High-precision spraying device and method for complex surface of a rotary body

Abstract

The application discloses a kind of high-precision spraying devices and methods of complex rotary body surface, device includes injection pump, six-axis robot, rotary table, precision spray gun and robot system, and complex rotary body workpiece is set on rotary table;Precision spray gun is set on six-axis robot, injection pump is used to inject coating to precision spray gun according to the set coating flow, and coating is sprayed to complex rotary body workpiece according to constant flow rate, spray width by precision spray gun;Feed line is connected between precision spray gun and injection pump;Through robot system, six-axis robot, rotary table, precision spray gun and injection pump are integrated control, so that the paint mist of precision spray gun is scanned with constant distance, speed and step all points on the surface of complex rotary body workpiece.This application can accurately control coating thickness, improve the resolution of coating, and also reduce environmental pollution during spraying.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surface coating, in particular to a high-precision spraying device and method for complex rotary body surfaces. BACKGROUND

[0002] Paint spraying devices are widely used in the fields of automobiles, furniture, household appliances, toys, construction, national defense and military industry, etc. In the process of paint spraying, the paint film thickness and thickness uniformity are key technical indicators of coating. In some special fields, the requirements for paint film thickness and thickness uniformity are extremely strict, and the shape of the workpiece is extremely complex, so uniform coating on the surface faces great difficulties.

[0003] For the spraying of complex rotary body workpieces, the commonly used automatic spraying device is composed of a six-axis robot, a feeding system, a spray gun and other supporting facilities. The feeding system generally adopts the forms of pressure barrels, diaphragm pumps and gear pumps, and the spray gun adopts the commonly used automatic spray gun. In these commonly used automatic coating devices, the coating flow provided by the feeding system is generally above 20 mL / min, and the spray width of the spray gun is above 5 cm. In the coating of complex rotary body surfaces, these commonly used automatic coating devices cannot meet the requirements of precise control of paint film thickness, and the coating process of the six-axis robot also relies on the combination of experience and engineering trial and error for programming. Therefore, in the coating of complex rotary body surfaces, these commonly used automatic spraying devices have the shortcomings of being unable to accurately control the coating thickness and being unable to guarantee the uniformity of the coating. SUMMARY

[0004] The present application aims to provide a high-precision spraying device and method for complex rotary body surfaces, to solve the technical problems that the existing automatic spraying device in the prior art cannot accurately control the coating thickness and cannot guarantee the uniformity of spraying.

[0005] The present application solves the above problems through the following technical solutions:

[0006] The application discloses a high-precision spraying device for a complex rotary body surface, which comprises an injection pump, a six-axis robot, a rotary workbench, a precision spray gun and a robot system, wherein the rotary workbench for the complex rotary body workpiece is arranged in the movement range of the six-axis robot; the precision spray gun connected with the injection pump is arranged on the six-axis robot, the injection pump is used for injecting paint to the precision spray gun according to a set paint flow, and the precision spray gun is used for spraying the complex rotary body workpiece according to a constant flow rate and a spraying width; a feeding pipeline is connected between the precision spray gun and the injection pump, the inner diameter of the feeding pipeline is not more than 2 mm; the six-axis robot, the rotary workbench, the precision spray gun and the injection pump are in communication connection with the robot system, so that the six-axis robot, the rotary workbench, the precision spray gun and the injection pump are integrally controlled by the robot system, and the paint mist of the precision spray gun is swept over all points on the surface of the complex rotary body workpiece at a constant distance, a constant speed and a step.

[0007] As a further improvement, when the precision spray gun sprays the complex rotary body workpiece, the constant flow rate is 0.01-10 mL / min, and the spraying width is 1-10 mm.

[0008] As a further improvement, the feeding pipeline is made of polytetrafluoroethylene material with an inner diameter of 1-2 mm.

[0009] As a further improvement, the precision spray gun comprises a paint interface connected with the feeding pipeline, a compressed air interface connected with compressed air, an atomization interface connected with atomization air, and a gun needle and an atomization sleeve arranged coaxially, the robot system controls the paint interface through the on-off control of the compressed air interface, the paint and the atomization air enter the precision spray gun respectively, and the atomized paint flows out through the gun needle.

[0010] As a further improvement, the rotary workbench comprises a table top and a plurality of stoppers uniformly distributed around the table top.

[0011] As a further improvement, the robot system comprises a motion control module and a paint control module,

[0012] The motion control module is used for controlling the coordinated motion of the rotary workbench and the six-axis robot, so that the spraying of the precision spray gun at a specified gun distance can sweep over all points on the surface of the complex rotary body workpiece at a constant speed and a step.

