CN201385337Y - Ultra-thick rotary-cut veneer - Google Patents

Abstract

The utility model provides an ultra-trick rotary-cut veneer with thickness of 4.5mm-12mm and spot-shaped or line segment-shaped cracks which are formed by press-rolling and defibering along grain direction at a loose side. Compared with common veneers, the ultra-thick rotary-cut veneer treated by press-rolling and defibering not only has the advantages of no warping, no deformation, high drying efficiency, reduction of glue application quantity in gluing technology of later period, and the like, but also can be broadly used for producing plywood, man-made boards of laminated veneer lumber and bamboo-wood composite materials, and the like.

Description

A kind of super thick rotary cut venner

Technical field

The utility model relates to the wood-based plate field, particularly a kind of super thick rotary cut venner.

Background technology

Glued board is the indispensable important component part of wood-based plate industry, is the important means that realizes the forestry sustainable development strategy and effectively utilize timber resources.China's glued board output reached 3561.56 ten thousand steres in 2007, increased by 30.52% than 2006, accounted for 40.29% of whole wood-based plate output, and veneer is the basic composition unit of glued board, and the quality of veneer directly has influence on the performance of glued board.Usually the veneer that timber is peeled into (1～3) mm in the prior art is produced glued board, laminated veneer lumber or bamboo-wood composite material.If timber is peeled into the veneer of (1～3) mm, be made into glued board again, the used veneer number of plies is more, and its glue-line is also just more, and glue consumption is just big.

It is bigger to adopt traditional explained hereafter to surpass the rotary cut venner difficulty of 3mm, mainly is because when timber was peeled into veneer, veneer was circular arc originally on juggle, and is evened up during rotary-cut, and back-flexing in succession.The result produces compression on the surface of veneer, produces tension at the back side of veneer:

${\mathrm{\σ}}_1=\frac{E\·S}{2{\mathrm{\ρ}}_1},$ ${\mathrm{\σ}}_2=\frac{E\·S}{2{\mathrm{\ρ}}_2}$

In the formula: ρ ₁Be the radius of curvature (mm) of veneer reset condition, ρ ₂Be the radius of curvature (mm) of veneer back-flexing, E is the elastic modelling quantity (MPa) of timber band direction, S be veneer thickness (mm) (artificial panel technology is learned, p46, China Forest publishing house, Hua Yukun).As can be seen, the diameter of log is more little from formula, and veneer thickness is big more, and then this internal stress of sheet material is big more, just is easy to generate buckling deformation (even causing as shown in Figure 1 Texturized) in the dry run of veneer more.When stress during greater than timber band tension or compression strength, veneer will produce cracking phenomena, and the appearance of these defectives will have a strong impact on volume recovery and the postorder manufacturing procedure such as the operations such as gluing, assembly of veneer.

The utility model content

The purpose of this utility model is to improve the deficiency in the existing technology, a kind of super thick rotary cut venner is provided, adopts to press to prick by loose side and discongest technology, reach the distortion that reduces veneer at veneer, reduce the energy consumption for drying of veneer, and the purpose of the minimizing glue consumption in the later stage bonding process.

For achieving the above object, the utility model is taked following process technology scheme:

The utility model by rotary-cut, forms the thick veneer of 4.5-12mm with log, pricks through overvoltage in the rift grain direction of loose side and discongests the crackle that forms point-like or line segment shape.

The average length of the described crackle on the described loose side is between 2.0cm～5.0cm, and mean depth is 1/4～1/2 of a thickness of slab; Perhaps,

The average length of the described crackle on the described loose side is between 2.0cm～5.0cm, and mean depth is 1/4～1/2 of a thickness of slab, and mean breadth is 0.8mm～3mm, and the average headway between the crackle is 0.5cm～5cm.

The utility model adopts the super thick rotary cut venner of 4.5mm～12mm, is that the common veneer of mm1～3mm is compared with thickness, and the composite board of compacting same thickness has reduced the number of plies of glue-line, has reduced resin added, thereby has reduced cost.Below be 1.5mm with the sandwich layer, 3mm, the veneer that 6mm and 9mm are thick, backboard and panel adopt the thick fancy veneer of one deck 1mm respectively, make the composite plate made from solid wood that target thickness is 18mm, and the relation between used veneer thickness and the resin added is described.

Relation between table 1 veneer thickness and the resin added

Veneer thickness (mm)	1.5	3	6	9
					Compression ratio (%)	10％	10％	10％	10％
Sheet material target thickness (mm)	18	18	18	18
					The veneer number (opening) that sandwich layer needs	18	6	3	2
Glue-line number (layer)	19	7	4	3
					Resin added (the g/m of each glue-line 2)	200	200	200	200
Total resin added (g)	3800	1400	800	600

As can be seen from Table 1, along with the increase of veneer thickness, resin added reduces, and produces the thick sheet material of 18mm equally, only is 21.05% of the super thick rotary cut venner of 1.5mm if adopt the thick veneer resin added of 6mm; If adopt the thick veneer of 9mm, its resin added only is 15.79% of the super thick rotary cut venner of 1.5mm.The minimizing of resin added greatly reduces the production cost of sheet material.

