Method for automatically identifying and sorting springs with surface defects during spring winding

Abstract

The invention relates to the technical field of spring detection equipment, in particular to a method for automatically identifying and sorting springs with surface defects during spring winding, which comprises the following steps of: A, pretreating a steel wire coil, namely performing parameter detection on the steel wire coil, performing flaw detection marking on the steel wire coil and performing surface treatment on the steel wire coil to obtain a steel wire coil to be wound; b, spring winding is conducted, specifically, the steel coil to be wound is placed in a spring winding machine, and springs to be screened are obtained through winding; c, detecting and sorting: before to-be-screened springs are cut off, automatically detecting parameters of the to-be-screened springs, and utilizing the characteristics that the induction heating speed is high, coatings sprayed on the same circumference of steel wires are not completely uniform, so that the cooling speeds of the steel wires are inconsistent, and obvious small bends appear under the condition of thermal expansion and cold contraction; in addition, after the coating is volatilized and cured, a hardened layer with high adhesive force is formed on the surface of the steel wire at the defect position, and mechanical property difference and surface difference between the defect position of the steel wire and the steel wire at the normal position are artificially caused.

Description

Technical Field

[0001] The invention relates to the technical field of spring detection equipment, in particular to a method for automatically identifying and sorting springs with surface defects during spring winding. Background Art

[0002] Common sources of surface defects in spring steel wire include rolling defects of wire rod and surface defects generated during the production process. Common rolling defects of wire rod include cracks, folds, scars, ears, rolling marks, pockmarks, pits, scratches, delamination and other defects. Production process defects include scratches, abrasions, transverse cracks and other defects. The surface defects of finished spring steel wire have a great influence on the service life of the spring. The stress on the secondary surface is the greatest when the spring is working, but fatigue damage is mostly caused by defects on the surface of the steel wire. If there are defects such as cracks, folds, pockmarks, pockmarks, scratches and indentations on the surface of the steel wire, it is most likely to cause stress concentration during the operation of the spring and form a source of fatigue fracture.

[0003] How to separate the steel wire with surface defects during the spring coiling process has a significant impact on the control of spring quality. In the actual production process, for important springs with high fatigue requirements, such as valve springs, suspension springs and clutch springs, in order to improve the surface quality of the material, a peeling or polishing process is generally used to peel off a layer of the material surface so that small defects and minor decarburization layers are completely removed. A small number of large defects can be calibrated by eddy current testing and removed in the subsequent spring making process. Eddy current testing is to coat the surface of the steel wire with white paint marks. The spring manufacturer separates the color-marked springs during the spring coiling process. The main pre-separation methods are "manual picking" and "online color mark recognition", but they have obvious shortcomings and low reliability. Common problems include: "manual picking" not only affects production efficiency but also increases the workload of workers. Their work quality and work attitude have a direct impact on the quality of picking; "online color mark recognition" is generally performed after spring winding, and the quality of the original color mark of the steel wire has a great impact on it; the color mark is easily fallen off, contaminated, and faded during the spring winding process, resulting in the inability of online color mark recognition to 100% identify problematic steel wires; the above two methods cannot fully guarantee that surface defects of the steel wire can be completely identified and separated. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for automatically identifying and sorting springs with surface defects during spring winding, which can accurately detect steel wire defects.

[0005] The present invention is realized by the following technical scheme: a method for automatically identifying and sorting springs with surface defects during spring winding, comprising the following steps: A. Pretreatment of the steel wire coil, including parameter detection of the steel wire coil, flaw detection and marking of the steel wire coil, and surface treatment of the steel wire coil to obtain the steel wire coil to be wound; B. Spring winding: placing the steel coil to be wound into a spring winding machine and winding the spring to be screened; C. Detection and sorting: Before the springs to be screened are cut off, the parameters of the springs to be screened are automatically detected to see if there are any marks. If the parameters are unqualified and / or there are marks, they are transported to the unqualified bin; if the parameters are qualified and there are no marks, they are transported to the qualified bin. In step A, flaw detection and marking of the wire coil includes the following steps: A1. Preparation for flaw detection: transfer the wire coil that has been tested for parameters to the unwinder, connect the starting end of the wire to the rewinder, install an eddy current flaw detector, an electromagnetic induction heating device, a sprayer, and a drying device between the unwinder and the rewinder in sequence, and also install a speed sensor for detecting the speed of the wire between the unwinder and the rewinder; A2. Flaw detection: start the unwinder, winder and eddy current flaw detector. When the eddy current flaw detector detects a defect on the surface of the steel wire, the speed sensor starts to work and calculates the time t1 when the surface defect moves to the electromagnetic induction heating device, the time t2 when the surface defect moves to the spraying machine, and the time t3 when the surface defect moves to the drying device. A3, marking, after the eddy current flaw detector detects the surface defects of the steel wire, the delay time t1, the electromagnetic induction heating machine works to raise the temperature of the steel wire to 300-400℃, the delay time t2, the spraying machine works to spray high adhesion coating on the surface defects of the steel wire, the delay time t3, the drying device works to harden the coating, In step A, the steel wire coil is subjected to surface treatment, including the following steps: A4. An oiler is installed between the drying device and the winder. The oiler is turned on at the same time as the unwinder. The oiled steel wire enters the winder for winding.