[0013] The paint control module is used for cooperating with the motion control module to control the precision spray gun and the injection pump, so as to provide the atomized paint with a constant flow rate and a spraying width to control the coating thickness.

[0014] In addition, the application solves the above problems through the following technical scheme:

[0015] A high-precision spraying method for a complex rotary body surface, comprising the following steps:

[0016] A. Fix the complex rotary body workpiece on a rotating workbench so that the complex rotary body workpiece is consistent with the rotating center of the rotating workbench;

[0017] B. Set the spraying flow rate at the spraying starting point and start the injection pump, open the precision spray gun to atomize the paint provided by the injection pump to generate atomized paint with a constant flow rate of 0.01-10 mL / min and a spraying width of 1-10 mm;

[0018] C. The robot system controls the coordinated motion of the rotating workbench and the six-axis robot, so that the precision spray gun sprays at a constant distance, speed and step at the specified gun distance to sweep all points on the surface of the rotary body workpiece.

[0019] As a further improvement, the control method of the robot system comprises:

[0020] S101. Establish a plurality of process parameter variables:

[0021] The variables at least include the linear speed of the precision spray gun relative to the motion of the complex rotary body workpiece, i.e. "gun speed"; the distance moved by the precision spray gun relative to the fixed reference after one revolution of the complex rotary body workpiece, i.e. "step", which can be the robot base coordinate system or the earth, the turntable, etc. fixed reference; the distance between the precision spray gun and the surface of the complex rotary body workpiece, i.e. "gun distance"; the flow rate of the paint, i.e. "flow"; the atomization pressure of the precision spray gun, i.e. "atomization";

[0022] S102. Establish a workpiece coordinate system (x, o, z), with the coordinate origin o located at the center of the lower end surface of the complex rotary body workpiece, the z-axis as the axis of the complex rotary body workpiece, and the x-axis and y-axis located on the lower end surface of the complex rotary body workpiece;

[0023] S103. Establish a tool coordinate system (x ’ , o ’ ,z ’ ), with the coordinate origin o ’ located at the tip of the precision spray gun, the z ’ axis located on the axis of the precision spray gun spraying direction, and the positive direction of the z ’ axis pointing from the tip of the precision spray gun to the tail;

[0024] S104. Select the part of the curve intersecting the plane of the workpiece coordinate system (x, 0, z) on the surface of the complex rotary body workpiece with x>0 and z≥0 as the generatrix of spraying;

[0025] When spraying, move from the X axis to the Z axis along the trajectory indicated by the spraying generatrix, and meanwhile, cooperate with the rotation of the complex rotary workpiece to realize the spraying of the whole curved surface of the complex rotary workpiece;

[0026] S105, define W1, W2, W3……W on the spraying generatrix starting from the X axis; n A plurality of position points W(x, 0, z);

[0027] S106, define a plurality of position points of the precision spray gun tip as G(x, 0, z), and G1, G2, G3……G n ,G1, G2, G3……G n W1, W2, W3……W n are in one-to-one correspondence;

[0028] S107, set the rotation speed of the rotary worktable at the G1 point and start the rotary worktable, so that the complex rotary workpiece rotates at the set speed;

[0029] S108, open the precision spray gun, set the flow rate as a variable "flow", start the injection pump, set the atomizing compressed air pressure as "atomizing", and open the compressed air for atomization;

[0030] S109, make the precision spray gun move in a straight line from the G1 point to the G2 point at the set speed;

[0031] S110, after the precision spray gun reaches the G2 point, update the rotation speed of the rotary worktable and the speed of the robot movement, and match the rotation speed and the speed of the robot movement;

[0032] S111, make the precision spray gun move from the G2 point to the G3 point at the set speed again;

[0033] S112, repeat S109-S112 until the precision spray gun reaches the G n point.

[0034] As a further improvement, the correspondence between the position points W(x, 0, z) and the position points G(x, 0, z) is that the spray gun always maintains perpendicularity with the surface to be sprayed, and the distance between the spray gun and the surface to be sprayed is always a variable "gun distance".

[0035] As a further improvement, in S110, the rotation speed and the speed of the robot movement are matched, and the specific method is:

[0036] Rotation speed = gun speed ÷ (2 × π × W nx ) × 60;

[0037] Wherein, π is the circular constant, and W nx is the x coordinate value of the workpiece surface to be coated.

