Dimension compensation method for printing roller forming

Abstract

The invention relates to a size compensation method for forming a plate roller, which specifically comprises the following steps of: placing a straight plate on a plate rolling machine, and inputting the perimeter and the material of the plate roller into the plate rolling machine; the plate rolling machine measures the actual length and thickness of the straight plate and the environment temperature in real time; a compensation model is established according to the actual length, thickness, material and environment temperature, a compensation value is given, and a compensation perimeter is calculated by combining the perimeter of the printing roller and the compensation value; the veneer reeling machine determines the lengths of the two straight edge parts according to the compensation perimeter, the length of the joint part, the lengths of the two edge closing parts and the arc lengths of the first arc part and the two second arc parts; and the plate rolling machine is used for plate making according to the length of each part. According to the method, the compensation model is established according to the actual length, thickness, material and environment temperature, the compensation value is given, the compensation perimeter is calculated according to the compensation value, compensation is carried out in the process of bending the straight plate into the plate roller, and the final forming precision of the plate roller is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of printing roller forming technology, and in particular to a method for dimensional compensation in printing roller forming. Background Technology

[0002] The purpose of plate rolling is for welding after seam joining. Existing automatic plate rolling systems require adjustments to meet requirements when product specifications or materials change frequently due to frequent product specification changes. To reduce influencing factors and achieve automated plate rolling, adjustments should be made only once to meet the production needs of different specifications when material properties change. Different materials and thicknesses of plates differ in terms of stress deformation and coefficient of thermal expansion. If uniform adjustment parameters are used, accuracy fluctuations can easily occur due to material mismatch. Compensation is needed during plate making to ensure the accuracy of the plate rollers.

[0003] The invention patent with publication number CN112894013A discloses a processing method for a pre-compensated molding roller, which relates to the technical field of molding roller processing methods. It solves the common problem of deformation during the operation of traditional molding rollers, where high-temperature areas bulge due to thermal expansion and low-temperature areas shrink and sink due to cooling, resulting in lateral bending deformation of the entire roller. The greater the temperature difference, the greater the deformation, leading to unstable film feeding and affecting product quality. The key technical point is to heat the hot area of ​​the workpiece roller to a set temperature t1 and cool the cold area of ​​the workpiece roller to a set temperature t2; and calculate the lateral bending deformation d of the workpiece roller. However, this patent only compensates based on temperature changes, and the compensation factor is singular.

[0004] Therefore, providing a multi-factor compensation method is an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of the prior art and provide a dimensional compensation method for printing roller forming.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] According to one aspect of the present invention, a method for dimensional compensation in printing roller forming is provided. The method involves controlling a plate rolling machine to form a printing roller of a preset size from a straight plate. The printing roller includes a first arc portion, a seam portion, two second arc portions, two straight edge portions, and two edge-receiving portions. The method specifically includes:

[0008] S1. Place the straight plate on the plate rolling machine and input the circumference of the plate roller and the material into the plate rolling machine;

[0009] S2. The plate rolling machine measures the actual length and thickness of the straight plate and the ambient temperature in real time.

[0010] S3. Establish a compensation model based on the actual length, thickness, material and ambient temperature, and give the compensation value. Calculate the compensation perimeter by combining the circumference of the printing roller and the compensation value.

[0011] S4. The plate rolling machine determines the length of the two straight edges based on the compensation perimeter, the length of the joint, the length of the two edge-cutting parts, and the arc length of the first arc part and the two second arc parts.

[0012] S5. The plate rolling machine makes plates according to the length of each part.

[0013] As a preferred technical solution, the establishment of the compensation model in step S3 specifically includes:

[0014] S31. Collect the ambient temperature, thickness, length and material data of the straight plate before roller making, as well as the length of the roller, the length of the joint, the length of the two edge-tightening parts, and the arc length data of the first arc part and the two second arc parts after roller forming.

[0015] S32. Use the data before and after the same straight plate is formed into the same set of training data.

[0016] S33. Create different straight-board designs and obtain multiple sets of training data;

[0017] S34. Using a random forest regression model, multiple sets of training data are used as training sets to establish the difference relationship between before and after roll forming, and a compensation model is obtained.

[0018] As a preferred technical solution, the specific process for obtaining the compensation value is as follows:

[0019] S35. Normalize the actual length, thickness, material and ambient temperature of the current roller plate and form an array;

[0020] S36. Input the array into the loaded compensation model, calculate the prediction error and extract the prediction error value;

[0021] S37. Transform the predicted error value into the actual error value, use the actual error value as the compensation value, and calculate the compensation circumference in combination with the circumference of the printing roller.

