A processing apparatus and method for a three-piece tinplate can body.

Abstract

This invention provides a processing apparatus and method for three-piece tinplate can bodies. The apparatus includes a slitting roll cutter, a strip conveyor table, a small sheet roll cutter, a first conveyor belt, a second conveyor belt, a turning conveyor belt, a middle small sheet conveyor belt, an edge small sheet conveyor belt, and a small sheet conveyor belt. The method involves designing the large sheet size so that the can body height direction is perpendicular to the steel coil rolling direction, cutting the large sheet into strips, processing the strips into small sheets, rotating the left small sheet 180 degrees and placing it on the same conveyor belt as the right small sheet, placing the middle small sheet on a separate conveyor belt, and sending them to a welding machine for welding using different welding processes. This invention solves the welding quality problems that occur when the can body height direction is perpendicular to the steel coil rolling direction, avoids the problem of incomplete welds on the edge cans and the problem of spatter on the welds on the middle cans, and improves product quality and production efficiency.

Description

Technical Field

[0001] This invention relates to the field of metal packaging, and specifically to a processing apparatus and method for a three-piece tin-plated can body. Background Technology

[0002] Tinplate, also known as tinplate, is a steel sheet with a thin layer of tin plating on its surface. It has good corrosion resistance, good formability, is easy to weld, and the plating is non-toxic and odorless. It can prevent iron from dissolving into the packaged goods, and the surface is bright. It can be printed with pictures to beautify the products. It is mainly used in the food and beverage industry, and secondly in packaging materials for chemical paints, oils, and pharmaceuticals.

[0003] Can manufacturing mainly falls into two categories: three-piece cans and two-piece cans. Two-piece cans are metal containers composed of a lid and a seamless, stamped can body with a bottom. Three-piece cans are made from tin-plated sheet through forming and joining processes, comprising a can body, a bottom, and a lid. The can body has seams, and the can body, bottom, and lid are rolled together for sealing. Three-piece cans are characterized by good rigidity, the ability to produce cans of various shapes, high material utilization, ease of size modification, mature manufacturing processes, and the ability to package a wide variety of products. They are commonly used for food, beverages, dry powders, chemical products, and aerosols.

[0004] There are two main methods for joining three-piece can bodies: soldering and resistance welding. The former was used earlier, but it is being phased out due to the lead content in solder. The production process of manufacturing can bodies using resistance welding is as follows: tin-plated sheet → coating (using a blank coating) → cutting iron → rolling → resistance welding → coating inside and outside the weld → flanging → sealing the can → rolling the seam → finished product. Resistance welding completely overcomes the lead pollution problem caused by traditional soldered cans, and it also has low energy consumption and low material consumption, making it far more widely used than two-piece shallow drawing and thin-walled deep drawing can manufacturing technologies.

[0005] The production process of small sheet metal for three-piece can bodies mainly includes: uncoiling and shearing tinplate steel coils into large sheets; processing these large sheets into strips using a slitting and rolling mill, then placing them on a strip conveyor table; transporting the strips to a small sheet rolling mill for further processing into smaller sheets; and placing these smaller sheets in a small sheet hopper. Once the hopper is full, the small sheet stack is conveyed by a conveyor belt to a welding machine for welding along the height of the can body. The equipment for processing small sheet metal for three-piece can bodies consists of: a slitting and rolling mill, a strip conveyor table, a small sheet rolling mill, and a small sheet hopper.

[0006] However, due to the deformation of the rolls during the rolling of tinplate steel coils and the additional electric field at the edges during tin plating, the substrate at the edges becomes thinner and the tin layer thickens within a 3-5mm range at the edges, a phenomenon known as the "edge effect." This results in changes in resistance and welding heat during can body manufacturing due to both the increased tin layer thickness and the thinner substrate, leading to welding quality issues.

[0007] Welding quality issues can be categorized into two scenarios. Scenario 1: The tank body height direction is perpendicular to the steel coil rolling direction. In this case, the weld direction is also perpendicular to the steel coil rolling direction. To ensure the welding quality of most intermediate tanks, the welding current is generally low, making it prone to incomplete welds at both ends of the welds on the side tanks. Scenario 2: The tank body height direction is consistent with the steel coil rolling direction. In this case, the weld direction is also consistent with the steel coil rolling direction. Again, to ensure the welding quality of most intermediate tanks, the resistance seam welding current is generally low. However, on the side tanks, due to the thicker tin layer and thinner substrate, the contact resistance is lower, and the weld heat is lower, making it prone to incomplete welds along the entire weld seam.