[0038] Speed = Step x Rotational Speed ÷ 60 x (G n Distance from the G n-1 point) / (W n Distance from the W n-1 point).

[0039] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0040] (1) The device of the present application adopts a robot system integrated control strategy, the robot system can perform integrated control on the six-axis robot, the rotary table workbench and the paint supply system, high-precision cooperation of the six-axis robot trajectory and coordinate position and the rotary table workbench rotation is realized, and complex and precise motion trajectory of the precision spray gun relative to the complex rotary workpiece can be realized. Moreover, a high-precision spraying method is adopted, uniform speed and equal distance complex motion trajectory of the spray gun on the complex rotary curved surface is realized, and an injection pump and a precision spray gun are adopted, the resolution of coating is improved, and the coating uniformity can reach ± 5 μm.

[0041] (2) The method of the present application establishes the relationship between the coating process parameters and the coating thickness by establishing a plurality of coating process parameter variables; at the same time, combined with the advantage that the injection pump can control the coating flow with high precision, high-precision control of the coating thickness is realized, and the thickness control precision can reach ± 1 μm.

[0042] (3) The present application controls the constant flow rate of the paint to be 0.1-10 mL / min, and the spraying width to be 1-10 mm, the flow rate of the paint and the spraying width are greatly reduced, the paint utilization rate is improved, and the environmental pollution during spraying is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 It is a structure schematic view of the high-precision spraying device for the complex rotary surface of the present application.

[0044] Figure 2 It is a structure schematic view of the precision spray gun of the present application.

[0045] Figure 3 It is a structure schematic view of the rotary workbench of the present application.

[0046] The figure mark: 1. injection pump; 2. supply pipeline; 3. precision spray gun; 4. rotary workbench; 5. six-axis robot; 31. gun needle; 32. atomizing sleeve; 33. precision spray gun; 34. atomizing interface; 35. compressed air interface; 36. paint interface; 41. table top; 42. stop block. DETAILED DESCRIPTION

[0047] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of the present application.

[0048] Embodiment 1

[0049] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of the present application. Figure 1 As shown in the accompanying drawings, a high-precision spraying device for a complex rotary body surface includes an injection pump 1, a six-axis robot 5, a rotary workbench 4, a precision spray gun 3, and a robot system, etc. The rotary workbench for the complex rotary body workpiece is installed in the movement range of the six-axis robot, and the six-axis robot 5 is installed in the form of ground installation, hoisting, etc. The precision spray gun connected with the injection pump is arranged on the six-axis robot, the injection pump is used to inject paint to the precision spray gun according to the set paint flow, and the precision spray gun is used to spray the complex rotary body workpiece according to the constant flow rate and spray width. A supply pipeline 2 is connected between the precision spray gun and the injection pump, and the inner diameter of the supply pipeline is not more than 2 mm. The six-axis robot, the rotary workbench, the precision spray gun, and the injection pump are in communication connection with the robot system, so as to perform integrated control on the six-axis robot, the rotary workbench, the precision spray gun, and the injection pump through the robot system, so that the paint mist of the precision spray gun sweeps all the points on the surface of the complex rotary body workpiece at a constant distance, speed, and step.

[0050] Specifically, in order to ensure the uniformity of the coating thickness at different positions of the complex rotary body surface, and to adapt the high-precision spraying device to the coating of the complex surface, the atomized paint mist must have high resolution, i.e. small spray width. In order to achieve the above purpose, a precision spray gun is adopted, and the spray width is 1-10 mm. At the same time, the atomizing sleeve of the precision spray gun adopts a small diameter, so that the spray gun can adapt to the complex structure of the workpiece surface. An injection pump is adopted for paint flow control, so that when the precision spray gun sprays the complex rotary body workpiece, the constant flow rate is 0.01-10 mL / min.

[0051] The injection pump 1 is composed of an injection pump body and a syringe. As an option, the syringe is made of glass to reduce the flow fluctuation caused by deformation of the syringe. The injection pump 1 is installed near or on the base of the six-axis robot. The precision spray gun 3 is connected to the six-axis robot 5 and is installed on the sixth axis of the six-axis robot 5. The outlet of the injection pump 1 is connected to the precision spray gun 3 through the supply pipeline 2. When the diameter of the supply pipeline exceeds 2 mm, air bubbles are easily left in the supply pipeline, which causes flow fluctuation or abnormal discharge of the precision spray gun. In order to ensure the uniformity of the coating thickness at different positions of the complex rotary body, the coating flow at any time during the coating process must be kept stable. As an option, a supply pipeline made of polytetrafluoroethylene with an inner diameter of 1-2 mm is used in this embodiment. The polytetrafluoroethylene material can ensure that the affinity between the coating pipeline and the coating is small, which reduces the resistance of the supply on the one hand and prevents the coating pipeline from being contaminated by the coating on the other hand. The injection pump is used for coating supply and flow control. The control signals of the rotary table 4, the six-axis robot 5, the injection pump 1 and the precision spray gun 3 are converted through the PLC and connected to the robot system through the 485 interface. The rotary table 4, the six-axis robot 5, the injection pump 1 and the precision spray gun 3 are controlled by the robot system.

