HF-TECHNOLOGY

High-Frequency curing is the ideal way for ultra-fast curing of glued components within the wood industry.

Obel-P is the leading manufacturer HF Generators and HF-presses. Our position as the leading supplier comes through excellent product design combined with a large experience in matching generators and presses in a working solution that provides trouble-free long term operation.

Below is a short description of High-Frequency Technology, the Obel-P product range and some examples of applications for high frequency curing.

THE PRINCIPLE OF HF CURING

HF = High Frequency is a Frequency band of Radio waves, in the scale from 3 to 30 MHz. HF is produced by converting AC power, to high powered DC current, normally from 7000 to 9000 volt DC. The energy generated by the HF-generator can be absorbed in materials containing bi-polar molecules such as water or glue. By using wood (a non electrical leading material) and glue (an electrical leading material) it’s possible to make the process oscillate = swing. When the process is oscillating, the press will work as a battery/condensator, which will try to recharge the wood. This means that electrons' are floating from + to - and back because the process is constantly oscillating. When the process oscillating, the molecules are pushed around in side the wood, and this is what produces heat in the wood.

MASTERING HF-CURING 1. DESIGNING THE PRESS AND ELECTRODES 2. MATCHING GENERATOR AND PRESS

Different types of electrodes are chosen for different tasks. The simplest form is a set of aluminium plates where the product to be cured is placed between. This is used very often for curing of Window components and wood glueboards. Another type is the “guirlande” electrode which is used for curing larger area with a low penetration into the field – e.g. for curing of skins onto doors. A third electrode is the “special shape” which is moulded to perform both the task of shaping the product and curing it. This is used often for corners of for pressing of “finer” shapes. Press and generator must be matched. This means that during design of the press careful attention is given to all details in the press relating to its function as electrical components in an oscillation circuit.       The equation above defines the frequence where generator and press are “in tune” and is the point where the system is close to ideal energy absorption in the glue. With trombone regulation combined with a fast PID-regulation loop it is possible to keep the process at this point even though the frequency will change during the curing cycle along with moisture content, temperature, etc. Obel-P has refined the art of matching generators and presses in finely tuned systems. As a result of our extensive experience we are often able to arrive at solutions requiring significantly smaller generators than other manufacturers might require. So with an Obel-P solution you also get a smaller requirement for cooling for your generator system. Electrode Design is a vital part of the HF-system.   Matching press and generator in the right way means that you can often chose a smaller generator.

News

We will be attending the big Ligna messe in Hannover on the 15. may. along with our other Obel-P Group members:

AAgaard A/S
PL Control Aps
Brodbaek & CO A/S

So if you are in the need of a new machine with special demands please come and see us. We take pride in offering professional service for all of our machines for all of their lifetime.