Buyer’s Guide: Rollstock Vacuum Packaging Equipment
“Knowing the rollstock equipment available will help you decide what best meets your packaging requirements”
Efficiency is critical when vacuum packaging products in bulk for optimal shelf life. Often times, a chamber sealer is used but these machines are very manual in nature, they require hand loading of vacuum pouches, and careful placement of the loaded pouches across seal bars. The cycle time on most chamber sealers is 30 seconds or more and once a cycle is completed the product must be removed at which time labeling may be required. Each of these steps adds up and with labor costs rising, business owners are searching for a solution to increase efficiency.
In many cases, the solution is a machine that is often referred to as a rollstock or a thermoformer. For the purposes of this article, we will use the term rollstock, as an industry term when referring to these machines. A rollstock packaging machine is constructed with suitable features that cost-effectively exceed expectations to accomplish your vacuum packaging goals. Not only do these machines improve the look of your vacuum packaged products, but they will pay for themselves in labor savings alone.
Factors to Consider When Choosing a Rollstock Machine
Variations exist between the rollstock machines including our JVR-certified rebuilt Rollstock machines and our manufacturing partner, Promarks. Knowing these will keep you informed on what features vary between machines to determine what best meets your packaging needs.
1. Die size – The die size will determine what divider sets or package configurations the machine can accommodate. The first step when determining the appropriate die size would be to measure and record the dimensions of the products you are packaging. Once this information is gathered, you can explore the available die sizes to see which will best fit your products. From here, we would determine the forming and non-forming film web widths that your machine will require for future film purchases.
2. Machine dimensions – Since these are large units, the storage space you have available will play a role in the size of the machine you can accommodate. Ultra-compact rollstock machines, such as our PRS Mini series, can be as short as 7’ in length or larger, whereas high-production units can exceed 20’.
3. Cycle times – This will range depending on the machine design, options, and required vacuum draw. Typically, rollstock machines can run as slow as necessary or up to 12 cycles per minute.
4. Does your application require gas flush? – We would determine whether this meets your packaging needs before ordering because there is no simple way of adding gas flush functionality. Typically, a pin-gas die set would be required when adding gas to your rollstock package.
Basic Overview of Rollstock Equipment
Knowing the rollstock equipment available will help you decide what best meets your packaging requirements. Additionally, you’ll want to make sure there is adequate support and availability of spare parts to limit down time when an unexpected failure occurs.
As you read through, you can refer to the image below to help identify key components of the rollstock packaging machine.
1. Forming Station
Forming Films
Bottom Web (forming web): This is provided in the spec document that the manufacturer will provide at the time of determining the die size of your rollstock machine. The forming web will always be slightly wider than the machine’s web width so some excess material is available to be held by the transport chains for advancements.
Thickness: Due to the thinning of the film during the forming process, we recommend that our customers choose a film thickness based on the three considerations noted below. JVR Industries stocks a range of 3-9 mil forming films as we focus more on flexible packaging, although the thickness can be found up to 16 mil for semi-rigid packaging.
1. As you increase the formed pocket depth, you’ll want to consider increasing the thickness of your forming film to ensure package integrity.
2. If you package meat containing bones or other products with sharper edges, consider a thicker forming film according to the puncture resistance required.
3. A thicker film may appeal as a higher quality package if packaging appearance is a priority.
Divider Sets
What is a Divider Set: Divider sets include both the forming insert located in the forming die and the seal grid located in the sealing die. Configurations are distinguished by the number of tracks and rows. Learn this terminology here.
The Roll of a Divider Set in Choosing a Rollstock Machine: Our sales department can discuss with you how to determine the divider set configurations you will most commonly use. Knowing the configuration sizes needed will, in turn, determine what rollstock die size you require.
Changing Out Divider Sets: Expect to spend 4-8 minutes to change over to a different divider set. Depending on the configuration, you may need to change over the rotary knives, crosscut knives, and product support rails.
Forming Die
The forming die lift and forming head work together to mold the forming film into pockets at the forming station. When the gripper chains advance the forming film forward into the forming station, air compression manipulates the film upwards to contact a heating plate located on the forming head. This causes the plastic to become moldable. The air compression system reverses quickly and pressure then forces the film into the forming mold to create pockets. The forming die will then vent and open, allowing the gripper chains to advance the pockets to the loading station.
2. Loading Station
After the film has advanced from the forming station, your products can then be placed into the formed pockets at the loading station. Programming in a delay between cycles may be useful if more time is needed between film advances.
3. Sealing Station
Top Web (non-forming web): Each machine manufacturer will provide specs for the film width, core size, and maximum roll diameter. This information can then be used to source film from a reliable supplier.
Thickness: Since this film type does not go through a forming process, 2.5/3 mil film will suffice for most applications. However, heavier 4 or 5 mil films may be appropriate to provide higher puncture resistance for bone-in meats.
Customization: We also provide customization to amplify your packaging appearance. Customize your non-forming film by incorporating easy-to-peel film, prints, stamps, labelers, and colors! Call us to find out your options!
Sealing Die
Includes the seal head and seal bucket assembly. Non-forming film is applied as the top layer over the pockets. Simultaneously, the vacuum seal process occurs. Valves open while the vacuum pump removes up to 99.8% of air from the packaging. If applicable, inert gas is injected. The seal plate lowers contacting the seal grid and seals the packaging creating an airtight seal.
Seal Plates
Various options are available for different packaging applications including total seal plates, perimeter seal plates, and peel corner seal plates. Read about our Rollstock Seal Bar Types to learn your options!
5. Cutting Station
Rows
Two options are available to cut the length of the rows. Most commonly, guillotine style knives cut across the width of each row. Another option is a flying knife that works by “flying” across each row with a fine razor blade. The simplicity of a flying knife system makes them more economical but are not recommended when cutting thicker films or heavy products as it will result in film sag.
Tracks
Rotary knives separate packages in the “track” direction and remove the outer edge that is held by the transport chains. As a result, this system produces a clean and trim package that enhances the look of your package products.
6. Trim Scrap Removal
The trimmed outer edge of film is collected by the trim scrap removal system. Suction or motorized winders are two common methods. Both systems have advantages and disadvantages that we would be happy to discuss!
Have Questions or Would like Personal Consulting?
Our team is glad to spend as much time as you need communicating about rollstock vacuum packaging machine equipment that will meet your specific requirements! Simply email us anytime or call us during our business hours from 8:30 am – 5 pm on Monday-Friday!
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