FAQs about packaging and contract packing

What is form, fill and seal? (FAQs about packaging and contract packing)

What is form, fill and seal?

Form, fill and seal refers to a method of packing where the bag is formed, then filled and then sealed by one packing machine and in one process. This means bags, sachets or pouches do not have to be supplied before the packing process. Rather, the raw material is run into the machine along with a plastic film which then becomes the bag or sachet. Form means the bag is created, filled means it is filled with a raw product and sealed means it is sealed shut.

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What is FFS technology?

FFS technology refers to form, fill and seal machines where a bag or sachet is created (formed) out of a sheet of plastic film, then filled with a raw product and then sealed to create a finished packed product. FFS technology is carried out by a form, fill seal machine. There are two types of FFS – vertical form fill seal (VFFS) and horizontal form fill seal (HFFS) which is also known as flow wrapping.

What is a FFS machine?

A FFS machine is a machine that carries out form, fill and seal packaging. There are two types of machines – vertical form fill seal machine where the product is poured in from the top and horizontal form fill seal where the product is pushed along and then packed.

What is BFS technology?

BFS technology stands for blow, fill and seal technology. It is similar to form, fill, seal technology, however the receptacle is formed by blowing air into the plastic, rather than putting the raw product in. It is commonly used where sterile packaging is necessary.

What is an aseptic package?

An aseptic package is a type of packaging that maintains the sterility of a product. Aseptic packaging is often made of a mixture of paper, polyethylene and an aluminium inner layer. The product in an aseptic will have been exposed to a very high heat for a very short amount of time, then rapidly cooled and filled into a sterilised container in a sterile environment.

What is aseptic canning?

Aseptic canning is the process of canning where the sterility of the product is preserved. The can will be pre-sterilised as will the raw product. The can is filled and sealed in sterilised environment. It is also known as high-temperature-short-time (HTST) processing.

What does retort packaging mean?

Retort packaging involves filling a pouch or can and heating it to very high temperatures to make the product sterile. It is an alternative sterilisation technique to aseptic packaging.

What is a blister package?

A blister package has a card back and a plastic protective bubble stuck to the front of the card in which the packaged product sits. The bubble can be a uniform shape, for example a semi-circle to protect tablets or it can be a customised shape made to fit the product.

A blister package is different from a clamshell package. A clamshell package can still have a card within it, but the cardboard is trapped between two bits of plastic, which are joined, and hinge at the bottom or side of the pack. The card can be printed and carry marketing blurb, instructions for use or other text.

What are the different types of packaging?

There are lots of different types of packaging. Some common types of packaging are:

The type of packaging used for different products comes down to things like:

  • Budget.
  • What kind of protection and sterilisation the product needs.
  • What kind of aesthetics the client wants and how it fits with their brand.
  • How heavy the packaging is and how small it can pack down for transportation.
  • Whether it needs to be tamper-proof i.e. it is easy to tell if someone has opened it. It is not easy to tell whether someone has opened a cardboard box, but it is very easy to tell if someone has opened a blister pack.


What is skin packaging?

A skin package has a card back which is then covered with a thin layer of surlyn flexible film that it is vacuum sealed using a mix of heat and vacuum so that it tightly covers the product, and fixes it securely to the card. To aid this process, the card is perforated to allow air through it.

What materials are used in food packaging?

There are number of materials used in food packaging. Each is chosen based on the amount of protection they offer the particular food and the budget of the client. The material that touches the food is called the “food contact material” and this often needs to be sterile, or the entire package has to be sterilised using techniques such as aseptic packaging or retort packaging. The following is a breakdown of how the use of different materials is distributed in the food packaging industry:

  • paper & board – 34%
  • rigid plastic – 27%
  • Glass – 11%
  • Flexible plastic – 10%
  • Beverage cans 0 6%
  • Other metal – 9%
  • Other – 3%

Source: Food Packing Forum

The outer material is often coated with an inner layer which is the food contact material. Below is a breakdown of common combinations of the main outer material and the food contact material:

Main material


Drink cartons

Aluminium cans

Food contact material

Glass and metal closure

Laminated plastic

Grease-proof coating

What is a heat sealer?

A heat sealer is a machine used to seal plastic packaging. Heat and pressure is applied to fuse the two layers of plastic together.

