How do metal can making equipment and metal can sealing equipment work How does the paint can sealing machine work？
(1) The sealing form of the metal container. Any two-piece can (barrel) body or three-piece can (barrel) body and the top or bottom of the joint, there is at least one.
Or two seams (except for single-piece spray cans). The only opening method that has been used on metal containers for more than a hundred years is double crimping (doubleam), can withstand the strict drop test requirements, the vat adopts triple seam (triple seam). According to the different requirements of the content, the degree of sealing after sealing can be divided into air-tight mouth (closed form that does not leak gas at the seal), liquid-tight mouth (closed form that does not leak liquid at the seal) and tightly sealed mouth (not at the seal) Closed form of leaking solid).
Metal containers have an irreplaceable position because they can store food for a long time, but they also have disadvantages, that is, leakage at the seal is easy.
Leakage, causing corruption or leakage of the contents. According to statistics from the light industry department, nearly 70% of the quality accidents of food cans in my country are caused by sealing problems, which shows the importance of metal container sealing.
(2) The structure of double crimping The double crimping is the combination of the can (barrel), the lid and the bottom, and it is a five-layer occlusal connection.
Its structure is shown in Figure 3-1. It is composed of two-layer tank (barrel) body material, three-layer tank (barrel) top and bottom cover material and sealant embedded between them. Hemming thickness (T), hemming width (W) in double hemming structure; countersunk, body hook length (BH), cover hook length (CH), overlap length (a, overlap rate), wrinkles Indexes such as degree (tightness) are the elements that constitute the double hemming.
Although the basic structure of the double hemming has not changed, there are some changes in its form, such as changing the shape of the hemming, or shifting the hemming, or reducing the size of the hemming structure. The appearance of double curling has two forms: ear-shaped and rectangular. The economical sealing method is shown in Figure 3-2. The curling is different from the common curling. It is located at the bottom of the can. This change in form does not change the basic structure of the double curling, but only changes its position. As a result of this change, 28% of the can lid material can be saved. In addition, a kind of micro-shaped crimping (Iminiscaimling) used for 206 beverage cans also only changes the size of the double crimping, without changing its basic structure, that is, the common crimping length is reduced, and the sealing performance after the change is completely possible. It satisfies the sealed storage requirements of beverage cans, and also saves lid materials and can sealing glue.
(3) The main components of the crimping mechanism and its functions The crimping mechanism is composed of three parts: the seaming chuck (seaming chuck) sealing wheel (wmtd) and the (base plate). These three parts are called the three elements of the crimping seal. ,Indispensable.
①Sealing wheel The sealing wheel is divided into one sealing wheel and two sealing wheels according to the working order. There are three forms of sealing wheel: outer plate.
Line sealing wheel, inner curve sealing wheel and inner curve sealing rail.
a. Outer curve sealing wheel The sealing surface of the outer curve sealing wheel is on the outer circle. This form of sealing wheel is easy to process, detect and manufacture.
Low cost, simple installation and adjustment. Since the sealing wheel is on the outside of the sealed can, two or four sealing wheels can be distributed on the circumference, which can complete one and two sealing processes on a curling mechanism at the same time. The sealing wheel is equipped with a centripetal thrust bearing. During the sealing process, due to the sealing force, the sealing wheel rotates freely (slave) around the installation axis.
b. The inner curve sealing wheel (less common) The sealing curve of the inner curve sealing wheel is on the inner side of the inner hole of the sealing wheel, and the optical projection method cannot be used.
Method inspection, so processing and inspection are inconvenient and the manufacturing cost is high. At the same time, because the sealing wheel covers the lid of the can, it is impossible to complete one and two winding sealing processes on a curling mechanism at the same time, so the machine structure is more complicated, the efficiency is lower, and the cost is higher. However, the inner curve sealing wheel also has its advantages. Because the inner curve aperture of the sealing wheel is closer to the diameter of the can lid, the contact surface between the sealing wheel surface and the can lid during the rolling process is much larger than the outer curve sealing method, so the inner curve sealing wheel The sealing process is more reasonable and the quality will be higher.
The inner curve sealing wheel is the same as the outer curve sealing wheel, which is mounted on the centripetal thrust bearing. During the sealing process, the sealing wheel rotates freely around the installation shaft (driven) due to the sealing force.
c. The inner curve sealing track The inner curve sealing track is the same as the inner curve sealing wheel in that both use the inner sealing curve.