The utility model has carried out pressing pricking to super thick rotary cut venner discongests processing, compare with untreated veneer, after the overvoltage bundle is discongested processing, formed the crackle of point-like or line segment shape in the rift grain direction of the loose side of veneer, it has tangible advantage: at first, produce compression according to the veneer surface, the back side produces the tension formula:

${\mathrm{\σ}}_1=\frac{E\·S}{2{\mathrm{\ρ}}_1},$ ${\mathrm{\σ}}_2=\frac{E\·S}{2{\mathrm{\ρ}}_2}$

In the formula: ρ ₁Be the radius of curvature (mm) of veneer reset condition, ρ ₂Be the radius of curvature (mm) of veneer back-flexing, E is the elastic modelling quantity (MPa) of timber band direction, S be veneer thickness (mm) (artificial panel technology is learned, p46, China Forest publishing house, Hua Yukun).Through overvoltage prick discongest processing after, weakened the transverse modulus of elasticity of super thick rotary cut venner, reduced the veneer surface and produced compression, the back side produces tension, thereby has avoided the problems such as warpage, distortion of veneer; Secondly, through overvoltage prick discongest processing after, the internal stress of veneer obtains degraded, can reduce the loss of breaking and causing because of veneer in operations such as follow-up drying, applying glue, assembly, thereby improves the utilization rate of timber; Moreover, after the overvoltage bundle is discongested processing, formed the crackle of point-like or line segment shape on the veneer surface, increased the specific area of veneer, the resistance of the moisture discharge of timber is significantly reduced, thereby increase the rate of drying of veneer, the energy consumption when having reduced veneer drying.

The utility model is described in further detail below in conjunction with specific embodiment, is not to restriction of the present utility model, every any this area of being carried out according to the utility model disclosure be equal to replacement, all belong to protection domain of the present utility model.

Description of drawings

Fig. 1 is the buckling deformation without the thick veneer generation of 4.5mm～12mm of overstress degraded

Fig. 2 is the super thick veneer of 4.5mm～12mm through the stress degraded

The specific embodiment

Timber such as poplar, eucalyptus, birch, willow, masson pine, larch, China fir, cryptomeria, metasequoia, fir saw is cut into the juggle that length is 2500mm;

Above-mentioned juggle is peeled into cylinder by pre-rounding;

By the described rotary trunk-layer stripping machine without clamper of patent (ZL00106076.7), being peeled into thickness is 4.5mm～12mm with above-mentioned cylinder juggle, and length is the super thick rotary cut venner band of 2500mm; Be cut into the veneer that width is 1300mm again;

Above-mentioned super thick rotary cut venner is pricked fluffer by the described pressure of ZL01280006.6, press bundle to discongest processing to above-mentioned veneer, make described veneer vertically form the veneer of the crackle a of point-like or line segment shape after treatment at the loose side of veneer, the average length of described crackle a on the above-mentioned loose side is about 3.0cm, mean depth is 1/4 of a thickness of slab, mean breadth is 0.2mm, and the average headway between the crackle a is 2.0cm (referring to Fig. 2).

Described rotary trunk-layer stripping machine without clamper adopts universal drive shaft as transmission mechanism, and two of being adopted are universal becomes concentric rotation; Simultaneously on the bearing that roll shaft and several ball bearings that friction mandrel adopts two ends to have to tighten nut and the roller cone bearing that is arranged in two ends support, adopting rolls cooperates, after being installed in all bearings, the body of roll and spacer on the bearing successively, tighten the nut that tightens at bearing two ends, make the end face of bearing, the body of roll and spacer mutually near becoming as a whole, guaranteed that friction mandrel is on the same linear axis; Enforcement by above two key technologies, reduced frictional force between timber and the friction roller simultaneously in the precision that increases rotary-cut, reduced the resistance of rotary-cut, reached the purpose that small diameter grade artificial fast growing wood timber is peeled into super thick rotary cut venner, its rotary cutting process is identical with the rotary cutting process of existing common no axis.

Described veneer presses friction roll wheel shaft system and the special-shaped stack geared rotor system of pricking the feeding of fluffer employing active rotation to combine, making friction roller is driving shaft, pressing bundle to discongest roller is driven axle, utilize splitting degraded mode that the lateral stress of timber is degraded, reached and do not destroyed under the prerequisite of timber longitudinal strength, finish the pressure of timber and pricked the purpose of discongesting, it presses the bundle carding process that loose side is discongested roller towards pressing to prick, pilled-in selvedge is towards friction roller, discongest through finishing after the degraded to press to prick according to the palliating degradation degree adjustment in the gap of degraded roller and friction roller.

Above-mentioned veneer by dry, is controlled at moisture content between the 8-20%.

Claims (3)

1. super thick rotary cut venner, it is characterized in that: described super thick rotary cut venner thickness is 4.5mm～12mm, has through overvoltage in the rift grain direction of loose side and pricks the point-like discongesting and form or the crackle (a) of line segment shape.

2. super thick rotary cut venner according to claim 1 is characterized in that: the average length of the described crackle (a) on the described loose side is between 2.0cm-5.0cm, and mean depth is the 1/4-1/2 of thickness of slab.

3. super thick rotary cut venner according to claim 2, the average mean breadth of the described crackle (a) on the described loose side is 0.8mm-3mm, the average headway between the crackle is 0.5cm-5cm.

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