Eppingen - The centerpiece of a Dieffenbacher plant, the CPS, has always been an example of reliability and precision, combined with design flexibility. This is not only shown in the cost-effective production of high-quality standard panels but is .particularly evident for new innovative products such as lightweight panels, boards made from alternative raw materials or thin panels,, The new Dieffenbacher CPS is extremely versatile and ideally equipped to meet future requirements.

Three key technical features mean that the current CPS model offers more than just competitive performance. Perfectly smooth surfaces with tolerances down to +/- 0.05 mm reduce material consumption and result in panels with perfect and constant quality. Furthermore, the CPS, with its extremely wide range of panel densities from 350 to 1000 kg/m³, perfectly meets all product requirements — even for material-saving lightweight panels.

Precise Pressure Distribution with the Parallel Press Gap System

A decisive equipment feature is the PPS (parallel press gap system). The innovative pressure distribution principle for extremely low press gap variations in the work flow direction was originally developed in 2006 for thin panel production but is now used in all Dieffenbacher presses in the meantime. Targeted displacement of the upper and lower frame elements creates an extremely even pressure distribution along the press.

New Mulitpot Arrangement

The well-known Multipot cylinders ensure high-precision thickness control across the width of the panel. Lightweight panels, which are produced over large areas of the press with pressures below 0.1 N/mm², require a perfectly stable heating plate alignment, regardless of the current mat counter pressure. This is achieved thanks to a combination of pushing and pulling Multipot cylinders. A special Multipot arrangement has now been developed for the press calibration zone where the final curing of the glue takes place. In this area, the Multipot cylinders can now also be arranged with an outer row. Specifically the fixed support of the heating plate slips inwards slightly, and a Multipot cylinder is arranged on the outer left and right side.

Furthermore, this arrangement ensures simple and highly precise thickness control along the press via the fixed support. At the same time, the Multipot cylinders now arranged on the outside guarantee that the thickness distribution is once again markedly improved for some very demanding products. It is well known, for example, that blowouts of strands and a loss of the PMDI's bonding capability can occur in the border area when PMDI resin is used in manufacturing OSB at extremely high speeds. This phenomenon can be successfully counteracted with the new Multipot arrangement with a targeted setting of the cross profile of press in the outfeed area. This important innovation can also be retrofitted on older CPS systems in most.

HMI for the New Multipot Control HMI (Human Machine Interface) and control of the CPS were also revised as part of these improvements. The aim was to significantly improve user friendliness and make it even easier for operators to set the CPS. One particular feature of note is the new electronic grouping of Multipot cylinders across several rows. Using a clearly arranged input mask, Multipot cylinders can be grouped by the operator and then positioned together or controlled by one mouse click. This makes everything much easier — particularly in the case of long presses. This allows the operators to concentrate on optimizing the overall system, and on other control tasks. These Multipot groupings and settings can be stored with the corresponding recipe settings for the individual panel types, and of course, allow the storing of different Multipot groupings and settings for different products.

Double Hinge Infeed for Fast Pressure Build-Up

A further advantage of the CPS product is the double hinge infeed system. Particularly at high press speeds, this system enables a problem free de-aeration of the mat, without blowouts and allows a simultaneously fast pressure build-up. The result is a high surface density that leads to excellent bending properties of the panels and even lowers varnish consumption when direct painting.

The CPS in Practice

The two wood based panel plants for Swedspan, with very different requirements, illustrate just how flexible the Dieffenbacher CPS press is in fact.

In 2012, Dieffenbacher started-up a thin panel plant for Swedspan with an annual capacity of 250,000 m³ in Orla, Poland. UTHDF (ultra-thin high-density fiberboard) is produced with panel thicknesses of one to three millimeters. The forming and press line is designed for a line speed up to 2,100 mm/s. These record values —1 mm panel thickness, speed of more than 2 m/s—are achieved only through the optimal interaction of highly accurate spreading with low weight and density tolerances and a press that guarantees precise pressure distribution lengthwise and crosswise to the panel even at top speeds.

Following the successful start-up, Swedspan also decided in favor of Dieffenbacher for its next wood based panel plant. This time, however, the direction is quite different. Since spring 2013, Dieffenbacher is erecting a new turnkey plant in Malacky, Slovakia, for the production of a new innovative lightweight panel product. In the preparation phase, extensive test series were carried out for this purpose at the technical center in Eppingen, Germany. Swedspan has been impressed by the test results and by the CPS that is perfectly suited for lightweight panel production. Dieffenbacher is supplying the complete process technology for this project — from wood preparation and drying through the gluing and forming station, and finally the finishing line behind the CPS.

Source: Dieffenbacher