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Machine for the application of thin layers of material (veneer, paper, foil, HPL) on panel materials with the help of pressurized and heated plates.

Structure

The machine frame is usually made of solid steel beams, which have been welded together in a shape of a box. In the space between the four lower beams usually the pressure pump of the hydraulic system is placed. The pressure table with the heated plates lies within the machine frame. There is a distinction between two different kinds of veneer presses cylinders: the downstroke press and the upstroke press. A downstroke press will move the abovelying cylinders towards the belowlying pressing plates; the upstroke press moves the belowlying cylinders towards the abovelying pressing platens. Interlinked toothed rack guides compensate the pressure difference in the hydraulic system and make sure that a precised closing of the plates is achieved.

Pressing surfaces and heating plates

Basic structure of a pressing table with aluminum heating plates:

  • approximately 12mm thick, solid aluminum plate with integrated wires for the electric resistance heating
  • a just few millimeters thin insulation layer for thermic separation
  • usually approximately 38 to 40 mm thick holder - and insulation platen made of chipboard
  • solid steel underconstruction for the even distribution of the pressure (pressure table)

The evenness of the pressing surface determines amongst others the quality of the workpiece surface and of the gluing performance. Uneven plates, remains of glue on the surfaces, scratches, irregular spread of the heat within the pressing surfaces are all possible causes for bad results in a glueing process. There are also other factors for this which do not have a correlation with the press, such as the quality and the choice of the glue, and the surface of the workpieces/materials.

Because heat stimulates a constant and quick drying process of the glue the most common kind of pressing surfaces are heating plates.

Common measures of plates

  • 2200 x 1100mm
  • 2550 x 1100mm
  • 2550 x 1350mm
  • 2750 x 1350mm
  • 3000 x 1350mm
  • 3300 x 1350mm
  • 3600 x 1350mm

In order to protect the pressing surfaces in a long-run and to simplify the process of cleaning, plastic foils which are glue-resistent can be spread over the pressing surfaces. (see picture) Through fed presses with automatic feeding will use these foils also for the transportation of the workpiece through the press.

Generation of the pressing pressure

  • Pneumatic: Entry-models of some presses generate the pressure via pneumatics. Some models use pneumatic cylinders, others use hoses (like fire engine hoses) which are mounted below the lower plate. (picture Joos Junior)
  • Hand hydraulic: by hand activated hydraulic pump, which step by step directs the plattern to its closer position, until the pre-set pressure has been build up.
  • Hydraulic: most of the modern veneer presses are equipped with electro-hydraulic pressure generation (hydraulic aggregate).

Safety equipments (selection)

Emergency Stop Line

Approximately 50 cm above the ground runs an emergency stop line all around the machine, which in a case of operation (pulling or pressing) immediately interrups the closing process of the press. (see picture Ott-press)

Table safety system

Under the lower pressing plate runs an emergency stop line all around the machine or there is a sensible contact strip, which if activated immediately stops the opening process of the press.

Protection of the jamming of the press plates after wrong use

see A.B.S.-safety system , FSS Funktions-Sicherungs-System

Alternative terms for veneer presses:

Typical question of a used press buyer: 'Are the plates still allright? "

Generally there needs to be a distinction, what application the second hand press should be used for. The highest quality level is a pressing of very fine and thin foils or veneers on big surfaces. Other applications that have lower demands for the quality of the plates are the work with thicker veneer or with solid wood, especially there is a further treatment of the surfaces after the press. In other words: not every scratch in the plates means that they need to be exchanged.

Testing options:

Optical test (unprecise)

Cracks, visible bumps or damages, remains of glue, ...

Oil droplet test (more accurate)

By a pipette, oil droplets are placed onto the lower plate in a semetrical order, so that are the closing of the platens will squash the droplets and create round circles. If these have a constant order it is a good sign for the quality of the plate, even if very high quality standards are needed.

Test pressing

With paper and glue on the real workpiece

Obrázky a videa

thermoölbeheizte Furnierpresse
ORMA, 1995
Mehretagenpresse AMD U 80
AMD, 1990
Pressenfolie an einer Durchlaufpresse
JOOS
Temperiergeräte für wasserbeheizte Presse
JOOS, 1996
Not-Aus-Leine
OTT, 2000
Presse mit pneumatischer Druckerzeugung: Joos Junior
JOOS, 2004
300K -H
OTT, 1970
Video
Etagenpresse mit wasserbeheizten Platten

Modelové řady (159)

FRAMA
HILLER