Talk about common problems in bag making machine o

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Talking about the common problems in the operation of bag making machine

common problems in the operation of bag making machine

bag making processing is the last process in the production and processing of plastic flexible packaging. If the bag making quality is unqualified or the consumption is too high, then at least the previous processes will be wasted, and at worst, the claim from customers will have a significant impact on the production and operation of the enterprise

the following are common problems in the operation of bag making machine for collection and sorting

1. What if the contents leak or deteriorate due to incomplete heat sealing of the bag making machine

cause: the anti pollution heat sealing property of the film is poor, mainly because the resin used in the inner sealing layer is inappropriate

countermeasures: use films with good pollution resistance and heat sealing. Generally speaking, LDPE has medium anti pollution heat sealing property, EVA has good anti pollution heat sealing property when the VA content is large, LDPE also has good anti pollution heat sealing property, and the minimum guaranteed interest rate sealing property of universal insurance will be released by the CIRC on February 16, 2015, while ionic resin and metallocene polymer have excellent anti pollution heat sealing property

2. What about the brittle and broken sealing of the bag making machine

reasons: (1) the heat sealing temperature is too high; (2) Excessive pressure; (3) The heat sealing time is too long; (4) The edge of the upper sealer is too sharp or the PTFE covered is damaged; (5) The silicone rubber at the bottom seal is too hard; (6) In the process of compounding and curing, part of the adhesive penetrates into the film. Due to the penetration of adhesive, the toughness (impact resistance) of the substrate decreases and the brittleness increases; (7) After cooling and placing, the heat sealing strength of plastic composite packaging bags increases, but also tends to become brittle

countermeasures: (1) select the appropriate processing temperature, pressure and heat sealing time according to the heat sealing characteristics of the inner seal material; (2) Improve the surface condition of the upper heat sealing knife to make the surface of the sealer smooth; (3) It is well covered with polytetrafluoroethylene cloth; (4) Choose silicone rubber pad with appropriate hardness

3. After heat sealing, the bag warped and successfully developed a kW aluminum air battery power generation system based on graphene air cathode (see Figure 2). What should we do

reasons: (1) the thickness of composite film is inconsistent; (2) The heat sealing temperature is too high or the heat sealing time is too long; (3) In the longitudinal heat sealing knife part, the running track of the composite film is not straight; (4) Insufficient cooling; (5) Insufficient ripening time; (6) The surface substrate film has poor heat resistance; (7 creeping (jumping) occurs in the sliding of the wedge-shaped block along the dovetail slope.) improper tension matching control of the composite substrate in the composite process leads to residual stress after curing and shaping, especially when the thickness of the composite film is thin

countermeasures: (1) adjust the tension of floating roll; (2) Select the inner sealing base material with low temperature heat sealing property; (3) Adjust the heat sealing temperature to the appropriate temperature; (4) Sufficient cooling; (5) Fully ripen; (6) Re select the surface substrate film;. (7) Adjust the tension of each part of the composite processing equipment, and try to make the retraction rate of the two composite substrates equal

4. What if the outer contour of the heat sealing surface is not clear? (the knife pattern is not clear)

reasons: (1) short cooling time; (2) Poor contact of cooling plate; (3) Because the silicone pad is heated, the edge part melts; (4) The longitudinal heat sealing force is uneven; (5) The edge of the heat sealing knife is irregular and blunt

countermeasures: (1) adjust the cooling time; (2) Adjust the cooling plate; (3) Replace or adjust the heat sealing knife; (4) Prevent the edge melting caused by overheating of silicone pad

5. What about poor heat sealing strength

reasons: (1) the adhesive in the composite film has not been fully hardened; (2) Improper heat sealing conditions; (3) The distance between the heat sealing knife and the cooling knife is too long; (4) There is a problem with the inner sealing film

(5) the poor heat sealing property of the ink leads to the reduction of the composite strength of the film at the heat sealing position; (6) Dust, dusting and other substances are attached to the thermal cover; (7) The composite strength is low or the composite strength at the heat seal decreases too much


(1) promote the hardening (curing and curing) of the adhesive through thermal insulation aging, and improve the composite strength and heat resistance of the composite film

(2) select the best heat sealing conditions (temperature, time and pressure) according to the composition structure and heat sealing state of the composite film, or improve the heat sealing method, and immediately cool after heat sealing

(3) check the storage period and storage conditions of the heat sealing film. If the heat sealing layer uses the film of the old batch number and the film after heat sealing treatment, pay special attention

(4) increase the thickness of the heat seal film

(5) change the type and grade of heat sealing film, and use inner sealing film with anti pollution heat sealing property

(6) check whether the grade of the adhesive meets the requirements (the exudation of low molecular substances in the resin sometimes affects the composition of the adhesive)

(7) improve the heat sealing performance of the heat sealing layer (substrate), control the content of the smoothing agent, and use mLLDPE film

(8) control the monomer content of MDI in the composite adhesive

(9) check the treatment degree of the heat cover

(10) change the ink (it is best to use two liquid ink)

(11) change the printing pattern of the packaging bag, so that the part printed with ink avoids the heat sealing part, or change the heat sealing method. (pay special attention not to print metal ink on the seal)

6. What about bubbles or uneven surfaces at the heat sealing part

reasons: (1) when heat sealing is carried out on the hygroscopic material structure containing nylon film, the hygroscopic film will absorb moisture and produce bubbles; (2) The heat sealing knife or heat sealing silicone pad is uneven; (3) Insufficient heat sealing pressure; (4) When using one component adhesive, such as neoprene adhesive, when making bags by heat sealing, uneven pits are easy to appear on the heat cover

countermeasures: (1) keep raw materials and semi-finished products properly to avoid moisture absorption; (2) Check or adjust the heat sealing knife and heat sealing silicone pad; (3) Replace the adhesive

7. What about poor smoothness

reasons: (1) the ripening temperature is high, and the smoothing agent loses its function at high temperature; (2) The adhesive seeps into the inner surface, which affects the friction coefficient of the substrate film surface, especially when the film is thin and corona treatment is excessive; (3) The film substrate itself has poor smoothness

countermeasures: (1) strictly control the ripening conditions (according to the product ripening operation instructions); (2) Check the type or grade of adhesive; (3) Replace the substrate or use powder spraying

8. What should we do if the composite membrane is hardened and it is difficult to receive materials

cause: quality problems of film and adhesive

countermeasures: sprinkle powder when making bags

9. What if the bag width deviates and the folding seam is not tight? (middle seal, side seal)

reasons: (1) uneven thickness of composite film; (2) The size of specification plate is out of tolerance; (3) The tightness of the film wrapped specification plate is improper

the tighter the wrapping, the greater the resistance, and also affect the forming width of the bag. If it is wrapped loosely, it is easy to have loose seams

countermeasures: (1) the performance of the foaming finished product obtained in this way is the best to adjust the specification board; (2) Adjust or replace the composite film; (3) Adjust the tightness of the film wrapping specification plate. For thin films, horizontal contraction will occur during tensioning, so the size of the template should be smaller than the standard size. For thicker films, due to the influence of thickness, the size of the template should also be smaller than the standard size

10. What if the upper and lower parts are not aligned

reasons: (1) the thickness of the composite film is uneven and there are ruffles; (2) The tension of double floating rollers is too small; (3) Some rolls rotate unevenly

countermeasures: (1) adjust the tension of double floating rollers; (2) Check and adjust relevant guide rollers (such as compensation roller, deviation adjusting roller, etc.)

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