Printing

Lamination, printing and textiles: High-performance temperature control units in use

Hollow or double-walled rollers are used in the printing industry and in lamination as a finishing process. In order to achieve the best results from the processes, it is necessary to use perfectly controlled temperature processes i.e. powerful and reliable temperature control units. Constant temperature control is the key to success in this sector.

In the textiles industry, rolls of textiles are often passed through systems of rollers to bind them with additional materials. Depending on the application, functional layers can be added to textiles. Depending on the desired function various different application methods are used to achieve. Temperature regulation is essential to these processes in order to properly adhere or seal materials to achieve the desired function of the textile laminate.

Calendering, double-walled rollers, hollow rollers:Temperature control requirements are as variedas the materials to be processed

Calendering units and rollers are used in the production of plastic, rubber and metallic films as well as in embossing, smoothing, compacting and finishing the surfaces of paper and textiles. The design and structure of the rollers and calenders are perfectly adapted to the material being processed. Temperature control needs are also different for each material and choosing the right temperature control or cooling unit means doing the right calculations beforehand.

Our specialists understand the particular differences between various roller designs and will be happy to help you determine which system is right for you.

Printing, lamination and textiles:Perfect control for perfect processing

Calenders are systems consisting of several cast iron or stainless steel heated and polished rollers arranged above one another. The material is passed through the gaps between these rollers. They are used to produce films made from plastic (PVC, PE, PS, etc.) or rubber and metal (aluminium, tin). Calendering is used to make relatively thick plastic films. These can be used as e.g. blister packaging in the pharma industry. Thin films made from PE (bin bags) are usually made using extrusion blow moulding for reasons of time and cost. Rubber films can be produced with thicknesses between 0.1 and 0.8 mm. These films are also laminated using calendering.

Calenders are also used for embossing, smoothing and finishing paper and textiles. Non-woven materials made from thermoplastic polymers can also be strengthened to made fleece fabrics. Calenders or groups of calenders are used in the a variety of ways in the textiles industry. This includes preprocessing materials to smooth their surfaces, for squeezing out excess dye liquor during hot fusion processes or to evaporate dye liquor residues. Different effects can be achieved by altering the pressure, temperature and speed of the rollers.

One specific characteristic of using temperature control with rollers is certainly the ability to create a wide range of different products and therefore the design of the calender and rollers vary greatly from one another.
As a manufacturer of temperature control and cooling units, we need to do the calculations and redesign products for each application. Alongside the temperature of the roller and the time required to get up to this temperature, the design of the rollers must be carefully considered. The permitted pressures on the swivel guides and return volumes must also be considered during the design phase.
The material to be used, the quantity and its properties also define the required heating and cooling capacity.

Many components play a role when selecting a suitable temperature control system. The design of the application is of high importance for calenders and rollers. The material to be used, the quantity and its specific properties, as well as the required throughput are also important factors to consider when selecting a temperature control system.

We will be happy to advise you and discuss the ideal heating and cooling solution for your needs. Our wide portfolio includes:

  • Water temperature control units / 90°C max. temperature / 9 – 96 kW heating power
  • Pressurised water temperature / 160°C max. temperature / 9 – 48 kW heating power
  • Oil temperature control units / 360°C max. temperature / 8 – 144 kW heating power

Producing high-quality coffee cups
This complex production system has a forward extruder system. The input material polystyrene (PS) is melted down and then passed over a calender with four rollers. The molten plastic with a temperature of 230°C flows over the four rollers to be smoothed and compressed. The purpose of this is to cool the molten plastic to a temperature of 120°C. At the start of the production process, the rollers are first heated up to the required temperature. Throughout the ongoing process, the heat from the plastic must be removed. Once the comparatively thick continuous film has passed over the calender rollers, the material is shaped using a deep drawing die. This deep drawing die is also temperature controlled. The temperature of the die is set to 40°C in order to remove the residual heat from the plastic film. The deep drawing die creates the final end product – high-quality coffee cups.

The solution provided by Tool-Temp
Two TT-137 N pressurised water units were each connected to a roller and set to a temperature of 60°C. With a material throughput of 580 kg/h, the purpose of the units was to cool the process. In order to handle the cooling capacity required for the comparatively low temperatures of 40°C and 60°C, a conscious choice was made to select a unit with integrated direct cooling.

A further challenge was the relatively large return volume that should flow back into the units when the process was stopped. This meant that the use of open temperature control systems up to 90°C was not possible. The pressure resistance of the roller feedthrough was the last problem to be solved. In order to prevent the TT-137 N entering into an overpressure state, the maximum temperature for the controller and the safety thermostats was set to +80°C. This meant that the effective pump pressure acted only on the system and the swivel guides were protected from excess pressure.
This modification successfully enabled the pressurised water units to be used in an application with rollers.
The units have now been in use for several years without any problems. The customer is very satisfied with this solution.

Manufacturers of plastic packaging films are using new and environmentally-friendly materials made from biodegradable PLA thermoplastic for food packaging such as drink bottle labels, film wraps for vegetables, etc. This high-tech material can be broken down by microorganisms and thus reduce the carbon footprint.

In the production process, a highly transparent technical plastic passes over a calender consisting of two temperature controlled rollers. The starting temperature of the film is approx. 300°C and is stretched over the rollers, compressed and cooled to a target temperature of about 70°C. When configuring the units, particular attention had to be given to ensuring sufficient return flow volume. The heating up time of the rollers to reach the operating temperature of 70°C should not be more than one hour. The customer requested one unit to operate both rollers. A TT-118 K was delivered for controlling both rollers. Both rollers were attached in parallel to the TT-118 K. The advantage of this method of connection is that both rollers are able to reach the same temperature. To ensure smooth functioning, sufficient circulation had to be ensured.
The customer uses several of our models with their production equipment and appreciates the robust construction, simple operation and the ease of maintenance and servicing.

 

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