[0006] Furthermore, in step A, parameter detection is performed on the steel wire coil, and the detection parameters include steel wire outer diameter detection and mechanical property detection.

[0007] Furthermore, the eddy current flaw detector is a rotary and through-type flaw detector produced by FOERSTER of Germany; The spraying machine is a spraying machine of FOERSTER of Germany.

[0008] Furthermore, the speed sensor is a German FOERSTER speed sensor.

[0009] Furthermore, in step C, the spring winding machine is a CNC-625D spring winding machine of Zhejiang Universal Spring Machinery Co., Ltd., which automatically detects the appearance parameters of the springs to be screened through camera detection and performs sorting.

[0010] Furthermore, the high adhesion coating is made of the following raw materials in weight percentage: 22wt% titanium dioxide, 13wt% ethanol, 10wt% water, 45wt% water-soluble acrylic resin AC-235, and 10wt% butyl acetate. The oiler applies oil to the steel wire, and the oil is rust-proof oil. The oiler applies oil to the steel wire, and the oil is rust-proof oil.

[0011] Furthermore, the electromagnetic induction heating device comprises an insulating tube, the steel wire passes through the insulating tube, an induction coil is sheathed outside the insulating tube, and the induction coil is connected to a power supply.

[0012] Furthermore, the drying device comprises a drying channel, the steel wire passes through the drying channel, and the drying channel is connected to a hot air blower.

[0013] The beneficial effects of the present invention are as follows: the induction heating speed is fast, and the coating sprayed on the same circumference of the steel wire is not completely uniform, resulting in inconsistent cooling speed of the steel wire, and obvious "small bends" will appear under the condition of "thermal expansion and contraction". After the coating evaporates and solidifies, a hardened layer with strong adhesion will be formed on the surface of the steel wire at the defective position; by using this marking method, the mechanical properties and surface differences between the steel wire at the defective position and the steel wire at the normal position are artificially caused, such as: a sudden change in the friction coefficient of the steel wire surface, an increase in the diameter of the steel wire, and a "small bend" in the local part of the steel wire, which destroys the stability of the spring winding and causes huge fluctuations in the size of the spring, and can be quickly detected and rejected after winding. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the machine train of Example 1; Figure 2 It is a schematic diagram of the structure of the electromagnetic induction heating device; Figure 3 It is a schematic diagram of the drying device structure.

[0015] Among them: 1. Steel wire; 2. Unwinding machine; 3. Eddy current flaw detector; 4. Speed ​​sensor; 5. Electromagnetic induction heating machine; 5-1. Induction coil; 5-2. Power supply; 6. Spraying machine; 7. Drying device; 7-1. Hot air blower; 7-2. Drying channel; 8. Oiling machine; 9. Winding machine. DETAILED DESCRIPTION

[0016] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0017] The following will be combined with the drawings in the embodiments of the invention to clearly and completely describe the technical solutions in the embodiments of the invention. Obviously, the described embodiments are only part of the embodiments of the invention, not all of the embodiments. Based on the embodiments of the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the invention.

