Design and pilot production of a "spiral-winder'" for the manufacture of cylindrical laminated veneer lumber

A new spiral-winder was developed for continuous manufacturing of cylindric al laminated veneer lumber (LVL), and a suitable resin adhesive for this cy lindrical LVL manufacturing system was investigated. This phase was followe d by trial manufacturing and evaluation of cylindrical LVL with the optimum resin adhesive identified. The results are summarized as follows. (1) The shortest gelation time was recorded with a mixture of two commercial resorc inol based resins (DF-1000 and D-33) at a weight ratio of 25:75. (2) Bath t emperature had a remarkable effect on the gelation time of the adhesive mix . (3) High bonding strength was recorded by 25:75 DF-1000/D-33 adhesive mix at a high press temperature despite a short pressing duration. Based on th e results of items (1) to (3), 25:75 DF-1000/D-33 is recommended for use in the new spiral-winder. (4) The mechanical properties of cylindrical LVL co uld be improved by using 25:75 DF-1000/D-33 with wider veneer width and lon ger pressing time. (5) The mechanical properties, especially the modulus of rupture, of the cylindrical LVL manufactured require further improvement f or practical structural application.