiency in detecting the thickness of coatings on curved surfaces and accurate detection data. Attached Figure Description
[0011] Figure 1 A schematic diagram of the structure integrating concave features for the calibration device; Figure 2 A schematic diagram of a structure integrating convex features into a calibration device; Figure 3 A schematic diagram of probe measurements when setting up application 1; Figure 4 A schematic diagram of probe readings acquired during calibration application 1; Figure 5 A schematic diagram of probe measurements when setting up application 3; Figure 6 This is a schematic diagram of the probe acquiring readings when calibrating application 3. Detailed Implementation
[0012] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. For ease of description, the terms "upper," "lower," "left," and "right" used below only indicate that they correspond to the upper, lower, left, and right directions in the accompanying drawings and do not limit the structure.
[0013] Taking a 300M steel part as an example, the cadmium plating thickness was measured on the outer diameters of R50mm±0.03mm and R60mm±0.1mm, and the inner concave diameters of R25mm±0.25mm and R40mm±0.25mm. The required plating thickness is 10-35μm.
[0014] The calibration method for measuring the thickness of a curved surface coating provided in this embodiment includes the following steps: (a) Calibration of the outer convex surface with R50mm±0.03mm and R60mm±0.1mm: Step 1, processing as follows Figure 2 The integrated convex calibration device A' shown is made of 300M steel. The calibration device has multiple arc segments with diameter values, such as R50mm and R60mm.
[0015] Step 2: Process two calibration plates B with thicknesses of 10μm±1.5μm and 35μm±5μm.
[0016] Step 3: Turn on the digital thickness gauge, install the battery and probe, and turn on the power. Create Application 1 (R50mm) and Application 2 (R60mm) for two sizes, R50mm and R60mm respectively. The two application packages are similar to empty folders.
[0017] Step 4: Select application 1 created in Step 1, press the ZERO key to start zeroing the application, and use probe C to measure on calibration block A' with a convex surface R50mm. Figure 3 (As shown), perform at least 5 measurements, then press ENTER to zero the reading. During the measurement, keep probe C perpendicular and stable to the contact surface, then lift probe C to take the next reading. Do not let probe C hover above the calibration block to avoid erroneous readings. This completes the setup of Application 1.
[0018] Step 5: Open the newly created application 1 using the CAL key and calibrate it: First, use probe C to measure 3-5 times on the convex R50mm calibration block A. Then place the 10μm calibration piece B on the convex R50mm calibration block A and measure 3-5 times (e.g., ...). Figure 4(As shown). During measurement, keep the probe perpendicular and stable to the contact surface, then lift the probe to take the next reading. When obtaining each reading, compare its deviation from the set measurement thickness range. If the reading exceeds or falls below the set measurement thickness range, press the up or down key on the thickness gauge to adjust the reading until it falls within the set measurement thickness range, and update application 1. Finally, place the 35μm calibration piece B on the convex R50mm calibration block A and measure 3-5 times, ensuring that each reading is within the set measurement thickness range. Complete the calibration of application 1.
[0019] The thickness of the first calibration piece should not differ from the upper limit of the measured thickness range by more than 15%, and the thickness of the second calibration piece should not differ from the lower limit of the measured thickness range by more than 15%. Calibration should be performed in order of thickness from thinnest to thickest.
[0020] Repeat steps three and five to complete the calibration of application 2.
[0021] (ii) Measurement of cadmium plating thickness on concave surfaces of R25mm and R40mm inner cavities Step 1, processing as follows Figure 1 The calibration device shown is an integrated concave calibration device A" made of 300M steel. The calibration device has arc segments with multiple diameter values, such as R25mm and R40mm.
[0022] Step 2: Process two calibration plates B with thicknesses of 10μm±1.5μm and 35μm±5μm.
[0023] Step 3: Turn on the digital thickness gauge, install the battery and probe and turn on the power. Create Application 3 (R40mm) and Application 4 (R25mm) for two sizes, R40mm and R25mm respectively.
[0024] Step 4, select application 3, press the ZERO key to start zeroing the application, and use probe C to measure on the calibration block A" with a concave R40mm surface. Figure 5 (As shown), the measurement should be performed at least 5 times, and press ENTER to reset to zero.
[0025] Step 5, press the CAL key to open application 3 and calibrate it: first use probe C to measure 3-5 times on the calibration block, then place the 10μm calibration piece on the calibration block. Figure 6 (As shown), measure 3-5 times, and finally place the 35μm calibration piece on the calibration block and measure 3-5 times to complete the calibration of application 3 (the calibration method is the same as application 1).
[0026] Repeat steps three and five to complete the calibration of application 4.
[0027] After calibration, select the corresponding application for the specified dimensions, measure and collect data on the curved surface of the part. Record and analyze the data to obtain the maximum, minimum, average, and standard deviation of the coating thickness. Measurement complete.
[0028] To ensure measurement accuracy, the application needs to be recalibrated after 50 measurements.
[0029] Based on the curved surface features of the special structure of the test part, this invention collects the part size and manufactures a series of integrated calibration blocks with the same material, size and surface condition as the test part. The integrated blocks have multiple size features, which improves calibration efficiency and quality and facilitates tooling management on the production site.
[0030] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.
Claims
1. A calibration method for measuring the thickness of a curved surface coating, characterized in that, include: Step 1: Machining a calibration device, wherein the calibration device has at least one arc segment with a certain diameter; Step 2: Process calibration pieces according to the coating thickness; Step 3: Create at least one application package on the thickness gauge; Step 4: Perform multiple measurements on a circular arc segment of a certain diameter using the thickness gauge probe, and reset the measurement value at each point to zero to complete the application setup. Step 5: Open the application created in Step 3. Place the calibration piece at a certain position on the arc segment surface from Step 3. Then, bring the probe into contact with the calibration piece to obtain a reading. If the reading is not within the set measurement thickness range, adjust the application until the reading is within the set measurement thickness range. Then, place the calibration piece at the next position on the arc segment surface and obtain a second reading, ensuring that this reading is within the measurement thickness range. Repeat the above steps to obtain multiple readings. The calibration of the application is now complete. Step six: Retrieve the calibrated application to measure the curved surfaces on the part.
2. The method of calibrating curved coating thickness measurements of claim 1, wherein, Two calibration pieces are processed. The difference between the reading obtained from the first calibration piece and the upper limit of the set measurement thickness value is ≤15%, and the difference between the reading obtained from the second calibration piece and the lower limit of the set measurement thickness value is ≤15%.
3. The method of calibrating curved coating thickness measurements of claim 1, wherein, Multiple calibration pieces are processed according to the range of coating thickness values, and the multiple calibration pieces are calibrated in order from thinnest to thickest.
4. The method of calibrating curved coating thickness measurements of claim 1, wherein, During measurement, the probe is perpendicular to the contact surface of the arc segment; and the probe is lifted vertically before measuring the next point.
5. The method of calibrating curved coating thickness measurements of claim 1, wherein, The material, shape, and size of each arc segment on the calibration device are the same as the corresponding part being measured.