At present, the filling machine used in the market is manual or semi-automatic, there are many need to make bags according to the filling requirements, feeding and weighing equipment is not accurate, filling speed and accuracy are not good. In view of the requirements of the feed industry on the filling machine, the existing feed filling machines on the market were investigated, and a set of DCS-50 small automatic quantitative filling machine with good versatility, stable performance and high precision was developed. This equipment is a mechatronic product, adopting microcomputer control technology, which can complete the functions of automatic feeding, weighing, bag clamping filling and sealing. This machine can also be applied to small filling in grain, chemical, food and medicine industries.

1 Structure and working principle

1.1 Structure

DCS-50 small automatic quantitative filling machine mainly consists of feeding parts, vibrating feeder, weighing parts, bag clamping mechanism, bag supplying and bag opening device, belt conveyor, sealing and filling device, upper frame, lower frame, transition hopper, suction hood, electric control cabinet and vacuum system, and electrical control system.

Feeding device mainly consists of three-stroke feeding mechanism and electromagnetic vibrating feeder. The three-stroke feeding mechanism is mainly composed of bucket, three-stroke cylinder, three degrees of arc cut-off door, the upper flange and the upper and lower adjustment structure and so on. This feeding mechanism adopts the self-weight feeding mode, the device structure is simple, safe and reliable action, good versatility, high feeding accuracy and speed. The three-stroke feeding mechanism is located at the top of the upper frame, and the vibrating feeder is located at the appropriate position between the three-stroke feeding mechanism and the weighing part, the joint use of the two mechanisms will ensure the feeding accuracy and improve the filling accuracy. The weighing part is mainly composed of weighing hopper body, movable door body, open/close door cylinder, load cell and metering module support. The weighing component is below the feeding device and above the transition hopper.

The three-stroke feeding mechanism, vibratory feeder and weighing components are fixed in the upper frame. The transition hopper is used to fix the clamping device and play the role of buffer material, the upper flange of the transition hopper is fixed between the upper frame and the lower frame, and the lower flange is connected with the bag clamping mechanism.

The bag clamping device mainly consists of bag clamping hopper, bag clamping rocker arm, bag clamping cylinder, bag tensioning mechanism and sealing device. The bag opening mechanism mainly consists of two groups of cylinders, vacuum suction cups, and guide rods that control the movement in horizontal and vertical directions respectively, and complete the bag opening action by combining the movement in horizontal and vertical directions. The bag clamping mechanism is below the transition hopper and connected with the lower flange of the transition hopper. The bag supplying device is mainly composed of bag storage box, bag taking cylinder and vacuum suction cup, bag moving cylinder, motor reducer, active roller, driven roller, belt, servo motor, photoelectric sensor, bag feeding arm, clamping finger cylinder and frame and foot cup. The bag supplying and bag tensioning device is located at the side of the whole machine, the bag feeding arm is controlled by the servo motor to rotate 90° and send the bag from the end position of the belt to the bottom of the bag clamping hopper.

The belt conveyor is mainly composed of motor reducer, bag holder plate, active roller, driven roller, belt, belt roller, height adjustment mechanism and so on. The belt conveyor is at the bottom of the whole machine, right below the bag clamping mechanism, right below the bag clamping mechanism, and the other end is at the side of the exposed whole machine.

Sewing and filling set by the outsourcing folding machine and sewing machine and the frame, which has a height adjustment device on the frame. The bag opening of the folding machine and the bag sealing opening of the sewing machine are located in the same straight line, and in a straight line with the center of the bag clamping opening. Sewing filler placement is located in the exposed end of the conveyor belt after the release, and in the side of the whole machine.

