Successful manufacture of automatic bag making machine with ultrasonic paste technology

After two years of research, Dr. Ngo Manh Dung (Nguyen Tat Thanh University) and his colleagues have successfully designed and manufactured an automatic machine for producing non-woven bags with ultrasound technology.

Non-woven fabric is made of synthetic resin, with additional ingredients depending on usage. During the manufacturing process, they are spun and bonded together by chemical or thermal solvents to form a light, tough and porous cloth. Because it does not go through the weaving process, it is called the nonwoven fabric, in order to distinguish it from the fabric interwoven between the warp and weft by knitting machines.

With characteristics such as light, load-bearing, toughness, waterproof, ventilating, elastic, low cost, environmentally friendly and hypoallergenic when in direct contact, non-woven fabric is commonly used. in sewing bags, environmental bags, fashion bags, advertising bags of businesses; pads in blankets, mattresses, shoes; etc. Non-woven fabrics are also used in the medical industry such as cosmetic masks, medical masks, operating room doctor’s clothes, clean rooms, etc. In addition, non-woven fabrics The weaving uses heat-press technology to weld and paste instead of the thread, so the production time is fast, not labor-intensive.

According to Dr. Dung, if producing handmade cloth bags by ultrasonic paste technology, first measure and cut cloth to size, then paste bags, giving low productivity (fastest 1 minute / bag). Not to mention, hand-painted products are not homogeneous, with many errors. If produced by an automatic machine, it can produce 30 – 120 bags / minute depending on the size. One machine can replace 60 manual machines.

Dr. Dung said, in Ho Chi Minh City, there are about 90 enterprises producing non-woven bags, most of which are produced manually with low productivity and high cost. Only a few large enterprises invest in automatic production line equipment. In the country, there is no unit that designs and manufactures equipment for producing non-woven bags with ultrasonic paste technology.

After two years of research, the authors have successfully manufactured equipment for producing woven fabric bags using ultrasonic paste technology, with parts such as fabric supply cluster, transverse welding pull assembly group, loop punching cluster, folding assembly. double cloth to create 2-layer shape for bags, clipping clusters and vertical seam welding, etc. To apply ultrasonic technology in welding, the team designed and manufactured two sets of ultrasonic welding (mouth and hip gluing), including transformer (piezoelectric transducer), amplifier and welding mold.

In addition, the system uses multiple control circuits such as controlling the fabric tension at the top of the feed, adjusting the edge of the fabric straight, gluing along the edges, punching holes, cutting bags. These control circuits are installed and adjusted to set the appropriate mode for each function cluster.

Software to control the entire production line was drafted and installed by the group into the PLC’s programmable controller. At startup, the software will perform initial status setting for function clusters, status display and system control. The controller on the PLC center monitors the operation of the function groups, collecting and handling errors. Errors are warned by buzzer and PLC stops operating when the cloth runs out of the feed rolls, error functions, production loss. The chain can be monitored remotely via a smart phone or an internet-connected computer.

The system has been put into trial production at Vietnam Ultrasonic Equipment Co., Ltd. (Ho Chi Minh City) with a minimum capacity of 40 bags / minute, with a common non-woven material of 80g / m². Machine can paste the bags: shock bottom with straps, bottom shock without straps, mango seed holes, etc.

Dr. Dung said that the test showed that the system met the requirements of automatic production, high productivity, easy to adjust and change for different bag sizes. The team has mastered the technology of manufacturing system equipment to be able to provide the market at a price that is only 50% of the imported price.

Productivity and Quality Office