Two Centuries of Three Piece Cans

Posted in Metal Decorating, News

Penny Laurann from Canmaking News Reports

 

Canning has been used to preserve and package food for two centuries. During this time, the three piece can has been an enduring and traditional container which has evolved as the industry developed. The basic principles of canning have not changed in the 200 years since the technique was first developed, but the techniques of Canmaking have undergone continuous refinements. This feature looks at the history and development of the three piece industry staple.

Stages in making a three-piece welded can

  1. Steel strip arrives at the can manufacturing plant in large coils.
  2. Steel strip is cut into large sheets
  3. To protect the can from corrosion and prevent interaction between can and contents, lacquer is applied to the side of the sheets that will become the internal surfaces of the finished cans
Lacquering

With nearly 90 years experience in making coatings and lacquers for metal–packaging Akzonobel was one of the first suppliers to the can market. It provides a range of internal and external coatings for food and drink packaging, including its Diaflex, Aquaprime, Aqualure and Vitalure and Vitalac coatings ranges. AkzoNobel recently perfected Aqualure 915 specifically for thin walled DWI cans. Aqualure 915, is an ultra-flexible lacquer which flexes with the new lightweight steel cans, yet still retains a perfect barrier to protect the drinks. The company innovations include Aquaprime 186 a tactile coating as used by brewers Heineken.

Metal Decoration

Increasingly the modern trend is to print the labelling onto the metal. For hygiene reasons, labels for food cans are usually made of paper and added after filling and cooking.

Printing onto tin plate requires specialist expertise, and the coat must be rub resistant and impervious to oil and moisture. With the high cost of tin plate and the demand for flawless print, metal decorators strive to control waste and quality.

By retrofitting a metal press with Epic’s Delta Dampening System, virtually defect-free printing can be achieved – minimizing waste, reducing press down time and saving hours of product inspection. The improved print quality, combined with the efficiencies gained in productivity, result in a rapid return-on-investment. Epic says that the system can be retrofitted to all makes and models of presses.

  1. Lacquered sheets are oven dried
Oven drying

Another established supplier to the Canmaking industry is oven specialist ARC Pacific With more than 75 years combined experience in product sourcing, engineering and producing ovens for steel and aluminum can manufacturing, ARC Pacific constructs state-of-the-art, thermal E3 oven products with energy-saving elements. The company combines China manufacturing with guaranteed quality and reliability. The company also works with customers to achieve continuous product improvement based on customer input and technological advancements. The beverage, food and aerosol cans product range includes drying ovens; pin ovens; internal bake ovens and cap cure ovens.

  1. Large sheets are slit into can size pieces
Slitting and detection

Italian company Cevolani, founded in 1900, prides itself on being a world-leader in the design and manufacturing of complete lines for the production of three-piece cans for food, aerosol and general-line. Latest developments include a new high production double slitter with ultra low change over time.

An automated detector is used to spot double sheets or double blanks before they cause damage to canmaking machinery. Sencon’s double sheet detector is a fully self-contained system, requiring only a pair of sensing heads to be fitted, together with connections for power/signals. The heads are made from stainless steel and all electronics are fully encapsulated for a lifetime of operation in the toughest factory environment. The sensor automatically calibrates at the beginning of a batch and constantly monitors its own settings. This sensor can also be used as a double end detector to protect the seamer on can filling lines.

  1. Each small sheet is rolled into a cylinder
  2. Cylinder edges are welded by squeezing them together whilst passing an electric current through them
  3. The inside surface of the weld is sprayed with lacquer and then cured by heated air
Protection of welded seams

To welded seam must be pore-free and able to withstand flanging, necking and beading processes as well as the aggressiveness of the product itself. Rising costs for lacquers containing solvents combined with stricter regulations to reduce volatile organic compounds (VOCs) mean that can manufacturers may be looking for new techniques in the future. Frei AG has developed a new system to powder coat the complete inside of drawn food cans, aerosol monobloc cans and tubes. Using powder virtually eliminates solvent emissions because there is no need to exhaust VOCs.

The machine concept consists of a chain conveyor on which the rotating cans travel in horizontal position past a group of parallel powder guns. The guns move along with the cans or tubes as they reciprocate in and out of the can bodies. In order to guarantee the industrial hygiene each coating station is provided with a dust extraction system adapted to the respective can diameter. Frei AG supplies components of proprietarily developed powder guns and offers a complete system including machine and safety engineering, controls, etc.

  1. Cans pass through a flanger where the top and bottom are flanged outwards to accept the ends

German company Lanico is a leader in the field of general line can making equipment. Lanico’s Can Former CF 412 is the latest development is the new series of CF 4xxx machines. It can operate as high speed machine for the production of round cans or three piece welded necked-in or straight walled aerosol cans, general line cans or food cans. Depending on the machine type and the toolsets mounted operations that it can perform include flanging, necking and flanging, bottom end and top end seaming. It is designed to combine a working range of up to 200 mm diameter, quick change-over of height and diameter and a high production speed of up to 300 cpm.

