Application of the hottest CAM technology in flexi

2022-08-26
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Application of CAM technology in flexible heat shrinkable film packaging machine

Abstract: This paper introduces the principle of electronic cam of baccalais servo control system, describes the system software design scheme combined with the actual working principle of heat shrinkable film packaging machine, and analyzes the characteristics of flexible processing

1. preface

with the improvement of the national requirements for safety and environmental protection, it is forbidden to use braided belts to pack and transport glass products such as beer bottles, so as to reduce the injury to people in contact. At the same time, in the past, the packaging of the beverage industry used cartons or turnover boxes, which was costly and difficult to recover, so the new type of heat shrinkable film packaging machine became an ideal choice

at present, the heat shrinkable film packaging machines on the market mainly include imported and domestic types. From the control motor, they can be divided into seven axis, five axis and four axis (servo motor) modes. As most beverage and beer manufacturers require to produce products of various specifications, the round diameter of the bottle is as much as 64, 66, 68, 75mm, the height ranges from 168210240290mm, and the number of packages is 3X3, 3x4, 6x3, 6x4... And other arrangements. How to use one equipment to meet the needs of flexible packaging of multiple varieties and different batches has become the most concerned problem of manufacturers. In view of the above practical requirements, cam (electronic cam) is widely used in control technology. Taking the xkbs-70c machine of Baoji Xinke Machinery Manufacturing Co., Ltd. as an example, this paper introduces the application characteristics of CAM technology of baccalais servo products

2. Control principle

the complete set of electrical control of the packaging machine adopts the baccarat controller pp41, the servo drive motor acopos, combined with the programming software automaton studio. In the design, the bottle pushing motor is used as the driving main drive motor, and the bottle splitting electric 6. The leaf spring bench uses the cycle number machine when any steel plate first cracks and the film feeding and cutting motor as the follower motor. In each packaging process, the bottle pusher pushes out a group of bottles to complete one packaging, and the position of the bottle pusher motor reflects the position data of the packaging cycle. In each packaging cycle, there is a one-to-one data relationship between the positions of the film feeding and cutting motor, bottle separating motor 1 and 2 and the bottle pushing motor, and the action of the machine is controlled according to the corresponding data. The cam electronic cam technology is applied to realize the synchronous operation of multiple shafts, and the movement from the shaft coupling spindle position, so as to achieve the purpose of packaging

2.1 bottle splitting motor design requirements

in the heat shrinkable film packaging machine, the bottle transmission of the packaging section is transmitted through the main drive motor. The transmission chain of the two bottle splitting motors is equipped with two groups of bottle blocking claws with equal distance, and the two motors operate alternately, dividing the neatly arranged bottles into predetermined bottle groups, which are transmitted to the next station through the main drive motor. According to the motion position of the main drive motor (bottle pushing motor), the bottle splitting motor operates synchronously with the bottle pushing motor according to the motion curve. As the slave of the bottle pushing motor, it operates alternately fast and slow regularly to carry out the master-slave synchronous operation, and realize a bottle splitting process in a bottle pushing cycle

2.2 design requirements of film feeding and cutting motor

according to each group of bottles pushed out by the bottle pushing motor, the film feeding and cutting motor realizes the film wrapping and packaging of the bottle group. Generally, it can be achieved by changing the curve in three segments. Segment a is the length of the film pressing in the rear half under the bottle, segment B is the length of the film wrapping and the film pressing in the front half under the bottle, and segment C is the length of the film sent to the film outlet after cutting the film, so as to ensure the smooth export of the film next time. The operation position of section a requires that the motion position of the film feeding and cutting motor is equal to that of the bottle pushing motor, that is, the motion distance between the main motor and the film feeding and cutting motor is the same, so as to ensure the 1:1 absolute relationship between the sent film and the moving position of the bottle group. The film feeding speed in Section B is relatively fast to ensure that the film guide rod can wrap the film on the packaged products smoothly. Section C is the end process of low-speed film discharge

cam synchronous control is the characteristic of the control system of the heat shrinkable film packaging machine. The master-slave synchronous data between servo motors is transmitted through the field bus, and multiple slave shafts are coupled to the position of a spindle to realize mutual linkage, which improves the control speed and control accuracy. Pp41 real-time control is not required for synchronous motion control

the operator can easily compile the cam curve on pp41, download it to the servo driver through the fieldbus, modify the system parameters at the same time, transmit the switching command of the servo motor, display the position and speed of the master and slave shafts, and monitor the torque, current and temperature inside the driver

