The knife is attached to a heat press and can be programmed to place precise amounts of product into the pouches before the product moves onto the next stage in the process. The type of vertical form fill seal machine being used will determine what type of knife you must purchase. Vertical form fill seal knives are usually made from stainless steel for food safety, whilst providing maximum strength and durability.
The components within a vertical form fill seal machine must be of the highest quality and able to offer maximum performance over the long term. These production lines can be extremely demanding and fast-paced, so the equipment must be able to withstand prolonged usage.
The same goes for the knives used with these machines, which are also a huge factor in quality control on bagged items. Poor quality blades that soon deteriorate can cause quality issues, interruption to your production lines and downtime which can affect output and increase your costs.
When choosing vertical form fill seal knives, there are a few considerations:
The knives that are used for the VFFS process play a major role in its success. With any operation, it’s important to choose quality over quantity: if you use low-quality knives then they will need frequent replacement and can cause delays in manufacturing, equipment malfunction or quality problems with products. However, with high-quality blades made from the right steel grade and purchased from MRMK, your operations run smoothly and efficiently. The most important factor when choosing blades is making sure the blade is of good enough quality even after hundreds of thousands of cycles through packaging machines.
Reliability of the Supplier
The best suppliers not only provide ‘off the shelf’ knives to buy, but they also offer custom made options to meet the exact specifications of your machinery. It’s also important to be able to find stock when you need them. An unexpected spike in demand or a change in ways of working that increases capacity may mean that yo need knife replacements quickly. Not receiving your blades for days or even weeks can result in bottlenecks and downtime which can cost your business money if this happens frequently.
Vertical form fill seal knives are intended to be an integral part of the production line. To make sure they continue working properly, it is essential that operators know how and where to get ongoing support for their VFFS knives after installation. The best suppliers will have a dedicated after-sales support team who are available to respond to queries and troubleshoot any problems.
Uses of Vertical Form Fill Seal Knives
The vertical form fill seal machine will go through a series of stages as it performs its various functions. These include:
Step 1: Dispensing Film
A roll of film (in a similar design to that of kitchen roll wrapped around a cardboard tube) will be fitted to the machine. This roll is referred to as the roll-stock. Films can be made from many different materials including paper and polyethylene laminates through to aluminium foils depending on the product to be packaged. These films may also have specific properties such as protecting the contents from UV light or preventing moisture from getting inside the packaging and spoiling the product.
The machine will pull the film off the roll and onto a transport belt. Some machines will also feature sealing jaws which will secure the film in place while pulling it downwards through the machine. The unwinding process can be improved through the use of a motor-driven surface which is particularly beneficial when the machine must cope with heavy rolls of film.
As the film unwinds, it is pulled from a roll and over one of several weighted pivot arms. The arm incorporates small roller-like features which make it easier to keep any movement under tension so that there are no unwanted side movements as they go through the process.
In some systems, there must be availability for the film to feature printed graphics or branding. Where this is required, the film will be fed through a printing unit which is either inkjet or thermal. The printer will then transfer any print such as dates, text or codes onto the film as well as graphics and other branded items.
Tracking and Positioning
When the film is passed through the printer, it will reach what is called the registration photo-eye. This is a feature that will identify any registration mark on the printed film, keeping the film in the right position to enable precision cutting.
Once the film is correctly positioned, the film will enter a forming tube assembly. The film is then sealed with a flat seal and fin seal. Lap seals are more aesthetically pleasing, and they are also more effective in terms of resource use because they use less material.
Bag Filling and Sealing
A hot, vertical seal bar will bond the two layers of the film together. However, heat sealing is not an option for certain products that are heat sensitive. This type of seal is called ultrasonic sealing which will use vibrations to generate heat only within the area of the seal, ensuring that the condition of the contents within the packaging remains intact.
Once the product has been deposited into the bag, a sharp knife will cut the bag. Depending on the capacity of the production line, the machine type and bag, vertical form fill sealing equipment can handle between 30 and 300 cycles in a minute.
Vertical bagging blades are a convenient tool used for the packaging industry and are found in many different packaging and production lines including confectionery, cereals, snacks and more. When it comes to receiving blades, it is important that you receive your blades promptly to minimise downtime.
Our knives are manufactured to the highest specifications and are wear-resistant to counteract the stresses of everyday use.
Speak to MRMK for further information on the vertical form fill seal knives
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