With the continuous improvement of production level in China's manufacturing industry, CNC punch machining, as a flexible sheet metal processing method, plays an extremely important role in the complex field of customized commercial sheet metal processing. In order to further leverage the role of sheet metal CNC machining in the entire production and manufacturing process, and to improve the application efficiency of punching machines, the commercial sheet metal processing workshop has integrated the application of CNC Punching and shearing composite machines. It is an efficient sheet metal processing equipment that integrates computer control technology, microelectronics technology, remote monitoring technology, and precision manufacturing technology. The CNC Punching and shearing composite machine is equipped with automatic loading and unloading devices, automatic sorting and stacking devices, and automatic docking devices for three-dimensional warehouses, and integrates information management methods, ultimately integrating a fully automatic CNC punching and cutting unit based sheet metal processing application mode.
The CNC punching and shearing composite machine mainly consists of a CNC punching machine and a CNC right angle shearing machine, as shown in Figure 1. A disc type rotatable mold library is installed on the CNC punching machine, which can achieve feature forming processing of sheet metal workpieces such as punching, trimming, and flanging; The CNC right angle shearing machine is equipped with X and Y direction scissors to shear and separate the plates after completing a series of feature processing.
The prerequisite for achieving fully automatic processing is that the parts must meet the processing range of the equipment, therefore, the basic processing parameters of the equipment need to be clarified first. The CNC punching and shearing composite machine has a punching pressure of 30t and a shearing force of 20t; The turret warehouse has 55 mold workstations, including 21 A workstations (mainly for small universal feature machining molds, which usually do not require frequent mold changes during order switching), 24 B workstations, and 2 special rotation workstations (mainly for medium-sized universal feature machining molds, with larger punching stroke to improve the processing efficiency of parts, and rotation workstations for convenient adjustment of rectangular, polygonal and other feature machining angles), 4 C workstations, and 2 D workstations, Two E workstations (C, D, E workstations are generally large universal edge cutting and special feature processing workstations such as louvers, flanging holes, and convex hulls); Different feature molds have dedicated codes, such as RO for circular holes, RE for rectangles, DJ for polygons, and SQ for squares; The maximum processing range of the equipment at once: X-axis 3000mm, Y-axis 1500mm, maximum processing plate thickness 6.35mm, and maximum plate thickness 4mm for right angle shear (made of Q235 steel plate); Punching machining accuracy: ± 0.10mm.
The two scissors of the CNC right angle scissors are perpendicular to each other, and one of the X-direction scissors can be continuously cut, eliminating the manual cutting process of raw materials before processing, improving the efficiency of sheet cutting in the production process. At the same time, it can also select the optimal layout according to the contour of the parts, effectively reducing the waste of raw materials. The layout of two CNC right angle scissors is shown in Figure 2, where the length of the X-direction scissors is longer than that of the Y-direction scissors, and the two are installed perpendicular to each other at a 90 ° angle. The CNC punching and shearing compound machine has two working modes for shearing: full shearing and half shearing. When full shearing, X and Y direction scissors cut up and down at the same time. The shape of the shearing parts is relatively regular, with obvious Cathetus edges; When half cutting, the Y-direction scissors are lifted overhead, and the X-direction scissors are cut separately up and down. The cut parts are generally larger in size and are mainly used when there is interference in the characteristic shape in the Y-direction. The CNC programming process sets them according to the actual situation.
The waste and parts separated by the right angle shear are transported through an automatic brush conveyor belt. Different sizes of waste materials are automatically fed into two different types of waste bins set up midway during the transportation process. The sorting process and cutting process of waste and parts are carried out simultaneously, while cutting and sorting are carried out. The small waste during the mold processing is transported synchronously by another conveying device, ensuring the continuous and stable operation of the punching machine and avoiding waste of equipment waiting. The entire processing process tries to convert internal switching to external switching, greatly improving the processing efficiency of sheet metal parts.
When CNC punching and shearing composite machines process sheet metal parts with different plate thicknesses, the CNC punching machine turret mold library replaces punching or forming molds with different clearances according to process standards. The CNC right angle shear adjusts the shear clearance through electrical control to ensure the cross-sectional quality of sheet metal parts processing.