[0008] However, to ensure the welding quality of the side tanks, the welding current must be increased, which makes the weld seam of the middle material prone to spatter. In order to ensure the welding quality of the side material, the welding current was increased to 3250A, which caused spatter in the C3 weld seam of the middle material, resulting in the weld seam failing the corrosion resistance test.

[0009] Chinese patents CN114932381A and CN118875653A propose two methods and equipment for processing three-piece tinplate can body sheets. Both methods involve aligning the can body height direction with the steel coil rolling direction to avoid weld quality issues. However, to save material, the can body height direction may be perpendicular to the steel coil rolling direction.

[0010] Therefore, it is necessary to develop a new processing device and method that can avoid welding quality problems even when the height of the tank body is perpendicular to the rolling direction of the steel coil. Summary of the Invention

[0011] The purpose of this invention is to provide a processing apparatus and method for a three-piece tinplate can body, which solves the welding quality problem that occurs when the height direction of the can body is perpendicular to the rolling direction of the steel coil.

[0012] To achieve the above objectives, in a first aspect, the present invention provides a processing apparatus for a three-piece tin-plated can body, comprising:

[0013] The uncoiling and shearing device uncoils the tinplate steel coil and cuts it into large pieces according to the design dimensions of the can body, ensuring that the height direction of the can body is perpendicular to the rolling direction of the tinplate steel coil.

[0014] The slitting roll cutter cuts the printed tin-plated sheet into N rows of strips, ensuring that the cutting direction is parallel to the height direction of the can.

[0015] The slab conveyor is used to transport the slabs after slitting and rolling to the small sheet roll cutter, and the conveying direction is perpendicular to the height of the can body;

[0016] The small sheet roll cutter is used to receive the sheet material conveyed by the sheet conveyor table, cut each row of sheet material into M columns of small sheets, and convey the first column of small sheets to the first conveyor belt, the Mth column of small sheets to the second conveyor belt, and the remaining small sheets to the middle small sheet conveyor belt.

[0017] A turning conveyor belt is used to receive small pieces of material from the first conveyor belt, rotate them 180°, and then transport them to the side small piece conveyor belt.

[0018] The edge small material conveyor belt receives small material pieces from the turning conveyor belt and the second conveyor belt;

[0019] The central small material conveyor belt and the side small material conveyor belt transport the small material pieces located on them to the small material conveyor belt in a time-sharing manner;

[0020] Small material conveyor belts are used to transport small material pieces to the welding machine.

[0021] In some alternative embodiments of the present invention, the welding machine uses an I1 current to weld incoming materials from the central small sheet conveyor belt and an I2 current to weld incoming materials from the side small sheet conveyor belt.

[0022] Preferably, I1 < I2.

[0023] In some optional embodiments of the present invention, the small material conveyor belt transports the incoming materials from the side small material conveyor belt and the middle small material conveyor belt to different welding machines or different welding stations of the same welding machine.

[0024] In some alternative embodiments of the invention, the turning conveyor belt includes two 90° turning conveyor belts spliced ​​together at 180°, which are used to rotate the first column of small pieces by 180°.

[0025] Secondly, the present invention provides a method for processing a three-piece tin-plated can body, comprising:

[0026] The steel coil is processed into a large sheet, the size of which is such that the height direction of the can body is perpendicular to the rolling direction of the steel coil.

[0027] The large sheet is cut into strips using a slitting roll cutter, and the large sheet is cut into N rows of strips along the direction perpendicular to the rolling direction of the steel coil;

[0028] Each strip is processed into M rows of small pieces using a small piece roll cutter;

[0029] After rotating the first column of small material pieces 180 degrees, place them on the edge material piece conveyor belt along with the Mth column of small material pieces, and place the remaining small material pieces on the middle material piece conveyor belt.

[0030] The central and side small material conveyor belts transport the small material pieces located on them to the welding machine in a time-sharing manner, and then perform welding using different welding processes.

[0031] In some optional embodiments of the present invention, the welding machine uses current I1 to weld incoming materials from the central small sheet conveyor belt and current I2 to weld incoming materials from the side small sheet conveyor belt; I1 < I2.

[0032] In some alternative embodiments of the present invention, the first column of small pieces is conveyed to the turning conveyor belt via the first conveyor belt, and the turning conveyor belt rotates them 180° and places them on the side small piece conveyor belt.