[0022] As a preferred technical solution, the material is encoded using a unique thermal coding system for the printing roller.

[0023] As a preferred technical solution, the seam portion is formed by two edge-sealing portions.

[0024] As a preferred technical solution, the printing roller is divided into an edge-receiving section, a second arc section, a straight section, a first arc section, a straight section, a second arc section, and an edge-receiving section in sequence.

[0025] As a preferred technical solution, the two edge-receiving portions, the two second arc portions, and the two straight portions are all symmetrical about the axis of the first arc portion.

[0026] As a preferred technical solution, the two edge portions are the same size, the two second arc portions are the same size, and the two straight portions are the same size.

[0027] As a preferred technical solution, the dimensions of the two straight sections are determined by subtracting the dimensions of the first arc section, the seam section, the two second arc sections, and the two edge-finishing sections from the compensated perimeter.

[0028] As a preferred technical solution, the dimensions of the first arc portion, the seam portion, the two second arc portions, and the two edge-finishing portions are fixed.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. This invention establishes a multi-factor compensation model based on actual length, thickness, material and ambient temperature, reveals the coupling relationship between different factors and gives compensation values, thereby calculating the compensation perimeter, and compensating for the process of bending straight plates into printing rollers to ensure the accuracy of the final forming of the printing rollers.

[0031] 2. The first arc portion, the seam portion, the two second arc portions, and the two edge-cutting portions of the present invention are all fixed dimensions. The circumference of the printing roller is the active dimension, and the dimensions of the two straight plate portions are the passive dimensions. When the circumference of the printing roller changes, the dimensions of the straight plate portions change accordingly, which simplifies the plate-making process. Different specifications of printing rollers can be produced simply by inputting the circumference.

[0032] 3. In this invention, the parameters are first normalized to calculate the prediction error value. This prediction error value has no actual physical meaning and needs to be converted into an actual error value based on a preset range. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the printing roller of the present invention;

[0034] Figure 2 This is a schematic diagram of the printing roller forming process of the present invention;

[0035] Figure 3 A schematic diagram illustrating the process of establishing the compensation model for this invention;

[0036] Figure 4 This is a schematic diagram of the process for calculating the supplementary perimeter in this invention;

[0037] 1. Seam section; 2. Edge finishing section; 3. Second arc section; 4. Straight section; 5. First arc section. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0039] Example 1

[0040] like Figures 1-4 As shown, a dimensional compensation method for forming printing rollers is disclosed. The method involves controlling a plate rolling machine to form a printing roller of a preset size from a straight plate. The printing roller includes a first arc portion 5, a seam portion 1, two second arc portions 3, two straight edge portions 4, and two edge-receiving portions 2. The method specifically includes:

[0041] S1. Place the straight plate on the plate rolling machine and input the circumference of the plate roller and the material into the plate rolling machine;

[0042] S2. The plate rolling machine measures the actual length and thickness of the straight plate and the ambient temperature in real time.

[0043] S3. Establish a compensation model based on the actual length, thickness, material and ambient temperature, and give the compensation value. Calculate the compensation perimeter by combining the circumference of the printing roller and the compensation value.

[0044] S4. The plate rolling machine determines the length of the two straight edge parts 4 based on the compensation perimeter, the length of the joint part 1, the length of the two edge-receiving parts 2, and the arc length of the first arc part 5 and the two second arc parts 3.

[0045] S5. The plate rolling machine makes plates according to the length of each part.

[0046] The establishment of the compensation model in step S3 specifically includes:

[0047] S31. Collect the ambient temperature, thickness, length and material data of the straight plate before roller making, as well as the length of the roller after roller forming, the length of the joint 1, the length of the two edge-gathering parts 2, and the arc length data of the first arc part 5 and the two second arc parts 3.

[0048] S32. Use the data before and after the same straight plate is formed into the same set of training data.

[0049] S33. Create different straight-board designs and obtain multiple sets of training data;

[0050] S34. Using a random forest regression model, multiple sets of training data are used as training sets to establish the difference relationship between before and after roll forming, and a compensation model is obtained.

[0051] The specific process for obtaining the compensation value is as follows:

[0052] S35. Normalize the actual length, thickness, material and ambient temperature of the current roller plate and form an array;

[0053] S36. Input the array into the loaded compensation model, calculate the prediction error and extract the prediction error value;

[0054] S37. Transform the predicted error value into the actual error value, use the actual error value as the compensation value, and calculate the compensation circumference in combination with the circumference of the printing roller.