The significance of CNC punching and shearing composite
The right angle cutting function provides a basic guarantee for the automatic sorting and stacking of parts in automatic nesting processing, and is an indispensable functional part of the processing unit to achieve fully automated processing. However, traditional CNC punch machining requires manual cutting of the sheet metal using a cutting machine according to the overall dimensions of the parts, and then editing the CNC program to enter the machining stage.
The advantages of CNC punching and shearing composite machine nesting processing are summarized as follows: ⑴ The processing layout is carried out by automatic nesting programming software, and the automatic cutting and separation of parts and waste materials are carried out, improving the utilization rate of raw materials; ⑵ The machine tool has a high degree of integration, eliminating the manual transportation process of sheet metal, improving the machining accuracy of sheet metal parts, reducing the waste of handling and waiting during the machining process, and improving the machining efficiency of the machine tool.
Composition of processing units
The fully automatic CNC punching unit is composed of automated hardware devices and information control systems, and its overall structure is shown in Figure 3. The automation hardware device includes 8 functional modules: raw material automatic docking trolley, raw material automatic loading device, CNC punching and shearing composite machine, waste automatic export device, automatic code spraying device, part automatic sorting and stacking device, part automatic docking trolley, and photoelectric protection device; The information control system includes a punch control system (CNC punching machining control system and CNC right angle shear control system), an interaction module of MES+WCS+punch control system, and an optoelectronic protection control system module. The eight major hardware functional modules are the foundation for the implementation of fully automated machining processes, while the MES+WCS+punch control system interaction module is the key to achieving information management in machining units.
The processing unit adopts the MES system for automatic production scheduling, and the programming software automatically captures the order details and performs nesting according to the order requirements to ensure that the parts automatically programmed according to the order can be produced using standard specifications of raw materials. Standard specifications of raw materials are the foundation of automated warehousing, and the raw materials after nesting are completely arranged to avoid waste of raw materials. The right angle shear function realizes the separation of parts after nesting.
Automatic feeding function
The automatic feeding function is the foundation for the automatic docking of raw materials between the processing unit and the three-dimensional library. The MES system not only dispatches order tasks to the punching machine unit, but also synchronizes the standard specification raw material information required for processing to the intelligent three-dimensional warehouse scheduling center. The scheduling center matches the required raw material pallets in the warehouse according to the order of outbound tasks and automatically issues outbound instructions. At this time, only confirm that the machine tool can process normally, and the corresponding raw material pallets will be sent to the raw material receiving port of the machine tool, Retrieve the raw material pallet through the docking of the automatic loading trolley and transfer the raw material pallet to the automatic loading position. To adapt to different sheet feeding, the automatic feeding device will partition the feeding suction cups to avoid empty suction of the sheet, as shown in Figure 4. The plate separation device is installed on the loading manipulator. While picking up the material, one corner of the plate is lifted, and the plate is continuously shaken to complete a complete set of actions for plate separation (simulating manual separation). After the suction is completed, automatic thickness measurement is also required. The thickness measurement is mainly to confirm whether the raw materials are consistent with the order requirements and avoid incorrect processing. If the thickness of the suction plate exceeds one sheet thickness, the plate detection device will alarm and the machine will stop working. If the suction plate thickness is detected to be the specified sheet thickness, the machine will continue to work. Finally, the raw materials are transferred to the machine tool positioning clamp through the feeding suction cup for positioning and clamping. At this point, the processing unit has completed a complete set of automatic raw material loading processes.
Automatic sorting and stacking function
The CNC right angle shear is a prerequisite for achieving automatic sorting and stacking of parts. The separated parts are semi-finished products, and the stacking device classifies and stacks the semi-finished products. The minimum size of the stacking plate required by the automatic stacking device is 400mm × 100mm, with a maximum format size of 3000mm × 1500mm, maximum plate thickness 4mm (carbon steel plate), minimum plate thickness 0.5mm, maximum stacking weight 3000kg.
The CNC program of the machining unit adopts automatic nesting programming software. After the machining program is generated, the sorting program module identifies the parts within the program. The parts with the same code are assigned to the same area of the semi-finished product tray, and the stacking area is shown in Figure 5. The maximum stacking height in the same area is 500mm. If the height exceeds this, the stacking area is reassigned to avoid the problem of excessive stacking caused by the excessive number of parts with the same code.