[0018] In the following implementations, Parameter detection refers to detecting the outer diameter and tensile strength of the steel wire 1 . Eddy current flaw detector 3 uses the rotary and through-type flaw detectors produced by FOERSTER in Germany. It uses the principle of electromagnetic induction to identify defects on the surface of the steel wire 1 that reach or exceed the alarm threshold. The use of dual probes and dual channels can ensure that surface defects of the steel wire 1 can be detected. The through-type channel has a relatively high detection sensitivity for inclusions, small pits, and flat tubes, and the detection effect is very good. The rotary channel also has a good detection effect on sawtooth defects with a certain width and depth; The electromagnetic induction heating device comprises an insulating tube, through which the steel wire 1 passes, and an induction coil 5-1 is sheathed outside the insulating tube, and the induction coil 5-1 is connected to a power source 5-2. By controlling the power of the induction coil 5-1 and the speed of the winding machine 9, the steel wire 1 passing through the insulating tube is heated to 200°C, thereby causing the surface defects of the steel wire 1 to expand due to heat; The high adhesion coating is made of the following raw materials in weight percentage: 22wt% titanium dioxide, 13wt% ethanol, 10wt% water, 45wt% water-soluble acrylic resin AC-235, and 10wt% butyl acetate. The materials are mixed and put into a blender, and stirred at room temperature for 30 minutes to obtain a low-viscosity mixture. Among them, ethanol, water, and butyl acetate are used as solvents, and water-soluble acrylic resin is selected to make the coating have a lower initial viscosity and higher fluidity, thereby filling the defects of the steel wire. Titanium dioxide is a filler, so that the high adhesion coating after fixation has a higher hardness. The test results are shown in Appendix 1; Schedule 1

[0019] In Appendix 1, the test process is to set a specified temperature in the oven, and after the temperature reaches a stable state, place the steel wire in the oven for 5 minutes, take out the steel wire, and quickly spray a certain amount of coating on the surface of the steel wire, and measure the time required for curing and the curing effect after 1 second. The curing effect is the situation after the coating part is bent at 90°C. It can be seen from Appendix 1 that the high adhesion coating can be quickly cured at 300-400°C, thereby deforming the defective part of the steel wire. After winding the spring, a spring with deformed size is obtained, which is then detected. In theory, the higher the temperature, the better the curing effect, but increasing the temperature requires higher heating power, and too high a temperature causes the generated ethanol to have a risk of combustion. Therefore, the heating temperature of the steel wire is selected to be 300-400°C; The spraying machine is a German FOERSTER spraying machine. The spraying machine is close to the electromagnetic induction heating device. The surface defect of the steel wire 1 moves from the electromagnetic induction heating device to the working position of the spraying machine within 3 seconds, and then the coating is sprayed. During the spraying process, the surface defect of the steel wire 1 is in a high temperature state; The drying device 7 includes a drying channel 7-2, through which the steel wire 1 passes, and the drying channel 7-2 is connected to a hot air blower 7-1, so as to further completely cure the coating. During the test, it was found that the temperature of the steel wire after passing through the sprayer was still as high as 70°C or more, which could promote the curing of the coating, but could not completely cure it. After being introduced into the drying device, the coating could achieve a completely cured effect. The oiler 8 sprays grease onto the entire steel wire 1, thereby reducing corrosion to the spring.

[0020] The German FOERSTER speed sensor 4 detects the conveying speed of the steel wire 1, and then determines the time when the surface defects of the steel wire 1 enter the electromagnetic induction heating device, sprayer, and drying device 7, and then performs precise processing to avoid energy waste; The high-speed camera is a built-in high-speed camera of the CNC-625D spring winding machine of Zhejiang Wanneng Spring Machinery Co., Ltd. The high-speed camera takes pictures of the spring shape to measure the outer diameter and length of the spring, and uploads them to the server. The server determines whether the spring shape parameters are qualified and whether there are marks. If the parameters are unqualified and / or there are marks, they are transported to the unqualified bin. If the parameters are qualified and there are no marks, they are transported to the qualified bin.

[0021] The spring steel wire 1 is fed into the spring winding machine by the roller. After contacting the semicircular groove at the front end of the top spring rod, it bends and deforms along the direction of the semicircular groove and periodically contacts the inclined surface of the pitch block. When a spring is wound, the feeding mechanism stops feeding and the cutter control mechanism forces the cutter to cut the spring. The reciprocating operation realizes the automatic forming of the spring.

[0022] By adjusting the position between the eddy current flaw detector 3 and the electromagnetic induction heater 5, the sprayer, and the dryer, as well as the speed of the winder 9, t1, t2, and t3 are set, where t1 and t3 are 0.5s, so that the electromagnetic induction heater 5 and the dryer are pre-started, and t2 is the time for the defect position to move from the electromagnetic induction heater 5 to the sprayer, so that only the defect position is sprayed.

