In the use of can welding machines, the welding machine manufacturers and users have such experience: although the maximum speed of the can welding machine is claimed to be 600 cans/min or 700 cans/min or even 1000 cans/min, when the can welding machine is used After the running speed of the welding machine exceeds 85% of the maximum designed speed, or experience shows that when the speed of the can welding machine exceeds 600 cans/min, the stability of the can welding machine running at high speed will decrease, the production efficiency will drop, and the can body will be damaged. Various quality parameters will be difficult to control. Therefore, in order to achieve stable operation speed and high production efficiency, smart operators often reduce the operation speed and find the stable operation speed of each can welding machine, rather than the highest speed of the can welding machine to produce.
Below we can summarize the problems faced by each component.
Tinplate silo and suction device (No.1 and No.2 in Area A) Due to various reasons, when running at high speed, the suction mechanism is often unable to absorb tinplate sheets, which brings difficulties to adjustment. In addition, there is the contradiction between vacuum suction and vacuum breaking when sucking materials, and the problem of ensuring the life of vacuum seals during high-speed operation. To solve this problem, when designing, the size of each part should be very reasonable. For parts running at high speed and reciprocating, in order to reduce the inertia of the parts, light materials should be used to reduce the impact and prolong the life of the parts. At the same time, it is more difficult to protect the card tank, and the wearing parts increase.
Pusher (No.3 in Area A) In the pusher device running at high speed, after the sucked iron sheet falls on the magnetic platform, when the pusher head pushes the tinplate sheet, if the design is unreasonable, a small pit will be formed. Especially thin iron sheets. In the design to take effective measures to solve. For the high-speed moving iron pusher, the material should be light in weight and good in strength, otherwise the service life will be short and the wearing parts will increase.
Card tank protection function When various parts are running at high speed, if there is an unexpected problem, the technical difficulty of overload protection of each part will increase, such as the torque overload protection components of clutches and inverters will face challenges. If the mass of the parts running at high speed is large, then a large torque is required to drive the parts to run, but when the tank is stuck or accidentally mechanically overloaded, the parts will be greatly impacted or damaged. However, the overload torque is small, and the parts running at high speed will cause the torque protection components to malfunction and cause unexpected shutdown.
Double sheet detection (No.5 in area B) Double sheet detection time and removal time are shortened, and it is more difficult to accurately realize the function.
Rounding Station (No.7 and No.8 in Area C) When the rounding speed exceeds 300 m/min, due to the high speed, the time for the iron sheet to be rolled and bent into a round is short, and the can body is in the process of rounding with each guide plate. , When the collision and impact of the capture device will cause the effect of the circle to deteriorate, it is easy to lose synchronization and cause the can body to jam. Due to the fast speed of the transmission shaft, high-quality bearings and shafts are required, and the lubrication is better, otherwise the life of the corresponding parts will be shortened.
Due to the large impact and fast wear of the support screws and support blocks, the gaps between the transmission shafts on the rounding station are unstable, and cemented carbide materials are required for key parts.
Because the speed of the rounding station is accelerated, the life of the transmission belt of the rounding station is reduced.
Lubrication device The automatic lubrication system of the high-speed can welding machine is very important. Usually, oil should be added every 2 to 4 hours to reduce the wear of parts running at high speed. If the design is unreasonable, the life of the components will be reduced.
Can conveying device (No. 9 in C area, No. 10 and No. 11 in D area) When pushing the can body at high speed, at the capturing station after rounding, the pushing and grasping of the chain or belt will hit the rear end of the can body, causing the back In addition, the crank mechanism and the conveyor belt are not well synchronized.
The movement of the conveyor belt is a curved movement. In order to reduce the phenomenon of knocking out the mark, when the push claw of the belt contacts the can body, the speed should be reduced to reduce the impact, and then the can body should be accelerated to take the can body out of the capture station. Due to the large speed change, the inertia of the belt system is required to be small, and the design requirements for the servo motor mechanism are relatively high, such as the inertia of the parts, the motion curve and the speed.