[0052] Further, with reference to the accompanying drawings Figure 2 The precision spray gun 33 includes a coating interface 36 connected to the supply pipeline, a compressed air interface 35 connected to compressed air, an atomizing interface 34 connected to atomizing air, and a gun needle 31 and an atomizing sleeve 32 coaxially arranged, etc. The robot system controls the coating interface 36 through the on-off of the compressed air interface 35. The coating and the atomizing air enter the precision spray gun respectively, and the atomized coating flows out through the gun needle 31. Specifically, the precision spray gun is connected to compressed air, the atomizing sleeve 32 is arranged outside the gun needle 31, and the head of the gun needle 31 is exposed from the atomizing sleeve 32 by about 0.5 mm. In this embodiment, the gun needle 31 is a needle with an inner diameter of 0.1-1 mm, an outer diameter of 0.2-1.5 mm and a length of more than 10 mm. The atomizing sleeve 32 is a metal pipe with an inner diameter of 0.8-2 mm and an outer diameter of 1.5-3 mm. The coating enters the precision spray gun 3 from the supply pipeline 2 through the coating interface 36 and flows out from the gun needle 31 of the precision spray gun 3. The robot system controls the coating switch inside the precision spray gun 3 through the on-off of the compressed air 35. The atomizing air enters the precision spray gun from the atomizing interface 34 and is finally sprayed from the gap between the atomizing sleeve 32 and the gun needle 31, so that the coating of the gun needle 31 is atomized. The robot system controls the final atomization effect by adjusting the air pressure of the atomizing air.

[0053] The rotating workbench 4 is driven by a servo motor and connected to the robot system through a PLC. The robot system can send instructions to make the rotating workbench rotate by a specific angle, rotate at a specific speed, and return to the original position. When the rotating workbench is in a stationary state, the robot system can send multiple angle instructions multiple times to make the rotating workbench rotate multiple times according to the multiple angle instructions, with an angle accuracy of 0.1°. When the rotating workbench is in a stationary or rotating state, the robot system can send multiple speed instructions multiple times to make the rotating workbench change its speed at will, with a speed accuracy of 0.01 rpm. At any time, the robot system can send an original position instruction to make the rotating workbench rotate back to the initial position.

[0054] Further, the rotating workbench includes a table top 41 and a plurality of stop blocks 42 arranged around the table top 41. Referring to the accompanying drawings, Figure 3 In this embodiment, the plurality of stop blocks 42 are arranged as four and uniformly arranged around the table top. The side of the stop block 42 facing the table top is a circular arc concentrically arranged with the table top, so that the plurality of stop blocks 42 are arranged in the circumferential direction of the table top 41. The four stop blocks ensure that the rotating workpiece and the rotating center of the rotating workbench are consistent, and prevent the workpiece from falling during rotation.

[0055] The robot system includes a motion control module and a paint control module, wherein,

[0056] The motion control module is used to control the coordinated motion of the rotating workbench and the six-axis robot to ensure that the precise spray gun can spray at a constant speed and step over all points on the surface of the rotating workpiece at a specified gun distance, which is one of the necessary conditions to ensure the uniformity of the coating thickness at different positions on the surface of the rotating workpiece.

[0057] The paint control module is used to cooperate with the motion control module to control the precise spray gun and the injection pump to provide a constant flow rate and high resolution atomized paint to achieve high precision control of the coating thickness.

[0058] During operation, the complex rotating workpiece is placed on the rotating workbench so that the rotating center of the complex rotating workpiece is consistent with the rotating center of the rotating workbench. The paint is loaded into the injection pump body, and the syringe is fixed on the injection pump. The robot system controls the injection pump to inject paint to the precise spray gun according to the set paint flow rate. At the same time, the robot system controls the precise spray gun to open, so that the paint flows out of the precise spray gun, and the precise spray gun outputs the set pressure of atomized compressed air, so that the paint is atomized. At the same time, the robot system controls the rotating workbench to rotate, so that the workpiece rotates. In addition, the robot system controls the six-axis robot to move cooperatively with the rotating workbench, so that the paint mist of the precise spray gun sweeps over all points on the surface of the workpiece at a constant distance, speed, and step.