It has the advantages and disadvantages of the inner curve sealing wheel. It is also different from the inner curve sealing wheel: first, the inner curve sealing track is fixed (that is, there is no rotating movement of its own), and the track does not move can simplify the machine structure, but it also makes the difference between the two because the track does not move with the tank. Large relative sliding is inevitably produced (the sealing equipment must be suitable for a certain tank diameter range. If the middle diameter of this range can be designed to be the smallest relative sliding, the relative sliding will occur when the tank diameter changes, and it will increase with the change of the tank diameter. The relative sliding volume causes scratches on the curling surface; secondly, the inner diameter of the inner curved track is very large, which can accommodate several or more curling mechanisms at the same time.
②The pressure head (also called seaming chuck) is used to fix the position of the can body and the can lid, so that the thickness of the coil is uniform and consistent.
Keep the seal tight. At the same time, the outer circle of the indenter is a cone of 4, which functions to generate enough friction with the pressure of the tray to prevent the can lid and the sealing wheel from stagnation or stagnation due to the deformation of the metal seal during the sealing process or between the can lid and the indenter. The countersunk depth and outer diameter of the pressure head should be consistent with the countersunk degree and can diameter of the can lid. The countersunk depth of the pressure head often affects the width of the lid hook.
The indenter often needs to be prepared with the can lid to ensure good performance.
③Tray (or supporting chassis, lifting plate) The tray is used to hold the can body, hold the can body with the lid to the sealing operation station, and press the lid and the can body together, and the spring of the tray pressure head will face the can Pressure is applied to the body and the lid of the can to prevent heading of the can in the sealing process.
(4) The forming process of double curling The double curling is carried out in two steps, which are completed by one sealing wheel and two sealing wheels respectively.
As shown in Figure 3-3. First, a sealing wheel moves radially relative to the can body. The sealing force of the sealing groove of the sealing wheel and the arc edge (or straight edge) of the can lid causes the outer edge of the can lid to curl in the normal direction of the groove curve, and a sealing When the wheel moves to position 3, the preliminary shaping of the sealing crimping is completed, so that the can cover and the can body flanging mouth along its periphery will be bent into an initial joint of a certain shape and size as required. Then a sealing wheel exits the roll-sealing position. At the same time, the second sealing wheel starts to work, moves radially relative to the tank body, pushes the curling edge that has a preliminary shape, and presses it firmly until the second sealing wheel completes the curling operation at 5 o’clock, so that the tank benefits and the tank The body forms a tight seam and the last two sealing wheels return, and the sealing process ends.
(5) The feed movement of the double crimping while the first and second sealing wheels move radially along the can body, the sealing wheel moves back relative to the can body.
Rotational motion, the combination of the two motions is called the feed motion, and the radial motion of the sealing wheel per revolution of the tank is called the feed. There are two forms of rotary motion: one is that the can body rotates and the sealing wheel does not move; the other is that the can body does not rotate, and the sealing wheel rotates around the can body. These two different exercises have the same effect on the sealing process. In the process of crimping and sealing, the metal of the part of the can body that participates in crimping has undergone tensile and compression deformation. In order to meet the requirements of the quality of the sealing and crimping, the crimping process should make the metal material deform evenly, and the amount of deformation per unit time is not too large, that is, the sealing wheel is along the diameter of the can body during the rotation of the sealing wheel around the can body. The feed amount in the direction is uniform and cannot exceed a certain limit. The feed rate is small, the sealing quality is good, but it will reduce the production capacity of the equipment; the feed rate is large, the equipment production capacity is improved, but the sealing quality is reduced. Generally, the feeding movement of one sealing wheel of the sealing machine is completed in about three revolutions of the sealing wheel around the can body, and the feeding movement of the second sealing wheel is completed in two revolutions of the sealing wheel around the can body. At present, there are two common feeding methods for the sealing wheel: one is an eccentric mechanism (commonly used for sealing equipment without rotation of the can body), the sealing wheel is installed on the eccentric shaft, and the planetary gear system drives the can body to rotate Movement, in the process of the sealing wheel rotating around the can body, the eccentric shaft rotates slowly and the eccentric shaft rotates one circle, which completes the feed motion of the two curling. This feed motion is not uniform, but close to the law of cosine; another One kind is to drive the swing arm by a cam. Its motion law depends on the design of the cam. In general, the cam can be designed to move at a constant speed except for the complicated motion wheel at the starting point, ignoring the slight difference between the swing arm and the linear motion. The inlet mode of the sealing wheel of the cam-driven swing arm is relatively close to the uniform feed motion. The more special one is the orbital sealing. This type of can sealing machine adopts a vertical type. The can body is driven by the pressure head and the tray to rotate. A workstation has multiple can bodies that rotate in this way and revolve around the rotation center of the workstation together. The arc center of the guide rail is installed eccentrically, and the amount of eccentricity is the total stroke of the sealing feed.