Can transport brake system (zone D, No.25, N.26) Since the belt conveyor system and the last push claw system are variable-speed motions, when the can body is being pushed, it is also a variable-speed motion. To synchronize the speed of the belt or the last push claw, use a friction brake wheel or a magnet to keep the tank body always leaning against the push claw of the tank conveying device to avoid the phenomenon of long and short legs in the welding seam of the tank body. However, due to the high-speed movement of the welding machine, the diameter and height of the can body are different, and the smoothness and friction of the printed iron on the can body are different, so the adjustment effect is different.
Welding device (No.14 in D area) The high-speed shearing machine requires high precision, and the burr of the shearing plate should be small, otherwise the quality of the welding seam and the stability of the suction system cannot be controlled. Due to the increased welding speed and short heating time, it is more difficult to control the stability of the weld quality. It is more difficult to eliminate the phenomenon of the weld seam and the cracks at both ends of the high-speed welding machine. Due to the large welding current, the large spatter of the welding seam, and the poor conductivity value of the welding seam repair coating, the difficulty of liquid repair coating is increased.
The lower welding arm (zone E), the upper welding arm and the welding wheel have large welding current and require better cooling of the welding arm. The welding frequency is high, and the induced current and eddy current are large, causing nearby parts such as bearings of various components to heat up. The welding current is large, and the induced current and eddy current make the bearing of the lower welding wheel easy to heat, and the service life and accuracy are reduced.
Correction caliper (zone F, No.25) Due to the high speed, before the final push claw pushes the can body into the welding wheel, the can body is easily separated from the push claw, resulting in the phenomenon of long and short feet at the weld end. If the design consideration is unreasonable, Will increase the difficulty of adjustment.
Copper wire system Due to the fast welding speed, the requirements for the strength of the copper wire are getting higher and higher, and the requirements for the width and size of the flattened copper wire are also high. Due to the fast welding speed, the guide pulley on the copper wire system is seriously heated. If no measures are taken, the welding quality will be affected and the bearing life will be reduced. If the design is not reasonable, the copper wire flattening and cutting device life will be shortened.
The increase in the production speed of the welding inverter requires the increase of the welding current and the increase of the welding frequency, which causes the parts to be easily heated. If the cooling water used is too cold, it is easy to produce condensed water. Because the IGBT of the welding frequency converter is hard-turned off, the increase of the welding frequency puts forward high requirements on the power components such as IGBT, and the unreasonable design is easy to cause damage; in addition, the increase of the welding frequency will also make the welding transformer iron core face challenges (high frequency). and high current will cause iron core saturation), the matching requirements for welding inverter and welding transformer are higher; at the same time, as the welding current stability decreases, the welding current will oscillate.
Control system interference problem Because the welding current increases, the welding frequency increases, and the induced magnetic field is strong, resulting in interference to the control circuit. Design with good shielding and grounding. Due to the increased probability of forming soft faults, the stability of the welding machine control system is reduced, and the difficulty of troubleshooting is increased.
The life of each component In order to improve the life of high-speed components and parts, the material quality requirements of parts are getting higher and higher, and the price is correspondingly increased. There are more and more wearing parts, which brings difficulties to maintenance and repair.
Weld repair coating and curing system With the increase of welding speed, the quality of weld repair coating and curing also faces challenges. The increase of weld spatter will make the quality of repair coating and curing more difficult.
Faced with the above-mentioned difficulties, how to break through the technical difficulties has aroused our deep thinking!
Innovative imagination of bilateral integrated can welding machine
In today’s fierce market competition, the improvement of the output speed of the can making welding machine is an increasingly important parameter for the cost of can making, especially in the face of the pressure of the output speed of the two-piece aluminum can making equipment (up to 2000 cans/min), This has to cause anxiety and worry for the three-piece can manufacturer!
In today’s rapidly changing science and technology, all walks of life are developing rapidly. In addition to keeping up with the development of high-tech in various fields, the can making industry has to break with tradition while improving automation and intelligence. structural innovation. In particular, China, which is developing rapidly, has reached a stage of surpassing and leading in learning foreign technologies.
Let’s observe other industries horizontally: when the speed and performance development of the computer’s single-chip CPU encounters a bottleneck, a CPU with a core and quad-core structure is created; When there was a problem, the four-wheeled car was born; when the speed of the single punch can lid punch in the can industry could not be improved, the multi-head whole tinplate punch was born.
