As the demand for different easy-to-open packaged products such as packaged food and canned beverages increases, the need for a more efficient method of packaging to meet this demand is also increasing. This includes the use of an automated tin canning machine to produce tamper-evident seals to ensure the safety of the consumers. Thus, manufacturers also need to innovate their products to keep up with this demand.
However, choosing a suitable can sealing machine for a certain application can be challenging as different tin/can seamer is needed for handling different types of products. Especially if you are new to the industry and know nothing about these machines. If you are having the same problems, then you are in the right place! In this article, we will help you familiarize yourself first with the basic principles of the machines before you start purchasing one.
A can seamer machine is used to hermetically seal a lid to a can body during the packaging process using a double, or sometimes triple, seam. The lid is usually made from tin-plated steel. Meanwhile, the can’s body can be made of paper (like whiskey cans), tin, aluminum, PET, plastic, or glass. The formed seam is usually leak-proof. However, this still depends on the type of products being packaged.
A can sealer machine can either have one or more seaming heads in which each head is considered as a separate machine. The most popular machines have 4, 6, or 12 heads with the number of heads increasing with the machine’s speed for production lines requiring higher demands.
Moreover, you can automate can seamers to streamline the packaging process to improve production efficiency and save on labor costs. Apart from these, you can also enjoy other benefits of integrating an automated packaging machine in your production line.
A can seamer machine has the following major parts:
The machine’s seaming chuck holds the can firmly together with the seamer turntable on the other side during the process of double seaming. It also protects the can from the pressure of the first and second seaming roller operations. The chuck’s dimensions will depend on that of the can’s diameter being sealed. Thus, different chucks are needed for different can diameters.
Also known as the compression plate, the seamer turntable which is a spring-loaded disc spins freely and gives support to the can body during the sealing process. It centers the can body in the correct position and transmits the pressure from the spring to the chuck through the container. Also, the base plate’s shape will depend on the can’s shape, allowing the can to be inserted into it correctly.
Can sealing machines consist of two seaming rollers having concave profiles that help in creating double seams. Depending on the speed of the machine, it can have one or more sets of seaming rollers.
The first seaming roller’s profile and its position with respect to the seaming head are critical in producing a reliable double seam. The majority of the double seaming problems encountered arise from the incorrect setup of the first seaming roller operation. On the other hand, the second seaming roller’s groove will have a shape similar to that of the produced final double seam.
Can sealing machines, such as nitrogen filling vacuum sealing machines, perform the sealing process in sealed chambers especially when removing the oxygen from the containers prior to the sealing process. The removal of oxygen takes place inside a vacuum room under vacuum pressure. This maintains the integrity of the product inside.
The ejector is a rod equipped with a small disc at the end. It emerges at the seaming head’s center and moves vertically in a cam action. Also, it contributes to maintaining the proper placement of the lid on top of the can.
All automatic can sealing machines have cap feeders that take a lid from a pile of closures and transport the lid to the sealing station before the sealing process.
Every can sealer machine has its own way of transmitting the filled containers into the machine. But, the most common ones are power conveyors that continuously move the containers from one station to another during the sealing process.
Automatic can sealer machines will not need that much interaction with the operator during the sealing process because the majority of the processes are done automatically. The operator only needs to supply lids in bulk to the machine. Thus, these machines are recommended for businesses requiring high production demands. They often work with automatic can filling packing machine.
For semi-automatic can seaming machines, the operator needs to initiate the can seaming process usually through a finger or footswitch for each sealing cycle. These machines typically seal one container at a time so they are recommended for small productions or home use.
Rotary can seaming machines perform the sealing operation while the containers rotate on their axis. Fully automatic can seamers will usually have these types of designs allowing them to seal containers at fast speeds. Thus, making them ideal for industries with big operations.
Also, rotary can sealers are often used for seaming round cans and are equipped with up to 18 seaming heads revolving around a single head.
On the other hand, non-rotary can seaming machines allow the cans to remain stationary through the seaming process. This avoids damage to the cans being sealed and the products contained inside. Thus, making them ideal for dealing with liquid products packaging as they prevent spilling.
While rotary can sealing machines are mostly used for round cans, non-rotary ones are used for other shapes like oval, oblong, and rectangular cans. Also, most semi-automatic can sealing machines have non-rotary machine designs.
Before we proceed further on how can seaming machines work, knowing the common double seam terms first might help you better understand the double seaming principle.
Now, onto the double-seaming process. A can sealer machine creates reliable seams that ensure the absence of product leaks through a process called double seaming. The machine attaches the “end” or lid to the can body in three stages of operation: compression, first roller operation, and second roller operation. But of course, before the double seaming takes place, the containers need to be filled with the product first.
