Plastic bag making machine refers to equipment used to make plastic bags. The plastic commonly used is not a pure substance, it is made up of many materials. Among them, high molecular polymer (or synthetic resin) is the main component of plastic. In addition, in order to improve the performance of plastic, various auxiliary materials such as fillers, plasticizers, lubricants, stabilizers, colorants, etc. must be added to the polymer to become a plastic with good performance.

Plastic composition

Among them, high molecular polymer (or synthetic resin) is the main component of plastic. In addition, in order to improve the performance of plastic, various auxiliary materials such as fillers, plasticizers, lubricants, stabilizers, colorants, etc. must be added to the polymer to become a plastic with good performance.

1. Synthetic resin

Synthetic resin is the main component of plastic, and its content in plastic is generally 40% to 100%. Due to the large content and the properties of the resin often determine the properties of the plastic, people often regard resin as a synonym for plastic. For example, polyvinyl chloride resin is confused with polyvinyl chloride plastic, phenolic resin is confused with phenolic plastic. In fact, resin and plastic are two different concepts. Resin is an unprocessed raw polymer, which is not only used to make plastics, but also the raw material of coatings, adhesives and synthetic fibers. Except for a very small part of plastics containing 100% resin, most plastics need to add other substances in addition to the main component resin.

2. Filler

Filler is also called filler, which can improve the strength and heat resistance of plastics and reduce costs. For example, adding wood powder to phenolic resin can greatly reduce costs, making phenolic plastic one of the cheapest plastics, and at the same time significantly improve mechanical strength. Fillers can be divided into two categories: organic fillers and inorganic fillers. The former include wood powder, rags, paper and various fabric fibers, and the latter include glass fiber, diatomaceous earth, asbestos, carbon black, etc.

3. Plasticizer

Plasticizer can increase the plasticity and softness of plastics, reduce brittleness, and make plastics easy to process and shape. Plasticizers are generally high-boiling organic compounds that are miscible with resins, non-toxic, odorless, and stable to light and heat. The most commonly used are phthalates. For example, when producing polyvinyl chloride plastics, if more plasticizers are added, soft polyvinyl chloride plastics can be obtained. If no plasticizer is added or less plasticizer is added (dosage <10%), hard polyvinyl chloride plastics can be obtained.

4. Stabilizer"}]}]},

In order to prevent the synthetic resin from being decomposed and damaged by light and heat during processing and use, and to extend the service life, stabilizers should be added to the plastics. Commonly used ones are stearates, epoxy resins, etc.

5. Colorants"}]}]},

Colorants can give plastics a variety of bright and beautiful colors. Organic dyes and inorganic pigments are commonly used as colorants.

6. Lubricant

The function of the lubricant is to prevent the plastic from sticking to the metal mold during molding, and at the same time make the surface of the plastic smooth and beautiful. Commonly used lubricants include stearic acid and its calcium and magnesium salts.

In addition to the above-mentioned additives, flame retardants, foaming agents, antistatic agents, etc. can also be added to plastics to meet different usage requirements.

Classification and use

Types of plastic bags

(1) High-pressure polyethylene plastic bags (2) Low-pressure polyethylene plastic bags

(3) Polypropylene plastic bags

(4) Polyvinyl chloride plastic bags

Uses of plastic bags

(1) Uses of high-pressure polyethylene plastic bags:

A. Food packaging: cakes, candies, roasted nuts, biscuits, milk powder, salt, tea, etc.;

B. Fiber product packaging: shirts, clothing, knitted cotton products, chemical fiber products;

C. Daily chemical product packaging.

(2) Uses of low-pressure polyethylene plastic bags:

A, garbage bags, bacterial culture bags;

B, convenient bags, shopping bags, handbags, vest bags;

C, fresh-keeping bags;

D, woven bag inner bags

(3) Uses of polypropylene plastic bags:

Mainly used for packaging textiles, knitted cotton products, clothing, shirts, etc.