[0023] Example 1 like Figure 1-3 As shown, a method for automatically identifying and sorting springs with surface defects during spring winding includes the following steps: A. Pretreatment of the steel wire coil, including parameter detection of the steel wire coil, flaw detection and marking of the steel wire coil, and surface treatment of the steel wire coil to obtain the steel wire coil to be wound. B. Spring winding: placing the steel coil to be wound into a spring winding machine and winding the spring to be screened; C. Detection and sorting: Before the springs to be screened are cut off, the parameters of the springs to be screened are automatically detected to see if there are any marks. If the parameters are unqualified and / or there are marks, they are transported to the unqualified bin; if the parameters are qualified and there are no marks, they are transported to the qualified bin. In step A, flaw detection and marking of the wire coil includes the following steps: A1. Preparation for flaw detection: the steel wire coil that has been tested for parameters is transferred to the unwinder 2, and the starting end of the steel wire 1 is connected to the reel 9. An eddy current flaw detector 3, an electromagnetic induction heating device, a sprayer, and a drying device 7 are installed between the unwinder 2 and the reel 9 in sequence. A speed sensor 4 for detecting the speed of the steel wire 1 is also installed between the unwinder 2 and the reel 9; A2, flaw detection, start the unwinder 2, the winder 9, and the eddy current flaw detector 3. When the eddy current flaw detector 3 detects the surface defect of the steel wire 1, the speed sensor 4 works to calculate the time t1 when the surface defect of the steel wire 1 moves to the electromagnetic induction heating device, the time t2 when the surface defect moves to the spraying machine, and the time t3 when the surface defect moves to the drying device 7; A3, marking, after the eddy current flaw detector 3 detects the surface defects of the steel wire 1, the electromagnetic induction heating machine 5 starts to work after a delay of t1, so that the temperature of the steel wire 1 rises to 300°C, the spraying machine starts to work after a delay of t2, and sprays a high adhesion coating on the surface defects of the steel wire 1, and the drying device 7 starts to work after a delay of t3, so that the coating hardens. The surface treatment of the steel wire coil includes the following steps: A4. An oiler 8 is arranged between the drying device 7 and the winding machine 9. The oiler 8 is turned on at the same time as the unwinding machine 2 is turned on, and the oiled steel wire 1 enters the winding machine for winding.

[0024] The spring is a quenched and tempered SiCr valve spring. The steel wire 1 is made of SAE9254V, φ3.90 mm, with an outer diameter of D31 mm, a length of L555 mm, and a tensile strength of 1940 MPa.

[0025] The test results are shown in Appendix 2.

[0026] Example 2 A method for automatically identifying and sorting springs with surface defects during spring winding, which is different from Example 1 in that in step A3, A3, mark, after the eddy current flaw detector 3 detects the surface defects of the steel wire 1, the electromagnetic induction heating machine 5 is operated for a delay time t1 to raise the temperature of the steel wire 1 to 300°C, the sprayer is operated for a delay time t2 to spray a high adhesion coating on the surface defects of the steel wire 1, and the drying device 7 is operated for a delay time t3 to harden the coating.

[0027] The spring is a quenched and tempered SiCrV clutch damping spring. The steel wire 1 is made of 65SiCrV6, φ4.10 mm, the spring outer diameter D37 mm, the spring length L1250 mm, and the tensile strength of the steel wire 1 is 2140 MPa.

[0028] The test results are shown in Appendix 2.

[0029] Example 3 A method for automatically identifying and sorting springs with surface defects during spring winding, which is different from embodiment 1-2 in that in step A3, A3, marking, after the eddy current flaw detector 3 detects the surface defects of the steel wire 1, the electromagnetic induction heating machine 5 is operated for a delay time t1 to raise the temperature of the steel wire 1 to 400°C, the sprayer is operated for a delay time t2 to spray a high adhesion coating on the surface defects of the steel wire 1, and the drying device 7 is operated for a delay time t3 to harden the coating.

[0030] The spring is a quenched and tempered CrV clutch damping spring and pressure regulating spring. The steel wire 1 is made of 50CrVA, φ6.00 mm, the spring outer diameter is D45 mm, the spring length is L832 mm, and the tensile strength of the steel wire 1 is 1610 Mpa. The test results are shown in Appendix 2.

[0031] Schedule 2

[0032] In Schedule 2, the total number of springs refers to the total number of springs obtained by winding; The marking times refers to the number of times the sprayer works; The number of unqualified springs refers to the number of unqualified springs determined after secondary testing out of the total number of springs; The number of rejected unqualified springs refers to the number of springs in the unqualified bin; The number of qualified and marked springs refers to the number of springs that passed the secondary inspection but had marks, i.e., incorrect marks.

[0033] It can be seen from Appendix 2 that the probability of the marked springs being detected and rejected later is 100%. The method for automatically identifying and sorting springs with surface defects during spring winding provided by the present invention can greatly improve the spring test pass rate.