The vacuum system mainly consists of vacuum pump, flow control valve, directional control valve, pressure relay, silencer, vacuum suction cup, actuating cylinder, air pipe and so on. The placement of the vacuum system can be determined by the actual installation situation. The electrical control system includes weak power control part and strong power control part. The weak electric system is mainly PLC programmable controller, which controls the time and sequence of the three-stroke feeding mechanism, weighing part flap cylinder, sensor, clamping cylinder, bag supply mechanism motor, clamping finger cylinder, folding machine, sewing machine and so on. Strong electric part is mainly to control the vacuum pump, servo motor, electromagnetic vibration feeder, belt conveyor.

1.2 Special mechanism bag clamping device

The bag tensioning mechanism is a key mechanism in the bag clamping device, which plays an important role in the automation of the whole machine. Zhang bag mechanism is mainly composed of cylinder (cylinder X) to control the movement in the horizontal direction, cylinder (cylinder Y) to control the movement in the vertical direction, vacuum generator, vacuum suction cups and bag cylinder fixing plate. Each side in the same straight line side by side with two double-layer vacuum suction cups, the structure of which is shown in Figure 3. This bag clamping device is simple in structure, more clamping force when clamping the bag, will not fill the bag mouth damage; airtightness is very good for the dusty materials, the material will not be scattered dust, which affects the filling environment.

Vacuum suction cup is a kind of end actuator which is used to grab and hold the workpiece, this machine mainly uses vacuum suction cup to take the bag and open the bag. Vacuum suction cups are mainly used to withstand tensile force when picking up bags, and they are used to withstand both tensile force and shear force when opening bags. Because the vacuum suction cup is made of silicone and its other tree structure, the vacuum suction cup in the adsorption process has a certain degree of flexibility, even if the filling bag has a certain size deviation and positional deviation, can be adsorbed and fall off [”. Double-layer suction cups are more adsorptive than single-layer suction cups, more safe and reliable.

1.3 Working principle

DCS-50 small automatic quantitative filling machine can automatically complete the feeding, weighing, bag supply, bag clamping, filling, sewing six processes, the work process is mainly divided into two parallel routes to complete, then the working principle of the machine is divided into two parts.

The first part: the manual will be a stack of flat filler bags (about 400) neatly placed on the pallet in the bag storage box, press the start button, control the pallet lifting motor, belt motor and vacuum pump start, grating sensors to detect the height of the filler bags, the signal will be transmitted to the PLC to control the take the bag of the cylinder relay, take the bag of the cylinder downward outstretched, and at the same time the vacuum generator start vacuum suction cups ventilated rapid adsorption of the Filling bag. After contracting the bag cylinder upward, the signal will be transmitted to the relay controlling the bag shifting cylinder, and the bag shifting cylinder will be extended forward, then the vacuum suction cup will be cut off, and the bag will be shifted to the belt, and moved to the direction of the clamping device. At the same time, the bag feeding rocker arm is in the vertical direction and the clamping finger cylinder opens. When the photoelectric sensor detects the bag to a certain position, and the edge of the bag enters the finger cylinder opening, the finger cylinder closes, the signal is transmitted to the relay controlling the servomotor, the servomotor spindle rotates, and the bag feed rocker arm rotates counterclockwise by 90 °, which is just enough to send the bag to the bag clamping hopper at the bottom of the center of the body.

At this time, the bag clamping cylinder extends, the bag clamping rocker arm opens, the bag tensioning mechanism of the cylinder X and cylinder Y are in a contracted state. Begin to clip the bag, first of all, the cylinder Y down to extend, in place after the cylinder X are extended to the center, and then the vacuum suction cup ventilation, filler bags sucked. After keeping appropriate time (for example, set 0.5s), cylinder X are retracted to both sides, the bag mouth open. Cylinder Y contracts upwards and lifts the bag. After the cylinder Y is in place, the signal is transmitted to the relay controlling the bag clamping cylinders, the bag clamping cylinders contract, and the rocker arms on both sides close to the center, clamping the bag mouth on the outer wall of the bag clamping hopper body.

