Packaging: reliable welding with complex materials

Heaters

Reliable welding with complex materials: the custom heater with multiple independent zones

Problem

New heat-sealable films: an ever increasing issue

The material used in the packaging lines is the heat-sealable film. Ensuring uniform welding is becoming more and more difficult with the introduction of new more complex films characterised by differentiated thicknesses or multilayer structures.

These materials are indeed extremely sensitive to temperature changes, thus requiring a more precise and efficient heating sytem.

The Company we worked with already used custom heaters with differentiated power with good results in terms of thermal uniformity. However, the materials’ increasing complexity asked for an even more advanced and efficient solution.

CREI solution

After analysing the problem and our customer’s requirements, we have developed a custom cartridge heater with multiple independent zones.

We have designed a heater divided into 3 separate zones , each one with an independent temperature control . These 3 zones can be powered separately following the different welding needs.

Besides the heater is coupled with PT-100 multi-zone temperature sensors with the aim of monitoring and adjusting the temperature with high accuracy.

Thanks to this innovation, the customer has been able to realize a higly innovative new line of plants , improving welding quality and production efficiency.

ADVANTAGES

Several benefits have been brought to the customer by this implemented solution:

Increased temperature uniformity along the welding bar and no welding defects
Independent control of the zones allowing for varying temperatures to be set according to need.
Possibility of having unheated zones, useful for specific materials.
Accurate temperature regulation, thanks to the PT100 multi-zone probes.

Packaging: automatic filter packaging process for single-use infusion sachets

Packaging

Solving critical issues in the automatic filter packaging process for single-use infusion sachets.

Problem

The packaging process for single-use sachets is delicate: the automatic handling is managed by precision mechanics that dictate the fast pace of production, which can be summarised as several hundreds of operations per minute, always precise and constant. Once it has been filled with raw material, the container/filter undergoes a second processing step as it is placed in a further paper package.

It is at this stage of the process that the heating elements used in sealing the sachets make a series of seals around their perimeter. While one side of the pack is folded in on itself, the remaining three sides are heat-sealed by a mechanism powered by two cartridge heaters.

The solution used by the customer did not allow a sufficiently uniform heat distribution to achieve optimal sealing. The temperature difference between one soldering point and the next was a gap of 30°C.

CREI's Solution

Our many years of experience in the field of heaters with differentiated distribution has enabled a specific placement of power on specially manufactured cartridge elements. In this way, we achieved a distribution of heat over the soldering body and drastically reduced the temperature gap.

Benefits

Increased efficiency, fluidity and speed in the packaging cycle
Temperature gap reduction from 30°C to 2°C, so -93%
Increased welding speed/minute: +67%
Optimisation of energy efficiency with the same nominal power rating
Decreased active heating time

-0%

Temperature gap reduction

+0%

Increased welding speed/minute

Packaging: Vacuum Skin Packaging

Packaging

Vacuum skin packaging solution

Problem

The armoured round heater system in use did not allow for uniform heating of the dome moulds. This resulted in the sub-optimal thermoforming and sealing of the plastic film, as well as adversely affecting the integrity of the product to be packaged, altering its basic characteristics at the outset and significantly reducing its shelf life.

CREI's solution

Obtaining the desired result requires the use of heat systems that are able to guarantee the best heat distribution amidst significant suction flows that very often frustrate the perfect application of heat in the areas concerned.

The in-depth technical analysis of the data revealed the need to replace the large-section armoured heater element with other, less bulky heaters, which are pliable and flexible enough to be moulded to the shape to be packaged, and which are able to deliver the heat in the desired quantity and to the desired area.

This was achieved by inserting HMC series microtubular heaters with a square cross-section of 4×6 and 3.3×3.3 mm housed with suitable shapes into the thermoforming moulds, thanks to extremely simple and economical machining. CREI optimised the diffusion of the same power obtained with a single armoured heater into two microtubular heaters, applied both in the perimeter and in the central zone, reducing the temperature gap from 24°C to only 7°C.

Benefits

Thermal gap reduction: -70%
Reduced time taken to reach working temperature: -44%
Optimisation of energy efficiency with the same nominal power rating
Decreased active heating time

-0%

Thermal gap reduction

-0%

Reduced time to working temperature

Packaging: In-line bundling solution – shrink wrapping

Packaging

In-line bundling solution – shrink wrapping.

Problem

The significant size of the bundle to be packed required the customer to use a hot welding machine, which welded the material in one go. The large amount of power used resulted in a considerable machining cost for the housing and a critical tendency for the welder itself to deform, impairing the proper functionality of the process. This was further aggravated by an application of heat that was not planar and uniform, but through multiple and equidistant cusps.

CREI solution

We engineered the system with a different heating element in close cooperation with the customer’s R&D department. We designed a mouldable heater that can easily reach the decisive heating zones without wasting power and without temperature redundancies, which are as harmful as they are useless.

Advantages

optimising energy efficiency with the same nominal power rating
decreasing active warm-up times
use of less costly materials and processing
more responsive system
optimal heat diffusion in the particular working areas of the welder itself
unique system with a design identity that is difficult for third parties to replicate
competitive advantage for the customer.

-0%

Thermal gap reduction

+0%

Increased welding speed/minute