[0034] Taking full advantage of the fast induction heating speed, the coating sprayed by the spray gun to the cross section of the steel wire 1 is not completely uniform, resulting in inconsistent cooling speed of the steel wire 1, and obvious "small bends" will appear under the condition of "thermal expansion and contraction". In addition, after the coating evaporates and solidifies, a hardened layer with strong adhesion will be formed on the surface of the steel wire 1 at the defective position; using this marking method, artificial differences in mechanical properties and surface differences are caused between the defective part of the steel wire 1 and the normal position of the steel wire 1, such as: sudden changes in the friction coefficient of the steel wire 1 surface, enlargement of the diameter of the steel wire 1, and "small bends" in the parts of the steel wire 1, which destroy the stability of the winding spring and cause huge fluctuations in the size of the spring.

[0035] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for automatically identifying and sorting springs with surface defects during spring winding, characterized in that: The following steps are included: A. Pretreatment of the steel wire coil, including parameter detection of the steel wire coil, flaw detection and marking of the steel wire coil, and surface treatment of the steel wire coil to obtain the steel wire coil to be wound; B. Spring winding: placing the steel coil to be wound into a spring winding machine and winding the spring to be screened; C. Detection and sorting: Before the springs to be screened are cut off, the parameters of the springs to be screened are automatically detected to see if there are any marks. If the parameters are unqualified and / or there are marks, they are transported to the unqualified bin; if the parameters are qualified and there are no marks, they are transported to the qualified bin. In step A, flaw detection and marking of the wire coil includes the following steps: A1. Preparation for flaw detection: transfer the wire coil that has been tested for parameters to the unwinder, connect the starting end of the wire to the rewinder, install an eddy current flaw detector, an electromagnetic induction heating device, a sprayer, and a drying device between the unwinder and the rewinder in sequence, and also install a speed sensor for detecting the speed of the wire between the unwinder and the rewinder; A2. Flaw detection: start the unwinder, winder and eddy current flaw detector. When the eddy current flaw detector detects a defect on the surface of the steel wire, the speed sensor starts to work and calculates the time t1 when the surface defect moves to the electromagnetic induction heating device, the time t2 when the surface defect moves to the spraying machine, and the time t3 when the surface defect moves to the drying device. A3, marking, after the eddy current flaw detector detects the surface defects of the steel wire, the delay time t1, the electromagnetic induction heating machine works to raise the temperature of the steel wire to 300-400℃, the delay time t2, the spraying machine works to spray high adhesion coating on the surface defects of the steel wire, the delay time t3, the drying device works to harden the coating, In step A, the steel wire coil is subjected to surface treatment, including the following steps: A4. An oiler is installed between the drying device and the winder. The oiler is turned on at the same time as the unwinder. The oiled steel wire enters the winder for winding.

2. The method for automatically identifying and sorting springs with surface defects during spring winding according to claim 1, characterized in that: In step A, the steel wire coil is subjected to parameter detection, and the detection parameters include steel wire outer diameter detection and mechanical property detection.

3. The method for automatically identifying and sorting springs with surface defects during spring winding according to claim 1, characterized in that: The eddy current flaw detector is a rotary and through flaw detector produced by FOERSTER of Germany; The spraying machine is a spraying machine of FOERSTER of Germany.

4. The method for automatically identifying and sorting springs with surface defects during spring winding according to claim 1, characterized in that: The speed sensor is a German FOERSTER speed sensor.

5. The method for automatically identifying and sorting springs with surface defects during spring winding according to claim 1, characterized in that: In step C, the spring winding machine is a CNC-625D spring winding machine of Zhejiang Universal Spring Machinery Co., Ltd., which automatically detects the appearance parameters of the springs to be screened through camera detection and performs sorting.

6. The method for automatically identifying and sorting springs with surface defects during spring winding according to claim 1, characterized in that: The high adhesion coating is made of the following raw materials in weight percentage: 22wt% titanium dioxide, 13wt% ethanol, 10wt% water, 45wt% water-soluble acrylic resin AC-235, and 10wt% butyl acetate. The oiling machine applies oil to the steel wire, and the oil is anti-rust oil.

7. The method for automatically identifying and sorting springs with surface defects during spring winding according to claim 1, characterized in that: The electromagnetic induction heating device comprises an insulating tube, the steel wire passes through the insulating tube, an induction coil is sheathed outside the insulating tube, and the induction coil is connected to a power source.

8. The method for automatically identifying and sorting springs with surface defects during spring winding according to claim 1, characterized in that: The drying device comprises a drying channel, the steel wire passes through the drying channel, and the drying channel is connected to a hot air blower.

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