Automatic control solution of the hottest plastic

2022-08-08
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Plastic sealing and cutting machine automation control solution

plastic sealing and cutting machine is currently widely used in mainland China. Now let's grasp the solution of a project of the company in this regard and provide it. Welcome to mention more. We see that the future automobile also shows its emphasis on the Chinese market, and the industry is booming and valuable opinions

process requirements:

(1) 300 -900mm long plastic bags, production of about/min

(2) the length error is within 0.5mm

(3) the temperature line at the seal of the plastic bag should be strong and tensile resistant

(4) both fixed length sealing and cutting, and color tracing sealing and cutting

(5) when the color code signal is not detected for three consecutive times during color chasing sealing and cutting, it is necessary to automatically shut down and alarm

(6) it is necessary to have an early warning function (that is, when the production is fast to the set batch, it is necessary to prompt the alarm)

(7) speed regulation of main motor, feeding motor, servo motor speed regulation function

(8) automatic operation/manual debugging function

processing process of the equipment:

(1) after power on, The temperature controller controls the heater at the knife sealing position to heat

(2) after automatic starting, the feeding frequency converter drives the feeding motor to transport the plastic film at the set speed. When the feeding sensor detects that the plastic film unwinded at the feeding end is sufficient, the feeding motor stops feeding

(3) when the temperature reaches, the temperature signal is turned on, and the servo driver drives the main servo motor to control the up and down reciprocating motion of the cutter and cutter seal through the mechanical transmission device. Start calibration from the load of 50kN

(4) every time the cutter moves upward, the servo signal is turned on once, the servo motor drives the discharge roller to rotate once with the plastic film belt clamped, the cutter and the sealing knife are cut down, and the plastic bag is formed

(5) when the set number reaches or the stop key is pressed, the machine stops after the current plastic bag is formed, and the cutter and sealing knife stop at the high-level parking place

Technical Analysis

(1) in mechanical design, when the servo motor is working, the transmission ratio driven by the main servo motor, the cutter and sealing knife move back and forth for 120 times/minute. Under the condition that the actual continuous operation of the servo motor is convenient, and the later use speed should be less than or equal to its rated speed and other characteristics, the reasonable design of the transmission ratio of the servo mechanism and the outer diameter of the discharge roll is the key to meet the process requirement 1

(2) the servo transmission mechanism adopts synchronous belt transmission, and the pulse number of the servo encoder is 2000p/r, so its own error is far less than 0.5mm. The real reason for the large positioning error is that the starting and stopping of the servo motor is not smooth enough, or because the feeding speed at the feeding end is less than the discharging speed of the discharging roller, resulting in the relative sliding between the discharging roller and the plastic film, Therefore, the appropriate acceleration and deceleration time should be adjusted according to the start and stop speed of the servo motor, and the frequency of the feeding frequency converter should be adjusted so that the feeding speed is greater than the discharging speed of the discharge roller. The adjustment result should be based on the fact that there is no relative sliding between the discharge roller and the plastic film

(3) the set temperature of the temperature controller is generally set at about 180 ℃, and the set temperature of the temperature controller is adjusted appropriately according to the speed of the main motor, subject to the firmness and tensile resistance of the plastic bag seal. Because when the speed of the main motor is high, the sealing knife moves up and down quickly and the sealing time is short. If the temperature of the sealing knife is low, it will lead to the unstable sealing of the plastic bag. When the speed of the main motor is low, the sealing time is long. If the temperature of the sealing knife is high, the sealing part of the plastic bag will be scalded

(4) on the man-machine interface, you can set the fixed length sealing cutting or color chasing sealing cutting, bag cutting length, color chasing length, number of warnings, bag feeding speed, acceleration time, deceleration time. When the fixed length sealing cutting is selected, the color chasing sensor has no effect, and the motion control program in the trio motion controller is based on the mechanical transmission ratio of the servo mechanism, the electronic gear ratio of the servo driver (using pulse output mode) The number of lines of the servo motor coder and the circumference of the discharge roller set the moving equivalent. According to the moving equivalent, the pulse that the servo driver needs to receive when moving a bag length can be calculated, and the servo motor drives the discharge roller to rotate to bring out a certain length of plastic bag '. In this way, the fixed length control is realized

when selecting color tracking and sealing, the process is as follows: the servo start signal is turned on, and the servo motor performs accelerated motion, constant speed motion, deceleration motion, low-speed color tracking according to the motion curve preset in the motion control program of British trio digital motion controller. When the controller receives the color tracking signal, it immediately stops the servo motor by interruption. Generally, the chasing length is 10mm, and it is required that the chasing signal can only work within the chasing range, and its interference signal needs to be shielded in other ranges

during the debugging of color tracing sealing and cutting, set the constant speed of the servo motor on the human-machine interface, first set the acceleration time and deceleration time long, and then adjust the low-speed color tracing speed, so as to improve the low-speed color tracing speed as much as possible, subject to the stable and accurate color tracing. After adjusting the color chasing speed, adjust the acceleration time and deceleration time, and try to shorten the acceleration and deceleration time as much as possible, subject to the fact that the plastic bag and the discharge roller do not slide relatively and the color chasing is stable

(5) the motion control program in the controller counts the color tracking signal during color tracking and sealing. If it fails to detect for three consecutive times, the controller stops the operation of each motor and makes an output signal output to drive the alarm. At the same time, the motion controller program counts the batch. When the batch reaches the warning value, the output signal of the controller drives the alarm

(6) the speed of the main motor and the feeding motor can be adjusted through the external knob positioner, and the servo speed can be adjusted by changing the set value of the pulse output frequency of the controller on the man-machine interface

(7) the motion control program of the controller is divided into automatic operation program and manual debugging program. The automatic operation program is the production program, and the manual debugging program is used during machine adjustment or maintenance

electrical part configuration of equipment

(1) the digital motion controller

adopts the 3U structure independent board controller of euro-205x of British trio company. The controller adopts the latest DSP microprocessor technology and advanced servo control algorithm and network bus control technology. The serial port communication with Modbus protocol can exchange communication data directly with the human-machine interface. The controller can control both servo motor and stepping motor, and can also use 0 ~ ± 10V analog voltage output to control the frequency converter, and the number of axes can be arbitrarily defined according to the needs of the equipment. This controller can be up to 4 axes. Here we choose the servo base plate, and use pulse output to control the position control mode of two servo motors, A 0 ~ ± 10V analog voltage output controls the frequency converter to drive the speed of the feeding frequency conversion motor. With programmable input/output channels that can be defined arbitrarily

(2) servo driver and servo motor

the servo motor adopts the latest A4 series servo motor of Panasonic in Japan, mdddt/mdma082p 1g is used as the main drive servo motor for controlling the cutter, and mdddt/mhma152p 1g

(3) the man-machine interface adopts pws6600-s (end) of hitech

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