A method for detecting the offset of blank on the punching surface

Abstract

The present invention discloses a method for detecting the offset of a blank at a punching press, which belongs to the field of alloy sheet forming quality inspection. The inspection device includes: a bracket, a rubber wheel, a driving bevel gear, a driven bevel gear, a driving shaft, a driven shaft, an encoder, and a spring. During stamping, the blank drives the rubber wheel to rotate. The rotation angle is captured by the encoder and converted into the offset of the blank at the punching press, which is equivalent to the offset of the edge profile of the punching press. By using this device, the offset of the blank at the punching press can be obtained when the stamping is completed, and the qualified stamped part can be determined based on the offset. The present invention effectively improves the practicality and accuracy of stamping part forming quality inspection. It solves the current manual dependence of stamping forming quality inspection and improves the efficiency of product quality inspection. It can also provide a basis for stamping die debugging, changing the current model that mainly relies on the experience of die fitters, and can reduce the difficulty of inspection, shorten the inspection time, and the occurrence rate of defective products.

Description

Technical Field

[0001] The invention belongs to the field of alloy plate forming quality detection, and in particular relates to a device for detecting the offset of a blank on a stamping pressing surface. Background Art

[0002] In the automotive production process, approximately 60% to 70% of parts are stamped, such as hoods, frames, support components, and sheet metal parts. These parts require high precision and quality in stamping. Numerous factors influence stamping quality, including material properties, process parameters, die structure, and other parameters. Stamped parts that fail to meet product requirements often exhibit defects such as wrinkles, surface scratches, dents, collapses, pits, bulges, impact lines, slip lines, springback, and warpage.

[0003] Chinese patent application CN202211307103.3 proposes the idea of ​​real-time detection of stamping quality through the offset of the stamping blank contour. The measurement of the offset of the stamping blank contour is quite difficult in actual operation. Currently, a laser rangefinder is used to measure the offset of the blank edge, but the actual mold pressing surface is not flat, and due to vibration during the stamping process, the light source can easily lose the positioning of the blank edge. Therefore, it is necessary to propose a more practical and effective method for detecting the offset of the stamping blank contour based on the innovative ideas of this patent application. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a method for detecting the offset of a blank on a stamping binder surface. The technical solution adopted by the present invention is as follows:

[0005] The method of the present invention relates to a device for detecting the offset of a blank profile on a punching surface, which includes a bracket 6, a rubber wheel 1, a driving bevel gear 2, a driven bevel gear 4, a driving shaft 3, a driven shaft 5, an encoder 7 and a spring 8.

[0006] The driving bevel gear 2 and the driven bevel gear 4 are meshed to form a bevel gear pair. The driving bevel gear 2 is connected to the rubber wheel 1 through the driving shaft 3, and the driven bevel gear 4 is connected to the encoder 7 through the driven shaft 5; the rubber wheel 1 is composed of a steel disc with a groove and a nested rubber ring. The driving shaft 3 and the driven shaft 5 are fixed to the bracket 6. The outside of the bracket 6 is sealed, and a long hole is opened in the rubber wheel 1 so that the rubber wheel 1 partially extends out from the top of the bracket 6. A spring 8 is installed under the bracket 6.

[0007] The present invention provides a method for detecting the offset of a blank on a punching surface, comprising the following specific steps:

[0008] 1) according to the size of the blank offset detection device of the punching blank face, a groove of corresponding size is opened at the position of the characteristic point selected on the blank holder ring of the punching die;

[0009] 2) First install the spring 8 into the groove, then install the other parts of the punching blank offset detection device into the groove, the punching blank profile offset detection device is in clearance with the groove, and connect the data line of the encoder 7 to the computer;

[0010] 3) Place the stamping blank in the mold. At this time, the spring 8 is compressed and the rim of the rubber wheel 1 fits the stamping blank.

[0011] 4) Perform a stamping test. When the stamped blank is offset, the friction drives the rubber wheel 1 to rotate, and then drives the encoder 7 to rotate through the driving shaft 3, bevel gear pair, and driven shaft 5;

[0012] 5) Collect the rotation angle output by encoder 7 through the computer , and based on this data, calculate the arc length of the rim rotation of the rubber wheel 1, that is, the offset of the blank on the punching surface. The calculation formula is as follows:

[0013]

[0014] in, R is the radius of the rubber wheel.

[0015] Preferably, the number of the stamping blank profile offset detection devices placed in a set of dies should be based on the minimum number of characteristic points that can describe the stamping part.

[0016] Preferably, a stamping die using the device of the present invention needs to reserve a position for encoder wiring on the die.