[0055] The material is coded using a unique thermal coding system for the printing roller.

[0056] In this embodiment, a laser displacement sensor is used to measure the actual length of the straight plate; a laser thickness gauge is used to measure the thickness of the straight plate; and a temperature and humidity sensor and a high-precision handheld thermometer and hygrometer are used to measure the ambient temperature.

[0057] Compensated perimeter = Compensation value + Actual perimeter. Actual perimeter = Length of seam 1 + Length of two edge trims 2 + Arc length of the first arc 5 + Arc length of the two second arcs 3 + Length of the two straight edges. The compensated perimeter is the perimeter used by the industrial computer of this invention when performing the plate rolling operation.

[0058] Model loading:

[0059] In the industrial computer of the plate rolling machine control system, historical data is used as the training set for training. This historical data includes the actual length of the plate before it is made into a rolling mill, the circumference of the rolled mill after it is made, and the length of each structural component. Temperature and plate thickness information are also recorded. A traditional machine learning model (such as a random forest) is first trained, then converted to ONNX format. The trained model file (roller_error_rf_model.onnx) is loaded through the ONNX Runtime. A code example is shown below:

[0060] import onnxruntime as ort

[0061] import numpy as np

[0062] #Load ONNX model

[0063] ort_session=ort.InferenceSession("roller_error_rf_model.onnx")

[0064] #Get the model input node name (same as during training, such as "input")

[0065] input_name=ort_session.get_inputs()[0].name

[0066] #Get the shape of the input tensor (e.g., [1,4], representing 1 sample and 4 features)

[0067] input_shape=ort_session.get_inputs()[0].shape

[0068] Normalize the printing roller circumference, actual length, thickness, and ambient temperature. Assume the input printing roller circumference is 150.000, the measured actual length is 149.998, the ambient temperature is 25.2, and the sheet material code is 1 (304 stainless steel, with the unique thermal code being the first value in [1, 0, 0]). For example, the ambient temperature during training... min =15℃, x max =35℃, the normalized value for the current ambient temperature of 25.2℃ is:

[0069]

[0070] Organize the normalized values ​​into a NumPy array with the shape consistent with the model input requirements (e.g., [1, 4]), as shown in the example below: input_data = np.array([[150.000, 149.998, 0.51, 1]], dtype = np.float32).

[0071] Input the loaded ONNX model with input_data, and call the inference engine to calculate the prediction error. An example code is shown below:

[0072] #Execution Model Inference

[0073] outputs=ort_session.run(None,{input_name:input_data})

[0074] # Extract prediction error values ​​(outputs is a list, the first element is the prediction result)

[0075] predicted_error = outputs[0][0] # Example result: 0.7

[0076] The predicted error value needs to be restored to the actual error value through inverse transformation. For example, if the error range [-0.01mm, 0.01mm] is standardized to [0, 1], then the inverse transformation formula is:

[0077] y = y p ×(y max -y min)+y min =0.7×(0.01-(-0.01))+(-0.01)=0.004mm

[0078] y p For the prediction error value, y max The upper limit of the range is 0.01 mm, y min The lower limit of the range is -0.01mm.

[0079] The predicted error value (e.g., 0.004 mm) is transmitted in real time to the plate rolling machine's adjustment and control system to calculate the pre-compensation value for the straight edge length.

[0080] If the prediction error is positive (e.g., +0.004mm), it means that the actual length will be 0.004mm longer than the set value. Therefore, the target value should be adjusted to -0.004mm (e.g., 150.000 - 0.004 = 149.996mm).

[0081] If the prediction error is negative (e.g., -0.003mm), it means that the actual length will be 0.003mm shorter than the set value, and the target value should be adjusted to +0.003mm.

[0082] The seam portion 1 is formed by two edge-sealing portions 2.

[0083] The printing roller is divided into edge-receiving section 2, second arc section 3, straight section 4, first arc section 5, straight section 4, second arc section 3 and edge-receiving section 2 in sequence.

[0084] The two edge-receiving portions 2, the two second arc portions 3, and the two straight portions 4 are all symmetrical about the axis of the first arc portion 5.

[0085] The two edge-finishing portions 2 are the same size, the two second arc portions 3 are the same size, and the two straight portions 4 are the same size.