[0059] Example 2

[0060] A high-precision spraying method for a complex rotary body surface, comprising the following specific steps:

[0061] A, fix the rotary body workpiece on the rotating workbench, so that the rotary body workpiece is consistent with the rotation center of the rotating workbench, that is, the axis of the rotary body workpiece coincides with the axis of the rotating workbench; so that the robot system drives the rotary body workpiece by controlling the rotating speed and starting and stopping of the rotating workbench, and realizes high-precision spraying of the complex rotary body surface by the robot system.

[0062] B, the robot system opens the precision spray gun at the starting point of spraying, sets the flow rate and starts the injection pump, and opens the compressed air for atomization to produce high-resolution atomized paint with constant flow rate;

[0063] Among them, the injection pump injects paint to the precision spray gun according to the set paint flow rate, so as to use the injection pump for paint supply and high-precision control of the paint flow rate; as an optimization, the set paint flow rate is constant and controlled within the range of 0.01-10 mL / min, and the control error of the paint flow rate is less than ±1%.

[0064] The precision spray gun is controlled to be opened, so that the paint flows out of the precision spray gun, and the atomized compressed air with a set pressure is output to the precision spray gun, so that the paint is atomized, and the paint spraying width is controlled within the range of 1-10 mm.

[0065] C, the robot system controls the coordinated motion of the rotating workbench and the six-axis robot, so that the precision spray gun sprays at a constant distance, speed and step at the specified gun distance, so as to sweep all points on the surface of the rotary body workpiece, ensure the uniformity of coating thickness at different positions on the surface of the rotary body workpiece, and close the precision spray gun, injection pump and compressed air for atomization at the end point of spraying.

[0066] Since the coating thickness is linearly related to the flow rate, the reciprocal of the gun speed and the reciprocal of the step, adjusting the flow rate, gun speed and step can change the coating thickness; reducing the paint flow rate, increasing the spraying speed and reducing the spraying distance can reduce the spraying width and improve the coating resolution. Conversely, it will lead to a decrease in coating resolution.

[0067] Specifically, in order to ensure that the precision spray gun sprays at a constant speed and step at the specified gun distance, sweeps all points on the surface of the workpiece, and the motion control method of the robot system is:

[0068] S101, establish a plurality of process parameter variables:

[0069] The variables at least include the linear speed of the precision spray gun relative to the rotation body workpiece movement, i.e. "gun speed (mm / s)"; the distance of the spray gun relative to the fixed reference after the rotation body workpiece rotates one round, i.e. "step (mm)", the fixed reference can be the robot base coordinate system or the earth, the turntable and the like fixed reference, in the embodiment, the fixed reference adopts the robot base coordinate system; the distance of the precision spray gun and the surface of the rotation body workpiece, i.e. "gun distance (mm)"; the flow rate of the paint, i.e. "flow (mL / min)"; the atomization gas pressure of the precision spray gun, i.e. "atomization (bar)".

[0070] S102, a workpiece coordinate system (x, 0, z) is established, the coordinate origin 0 is located at the center of the lower end surface of the rotation body workpiece, the rotation body workpiece axis is the z axis, and the z axis is vertically upward, and the x axis and the y axis are located on the lower end surface of the rotation body workpiece.

[0071] S103, a tool coordinate system (x ’ , o ’ ,z ’ ) is established, the coordinate origin o ’ is located at the tip of the precision spray gun, the z ’ axis is located on the axis of the spray direction of the precision spray gun, and the positive direction of the z ’ axis is from the tip of the precision spray gun to the tail part;

[0072] S104, the part of the curve intersecting the plane of the workpiece coordinate system (x, 0, z) with x>0 and z≥0 on the surface of the rotation body workpiece is selected as the generatrix for spraying. When spraying, the six-axis robot moves from the X axis to the Z axis along the trajectory shown by the generatrix, and at the same time, the rotation of the rotation body workpiece is matched to realize the spraying of the entire curved surface of the rotation body workpiece.

[0073] S105, from the X axis, a plurality of position points W(x, 0, z) are defined on the generatrix for spraying, W1, W2, W3……W n .