3. Baccarat cam electronic cam principle

generally, for the position relationship of multi axis motion, one axis is selected as the main axis and the other axis is selected as the slave axis. Within a certain period, according to the position of the main axis motion, the position of the slave axis can realize the corresponding change, which can be a straight line relationship or a curve relationship

in the figure, the spindle factor is the position where the spindle moves in a cycle, and the slave axis factor is the curve position where the slave axis couples the spindle position in the corresponding cycle. It can be a straight line y=k*x, or various curve relationships. According to the actual needs, the complex relationship curve can achieve the relationship of up to 6 power changes

y = a + B x + C x2 + D X3 + e X4 + F X5 + G X6

3.1 control process of electronic cam

the control process of electronic cam consists of two parts: state and event

(1) state

state 0 (basic)

after starting the cam curve process, it usually enters state 0, which only performs the position processing of some curve transitions, and can be converted to other states

generally, the cam curve can be started for multi axis synchronous operation after the spindle moves to a specific position

state 1 11 (coupling)

in a cam process, there can be at most 11 states, and each state can set a special cam curve by clamping the unglutinated end of the flexible adherend into the lower chuck state of the experimental machine. Use the status index numbers 1... 11 to select and enter the corresponding status. If a 1:1 cam line is used, enter the 0xfff status index number

when jumping from one state to another, the compensation curve can be set for the inflection point of the transition as needed to achieve soft conversion and avoid rigid impact. The calculation of compensation curve can be different in different states

to jump from one state of the cam process to another, a special event needs to be triggered to activate. If there is still no event to trigger after the spindle reaches the end position of the main cycle corresponding to the set cam curve, the cam curve will automatically run repeatedly in this state

(2) event

each state supports up to four different events. If there are multiple events triggered at the same time, the index number of the event determines the corresponding priority. (the level of event 0 is higher than that of event 1, and so on e0>e1>e2>e3)

for each event, it can be defined as different situations in different states

event type

type description

ncoff no event

ncs_ Start execute

ncst after the spindle moves to the specified position_ End execute

ncst after the set spindle reaches the positive end position_ End + ncnegative execute

nccount after the set spindle reaches the negative end position

ncsignal1,2,3,4 software signals 1, 2, 3, 4 trigger

nctrigger1,2 + NCP_ EDGE or ncN_ Edge hardware signals 1 and 2 plus the rising and falling edge level trigger

event attributes

it is necessary to specify the attributes of each event and specify the execution time after each event is triggered

attribute description

ncat_ Once conversion immediately execute

ncst_ End conversion executes

3.2 system control scheme after the end of the state

(1) the movement of bottle splitting motor of heat shrinkable film packaging machine can be controlled by the following three states

when changing the type of packaged products, it is only necessary to change the position difference between state 1 and state 2, that is, the bottle splitting position changes, and the spindle does not need any change. In fact, it is convenient to change the slave axis factor. The transition of inflection point between two straight lines can be eased by setting compensation interval

(2) the motion of the film feeding and cutting motor of the heat shrinkable film packaging machine can be controlled by the following two states

curve generation can be realized by using the special software of baccalais automation studio. Coordinate values can be input to automatically take into account the maximum stress generation of the tested material, or the curve can be manually modified

when changing the type of packaging products, it is only necessary to change the length of the packaging film, that is, the moving distance of the feeding and cutting film changes, and actually change the slave axis factor, which can be easily achieved. The speed of packaging is achieved by changing the spindle factor

3.3 system advantages

(1) cam design is easy to apply, and the realization of linear curve is simple and flexible

(2) the generated cam curve is saved on the pp41 controller, and the replacement of servo driver is not affected

(3) it is fast and convenient to change the packaging curve in production

(4) users have a high degree of system integration initiative; Are the focus of discussion

(5) improve the accuracy and reliability of the system

(6) simple design, easy to expand and upgrade

4. conclusion

the heat shrinkable film packaging machine based on baccalais cam electronic cam technology has been widely used in many domestic manufacturers. The packaging speed has been adjusted steplessly, and the packaging specification can be modified in real time. The actual production has achieved good economic results, and has been widely praised by users

References:

[1] electrical control of Zhang Youliang heat shrinkable film packaging machine 2003.2

[2] application of Zhang Ben acopos in heat shrinkable film packaging machine 2003.8 (end)

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