Integrated and 'intelligent' label application lines

Production challenges will likely arise in the many application stages outlined above, and the key is how products are handled. Inconsistent product handling will make it very difficult to place labels consistently and accurately.

Items must be properly presented to the applicator system for labeling to take place, and for products to be taken away for onward handling. This can be achieved in one of three main ways:

1. The applicator is mounted over, or onto, an existing production line
2. The applicator is supplied as an integral unit with its own product handling or conveying system
3. The applicator is supplied on a pedestal stand or base which can be easily moved from one location to another for either semi- or fully-automatic application.

With the simpler semi-automatic label applicators, the product is manually loaded onto a table or plate at the applicator beak using either a hand-loaded jig fixture, by pushing the product along a short conveyor, or by hand feeding from another operation or a packing table. Product handling is largely manual and does not require sophisticated automation technology.

More sophisticated systems will be required as the line specification moves towards faster speeds, more automation, longer runs, application of two or more labels, the need to place labels in a recess or around corners and to control or orientate the packs. The product handling devices fitted to the labeler then need to become more sophisticated, incorporating conveyors, guide rails, belt assemblies, feed screws, hoppers, elliptical aligners, metering wheels and rotary turntables so the applicator can handle very small or difficult shapes, elliptical and rectangular containers, ampoules or vials, flat or flexible packs.

Verifiers, bar code readers, counters, visual camera/computer recognition, operator alarms, microprocessor-controlled electronics, and ever-more sophisticated operator and system controls may also be incorporated.

The three main methods for bringing the container or product to the applicator are:

Application on the production line. Many applicators can be supplied so that the application head is mounted in position over the customer’s existing production and packaging lines using a wide variety of moveable, static or adjustable brackets and angular devices to control the product and position it for application. Systems are quite flexible and can be built to be mounted above, to one or both sides and even under the production line.

Integral applicator systems. Applicators are frequently supplied as stand-alone systems with integral conveyor, container and product handling devices and with all the necessary interfaces. Both in-line and rotary systems are available.

Pedestal mounted and portable applicators. Flexibility in label application and the rapid deployment from one location to another can be achieved by the use of self-contained, pedestal, bench-operated or portable applicator systems. These can be quickly and easily moved to another production line without the need to be attached to a conveyor.

They may be used in semi-automatic or fully automatic modes.

Figure 5.1. shows a label applicator positioned over an existing conveyor production line to apply labels to the top surface of a product. Portable pedestal applicators can be installed anywhere along a conveyor line as required, depending on the specific application, with adjustable leveling pads fitted as standard.

We will now review some of the most common product handling devices and controls used with automated label applicators in a wide range of end-use applications.

Conveyor systems. There are various product handling conveyor systems used to present and control the product before, during and after the label application process.

Conveyors are available in different lengths, in single or multi-belt configurations, straight or curved (see Figure 5.2) and in a variety of different fabric types.

The most common types of conveyors are:

• Belt conveyors

• Roller conveyors

• Slat conveyors

• Flattop chain conveyors

Of the many types of conveyors, slat (most commonly used with in-line labeling machines. See Figure 5.3), flattop chain and belt conveyors are the ones used for transporting products during pressure-sensitive label application.

There are also various specialized conveyors available, as well as side alignment or wrap- around belts, top hold down conveyor belts, stabilization belts and rotary spacers.

Conveyor components. Conveyors used for product handling in label application lines will usually be on legs, either fixed or adjustable (casters optional), incorporate chains or belting, side supports and guide rails (see Figure 5.4) and, depending on the application, may also contain star wheels and scrolls. 

With a simple conveyor, guide rails will control the product reasonably well if the product is round, square, or rectangular. Oval shapes, such as shampoo bottles, cannot be controlled correctly without additional components.

Guide rail options include single or dual rails with adjustable in-and-out as well as up-and-down mounts (see Figure 5.5). They are used to direct the product through the system and ensure alignment at the peel tip for proper placement of the label.

The type of guiderail to be used must be selected after testing with the labels to ensure that there is no scratching or marking.

A sensor detects the product as it comes down the conveyor and triggers the application of the label at the proper time. Product handling must be tightly controlled to ensure accurate label placement.

Feed screws, also referred to as an In-feed Screw Assembly, enable products to be accurately metered, spaced and/or orientated on the conveyor line in preparation for label application.

Products will be consistently in the same position and at the same rate or speed as the conveyor at the end of the screw.

Single screw models are used for round products (as shown in Figure 5.6 top diagram), while dual screw models (Figure 5.6 bottom diagram) are available to accurately align and meter oval, elliptical, irregular and square products. Product can also be captured by a top hold down belt while they are still in the screws. 

In-feed screws are mainly used in primary labeling applications, such as consumer products, pharmaceuticals, home products and cosmetics.

Feed screws (Example shown in Figure 5.7), usually custom designed for each product, precisely control pitch and offer maximum product throughput at any given conveyor speed. In some cases, a single screw profile can be designed to accommodate multiple product configurations.

Most applications require multiple screw change parts.

Metering wheels are used to space products along the conveyor line just prior to label application. (This process can be seen in Figure 5.8).

Metering wheels do not provide product orientation and are mainly used on slower to medium-speed application lines.

In general, the higher the application speed, the more unstable the container, hence the need to move on to more accurate orientation and capture using top hold-down belts or a rotary platform (see also Figures 5.9 and 5.10).

Wrap belt assembly. Used with some label applicator and product handling systems to rotate or spin cylindrical products (typically a bottle) simultaneously to label application, so completing and finishing label adhesion to the product. The assembly consists of a coated timing belt and an adjustable padded back-up plate. They can also be used with square and rectangular-shaped products.

Foam rollers of different diameters and widths may be used as a secondary application device to ensure complete label adhesion to the product.

Modular options. Modular options include spacing wheels, product in-feed scrolls, in-feed and out-feed rotating tables.

Speed control. With label line integration it becomes important to track the varying speed of a product or web as production speeds ramp up and down. A bespoke speed control system, coupled with the stepper motor technology used in the label dispenser, is designed to ensure accurate labeling across the whole speed range of the production line.

Counting and tab inserting. With some integrated labeling lines it may be a requirement to incorporate a counting and tab inserting machine that counts exactly sheets of cartonboard, paper, plastic, inserting tabs if required.