The welded or drawn can bodies are fed vertically to the machine, separated by infeed spirals and transported to the first of up to two flanging or necking carousels. On completion of this operation the can bodies are transferred to the next carousel wheels for seaming bottom and top ends or other optional operations. One of the main features of the Can Former is the use of modular change parts allowing diameter changes to be undertaken within a short time. The pre-set change parts minimise further adjustments. Height changes are performed by the motor driven adjustment system and are completed within seconds. A video monitoring system allows a visual inline check of the neck shape.

Typical applications for CF 4xxx include the production of large paint cans, beer kegs, large milk powder can, and large food and general line cans

  1. Plain ends are seamed to the can bodies to close one end of every can.
Seaming

Seaming machines for the food industry are the speciality of Spanish company Montajes Conserveros De Galicia (MCG ). Created in 1994, MCG has designed and manufactured a range of seamers that provide better seam quality with new material and ends systems, consistency, bigger output and state of the art hygienic and safety systems. The company manufactures a wide range of seaming machines for all type of cans: round, rectangular, oval, etc made from tinplate or aluminium for the food industry, for small and larger can sizes and output. Its complete range of seamers has 3,4,6,8 and 12 seaming stations and capacity up to 1.200 cpm. The technology which recently won the IPA packaging innovation award, is targeted at the fish, processed meat and shellfish segments. Future applications are slated for milk powder, coffee powder and nuts – with the company looking to incorporate a gas chamber to facilitate these. In collaboration with the University of Carthegana it is developing a new range of vacuum seamers for irregular cans. Work is ongoing to boost the current prototype performance from 100 to 300 cans per minute.

  1. Cans are passed through a beader where the walls of the cans have circumferential beads formed to give added strength
  2. Cans pass through a pressure tester, which automatically rejects any cans with pinholes or fractures
Inspection

The Quality by Vision Can Profile Analyzer uses moving laser profiling technologies for can profiling inspection. This is an ingenious new method of analyzing the can profile and its designers say that it offers the first ever completely automated solution for bead measurements. This new system means can manufacturers can swiftly and accurately measure cans in the production environment. Using state-of-the-art optics, a typical can profile can be measured in seconds. The completely automated software automatically detects the beads, flanges and can height in optimal accuracy at this top speed.

Ad-hoc measurements can also be taken anywhere on the scanned profile. A certified calibration gauge can be added to the system for full ISO 9000 compliance. The Can Profile Analyzer can integrate additional measurements and values into its reports (e.g., additional can diameters) using standard gauges/calipers or even using the keyboard. Measurements and reports can be exported into any popular file format, including Microsoft Word, Excel and even Internet formats.

  1. Finished can bodies are then transferred to the warehouse to be automatically palletised before despatch to the filling plant
Milestones in the development of 3 piece cans
1795 France Emperor Napoleon offers 12,000 francs prize for devising a way of preserving food for his troops
1809 France Confectioner Nicholas Appert receives the 12,000 franc prize from the for idea of packing food into special “bottles”
1810 England Patent awarded to Peter Durand for using tinplated iron as food container
1812 America Englishman Thomas Kensett starts a plant in New York canning oysters, meats, fruits and vegetables in hermetically sealed containers.
1813 England John Hall and Bryan Dorkin open England’s first commercial canning factory
1818 America Peter Durand introduces tinplated iron can in America
1819 America Thomas Kensett and Ezra Gagett start selling products in canned tinplate cans
1825 America Kensett awarded American patent for tinplated cans
1830 England Huntley & Palmer start selling biscuits in tins
1856 Canned condensed milk patent
1849 Patent awarded for the pendulum press – capable of making a Can End in single operation. Production increases to about 50 cans per hour
1858 America First can opener patented
1866 E.M. Lang is granted a patent for sealing tins by casting or dropping solder on can ends
1875 Sardines canned
1880 Semi-Automatic Can Making machinery is first introduced.
1890 America George W. Cobb preserving company perfects the sanitary can. It takes two more years before sanitary ends are adopted for food canning in Europe.
1909 America Tuna canned
1914 Introduction of continuous ovens to dry inked tinplate
1926 Ham (SPAM) canned
1935 USA Wales Introduction of the beer can.  “Krueger Cream Ale” – Richmond, Virginia.
Felifoel Breweries Wales
1957 Aluminium introduced into cans
1959 First all-aluminium beer can
1960 Easy open cans introduced
1964 Development of two piece can
21st century Worldwide Three piece can continues to be in use across the world

Penny Laurann
penny@jaymac.co.uk

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