Steel "bottle-shaped cans"

The "bottle-shaped can" originally made of aluminum coated with PET was originally introduced in the United States. In a new factory, its material was replaced with steel.

The two canning lines at DS Containers in Batavia, Illinois, United States, from unwinding, stamping to printing, and palletizing are simply miracles of power, precision, and automation. The finished products they produce are now impressive in every detail of the two-piece cans that are currently used in aerosol products (and, of course, also in emulsions or gels). There are no seams that can damage the sidewalls; a full round top shape increases the feel of the touch; and up to 8-color offset printing greatly increases the shelf impact of the product.

DSC's 236,000-square-foot facility is also very special, mainly because it avoids the release of toxic substances. Because the company used PET-coated steel to produce metal cans, the paint used in traditional cans was not used in the entire production process. Because no paint is used, there is no need for an oven for removing these paints, so that the emissions produced during the production process are very small.

DSC's patented "coil to can" patent technology is based on the similar technology of the revolutionary "bottle-can" technology introduced by Daiwa Cannery 5 years ago, except that the material used in the latter is coated. PET aluminum instead of steel.

The connection with Daiwa also explains the origin of the DSC company name because DS comes from Daiwa-Seikan. "Seikan" means making cans in Japanese. DSC is one of the members of Japan's Daiwa canning company.

Another link behind this is that DS Smith's chairman and CEO, Bill Smith, was an executive vice president of the American Can Making Company in the 1980s. He was responsible for managing the technology and licensing agreement between the Daiwa canning company and the American can making company. After Smith became the CEO of the American Can Making Company, he remained in close contact with Daiwa, and he also acted as an advisor during the development of aluminum cans in Daiwa. It's Smith's idea to introduce the jar into the United States.

Two-piece cans advantage

In introducing this patented technology into the United States, DSC replaced aluminum with steel. Because of the lower cost of steel, it is probably about 20% lower than aluminum. The PET-coated steel is supplied by Corus Packaging Plus, an Anglo-Dutch steel company that uses PET to coat the steel during coil production.

In order to be fully aware of the unique features of this container, it is necessary to point out that most aerosol cans currently in the US market are three-piece cans. This makes them require multi-step production processes and involves many logistics operations in production, including:

● The iron sheet will be processed into sheets;

● The sheet is printed and cut to the size required for a single tank;

● manufacture tank bottom;

● Manufacturing cylindrical can bodies with welded seams;

● Join the tank bottom with the tank body;

● Coating and drying.

However, DSC uses a one-step process to produce its two-piece cans, which takes about 20 minutes from unwinding to stacking. Even the 8-color offset printing process is inline. According to Ron DeSimone, director of marketing at DSC customer Chase Products in Illinois, USA, this on-line can making process significantly reduces time-to-market. He said that generally three pieces of steel aerosol cans need 6 weeks to be produced and shipped to customers, and the DSC two-piece cans only takes about two weeks.

Other benefits include:

• Eliminate the necessary welding seams for the three-piece cans, which makes the cans smoother and eliminates any possibility of rusting the can bodies.

● The PET coating on the inner and outer walls also prevents the generation of rust along the bottom of the tank.

The minimum number of orders for three-piece cans is approximately 50,000; while the DSC two-piece cans have a simpler in-line process, and its minimum order quantity can be 4,000.

For one reason or another, Chase Products became one of the first companies to commercialize DSC's two aerosol cans.

Metal can manufacturing

The simple and smooth production process of these two can production lines gives a deep impression, and the new two-piece cans produced are satisfactory.

In addition, the two production lines are also impressive because of their unimaginable production speeds. Rolled steel can be stamped with extremely high accuracy and a speed of 600 pcs/min. The metal can handling system provided by Fleetwood, a subsidiary of Barry-Wehmiller, uses vacuum and magnetic methods to transfer these cans from one machine to another. Can forming, cutting and crimping equipment were provided by Shin Nippon Koki, a subsidiary of Daiwa Corporation.

When 8mil thick steel passes through a press, the production process begins. This press uses a 6-tooth tool to make a sheet-like parison from about 5 inches in diameter and about 2 to 3 inches deep.

When passing through the second punch, these cup-shaped parisons are stamped to a depth of 6 inches on the 21 1/604 (18 ounce) can line, and are stamped into the 21 1/713 (22 oz) can line. 7 inches deep. Then a magnetic conveyor belt will send them to an oven.

"This oven will do some chemical treatment of the polymer coating, just like the drying process, to ensure the stability of the coating." Company CEO Smith said.

After leaving the oven, a cutting table cuts off the excess edge of the mouthpiece. The metal cans can then be printed, and two offset Rutherford printing opportunities provided by Stolle Machinery are doing the job. Immediately after the pressroom is a drying oven for drying the ink.

“A big bottleneck in the manufacture of traditional three-piece aerosol cans is the printing part,” said Smith. Because it is an off-line sheet-fed printing process, it is only suitable for producing long-lived jobs, and short-lived jobs will take up too much product conversion time. In DSC, this is not a problem at all.

“Every production line has two high-speed metal presses,” said Smith. “To switch to another printing pattern, we can simply continue the production by switching the press.”

Next on the production line is the third press. This punching machine is responsible for forming the beveled shoulder and neck of the can. Followed by another oven for drying PET coating. A conveyor belt again sent the metal cans to the cutting table, cutting off the edge of the opening sheet a little more. Then a conveyor belt mounted on the upper part will send the metal cans to a combination machine, which cuts off the top of the can neck, curls it, curls it, and curls it a third time. A vision system with four cameras will inspect the crimps and any metal cans with defects will be removed.

Tank bottom molding

The metal cans that left the first assembly machine were then sent to another combination machine. The object of processing this time is the bottom of the tank. Similarly, the four unique worktables are necked and crimped, and then a seam is formed in the lower part of the can body. The bottom of the can is then combined with the can body. The bottom of the tank is automatically fed to the welding machine via a Fleetwood feeder.

Two vision systems were used here to test metal cans. One is responsible for checking the integrity of the curls, while the other is responsible for checking the interior of the metal cans. If any lace or scratches are found, the metal can is removed. Not far downstream of the production line is the reject device. An air test facility applies 120 psi pressure to each tank and any metal cans with pinholes are detected and removed.

The operations at the end of the production line are also all automated, just like the previous canning process. The Goldco palletizer provided by Barry-Wehmiller company neatly stacked metal cans on pallets. Two Signode balers made each level very stable, and the entire pallet was packaged by a Lantech stretch packer.

Smith also agreed that the two lines are very similar to Daiwa's aluminum can line in Japan, but he emphasized that using steel as aerosol cans will require a lot of stamping and re-pressing operations, but Less need for leveling operation.

“The flattening operation will make the aluminum bottle-shaped tank thinner, but here we are more concerned with ensuring the thickness of the tank to achieve sufficient strength,” Smith said. “Remember that it must be able to withstand aerosol products. We want it to be as strong as a tank."

Source: International Packaging Business