What is vacuum packaging?

Vacuum packaging involves using a vacuum to remove air from a package to form a tight film around the product that is then sealed. Vacuum packaging is often used to increase the shelf life of products, especially food products, removing the majority of oxygen to decrease speed of deterioration.

An alternative to vacuum packing is modified atmosphere packaging, which also increases the shelf life of products.

What is stretch wrap used for?

Stretch wrap is used as outer packaging to protect a product. It’s wrapped around a bulk of products to keep them tightly bound.

What kind of plastic is shrink wrap?

It varies, but polyolefin (POF) is a common type of shrink wrap, as is PVC shrink wrap.

What does the gauge on stretch wrap mean?

The gauge is the thickness of stretch film. 1 gauge is one-hundredth of a millimetre, so 100 gauge is one-millimetre thickness. The most common gauge for stretch wrap is 80. Heavy boxes and bundles (loads up to 2800 – 3000 lbs) will work better with a gauge of around 100. As a general rule, the lower gauges are best suited to lighter, smaller loads. As the gauge increases the strength of the wrap increases making it more suitable for heavier loads, or loads with more sharp corners.

What is retort sterilization?

Retort sterilization involves putting food into a special pouch called a retort pouch that can withstand high temperatures. The pouch is exposed to high temperatures or hot steam to sterilise the food.

What is a flow wrapper?

A flow wrapper is a machine that pushes a product along a conveyor belt, wraps it in film and seals it at either end in one process. This creates a kind of sachet around the product. Find out more about flow wrapping here.

What is a clamshell package?

A clamshell package is a type of blister packaging. It consists of two bits of plastic hinged together. The front plastic has a bubble shape in it that sits around the product to protect it. The back is normally just a flat sheet. Clamshell packages often have bits of cardboard sandwiched between the two bits of plastic that explain what the product is. To find more about clamshell packaging read our guide.

What is blister packaging made out of?

Blister packaging is normally made out of PET or PVC plastic. PET is very clear strong and holds shape well so is normally favoured. PVC works fine, but is slightly less transparent.

What should be in a contract packaging agreement?

A contract packaging agreement is a legal document that outlines what work a contract packer will undertake for you. It doesn’t really matter what discussions have taken place beforehand – if the work isn’t detailed in the contract then you have no recourse to ensure it will happen.

The agreement must have certain parts in it that are common to all contracts, and some parts that are specific to the contract packing industry. A contract packaging agreement must have:

  • The full names of both parties
  • The date of the agreement
  • The time period covered by the agreement
  • A point-by-point summary of what has been agreed upon
  • Price details
  • Who is responsible for the conformance of materials used
  • A commitment to quality control procedures
  • Exit clauses
  • Signatures and names of people who sign on behalf of parties. The names must be present for it to be legitimate; the signature is not enough
  • Signature and names of witnesses

To find out more about what should go into a contract packing agreement

What is WePack’s delivery process?

We offer sophisticated, fully-tracked delivery services whether you need international delivery or something more local.

For delivery local to us, we have our own fleet of vehicles to fulfil your needs. For international delivery or anything further afield we work closely with reputable haulers to provide fully-tracked worldwide services.

The process is simple. If you require delivery it will be included in your contract with us. We organise all aspects of it and will let you know all the consignment details. When the goods are on their way you will receive a notification from us, we also provide you with tracking references so you can keep up to date on the movements of your products.

Can you store my products?

Yes, we can offer long-term and short-term storage and our facilities are considered amongst the best in the UK. We have an in-house state of the art system to keep track of your products and we carry out monthly stock quality checks to ensure everything is in order.

Find out more about our storage capabilities here.

Can you fill aerosols?

Currently we cannot fill aerosols, but we can recommend a company that can.

Can you pack beverages?

Yes, we can pack both non-alcoholic and alcoholic beverages.

What is a contract filler?

A contract filler is similar to a packer but specialises in contract filling services specifically. They may offer specialist mixing services, but won’t necessarily offer the range of services that a contract packer can offer. WePack are both contract packers and contract fillers!

Do you offer a tablet counting service?

Yes, we offer a full tablet and gel capsule counting services for packing into stand up pouches, bottles and jars.

To find out more about our tablet counting service please contact WePack on 0115 852 9000 or get in touch via the form below.