[0033] In some alternative embodiments of the present invention, the Mth column of small material pieces is placed directly on the edge material piece conveyor belt via the first conveyor belt.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The processing apparatus and method provided by this invention weld the middle tank body and the side tank bodies separately. The middle tank body is welded using normal current, while for the side tank bodies, an additional current is applied to the areas with "side effect" to avoid the impact of the side effect on weld quality. In this way, the weld quality of both the side and middle tanks can meet the requirements. In particular, this invention achieves good weld quality even when the height direction of the tank body is perpendicular to the rolling direction of the steel coil, effectively solving the problems of incomplete welds or spatter in traditional processes, and improving product quality and production efficiency. Specifically:

[0036] 1. By treating the middle tank body and the side tank body separately and using different welding current parameters, the welding quality problem caused by the edge effect of tinplate is effectively solved, ensuring that the welding quality of all tank bodies meets the requirements.

[0037] 2. In the processing of small edge pieces, by rotating the left side piece by 180° and placing it on the same conveyor belt as the right side piece, the edge effect of the two is made consistent, and the same welding parameters can be used for processing, which simplifies the process and improves production efficiency.

[0038] 3. Even in processing methods where the height of the tank body is perpendicular to the rolling direction of the steel coil, the welding quality can be guaranteed by the method and apparatus of the present invention, which increases material utilization and reduces production costs.

[0039] 4. The device structure of the present invention is relatively simple and easy to implement. It can be integrated into the existing three-piece can production line, and has good practicality and economy. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments disclosed in this invention, the accompanying drawings of the embodiments will be briefly described below. These drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0041] Figure 1 This is a schematic diagram of the processing device for the three-piece tin-plated can body of the present invention;

[0042] Figure 2 This is a flowchart illustrating the processing method of the three-piece tin-plated can body of the present invention;

[0043] Figure 3 This is a schematic diagram of the welding current of the middle tank in this invention;

[0044] Figure 4 This is a schematic diagram of the welding current for the side tank of the present invention. Detailed Implementation

[0045] The technical solutions (including preferred technical solutions) of the present invention will be further described in detail below with reference to the accompanying drawings and by way of listing some optional embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] This embodiment provides a processing device for a three-piece tin-plated can body, such as... Figure 1 As shown, the device includes a slitting roll cutter 1, a strip conveyor 2, a small sheet roll cutter 3, a first conveyor belt 4, a second conveyor belt 5, a turning conveyor belt 6, a middle small sheet conveyor belt 7, an edge small sheet conveyor belt 8, and a small sheet conveyor belt 9.

[0048] An uncoiling and shearing device (not shown in the figure) is used to uncoil tinplate steel coils and cut them into large sheets 10 according to the design dimensions of the can body, ensuring that the height direction of the can body is perpendicular to the rolling direction of the tinplate steel coil. Figure 1 As shown;

[0049] The slitting roll cutter 1 is used to cut the printed tin-plated sheet into 7 rows of strips 11 (i.e., A, B, C, D, E, F, G), and ensure that the cutting direction is parallel to the height direction of the can body, that is, perpendicular to the rolling direction of the steel coil.

[0050] The slab conveyor 2 is used to convey the slab strips 11 after slitting and rolling to the small sheet roll cutter 3, and the conveying direction is perpendicular to the height direction of the can body;

[0051] The small sheet roll cutter 3 is used to receive the sheet material conveyed by the sheet conveyor 2 and cut each row of sheet material into small sheets. The first column of small sheets, i.e. the left side small sheets, such as G1 and F1, are conveyed to the first conveyor belt (i.e., the edge small sheet transition conveyor belt 4); the seventh column of small sheets, i.e. the right side small sheets, such as G7 and F7, are conveyed to the second conveyor belt 5; and the remaining small sheets, i.e. the middle small sheets, such as G2 to G6 and F2 to F6, are conveyed to the middle small sheet conveyor belt 7.

[0052] The turning conveyor belt 6 is used to receive small pieces from the first conveyor belt 4 and rotate them 180° before conveying them to the side small piece conveyor belt. The turning conveyor belt 6 includes two 90° turning conveyor belts 6.1, which are used to rotate the left side small piece by 180° so that the edge effect of the left side small piece is consistent with the edge effect of the right side small piece, which facilitates the use of the same welding process in the future.

[0053] The edge small material conveyor belt 8 receives small material pieces from the turning conveyor belt 6 and the second conveyor belt 5;

[0054] The middle small material conveyor belt 7 and the side small material conveyor belt 8 transport the small material pieces located on them to the small material conveyor belt 9 in a timely manner;

[0055] Small material conveyor belt 9 is used to transport small material pieces to the welding machine (not shown in the figure).