[0074] The x and z coordinate values of W n can be directly read on the drawing of the workpiece, and do not need to be obtained on site through the teach pendant, and the relationship between the point density and the coating thickness error is:

[0075] H n / H n-1 =W (n-1)x / W nx ;

[0076] H n is the thickness of the coating at the nth point, W nx is the W nThe x coordinate value of the point. According to the above mathematical relationship, the points should be taken according to the geometric progression of x, and the common ratio of the geometric progression is the allowed thickness error of spraying. The closer the common ratio is to 1, the more the number of points taken, and the higher the precision of spraying.

[0077] S106, define the position point of the precision spray gun tip as G(x, 0, z), G can take multiple points, G1, G2, G3……G n ,G1, G2, G3……G n And W1, W2, W3……W n It is a one-to-one correspondence.

[0078] Specifically, the corresponding relationship between the position point W(x, 0, z) and the position point G(x, 0, z) is that the precision spray gun is offset along the z' axis of the tool coordinate system(x', o', z') in the positive direction, and the offset distance is the variable "gun distance", that is, the coordinate value of the position point G(x, 0, z) corresponding to the position point W(x, 0, z) is obtained; The posture of the precision spray gun at the position point W(x, 0, z) is the z' axis of the tool coordinate system(x', o', z'), and is perpendicular to the tangent plane of the position point G(x, 0, z) of the complex rotational body workpiece.

[0079] The position point W is a point on the surface of the workpiece, and the coordinates are directly obtained from the workpiece drawing. It is necessary to convert the position point W to the position point G of the spray gun according to the spraying process requirements, and the conversion relationship is:

[0080] The distance between W and the corresponding G point is "gun distance"; the posture of the spray gun at G is always perpendicular to the tangent plane at the W point on the workpiece surface; the axis of the paint mist of the spray gun points to the W point on the workpiece surface.

[0081] The coordinates of G point obtained from W point are generally directly realized by program algorithm, and teaching can also be realized, but the programming efficiency is very low, and the precision is very poor: for example, when the spraying generatrix is a circular arc, it can be easily realized according to the following logic:

[0082] 1. The spray gun rotates around the tool coordinate system to make the spray gun perpendicular to the workpiece surface;

[0083] 2. The spray gun is offset along the positive direction of the Z' axis of the tool coordinate system by a distance "gun distance"

[0084] 3. Loop the above process to obtain all G point coordinates.

[0085] The coordinates of the G n point corresponding to the W n point are calculated from the coordinates of the W n point, and the specific calculation method is:

[0086] First, make W nThe tangent line of the point where the spray bus is sprayed is calculated, and the included angle between the tangent line and the z-axis of the workpiece coordinate system is θ. When the tangent line intersects with the positive direction of the z-axis of the workpiece coordinate system, θ is recorded as a positive value, and when the tangent line intersects with the negative direction of the z-axis of the workpiece coordinate system, θ is recorded as a negative value. Then, taking W n as the reference, the precision spray gun is rotated by an angle θ around the x-axis of the tool coordinate system to obtain a first process point. Subsequently, taking the first process point as the reference, the spray gun tip is offset along the positive direction of the z' axis of the tool coordinate system, and the offset distance is the variable "gun distance (mm)", that is, the G n corresponding to W n is obtained. The above calculation process will have the following effects: no matter how the surface shape changes, the spray gun always maintains perpendicularity with the surface to be sprayed, and the distance between the spray gun and the surface to be sprayed is always the variable "gun distance (mm)".

[0087] The above calculation process will have the following effects: no matter how the surface shape changes, the spray gun always maintains perpendicularity with the surface to be sprayed, and the distance between the spray gun and the surface to be sprayed is always the variable "gun distance (mm)".

[0088] S107, set the rotating speed of the rotary table at the G1 point and start the rotary table, so that the rotary workpiece rotates at a set specific rotating speed.

[0089] The setting method of the rotating speed of the rotary table at the nth point is as follows: rotating speed = gun speed ÷ (2 × π × W nx ) × 60, π is the circular constant, and W nx is the x-coordinate value of the surface to be coated of the workpiece.

[0090] S108, open the precision spray gun, set the flow rate to the variable "flow rate (mL / min)", start the injection pump, set the atomized compressed air pressure to "atomization", and open the compressed air for atomization.

[0091] S109, control the robot to move the precision spray gun from the G1 point to the G2 point at a set speed through a linear motion instruction. The setting method of the speed of the robot at the nth point is as follows: speed = step × rotating speed ÷ 60 × (G n -G n-1 distance) / (W n -W n-1 distance).

