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This is the third article in a series of blogs intended to educate users new to flow wrapping as well as to help experienced users looking for a quick reference. It explains the basic calculations used to determine film dimensions to flow wrap a specific product.  (Read the other articles in this series Principle of Operation of a Horizontal Flow Wrapper and Sealing Fundamentals of Horizontal Flow Wrapping)

Cut-off Length (package length)
First of all it is important to determine the correct cut-off length. This is especially critical for registered film that incorporates graphics that need to be centred on each package. The diagram and formula below explain how to calculate this distance.

Cut-off length

Cut-off Length = Product Height divided by 0.86603 + Total Crimper Width + Total Product Length

 

Web Width
Secondly, you must determine the film web width.  Again, one the key inputs for this calculation is the product dimensions. For products with more variable dimensions, such as bakery products, the film width must be increased to allow for bigger variations. This however, creates looser packs with wider finseal areas.

product dimensions

Web Width = 2 x (Product Width + Product Height + Fin Seal Roller Height + 5mm)

The 5mm (o.2″) can be explained by the distance (including the height and thickness of the deckplates) from the product to the fin seal rollers and some extra film to assure good tracking in the fin seal rollers.  Common fin seal roller heights are 6, 9 and 15 mm.  Together with the 5mm of film for tracking purposes, this results in finseal widths of 11, 14 and 20 mm respectively.

Use the formulas mentioned in this blog for a starting point only. Testing on your machine with actual product and film is necessary to determine film sizing and cut off.

More explanation on the basic calculations used to determine the film dimensions and flow wrapper configuration can be found in Bosch’s Guide to Flow Wrapping. Feel free to download it under the “Links and Downloads” section on the Pack 101 flow wrapper webpage on the Bosch Packaging website. This guide contains other sections to assist users in initially setting up their wrapper, changing over to new products, or solving problems common in flow wrapper operation.

Bosch at Expo Pack 2013

The Bosch booth at Expo Pack, Mexico in 2013.

Visit Bosch at Expo Pack in Mexico City, June 17-20 at booth #1716 in the PMMI pavilion.

Bosch will showcase two new entry-level solutions at Expo Pack for small to midsized businesses looking to automate their packaging. The first, is the new Pack 101 horizontal flow wrapper.  It is ideal for this segment because it packages the widest product size range currently available on wrappers of comparable price points. The machine features a low-maintenance, all-servo-motor design that has the flexibility to facilitate quick and easy setup and changeovers, while reducing product and film waste during operation.

The second new entry-level solution on display at the show is the SVI 2600, a vertical form, fill and seal (VFFS) machine designed for growing confectionery, snack, grains, and other manufacturers. Reliable, high efficiency operation is guaranteed with a number of the same Bosch technologies found on higher-end baggers, such as servo-driven cross-sealing units, vacuum-film belts, and Beckhoff/Rexroth controls. The intermittent motion bagger can produce pillow, gusseted and block bottom bags at rates of up to 120 bags per minute and is available with options such as hole punch and gas flushing.

In addition, Bosch will display a Doboy B-550M medical pouch sealer with an integrated InteliJet TS thermal ink jet printer.  Designed to meet the medical packaging industry validation requirements for sanitary and sterile applications, the Doboy B-550M medical sealer regulates and displays temperature, pressure, and speed. The result is a secure, hermetic seal essential for medical pouches and other sanitary packaging. With all Bosch medical heat sealers, support is provided for qualification and validation.

Last but not least, Bosch Packaging Services will be showcasing a few of it aftermarket products including Format, Size and Change Parts for Bosch Wrappers as well as Remanufactured Equipment.  Throughout the last year, Bosch Packaging Services has developed a Remanufactured Equipment business where a team of highly skilled engineers, project managers and technicians, concentrate exclusively on building and rebuilding upgrade panels, assembling kits and performing complete machine remanufactures of customer equipment as well as equipment planned for future resale.

This is the second in a series of blog articles intended to educate users new to flow wrapping and serve as a quick reference for experienced users .  It explains the sealing fundamentals of horizontal flow wrapping. This is useful in selecting the general type of packaging material and determining the machine settings that can be adjusted to influence the seal quality. (Read the first article in the series “Principle of Operation of a Horizontal Flow Wrapper“)

Generally speaking, two types of film can be distinguished: (1) heat seal film and (2) cold seal film. The choice of using heat or cold seal film depends on a variety variables, such as:

  • Product characteristics
  • Material costs
  • Required capacity/speed
  • Necessary barriers (Ultraviolet, Oxygen, etc.)
  • Hermetic seal strength or integrity

 Cold seal films consists of a base material (carrier) and a thin layer of glue. The sealing of this type of film is achieved by pressing the two layers of glue together. One of the advantages of this film is that it can be used at higher film speeds than heat seal films.   It also requires no heat to seal, so the lack of hot machine surfaces may be beneficial when dealing with temperature sensitive products, such as chocolate. However, there are some disadvantages.  Primarily that they can never offer the same protection and hermetic seal qualities as heat seal film.  They also need to be stored in a climate controlled room and lastly, the cost is generally higher than that of heat seal film. Therefore this type of film is less common than heat seal film.