The compression stage provides the force necessary in holding the can body against the seaming chuck which is gripping the can’s lid in place for attaching to the can body later. The seamer turntable pushes the can body upwards towards the chuck. Do remember that in vacuum can sealing machines, the oxygen inside the container is vacuumed first before the double seaming process takes place.
When the lid is already on top of the can body, the process of double seaming initiates which interlocks the lid and can body’s flanges together to form a hook. The interlocking process is done using two seaming roller operations as will be discussed in the succeeding stages.
The first roller operation stage is a crucial one because the resulting hook will impact the final double seam’s integrity. The processes below take place during this operation:
For the second roller operation, the following processes are done
Another type of can seaming machines are aluminum foil induction can sealing machines that seal containers through a non-contact process. Once the containers have been filled and capped, they pass underneath the machine’s sealing head for the sealing process. An aluminum foil induction can sealing machine’s head houses a conductor placed inside a plastic casing.
The heat induction sealing process involves the application of a current that heats the multi-laminate liner put inside the container’s plastic closure. The liner is composed of four layers:
The layer of polymer should match the container’s material so that when it is heated, it efficiently seals the container’s lip.
The points below summarize the sealing process:
Now that you are already familiar with the parts of a can seaming machine and how it works, let us now proceed on the basic things you need to know in setting up a can seamer machine.
Just like art, setting up a can seamer requires perfect adjustments of several settings to form a correct seam in which most do not follow carefully enough, causing unscheduled stops and bad seams. A can sealer that is completely set up should have the following features:
The first steps you need to do when setting up your can seaming machine is to:
Next, set up the lifter plate pressure along with the pin height.
Then, install the first seaming roller and test it by running sample cans on it using the SEAMetal system and then validating the resulting data.
Finally, put the second seaming roller into place and then test the sealed cans visually for double seam defects. If any defect is found on the resulting cans, you need to redo the whole set up again to correct these.
You can set up the seaming rolls using two methods:
These methods are used in setting up the rolls in their optimal position which are usually identified using a special mark found on the sealer.
Using a feeler gauge when setting up a seamer is a go/no-go technique. In this method, you enter a feeler gauge that is smaller/thinner than the one you are looking for into the gap you are measuring. Then, you need to verify that a thicker gauge will not enter the gap. This method gives a rough estimate of the distance between the chuck and the roll.
But, do note that this solution cannot prevent accidents in the set up that can damage the rolls, bearing, and chucks. Also, it does not guarantee the correct set up of the rolls resulting in unexpected damage between the chuck and roll.
An alternative to the feeler gauge is the clearance gauge method. This instrument can test both the horizontal and vertical positions of the rolls to make sure that any damage will not happen to the seamer’s toolings. Moreover, it helps in identifying broken bearings and toolings while guaranteeing that the seamer set up is at the optimal settings.
To use the clearance gauge, just insert it into the can seamer machine. This is attached to the seaming head/chuck and then it produces a visual image of the gap between the roll and chuck.
Thus, letting you identify defects to properly set up the rolls. Check out the video below on how to do the clearance gauge method.
Can sealing machine manufacturers will usually provide instructions in setting up their can seaming machines. So it is better if you contact your can seaming machine suppliers for the exact instructions.
After setting up your can sealing machine to its optimal configurations, you can now start using it without any problem.
After setting up your can sealing machine to its optimal configurations, you can now start using it without any problem.
Choosing an appropriate can sealer machine for your application is crucial in ensuring that your production will be a successful one. So in this section, we will give you the key things you need to consider when selecting one.
The most important thing you need to do first when choosing any machine is to determine your specific requirements including the following:
Your production demand will determine what level of automation you will be needing for your machine. Also, different types of can seamer machines can handle different types of materials and products so you have to be definite about what you really need.
Can seaming machines even come in different sizes and layouts so you have to consider your factory’s space. Most importantly, think of your available budget but do not ever compromise quality because this will affect your production line in the long run.
You will not always be producing in small quantities. If you are planning to expand your business in the future, choose a can seaming machine which you can upgrade to accommodate your increased production requirements when the time comes.
Even if a can sealer machine has safety guards and your operators are trained very well, accidents in the packaging process might always happen. So, emergency switches are important on any machine including can seamers.
Lastly, it is also essential to know your machine’s durability and warranty period because this secures your rights and guarantees that your can sealing machine supplier will compensate you in case any issue occurs.
Being knowledgeable on any type of machine you are purchasing always helps in guaranteeing that you get the ideal machine for your application. It also ensures that you will have a problem-free production line. It does not only lower the chances of errors but also decreases operation costs which help you generate promising revenues that will benefit your business in the long run.
Levapack, a bespoke can packaging manufacturer in China including can seaming machines and can filling machine does not only make sure that you get solutions perfectly tailored to your needs but also ensures that you’ll have durable and high-performance machines thoroughly crafted. Contact us now for a perfect packaging solution!