The applicator module on a label printer applicator has what seems to be a simple task to perform. It grabs a label as it leaves the printer and then applies it to the correct position on the object to be labeled – this might be a pallet, a box or some other object.
Of course, a lot of thought goes into the applicator module design, because of the multitude of ways the product might need to be labeled – a single label on the side, on two adjacent sides, corner wrap, etc. In most cases, the labels are transported and applied using vacuum or a flow of air to hold the labels against a pad or belt until applied to the product.
Traditionally, these vacuum pads would utilize pneumatic cylinders to control the movement to the product, although there has been a trend of late to switch to electronically powered solutions, using servo or stepper motors. Which is best for your application?
Here at ID Technology, we build label printer applicators of both types, heavy duty pneumatic applicators as well as servo powered electronic applicators. For the majority of our applications, we prefer to use the pneumatic solution. Why is this?
Let’s face it, pneumatic cylinders and valves have been around forever (I tend to think of it being an Industrial Revolution technology), while servo motors are newer and more trendy. Does newer equate to better? Let’s look at some advantages and disadvantages of the two systems.
For me, the greatest advantages of the pneumatic solution is robustness and simplicity. By specifying high quality cylinders and valves, the applicator can be designed to work for long periods of time with virtually no maintenance. We have ID Technology labeling systems that have been working hard for over 13 years without needing to be repaired.
For electronic applicators, the biggest advantage is that the system doesn’t need to plug into plant air. We are often told that plant air is expensive to produce, so having a system that doesn’t require it must be good – right?
This can certainly be true to some extent, but let’s try and put things in perspective.
On a pneumatically actuated label printer applicator (LPA) the air has three (or four) main jobs to perform.
When the label is peeled from the backing liner after leaving the print engine, it doesn’t always peel and feed onto the vacuum pad in a nice controlled manner – the labels have a tendency to curl and not cooperate with laying flat on the pad. In order to keep the label flat against the vacuum tamp pad, until the vacuum has it under control, an air assist tube is usually used.
The air assist tube is a tube (plasma coated to prevent labels from sticking to it, in the case of an ID Technology machine) with small holes that is used to accurately direct the label against the pad, using compressed air. To minimize the air usage, the valve controlling the air assist is only actuated while the label is feeding.
The vacuum needed to control the label on the tamp pad is often created using a venturi system – again, this is only in use while the label is on the pad.
Once the label is safely in the correct position on the vacuum tamp pad, the applicator module uses air actuation to move the pad and label close to the product that needs to be labeled.
This then brings us to the fourth use of air on the label printer applicator. On a tamp/blow unit, a jet of air is activated for a very short period to blow the label against the product. This ensures that the label is properly adhered and doesn’t remain on the pad. It is also helpful for (very common) occasions when the product might not be exactly lined up with the applicator, or perhaps is a little uneven.
On an electric tamp machine, alternative ways to achieve these features must be employed.
An electric fan replaces the label feed air assist and another provides the vacuum or air flow to hold the label on the pad. One or more stepper or servo motors (along with the associated controls) has the responsibility to move the label to the product.
The one pneumatic feature that is not available on an electric applicator is the tamp/blow. The electric machine has no way to send a jet of air through the tamp pad so to apply the label to the product, the pad has to hit the product every time. While the electric machines use trick such as flexible tamp pads to try and overcome this, a tamp/blow solution generally works better in the real world.
|Direct label onto tamp pad||Air Assist tube – Plasma Coated non stick||Electric Fan and control|
|Hold Label on tamp pad||Vacuum generator||Additional Electric Fan and control|
|Move tamp pad to and from product||Robust air cylinder and valve||Stepper/servo motor; Stepper/servo Control board; linear slide; Sensors; Power Supply|
|Blow label onto product||High speed valve||Not available|
Whether for simple tamp applicators or systems that can apply up to 3 labels to different faces of the product, we have a simple durable option.
For some special jobs (such as our 350EHS machine that can label the tops of boxes even if the height varies by over 2 feet) we do use the electronic servo system. Even with our electronic machines, we prefer to use the tamp/blow system so the pad doesn’t have to hit the product each time.
A big part of our focus at ID Technology is to offer our customers the best, most cost effective, solutions possible. That’s why we like our designs to be open and repairable as much as possible and why we can provide both electric and pneumatic based label printer applicators.
Want to enhance you labeling operations? We have years of experience in label printing and application and would love to help!
Call ID Technology toll free at: 888-438-3242 Option#3 or you can contact me directly at firstname.lastname@example.org
Source: Labeling News