Heat seal jaws cutting and sealing packages on a Pack 101 flow wrapper.

Heat seal jaws cut and seal packages on a Pack 101 flow wrapper.

Heat seal films are often multi-layered and consist of an outer coating that prevents the film from melting,  the core of the film such as polypropylene, and a sealant layer on the interior which has a lower melting temperature and bonds to seal the package together.  When high integrity seals are required, heat seal film offers the best alternative.  Generally, it is also less expensive than cold seal films.   Heat seal films are also offered in a wide range of laminations so that barrier properties can be optimized to meet product protection requirements.

The three important factors that should be kept in mind and controlled when producing a seal are:
(1) Heat: Temperature of the sealing surfaces (heat is not necessary with cold seal film)
(2) Dwell: Amount of time the machine jaws are in contact with the sealing material
(3) Pressure: Amount of pressure applied to the sealing material

Whenever a change is made in any one of these factors, one or both of the other two factors must be adjusted to compensate for this change. For example, when machine speed increases significantly, the dwell time will drop, so the temperature (and sometimes pressure) may need to be increased to compensate for this.

More details on optimizing sealing parameters and an overview of  different packaging films and their uses can be found in Bosch’s Guide to Flow Wrapping. It’s available for free download under the “Links and Downloads” section on the Pack 101 flow wrapper webpage on the Bosch Packaging website. This guide contains other sections to assist users in initially setting up their wrapper, changing over to new products, or solving problems common in flow wrapper operation.

Bosch is currently looking for six young people from across the globe to take part in the Bosch World Experience. Bosch will be sending participants on a 16-day trip around the world to visit well-known projects that Bosch is involved in. Destinations on this summer’s trip will include London, Panama City, San Francisco, Shanghai, and Singapore. Applications will be accepted between April 7 and May 16, 2014 at http://www.experience-bosch.us.

Bosch is more than you think
Six women and men will be travelling to three continents to discover the ways in which Bosch leaves its mark on the world with technologies that are “Invented for life.” “Many people are only familiar with a fraction of the solutions that Bosch offers to improve the quality of life and spark people’s enthusiasm. Bosch World Experience will offer its international participants an exclusive look behind the scenes of six major projects in which Bosch is involved, including in areas where one might not expect to find us,” says Karoline Hagen, a Bosch marketing manager, in describing the aim of the trip. Participants will learn, for instance, how container ships will soon be lowered and lifted a total of 26 meters in the Panama Canal’s new locks, which are equipped with Bosch Rexroth hydraulics. Each of the stops on the trip will include a full program of complementary activities. In London, for instance, Bosch World Experience participants will take part in a blogger workshop. And in San Francisco, they will take a tour of the city on e-bikes.

Involving the online community via social media
Participants will report on their experiences with posts, pictures, and videos on their social media channels. The online community can interact with participants via these channels, and thus also take part in the Bosch World Experience. Contributions will then be summarized in a blogumentary on a special website.
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Participants should have an affinity for social media and a sense of curiosity
Applications will be accepted starting April 7, 2014, at http://www.experience-bosch.us. Applicants must first register, answer questions on each of the destinations, and provide their personal details. They should have an affinity for social media and a sense of curiosity. Following the application phase, six participants from around the world will be chosen.

This is the first article in a series of blog articles intended to educate users new to flow wrapping as well as to help experienced users looking for a quick reference.   It covers the basic operational principles of horizontal flow wrapping. These principles are the same for every horizontal flow wrapper, often referred to as horizontal form fill and seal (HFFS) machines.

Every wrapper has an infeed conveyor, a film feed assembly (backstand), a film forming area (former), bottom seal (finseal), a cutting head and a discharge area. Food and non-food products created by processing equipment, are placed on the infeed conveyor of the flow wrapper. This can be done by hand feeding or by using an automated feeding solution. As the infeed conveyor delivers product to the forming area, film is drawn from the film feed assembly into the forming area, where a film tube is formed around the product and a finseal is created. The film tube and the product are then delivered to the cutting head. The cutting head creates the end seals while it cuts apart adjoining wrapped products into individual packages, and delivers the packages to the discharge area. From the discharge area, the packages can be either cartoned at a packing station or accumulated for packing at a later time.

Flow Wrapper Principle

 

More details on the basic principles of horizontal flow wrapping can be found in Bosch’s Guide to Flow Wrapping.  Download your copy today under the “Links and Downloads” section on the Pack 101 flow wrapper webpage on the Bosch Packaging website. This guide contains other sections to assist users in initially setting up their wrapper, film selection, changing over to new products, or solving problems common in flow wrapper operation.

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