After the processing program is issued, the system will confirm the actual placement of the parts in the stacking area again, and the photoelectric induction system will also detect the stacking height of the parts. If there is a situation where the parts in the semi-finished product stacking area are taken away by the next process urgent order, the operator needs to reset the corresponding number of the stacking area, so that the system can re include them in the storage area and avoid space waste in the stacking area. After confirming that the stacking area meets the requirements for part stacking, the sorting device will separate and load the parts with the same code and stack them in sequence. The sorting adopts a split roller type automatic sorting and palletizing device, which automatically sorts and palletizes the cut workpieces into semi-finished pallets. The pallets are placed on a special cutting interactive trolley. After completing the order processing, the interactive trolley receives the semi-finished product return instruction and transports the semi-finished product pallets to the corresponding processing unit entrance of the three-dimensional warehouse. The three-dimensional warehouse shuttle car automatically enters the semi-finished product pallets, The MES system synchronizes the creation of semi-finished pallet return information. When leaving the warehouse, you only need to search for the corresponding order number to find the location and pallet number of the three-dimensional warehouse where the order is located. This creates an automatic outbound task order and realizes the outbound of semi-finished parts.
MES automatic scheduling and dispatching
The production orders of the processing unit are automatically dispatched by the MES system according to the planned scheduling logic. The order information includes necessary information data for production, such as part materials, quantities, size specifications and codes, graphic and textual information, program information, process flow information, processing hours, etc. Scholars such as Li Yakai and Shen Yan discussed the production scheduling system that coordinates SOA and flexible manufacturing technology, specifically analyzing the planning and scheduling problems in the production process, and describing the way and implementation of production dispatch to the machine, providing a solution for the dispatch problem of processing units. The production task of the fully automatic CNC punching unit adopts one backup and one use, that is, the MES system assigns two orders to the same machine tool, the first being an in process order and the second being a preparatory order. After the completion of the in process order, the preparatory order is automatically converted into an in process order. The automatic equipment production task list is shown in Figure 6. The interaction module between MES and WCS simultaneously schedules the three-dimensional warehouse to issue raw material outbound tasks and the previous order raw material inbound tasks. Preparation before processing begins, and through order cross operation, internal switching time is reduced, machine tool standby is reduced, equipment utilization is improved, and efficient production is ultimately achieved.
Fully automated production of processing units
After receiving the production task assigned by the MES system, the fully automatic CNC punching unit only needs to verify the mold configuration requirements of the processing program and confirm the safety of the production environment to start the production of the order. At this time, the equipment will process according to the program NC code. If the parts involved in the order have special processes, the system will provide a mold replacement prompt when starting order production, and the corresponding molds for the process will be manually replaced and supplemented.
When the MES system receives feedback on the processing information of the order task initiated by the processing unit, it synchronously sends the corresponding raw material outbound task to the three-dimensional warehouse WCS scheduling system. The three-dimensional warehouse shuttle truck transports the corresponding raw material pallet to the docking position of the processing unit's receiving trolley. At this time, the processing unit receives the raw material arrival information, and the system dispatches the receiving trolley for material retrieval. The entire processing process will not require manual intervention, After processing, automatic sorting and stacking of parts and waste transportation are carried out. The sorting and stacking system is divided according to the type of parts and completes the sorting and stacking work in sequence. The system takes orders as a cycle and records the status information of the entire processing unit until the order is completed. During the process, work is automatically reported, and the production line information management dashboard is shown in Figure 7. After the order is completed, the semi-finished parts are automatically docked with the three-dimensional warehouse shuttle for warehousing, and the warehousing information is synchronized to the MES system.
In addition, the processing unit is equipped with a networked PC all-in-one machine, which allows operators to log in to the MES system interface through the PC all-in-one machine. On the order reporting information page, they can directly enter the company's internal basic document system by clicking on the graphic number, which is associated with the processing requirements and design drawings of the corresponding parts, in order to conduct the initial inspection of the parts. The information management process greatly facilitates on-site operations.
With the continuous development of China's manufacturing industry, the application of fully automated machining units that integrate automation and informatization will become increasingly widespread. The fully automated CNC punching and cutting unit described in this article, with CNC punching and shearing composite machines as the main body, utilizes an information-based process management approach, fully leveraging the processing advantages of automation equipment, and to a certain extent achieving a less human oriented sheet metal production mode. This has important reference significance for achieving fully automated production in discrete manufacturing industries such as sheet metal processing.
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