Veneering Process At Hunsply
Producing quality veneer demands proper care and attention at every stage of the process. All stages complement each other and the quality with which veneer is treated in each stage is duplicated in all the other stages.
Flitches are stored in moist conditions to prevent these from over drying and extensive exposure to heat. Treatment includes the use of storing tanks in which flitches are kept in cold water to keep them moist in many cases sprinklers are also used.
Prior to actual slicing of veneer, flitches are placed in soaking vats, which are heated by steam. Soaking the flitches are necessary to soften the flitches before it is fed into the slicer. Duration of soaking depends on the type of wood, as some hardwoods will need more time to soften than others.
After soaking, flitches are then fed into the slicer as soon as these are pulled out from the soaking vats since wood slices better while still warm. The flitches are fed into the slicer which slices the flitch into the desired veneer thickness. Standard thickness is 0.55mm to 0.35 mm millimeter based on the price of logs.
The sliced veneer strips are then fed into a dryer where moisture content is reduced to 8% to 12%. Bringing moisture content down to these levels is imperative as woods react by either contraction/shrinkage or expansion to temperature changes when damp. After drying, strips are fed into a trimmer, which manufactures perfect parallel joints in preparation for gluing and splicing.
Strips are then spliced or composed into veneer sheets with pre-set dimensions. These are composed into sizes matching the dimensions of the substrate on which these are to be laminated.
Lamination is carried out in two steps. The substrate which will serve as the base of lamination is fed into a glue-spreading machine which uniformly applies a thin coat of glue over the substrate. As the substrate is pulled out of the glue spreader, the spliced veneer sheet is laid-up on top of the substrate. Both are then fed into a Hot Press which laminates the veneer sheet on the substrate at high temperature and in just a little over 2.5 minutes.
The laminated veneer sheet (final product) is then sanded to ensure a level and smooth surface & once again graded and selected pattern wise to give us group matching as required by customers and clients.
It is important to note that quality control is enforced at every stage, as the veneer process requires specific quality control measures from the very start, selecting the flitches to slice, correctly matching veneer strips and checking these for knots, tears or discoloration, pin holes and other factors which may lead to sub-standard veneer and thus substandard decorative Plywood.
This is only a attempt to explain the process of veneering in a simplified fashion and as such the variations in the actual process are innumerable.