At this point, the first route for the bag, clip the bag action is complete. It should be noted that each machine is equipped with two bag storage box, when a bag storage box before the bag is used up, prepare in advance to change the bag storage box, to ensure that the machine does not stop running, each action without interruption.

The second part: the feeding system begins to feed the material, the signal will be transmitted to the control of the three-stroke cylinder and electromagnetic vibration feeder relay, the initial three-stroke cylinder is in a contracted state. When the fast plus a certain period of time (for example, set the time 1s), the three-stroke cylinder began to extend the first stroke, the three openings arc cut-off door opening reduces a certain angle, this time is actually in the plus state. When the weighing hopper in the material measurement to reach a certain (for example, set to 85% of the theoretical measurement), three-stroke cylinder extends the second stroke, leaving only three degrees of arc-shaped cut-off door of the small mouth of the material, this time the actual is slow to add state. When the theoretical measurement or slow feeding to time, three-stroke cylinder extends the third stroke, three degrees arc cut-off door completely closed, stop feeding. If the three degrees of arc cut-off door is completely closed but the measurement does not reach the theoretical measurement, electromagnetic vibrating feeder start, small flow slow feeding, so as to further improve the feeding accuracy, to ensure the weighing accuracy. When the measurement reaches the theoretical measurement, the three-stroke feeding mechanism of the feeding device and the electromagnetic vibrating feeder stop feeding. And the signal will be transmitted to the relay controlling the valve cylinder of the weighing device, and the valve cylinders on both sides will be extended, the valve will be opened, and the feeding and filling will start. After the filling is completed, the bag clamping cylinder contracts, the bag clamping rocker arm opens, and the filling bag falls on the belt conveyor. Control weighing device valve cylinder contraction, valve closed, waiting for the next cycle.

So far, the second route on the feeding, weighing, filling action is completed. The next step is to complete the subsequent actions of folding, sewing and conveying in sequence during the conveyance on the belt conveyor.

It should be noted that the three-stroke feeding mechanism fast plus, medium plus, slow plus time should be based on different materials, different feeding speed, three-stroke feeding mechanism to the height of the weighing device and other factors to set the parameters. These parameters include the sensor accuracy compensation variables, three degrees of opening degree arc-shaped cut-off door opening time, each opening degree and opening speed. Also according to these factors to set the three-stroke cylinder ventilation, so as to control the three degrees of arc cut-off door action fast and slow. Also set the vibration frequency of the electromagnetic vibrating feeder.

2 pneumatic system

2.1 Pneumatic system composition

Pneumatic system mainly consists of gas source device, actuators, control components, auxiliary components of four devices. Air source device that is the generation of compressed air device, the main part of which is the air compressor. It will be the prime mover (such as electric motors) of the mechanical energy into air pressure energy and purification equipment purification, for all types of pneumatic equipment to provide clean compressed air. The actuator is the energy output device of the system, such as cylinders and vacuum suction cups, they will convert the pressure energy of the gas into mechanical energy, and output to the working mechanism. Control components are used to control the regulation of compressed air pressure, flow, flow direction and system actuators of the work program components, such as pressure valves, flow valves, directional valves and so on. In addition to the above three types of components in the system, the rest of the components are called auxiliary components, such as various filters, oil mist, mufflers, sensors and pipe fittings, etc., which play a very important role in keeping the system reliable, stable and lasting work.

3 Vacuum system

The vacuum system of DCS-50 small automatic filling machine is mainly composed of air compressor, two-position three-way solenoid valve, air pressure relay, vacuum generator, vacuum suction cup, air pipe and so on.

4 Conclusion

The first DCS-50 small automatic quantitative filling machine developed has reached the expected work requirements and performance requirements, and can successfully complete the six processes of feeding, weighing, bag supply, bag clamping, filling, sewing, and can adapt to a variety of materials to fill, and has stable performance, high precision, good reliability, simple operation, easy maintenance, and meets the user's needs.