[0056] In this embodiment, the welding machine uses current I1 to weld the incoming materials from the central small sheet conveyor belt, namely: A2~6, B2~B6, C2~C6, D2~D6, E2~E6, F2~F6, G2~G6; and uses current I2 to weld the incoming materials from the side small sheet conveyor belt, namely: A1, B1, C1, D1, E1, F1, G1, A7, B7, C7, D7, E7, F7, G7; where I1 < I2, as shown below. Figure 3 , Figure 4 As shown.

[0057] Small material conveyor belt 9 transports the incoming materials from the side small material conveyor belt 8 and the middle small material conveyor belt 7 to different welding stations of the same welding machine. By adjusting the welding current parameters of different stations, differentiated welding processing of small material pieces from different sources can be achieved.

[0058] Example 2

[0059] Based on Example 1, such as Figure 2 As shown in the figure, this embodiment provides a method for processing a three-piece tin-plated can body, and the specific steps are as follows:

[0060] Step 1: Process the steel coil into large sheet 10, the dimensions of which are such that the height direction of the can body is perpendicular to the rolling direction of the steel coil, such as... Figure 1As shown; this step is usually completed on the production line using equipment such as unwinding and shearing.

[0061] Step 2: Use slitting roll cutter 1 to cut the large sheet into strips, and cut the large sheet into 7 rows of strips (A, B, C, D, E, F, G) along the direction perpendicular to the rolling of the steel coil;

[0062] Step 3: Use a small sheet roll cutter to process each strip into small sheets;

[0063] Step 4: The first column of small material pieces (A1, B1, C1, D1, E1, F1, G1) is conveyed to the turning conveyor belt 6 via the edge small material piece transition conveyor belt 4. The turning conveyor belt 6 rotates them 180° and places them on the edge small material piece conveyor belt 8. The seventh column of small material pieces (A7, B7, C7, D7, E7, F7, G7) is placed directly on the edge small material piece conveyor belt 8. The remaining small material pieces (A2-6, B2-B6, C2-C6, D2-D6, E2-E6, F2-F6, G2-G6) are placed on the middle small material piece conveyor belt 7.

[0064] Step 5: The small material sheet conveyor belts 7 and 8 in the middle and the small material sheet conveyor belts 9 transport the small material sheets located on them to the welding machine, where they are welded using different welding processes.

[0065] In this embodiment, the welding machine uses current I1 to weld the material coming from the middle small sheet conveyor belt, and uses current I2 to weld the material coming from the side small sheet conveyor belt; I1 < I2.

[0066] Using the above method, the left side small material piece (1 column of small material pieces) is rotated 180 degrees and placed on the side small material piece conveyor belt 8 along with the right side small material piece (7 columns of small material pieces). The side effects of the two are consistent, and the same welding parameters can be used for processing, which simplifies the process and improves production efficiency.

[0067] Example 3

[0068] Based on Examples 1 and 2, such as Figure 3 and Figure 4 As shown in the figure, this embodiment explains the welding current for the edge small sheet and the middle small sheet.

[0069] The small sheet in the middle is made of, for example Figure 3 The welding current shown does not have the "edge effect" in the middle blank, and the tin plating layer thickness and steel plate thickness are uniform. Generally speaking, the current should remain constant throughout the weld. However, considering that the two ends of the tank body need to be processed again, the weld connection is required to be more reliable. Moreover, the ends of the weld do not have the cumulative effect of welding heat as the middle. Therefore, in this embodiment, the welding current is increased by 1 to 5% at both ends of the weld of the small blank in the middle.

[0070] In other words, the welding current I3 for the middle part of the weld seam of the small material piece in the t1 to t2 welding, and the welding current I4 for the two ends of the weld seam of the small material piece in the 0 to t1 and t2 to t3 welding are 1 to 5% higher than I3.

[0071] The small edge pieces are made of materials such as Figure 4 The current welding shown exhibits an "edge effect" at one end of the weld seam for the small edge pieces compared to the central small pieces, such as... Figure 1 As shown in the diagram. Therefore, when welding small edge pieces, the welding current I5 (t'2~t'3) at the weld end with the "edge effect" is 1~5% higher than the welding current I6 (0~t'1) at the other end, and I6 is 1~5% higher than the welding current I7 (t'2~t'3) in the middle part of the weld of the small edge pieces.