[0017] Preferably, the groove inserted into the device of the present invention should be opened on the outside of the drawbead. In this case, the device of the present invention will not affect the forming, and the offset of the blank on the stamping surface can be measured more accurately.

[0018] Beneficial effects of the present invention:

[0019] The blank offset of the punching blank surface measured and calculated by the present invention is equivalent to the offset of the edge profile of the punching blank, which solves the problem of inaccurate positioning when measuring the offset of the blank edge with a laser rangefinder.

[0020] By using this device, the offset of the blank on the punching surface can be obtained when the stamping is completed, and the quality of the stamped part can be determined based on the offset. The present invention solves the current dependence of stamping quality inspection on manual labor and improves the efficiency of product quality inspection. At the same time, the method of the present invention provides a basis for stamping die debugging, changing the current model that relies mainly on the experience of die fitters. It can reduce the difficulty of inspection, reduce labor costs, save costs, shorten the inspection time and the occurrence rate of defective products, improve the efficiency of mold testing, and thus reduce enterprise costs.

[0021] The device can also perform measurements under non-planar molds. It only needs to match the shell surface shape according to the mold shape, and can ensure the accuracy of the blank offset on the stamping press surface. This is a major advantage of the device of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the workflow of the embodiment of the present application, a brief introduction to the drawings of the embodiment is given below.

[0023] Figure 1 It is a schematic diagram of the device of the present invention;

[0024] Figure 2 It is a three-dimensional schematic diagram of the internal structure of the present invention;

[0025] Figure 3A It is a left side sectional view of the device of the present invention, Figure 3B This is a front sectional view of the device of the present invention, Figure 3C is a top cross-sectional view of the device of the present invention;

[0026] Figure 4 It is a cross-sectional schematic diagram of the present invention used in a stamping die. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described in detail below in the form of specific embodiments in conjunction with the accompanying drawings. Example

[0028] like Figure 1~Figure 2 and Figure 3A to Figure 3C As shown, this embodiment provides a device for detecting the offset of a blank on a stamping press, which includes: a bracket 6, a rubber wheel 1, a driving bevel gear 2, a driven bevel gear 4, a driving shaft 3, a driven shaft 5, an encoder 7 and a spring 8.

[0029] The driving bevel gear 2 and the driven bevel gear 4 are meshed to form a bevel gear pair. The driving bevel gear 2 is connected to the rubber wheel 1 through the driving shaft 3, and the driven bevel gear 4 is connected to the encoder 7 through the driven shaft 5; the rubber wheel 1 is composed of a steel disc with a groove and a nested rubber ring. The driving shaft 3 and the driven shaft 5 are fixed to the bracket 6. The outside of the bracket 6 is sealed, and a long hole is opened in the rubber wheel 1 so that the rubber wheel 1 partially extends out from the top of the bracket 6. A spring 8 is installed under the bracket 6.

[0030] Working principle:

[0031] The spring 8 is placed in the hole opened in the blank holder of the mold and contacts the lower surface of the bracket 6 to support the bracket 6 so that the rim of the rubber wheel 1 always maintains positive contact pressure with the blank surface, ensuring sufficient friction between the rim and the blank surface; the bracket 6 is used to fix the driving shaft 3 and the driven shaft 5, and its outer surface is clearance-matched with the inner surface of the hole opened in the blank holder of the mold (such as Figure 4 ) and can move up and down along the hole wall. Supported by a spring, the rim of rubber wheel 1 contacts the blank's binder surface and, due to friction, rotates due to the flow of the blank. A bevel gear pair, consisting of a meshing driving bevel gear 2 and a driven bevel gear 4, transmits the rotational motion of rubber wheel 1 to encoder 7 at a specific transmission ratio, deflecting the rotating shaft 90°. Encoder 7 collects the rotational displacement and transmits it to a computer, which processes and converts it into a numerical value for the blank's offset from the binder surface.

[0032] When stamping begins, the blank is placed on the lower die, where it contacts the rubber wheel 1, followed by edge pressing. After edge pressing, stamping begins, and the rubber wheel moves with the blank during the stamping process. When the rubber wheel 1 in the device deviates from the stamped blank, it rotates by an angle, similar to the driving gear. According to the arc length calculation formula:

[0033]

[0034] in is the arc length; n is the rotation angle; R is the radius of the rubber wheel.

[0035] From this, we can calculate the arc length of the rubber wheel 1, and the driving bevel gear 2 has the same rotation angle as the rubber wheel 1. The driving gear and the driven gear have a certain transmission ratio, which is calculated by the formula:

[0036]

[0037] in is the transmission ratio is the angular velocity of the driving gear; is the angular velocity of the driven gear.

