... drying. It has two advantages 1) High frequency heating, more equal, dry faster; 17times faster than wood ... rare wood material.Advantage and charactor:HF and Vacuum condition:As HF heats from inside, so the core ... and leave permanent defect on the wood, but HF vacuum condition will totally eliminate the problem.3) ... if the temperature reaches the max limit, the heating stop, but if it falls to the min, ...