[0092] S110, after the precision spray gun reaches the G2 point, update the rotating speed of the rotary table and the speed of the robot movement, and match the rotating speed and the speed of the robot movement;

[0093] The setting method of the rotating speed of the rotary table at the nth point is as follows: rotating speed = gun speed ÷ (2 × π × W nx ) × 60, π is the circular constant, and W nxThe x-coordinate value of the position to be coated on the surface of the workpiece.

[0094] The speed setting method of the spray gun moving at the nth point is as follows: speed = step x rotation speed ÷ 60 x (G n distance from the G n-1 point) / (W n distance from the W n-1 point).

[0095] S111, control the robot to move the precision spray gun from the G2 point to the G3 point at the set speed through the straight line motion instruction.

[0096] S112, repeat S109-S112 until the precision spray gun reaches the G n point, turn off the precision spray gun, the injection pump, the compressed air for atomization, and finally turn off the rotary workbench.

[0097] The present application can obtain low flow rate and small width spray by the injection pump cooperating with the precision spray gun, which improves the resolution when spraying the workpiece of the rotary body. Moreover, it has high flow control precision and flow rate stability, which is beneficial to improve the uniformity of coating thickness at different positions and the control precision of coating thickness. In the debugging process of the spraying process, the gun distance, the spray gun angle, the spray gun position, the spraying speed and the flow rate are usually optimized according to the spraying effect and the coating thickness distribution at different positions to improve the uniformity of the coating thickness. For the spraying of the workpiece of the complex surface of the rotary body, the above optimization process usually involves tens of iterations of the spraying system, and the programming efficiency is low. The method of the present application can directly change the coating thickness and coating effect of the workpiece of the complex surface of the rotary body by changing the specific values of the four process parameters of flow rate, gun speed, step and gun distance, without affecting the uniformity of the coating thickness and without the need to modify the spraying system again, so that the parameterized control of the coating thickness can be realized, and the surface coating of the workpiece of the complex surface of the rotary body can be realized.

[0098] Although the present application has been described with reference to the explanatory embodiments thereof, the above-described embodiments are merely preferred embodiments of the present application, and the embodiments of the present application are not limited to the above-described embodiments. It should be understood by those skilled in the art that many other modifications and embodiments can be designed, which will fall within the scope and spirit of the principles disclosed in the present application.

Claims

1. A high-precision spraying method for a complex surface of revolution, characterized in that, The application relates to a spraying method and a spraying system for a complex rotary workpiece. The complex rotary workpiece is fixed on a rotating workbench, and the rotating center of the complex rotary workpiece is consistent with the rotating center of the rotating workbench; A spraying flow rate is set at a spraying starting point, an injection pump is started, a precision spraying gun is opened to atomize paint provided by the injection pump, atomized paint with a constant flow rate of 0.01-10 mL / min and a spraying width of 1-10 mm is generated, a robot system controls the rotating workbench and the six-axis robot to move coordinately, the precision spraying gun sprays at a constant distance, speed and step at a specified gun distance, and all points on the surface of the complex rotary workpiece are swept. The control method of the robot system comprises the following steps: S101, a plurality of process parameter variables are established; The variables at least include a linear speed of the precision spraying gun relative to the complex rotary workpiece, that is, a "gun speed", a distance of the precision spraying gun relative to a fixed reference after the complex rotary workpiece rotates one round, that is, a "step", a distance between the precision spraying gun and the surface of the complex rotary workpiece, that is, a "gun distance", a flow rate of paint, that is, a "flow", and an atomization air pressure of the precision spraying gun, that is, "atomization". S102, a workpiece coordinate system (x, o, z) is established, the coordinate origin o is located at the center of a lower end surface of the complex rotary workpiece, a z-axis is an axis of the complex rotary workpiece, and x and y axes are located on the lower end surface of the complex rotary workpiece; S104, an x>0 and z>=0 part of a curve intersecting the plane of the workpiece coordinate system (x, 0, z) on the surface of the complex rotary workpiece is selected as a spraying generatrix. S103, establish a tool coordinate system (x ’ , ’ , z ’ ), with the coordinate origin o ’ located at the tip of the precision spray gun, the z ’ axis located on the axis of the spray direction of the precision spray gun, and the positive direction of the z ’ axis pointing from the tip to the tail of the precision spray gun; During spraying, the precision spraying gun moves from the X-axis to the Z-axis along the trajectory indicated by the spraying generatrix, and the spraying of the whole surface of the complex rotary workpiece is realized by matching the rotation of the complex rotary workpiece. S107, the rotating speed of the rotating workbench is set at the G1 point, and the rotating workbench is started to rotate the complex rotary workpiece at the set rotating speed. S105, defining W1, W2, W3...W on the sprayed generatrix from the X axis n a number of position points W(x, 0, z) S106, define several position points of the precise spray gun tip as G (x, 0, z), and G1, G2, G3……G n ,G1, G2, G3……G n W1, W2, W3……W n are in one-to-one correspondence; S108, the precision spraying gun is opened, the flow rate is set as the variable "flow", the injection pump is started, the atomization air pressure is set as "atomization", and the atomization air is opened. S109, the precision spraying gun is linearly moved from the G1 point to the G2 point at the set speed. S110, after the precision spraying gun reaches the G2 point, the rotating speed of the rotating workbench and the moving speed of the robot are updated, and the rotating speed and the moving speed of the robot are matched. S111, the precision spraying gun is moved from the G2 point to the G3 point at the set speed. The corresponding relationship between the position point W (x, 0, z) and the position point G (x, 0, z) is that the spraying gun is always perpendicular to the surface to be sprayed, and the distance between the spraying gun and the surface to be sprayed is always the variable "gun distance". S112, repeat S109-S112 until the precision lance reaches G n point.