Therefore, in the field of can-making resistance welding machines, we should also broaden our horizons and learn from Chinese military enterprises: one generation of equipment, one generation of development, one generation of pre-research, and one generation of conception. Now Chinese manufacturers have begun to design and develop bilateral integrated can-making resistance welding machines, and a manufacturing plant in China has entered the R&D and manufacturing stage.
Adopting the bilateral working structure, the main purpose is to solve the contradiction between the output speed and operation stability of the can welding machine, and to solve the above problems and challenges when increasing the welding machine speed. When the unilateral speed of the bilateral integrated can welding machine is 300 cans/min, the speed of the whole machine is 600 cans/min; if the unilateral speed is 500 cans/min, the total speed is 1000 cans/min. For most of the existing Chinese can welding machine manufacturers, this can be achieved on the basis of the existing technology, thus improving the stability and having a good cost performance.
In addition, the bilateral working structure also includes the following other advantages.
When running at high speed on both sides, the stability of the machine is improved, and it has redundancy technology. When one side cannot run due to some mechanical failure, the other side can still produce.
It has a certain flexibility, and can produce different tank types on both sides according to production needs.
It is easy to repair and troubleshoot. Because many components on both sides are similar, problems can be found quickly by exchanging them.
The cost is lower, for example, one set of spare parts is used on both sides, and the cost of spare parts is reduced; the manufacturing cost of the bilateral complete machine is much lower than the total manufacturing cost of two unilateral equipment; the cost of operators is low; only one set of air and water systems and For the electrical control system, some components can be used in one set, which is lower cost than 2 sets of can welding machines.
The copper wire cutting and copper wire feeding devices are separated from the main machine, which is convenient for feeding and recycling; the copper wire guide wheel has a braking torque, which can prevent the copper wire from loosening during operation; the modular assembly is convenient for installation and manufacture.
The bed is a simple steel beam frame structure with a compact structure. Compared with the two resistance welding can welding machines, the space utilization rate is greatly improved.
Two sets of welding current frequency conversion regulators, located separately from the main control system electric box, are placed in the bed, close to the welding transformer, to avoid the welding current interfering with the control system.
Wireless operation screen, 6-10 inch tablet computer screen. Two sets of remote controls, touch screen multimedia display, in addition to control, the operation screen contains multimedia dynamic movie manuals, multi-language subtitles. Operation panel holder with charger.
Suggestions for process improvement before and after tank body welding
The birth of the bilateral integrated tank welding machine has improved the working speed and cost-effectiveness, but it has also brought challenges and opportunities to the innovation of subsequent weld repairs (liquid repairs, powder repairs) and curing equipment: although the original traditional However, since many components and components can be used in one set, the cost-effectiveness of the equipment will be different. Great improvement.
The subsequent welding seam repair coating and curing can use the induction cooker drying and curing system, which is designed as a double-sided integrated machine, which can reduce the length of the curing equipment and curing efficiency. The rear end outlet adopts a two-in-one tank road. The technical requirements for tank adjustment and design of tanks are reduced. After passing through the two-in-one tank platform, it is connected with a follow-up high-speed bead rolling and flanging sealing equipment, and the entire can-making line speed can reach 600-1000 cans/min. The structure is greatly improved.
Nowadays, the output speed of the world-class resistance welding can making machine has reached 1000 cans/min, and the overall output speed of the bilateral integrated can resistance welding machine can theoretically reach 2000 cans/min. Although the world’s highest output speed of offline equipment such as flanging machines and sealing machines is currently 1200 cans/min, if the overall output speed of the double-sided integrated can resistance welding machine exceeds 1200 cans/min, or the unilateral output speed exceeds 600 cans/min Tanks/minute, because the production efficiency and capacity cannot be improved due to the limitation of the output of the subsequent offline equipment, it is of little significance unless the subsequent offline equipment is improved or innovated. At the same time, the automatic feeding mechanism of the front process of the can-making resistance welding machine is also facing redesign to meet the requirements of the bilateral integrated can welding machine.