(4) Uses of polyvinyl chloride plastic bags:

A, gift bags;

B, luggage bags, knitted cotton product packaging bags, cosmetic packaging bags;

C, (zipper type) document bags, information bags.

Composition and structure

A plastic bag making machine is mainly composed of: storage device, stepping device, frequency conversion device, bag making device, heat sealing cutter and control device. The main features are that the storage device stores the corresponding amount of raw materials, the stepping device drives the raw materials, the frequency conversion device drives the heat sealing cutter, the bagging device makes bags after producing a fixed number of bags, the heat sealing cutter controls its temperature through the temperature controller to seal and cut the raw materials, and the control device coordinates all aspects of the action.

The frequency converter adopts Delta M series frequency converter. Delta M series frequency converter has functions such as automatic torque compensation, slip compensation, and automatic voltage stabilization. In the case of frequent motor start and stop, it can effectively protect the motor and avoid the impact of starting current on the power grid, and at the same time can effectively achieve energy saving and consumption reduction. Delta DTA4848R is used as the temperature controller. Delta air conditioner has self-tuning function, and the temperature error is controlled within 0.1 degrees. The main control methods are as follows: 1. Open the material release switch, and control the action of the material storage motor through the material storage photoelectric control to store quantitative materials. 2. Turn on the heating control switch and heat the hot knife through the temperature controller. 3. The stepper motor drives the raw material to move. The sealing and cutting of white bags is to determine the fixed number of steps of the stepper motor to stop to achieve fixed length control; the sealing and cutting of color bags is to detect the corresponding signal by the electric eye to stop the stepper motor to achieve positioning control. 4. After the stepper motor stops, the three-phase asynchronous motor drives the hot knife to seal and cut. 5. After the set number of bags are sealed and cut, the whole bag is made.

Cutting system

The cutting system consists of a cutter, a length adjuster, an overrunning clutch, and a welding line adjustment.

1. Cutter: It is the most important component of the system. It adopts a moving knife and a sliding guide, and a floating mechanism compressed by a spring. The upper and lower knives can be adjusted. There is an adjusting screw that can be used to adjust the tightness of the cutter 186181 42980 Zhang Qingbo can well eliminate the phenomenon of difficult cutting of raw materials.

2. Bag making length adjuster: The adjustment of the bag making length controls the bag making length by changing the position of the connecting rod sleeve on the eccentric slide plate, and the bag making size is adjusted by loosening the hand wheel and the nut.

3. Overrunning clutch: Overrunning clutch is an important part of this machine. Its quality and performance directly affect the error of product length. However, during use, due to the high working frequency, its life span is also limited. If the error of bag making length is found during production (generally after half a year of continuous production), and other faults cannot be solved after eliminating them, the clutch can be disassembled for inspection and repair.

4. Adjustment of the distance between welding line and cutting line: The distance between welding line and cutting line is generally 5-10mm. Turn the hand wheel on the adjustment frame to make the crossbeam roller rise or fall a certain distance to obtain the ideal cutting line. In order to facilitate the observation of the quality of welding line, the welding line position of the single bottom line can be adjusted to the outer end of the machine cutter. If the welding line and the bottom line are not parallel, loosen the fixing screw of one bevel gear, turn the hand wheel to raise or lower one end of the crossbeam roller; after the production is stable, tighten the screw of the gear.

5. Welding knife adjustment method: Place a piece of thin paper on the support seat, turn the large hand wheel in the machine box by hand to make the welding knife at the bottom dead center, loosen the nut, adjust the nut, and try to pull the two ends of the thin paper by hand to tighten until they are roughly equal. After adjustment, tighten the nut to prevent loosening.

6. Automatic light-controlled feeding device: This device consists of a servo motor, a feeding rubber roller, a light-controlled film shielding device, a curtain, a photoelectric tracking machine, and an electric control line. Its function is to maintain normal film feeding during the production process. When the machine is running, if the film feeding speed is too fast and blocks the light-controlled rays, the device will issue a command to stop the motor from rotating and feeding.