[0086] The dimensions of the two straight sections 4 are determined by subtracting the dimensions of the first arc section 5, the seam section 1, the two second arc sections 3, and the two edge-finishing sections 2 from the compensation perimeter.

[0087] The dimensions of the first arc portion 5, the seam portion 1, the two second arc portions 3, and the two edge-finishing portions 2 are fixed.

[0088] In this embodiment, the two straight sections 4, the two second arc sections 3, and the two edge-receiving sections 2 are all symmetrically arranged with respect to the axis of the first arc section 5, and the axis of symmetry of the first arc section 5 and the seam section 1 are aligned. The first arc section, the seam section, the two second arc sections, and the two edge-receiving sections are all fixed in size. The circumference of the printing roller is the active dimension, and the dimensions of the two straight sections are the passive dimensions. When the circumference of the printing roller changes, the dimensions of the straight sections change accordingly, which simplifies the plate-making process. Different specifications of printing rollers can be produced simply by inputting the circumference, which is convenient and quick.

[0089] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for dimensional compensation in printing roller forming, the method comprising controlling a plate rolling machine to form a printing roller of a preset size from a straight plate, characterized in that, The printing roller includes a first arc portion (5), a seam portion (1), two second arc portions (3), two straight edge portions (4), and two edge-trimming portions (2). The method specifically includes: S1. Place the straight plate on the plate rolling machine and input the circumference of the plate roller and the material into the plate rolling machine; S2. The plate rolling machine measures the actual length and thickness of the straight plate and the ambient temperature in real time. S3. Establish a compensation model based on the actual length, thickness, material and ambient temperature, and give the compensation value. Calculate the compensation perimeter by combining the circumference of the printing roller and the compensation value. S4. The plate rolling machine determines the length of the two straight edge parts (4) based on the compensation perimeter, the length of the joint part (1), the length of the two edge-receiving parts (2), and the arc length of the first arc part (5) and the two second arc parts (3). S5. The plate rolling machine makes plates according to the length of each part.

2. The dimensional compensation method for printing roller forming according to claim 1, characterized in that, The establishment of the compensation model in step S3 specifically includes: S31. Collect the ambient temperature, thickness, length and material data of the straight plate before roller making, as well as the length of the roller after roller making, the length of the joint (1), the length of the two edge-cutting parts (2), and the arc length data of the first arc part (5) and the two second arc parts (3). S32. Use the data before and after the same straight plate is formed into the same set of training data. S33. Create different straight-board designs and obtain multiple sets of training data; S34. Using a random forest regression model, multiple sets of training data are used as training sets to establish the difference relationship between before and after roll forming, and a compensation model is obtained.

3. The dimensional compensation method for printing roller forming according to claim 2, characterized in that, The specific process for obtaining the compensation value is as follows: S35. Normalize the actual length, thickness, material and ambient temperature of the current roller plate and form an array; S36. Input the array into the loaded compensation model, calculate the prediction error and extract the prediction error value; S37. Transform the predicted error value into the actual error value, use the actual error value as the compensation value, and calculate the compensation circumference in combination with the circumference of the printing roller.

4. The dimensional compensation method for printing roller forming according to claim 2, characterized in that, The material is coded using a unique thermal coding system for the printing roller.

5. A method for dimensional compensation in printing roller forming according to claim 1, characterized in that, The seam (1) is formed by two edge-finishing parts (2).

6. A method for dimensional compensation in printing roller forming according to claim 1, characterized in that, The axial cross section of the printing roller is divided into the edge-receiving part (2), the second arc part (3), the straight part (4), the first arc part (5), the straight part (4), the second arc part (3), and the edge-receiving part (2) in sequence.

7. A method for dimensional compensation in printing roller forming according to claim 1, characterized in that, The two edge-receiving portions (2), the two second arc portions (3), and the two straight portions (4) are all symmetrical about the axis of the first arc portion (5).

8. A method for dimensional compensation in printing roller forming according to claim 1, characterized in that, The two edge-receiving portions (2) are the same size, the two second arc portions (3) are the same size, and the two straight portions (4) are the same size.

9. A method for dimensional compensation in printing roller forming according to claim 1, characterized in that, The dimensions of the two straight sections (4) are obtained by subtracting the dimensions of the first arc section (5), the seam section (1), the two second arc sections (3), and the two edge sections (2) from the compensation perimeter.

10. A method for dimensional compensation in printing roller forming according to claim 1, characterized in that, The dimensions of the first arc portion (5), the seam portion (1), the two second arc portions (3) and the two edge-finishing portions (2) are fixed.

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