2. The high-precision spraying method for a complex surface of revolution according to claim 1, characterized in that, In S110, the rotating speed and the moving speed of the robot are matched, and the specific method is that 3. The high-precision spraying method for complex surface of revolution according to claim 1, characterized in that, ​ Rotational speed = bullet speed ÷ (2 x π x W) x 60 nx ) x 60; wherein, π is a circle constant, W nx is the x coordinate value of the position to be coated on the surface of the workpiece; Speed = Step x Rotational Speed ÷ 60 x (G n With G n-1 The distance of the point) / (W n With W n-1 The distance of the point).

4. A high-precision spraying device for complex surface of revolution, using the high-precision spraying method for complex surface of revolution according to any one of claims 1-3, characterized in that, The system comprises an injection pump, a six-axis robot, a rotary table, a precision spray gun and a robot system, the rotary table for setting a complex rotary workpiece is installed in the movement range of the six-axis robot; the precision spray gun connected with the injection pump is set on the six-axis robot, the injection pump is used for injecting paint to the precision spray gun according to the set paint flow, and the precision spray gun sprays the complex rotary workpiece according to the constant flow rate and the spraying width; and the precision spray gun and the injection pump are connected with a feeding pipeline, the inner diameter of the feeding pipeline is not more than 2 mm; the six-axis robot, the rotary table, the precision spray gun and the injection pump are in communication connection with the robot system, so as to control the six-axis robot, the rotary table, the precision spray gun and the injection pump through the robot system, and the paint mist of the precision spray gun sweeps all points on the surface of the complex rotary workpiece at a constant distance, speed and step.

5. The high-precision spraying device for complex surface of revolution according to claim 4, characterized in that, When the precision spray gun sprays the complex rotary workpiece, the constant flow rate is 0.01-10 mL / min, and the spraying width is 1-10 mm.

6. The high-precision spraying device for complex surface of revolution according to claim 4, characterized in that, The feeding pipeline is made of polytetrafluoroethylene material with an inner diameter of 1-2 mm.

7. The high-precision spraying device for complex surface of revolution according to claim 4, characterized in that, The precision spray gun comprises a paint interface connected with the feeding pipeline, a compressed air interface connected with compressed air, an atomizing interface connected with atomizing air, and a gun needle and an atomizing sleeve coaxially arranged; the robot system controls the paint interface through the on-off control of the compressed air interface, the paint and the atomizing air enter the precision spray gun, and the atomized paint flows out through the gun needle.

8. The high-precision spraying device for complex surface of revolution according to claim 4, characterized in that, The rotary table comprises a table top and a plurality of stoppers uniformly distributed around the table top.

9. The high-precision spraying device for complex surface of revolution according to any one of claims 4-8, characterized in that, The robot system comprises a motion control module and a paint control module, The motion control module is used for controlling the coordinated motion of the rotary table and the six-axis robot, so that the spraying of the precision spray gun at the specified gun distance can sweep all points on the surface of the complex rotary workpiece at a constant speed and step; The paint control module is used for cooperating with the motion control module to control the precision spray gun and the injection pump, so as to provide the atomized paint with constant flow rate and spraying width to control the coating thickness.

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