Paper corner guards are used for corner reinforcement of packaging cartons, as shown in Figure 1. The paper corner protector is formed by shaping and pressing the yarn tube paper and kraft linerboard by a complete set of corner protector. The two ends are smooth, flat, free of obvious burrs, and perpendicular to each other. Paper corner guards are widely used in the packaging and transportation of electronic and electrical appliances, high-tech products, clubs and other products. Paper corner protection is also called paper channel steel, paper wrapped corner, corner protection plate, corner protection strip, paper angle iron, paper angle strip, corner protection paperboard, edge plate, Corner paper and paper angle steel. The paper corner protector can be used together with winding film, packing belt, paper fumigation free tray, etc. to realize medium and heavy-duty all paper natural degradation and environmental protection packaging. Paper corner protection packaging is an advanced packaging technology in the international logistics industry with simple and convenient operation and strong compression stacking and load-bearing.
Figure 1 paper corner guard
The CNC high-speed corner protection machine of a packaging machinery and equipment manufacturer in Shanghai is used to cut corner protection materials of various lengths at high speed. The cutting method of paper corner protection is different from that of flying shear, which belongs to chase shear control. The servo motor moves back and forth, which is consistent with the feeding speed in the synchronization area to complete the shearing and quickly return in reverse. The customer's equipment was originally controlled by ordinary PLC, which can not stably meet the production demand of chasing shear and fixed length cutting control. The main problem is the poor synchronization accuracy during high-speed operation. Based on the equipment requirements, delta provides the electronic cam solution of dvp-20pm00d motion control PLC. After practical application, it fully meets the expected requirements of customers.
two Â Delta dvp-20pm00d solution
The high-speed NC angle protector is composed of frame, measuring mechanism, cutter mechanism, belt drive and electric control system, as shown in Figure 2.
Figure 2 CNC high speed angle protector
2.1 introduction to motion control PLC
Delta dvp-20pm00d is a programmable controller with special function of motion control. The biggest feature of dvp-20pm00d is that the PLC host directly provides electronic cam function, or dvp-20pm00d is a PLC with built-in electronic cam function, so some places directly call dvp-20pm00d Delta 20pm motion controller, as shown in Figure 3.
The 20pm has two 500KHz inputs and outputs. In the electronic cam function, the x-axis is defined as the slave shaft and the encoder input shaft is the spindle. After the cam table is defined, the slave shaft follows the spindle according to the defined curve. Adopting the high-speed dual CPU structure and using the independent CPU to process the motion control algorithm, we can well realize various motion trajectory control, logic action control, linear / arc interpolation control, etc. the NC High-speed angle protector uses the electronic cam function of 20pm motion controller to solve the above problems of unequal length in high-speed cutting. Main features of 20pm:
(1) 20pm is suitable for high-speed, high-precision and highly complex motion control occasions;
(2) Multi segment speed execution and interrupt positioning;
(3) 64K large capacity, built-in flash memory;
(5) Two groups of differential pulse output, with the highest pulse output up to 500KHz;
(6) Two groups of hand wheel control;
(7) Built in electronic cam function, easy to realize winding, flying shear, chasing shear and other applications;
(8) Support PLC Sequential Logic Control and NC control (G code and M code).
Figure 3 delta motion controller dvp-20pm00d
2.2 solution analysis of high-speed chasing shear
Ordinary PLC generally uses high-speed counting and inputs it to the built-in high-speed input point of PLC through the encoder. The high-speed input code is connected with the fixed length pressing wheel to collect the linear speed. The collected pulse frequency is multiplied by a certain speed ratio, and then it is used as the output high-speed pulse to drive the servo to simply synchronize the action speed with the speed ratio of the linear speed of angle protection, At the same time, the encoder value is compared with the preset length value. When it reaches the preset value, such as 650pulse, an interrupt is generated to make the cutter act. In this method, the cutter action always lags behind. Affected by linear speed and PLC operation, the synchronization accuracy is poor, the amount of calculation is large, and the CPU processing time is long. Therefore, there will be problems such as uneven fixed length, which will seriously affect the quality of finished products. In the case of low speed (about 10m speed), it can basically meet the requirements, but when the speed exceeds 20m, it will be different in length, with an error of more than 2mm.
20pm has built-in electronic cam function and adopts independent motion processing chip. Through hardware, it can process the motion relationship between master and slave shafts in real time. The synchronous control time of two shafts is less than 0.5ms, so as to ensure the position and speed relationship between main shaft and slave shaft at high speed, solve the problem of different length of high speed, and reach the production speed of 50m at the limit of customer equipment, The error is basically within 0.1mm. The hardware configuration of high-speed chasing shear solution based on 20pm is shown in Table 1.
Table 1 hardware configuration
The software setting of electronic cam of high-speed chasing shear solution based on 20pm is shown in Figure 4. The cam (numerical control programming) diagram of chasing shear control is shown to have some changes with the cam diagram of flying shear control. Observe the cam speed relationship diagram. The moving mechanism operates repeatedly, and the feeding speed is consistent with the material in the synchronization area. After cutting, it returns quickly in the reverse direction, and then it is consistent with the material feeding speed in the synchronization area again. Encoder pulse input and PLC pulse output completely correspond to each other according to the track, without PLC program scanning. Therefore, it overcomes the problems of large fixed length error at high speed and frequent overshoot of motor in the past.
Figure 4 electronic cam software setting
three Â Conclusion
Through the successful application of 20pm in the cutting equipment of high-speed angle protection machine, it can be extended to other occasions similar to chase shear control, such as beverage filling. Its action is the same as that of chase shear, but the mechanism is changed from knife to injection port. By changing different control curves, this work can also be widely used in various motion control with high requirements, such as the cam (numerical control programming) function of 20pm will be used in the continuous filling action of electronic cam spinning frame and packaging machinery in textile machinery, the cross cutting heat sealing action of vertical packaging, the spring reducing machining in metal processing, shear bending, etc.