[0072] In one specific embodiment of the present invention, for a certain tin-plated plate with a thickness of 0.18 mm and a tin plating amount of 1.1 / 1.1 g / mm, 2 When the welding speed is 80m / min, the welding pressure is 42kg, and the overlap is 0.42mm.

[0073] Welding current for the small sheet in the middle: 3510A for the middle part and 3580A for both ends.

[0074] Welding current for small edge pieces: 3510A for the middle part, 3580A for one end, and 3680A for the other end which has an "edge effect".

[0075] Example 4

[0076] Based on embodiment 1, 2 or 3, this embodiment sets up two small material conveyor belts 9 to respectively transport the incoming materials from the side small material conveyor belt 8 and the middle small material conveyor belt 7 to two different welding machines. The two welding machines can perform welding operations simultaneously, further improving production efficiency.

[0077] Specifically, the first welding machine is dedicated to processing small pieces of material in the middle, using current I1 for welding; the second welding machine is dedicated to processing small pieces of material at the edges, using current I2 for welding. In this way, the two types of small pieces of material can be welded simultaneously without needing to be processed in separate times, further improving production efficiency.

[0078] It will be readily understood by those skilled in the art that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, substitutions, improvements, etc., made under the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A processing apparatus for a three-piece tin-plated can body, characterized in that, include: The uncoiling and shearing device uncoils the tinplate steel coil and shears it into large pieces according to the design dimensions of the can body, ensuring that the height direction of the can body is perpendicular to the rolling direction of the tinplate steel coil. The slitting roll cutter cuts the printed tin-plated sheet into N rows of strips, ensuring that the cutting direction is parallel to the height direction of the can. The slab conveyor is used to transport the slabs after slitting and rolling to the small sheet roll cutter, and the conveying direction is perpendicular to the height of the can body; The small sheet roll cutter is used to receive the strips conveyed by the strip conveyor table and cut each row of strips into M columns of small sheets. The first column of small sheets is conveyed to the first conveyor belt, the Mth column of small sheets is conveyed to the second conveyor belt, and the remaining small sheets are conveyed to the middle small sheet conveyor belt. A turning conveyor belt is used to receive small pieces of material from the first conveyor belt, rotate them 180°, and then transport them to the side small piece conveyor belt. The edge small material conveyor belt receives small material pieces from the turning conveyor belt and the second conveyor belt; The central small material conveyor belt and the side small material conveyor belt transport the small material pieces located on them to the small material conveyor belt in a time-sharing manner; Small material conveyor belts are used to transport small material pieces to the welding machine; The welding machine uses current I1 to weld materials coming from the middle small sheet conveyor belt and current I2 to weld materials coming from the side small sheet conveyor belt, and I1 < I2.

2. The processing apparatus for a three-piece tin-plated can body according to claim 1, characterized in that: The small material conveyor belt transports the incoming materials from the side small material conveyor belt and the middle small material conveyor belt to different welding machines or different welding stations of the same welding machine.

3. The processing apparatus for a three-piece tin-plated can body according to claim 1, characterized in that: The turning conveyor belt includes two 90° turning conveyor belts spliced ​​together at 180°, which are used to rotate the first column of small pieces by 180°.

4. A method for processing a three-piece tin-plated can body, characterized in that, include: The steel coil is processed into a large sheet, the size of which is such that the height direction of the can body is perpendicular to the rolling direction of the steel coil. The large sheet is cut into strips using a slitting roll cutter, and the large sheet is cut into N rows of strips along the direction perpendicular to the rolling direction of the steel coil; Each strip is processed into M rows of small pieces using a small piece roll cutter; After rotating the first column of small material pieces 180 degrees, place them on the edge material piece conveyor belt along with the Mth column of small material pieces, and place the remaining small material pieces on the middle material piece conveyor belt. The central small material conveyor belt and the side small material conveyor belt transport the small material pieces located on them to the welding machine in a time-sharing manner, and then perform welding using different welding processes. The welding machine uses current I1 to weld materials coming from the middle small sheet conveyor belt and current I2 to weld materials coming from the side small sheet conveyor belt; I1 < I2.

5. The processing method for a three-piece tin-plated can body according to claim 4, characterized in that: The first column of small material pieces is conveyed to the turning conveyor belt via the first conveyor belt, and the turning conveyor belt rotates them 180° before placing them on the side small material piece conveyor belt.

6. The processing method for a three-piece tin-plated can body according to claim 4, characterized in that: The Mth column of small material pieces is placed directly onto the side small material piece conveyor belt via the second conveyor belt.

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