[0038] According to the formula of angular velocity:

[0039]

[0040] in n is the rotation angle, t is the rotation time.

[0041] Therefore, when the encoder outputs its rotation angle, the arc length of the rubber wheel during rotation can be derived from the above formula; that is, the offset of the stamping blank line, which can be expressed as:

[0042]

[0043] in, is the rotation angle of the driven gear, which is the encoder.

[0044] A method for detecting the offset of blanks on a stamping binder surface based on the device comprises the following specific steps:

[0045] 1) According to the size of the blank offset detection device on the stamping press surface, a groove of corresponding size is opened at the position of the characteristic point selected on the blank holder ring of the stamping die;

[0046] 2) First install the spring 8 into the groove, and then install the other parts of the punching blank offset detection device into the groove, such as Figure 4 As shown, the data line of the encoder 7 is connected to the computer;

[0047] 3) Place the stamping blank in the mold (such as Figure 1 As shown), at this time, the spring 8 is compressed, and the rim of the rubber wheel 1 fits in with the stamping blank.

[0048] 4) Perform a stamping test. When the stamped blank is offset, the friction drives the rubber wheel 1 to rotate, and then drives the encoder 7 to rotate through the driving shaft 3, bevel gear pair, and driven shaft 5;

[0049] 5) Collect the rotation angle output by encoder 7 through the computer , and based on this data, calculate the arc length of the rim rotation of the rubber wheel 1, that is, the offset of the blank on the punching surface. The calculation formula is as follows:

[0050]

[0051] in, R is the radius of the rubber wheel.

[0052] The number of the invention devices placed in a set of molds should be based on the number of feature points that can at least describe the stamping parts. The encoder in the invention device needs to be connected to the computer, and a wiring position needs to be reserved in the mold.

[0053] It is worth noting that the groove inserted into the device of the present invention should be opened on the outside of the drawbead. In this case, the device of the present invention will not affect the forming, and the measured offset of the blank on the stamping surface is also accurate.

[0054] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

Claims

1. A method for detecting the offset of the blank profile of a stamping blank, characterized in that: The specific steps of this method are: 1) Grooves of corresponding sizes are opened at several characteristic point positions selected on the blank holder ring of the stamping die according to the size of the blank profile offset detection device for the stamping blank surface; the blank profile offset detection device for the stamping blank surface comprises: a bracket (6), a rubber wheel (1), a driving bevel gear (2), a driven bevel gear (4), a driving shaft (3), a driven shaft (5), an encoder (7) and a spring (8); The driving bevel gear (2) and the driven bevel gear (4) are meshed to form a bevel gear pair. The driving bevel gear (2) is connected to the rubber wheel (1) through the driving shaft (3), and the driven bevel gear (4) is connected to the encoder (7) through the driven shaft (5); the rubber wheel (1) is composed of a steel disc with a groove and a rubber ring nested therein. The driving shaft (3) and the driven shaft (5) are fixed to the bracket (6). The outer side of the bracket (6) is sealed, and a long hole is opened at the rubber wheel (1) so that the rubber wheel (1) partially extends outward above the bracket (6). A spring (8) is installed below the bracket (6); 2) first install the spring (8) into the groove, then install the other parts of the punching blank profile offset detection device into the groove, the punching blank profile offset detection device is in clearance with the groove, and connect the data line of the encoder (7) to the computer; 3) The stamping blank is placed in the die, at which point the spring (8) is compressed and the rim of the rubber wheel (1) fits the stamping blank; 4) Perform a stamping test. When the stamped blank is offset, the rubber wheel (1) is driven by friction to rotate, and the encoder (7) is driven to rotate through the driving shaft (3), the bevel gear pair, and the driven shaft (5); 5) Collect the rotation angle output by the encoder (7) through the computer , and based on the data, the arc length of the rim rotation of the rubber wheel (1), that is, the offset of the blank profile of the punching press surface, is calculated. The calculation formula is as follows: in, R is the radius of the rubber wheel.

2. The method for detecting the offset of the blank contour of the stamping binder surface according to claim 1, characterized in that: The number of the blank contour offset detection devices placed in a set of dies should be based on the minimum number of characteristic points that can describe the stamping part, and the number of characteristic points is determined according to the flow law of the blank.

3. The method for detecting the offset of the blank contour of the stamping binder surface according to claim 1, characterized in that: A space is reserved on the mold for routing the encoder (7).

4. The method for detecting the offset of the blank contour of the stamping binder surface according to claim 1, characterized in that: The groove is opened on the outside of the drawbead.

Images