Glued laminated timber beam (Illustration)

Production process

Glued laminated timber

Glued laminated timber (Glulam, BSH) is an industrially manufactured construction product for load-bearing constructions. It is made of slat boards that are laterally finger-jointed and then glued to each other with parallel grain. Thus glued laminated timber offers a great advantage as a construction product in comparison to solid beams: On the one hand, the load-capacity is larger than with solid wood, as imperfections (branches, etc.) can be cut out in advance, and gluing creates a homogenous cross-section. On the other hand, finger-jointing allows larger beam lengths. This means that span widths for roof-beams can be implemented up to 60 m without support. BSH glue connections  must be made extremely carefully.

Glued laminated timber is produced as a standard or short-term delivery good in any desired length and dimension.  Special construction parts are available, too,  that exceed standard measures, and also shapes, such as higher raised beams, monopitch roof girders, arch girders, and free shapes. Roof elements can also be created out of glued laminated timber.

Glued laminated timber has become a sophisticated universally usable product in wood construction. Globally around 7-8 million square metres of beams are produced. Main production countries are Japan, Austria and Germany. At a distance, USA, Russia and Finland are next in line. The best known producers are, among others, Mayr-Meinhoff, Hasslacher, Binderholz, Stora Enso, and Chugoku Mokuzai. Larger span widths are produced by companies such as WiesnerHager and Derix. 

Source product

BSH consists of board slats, just like BSP, and is technically dried to a certain wood moisture level. Typical construction timber is used, i.e. conifers, such as spruce, pine, larch or douglas fir. In rare cases, deciduous timber is used. 

Production Process

  • Slat production

    Finger-jointed slat (Illustration)

    Pre-planing

    The slat boards are pre-planed on four sides.

    Machines:
    Planing machine

    Tools:
    Planer head

    Sorting timber

    The pre-planed and technially dried slats are sorted visually or by machine according to solidity. The cover slats are sometimes also additionally chosen according to optical criteria.

    Machines:
    Sorting system

    Optimising

    Imperfections with stability reducing or ugly deviations (e.g. large branches, pitch pockets, bark inclusions) are cut out according to the stability and surface class when the slats are sorted.

    Machines:
    Optimising cross-cut saw

    Tools:
    Sawblade

    Slat finger-joints

    The individual slat boards are pushed longitudinally through a finger-shaped, force-fitting glue connection, the finger-joint. Thus an endless board is created out of short individual parts.

    Machines:
    Finger-jointing line

    Planing finger-jointed slats

    The endless boards are planed to a uniform thickness.

    Machines:
    Moulder

    Tools:
    Planer head

    Slitting to laminated measure

    The endless boards are cut in length.

    Machines:
    Cutting line

    Tools:
    Sawblade

  • Creating layers

    Slat boards with glue application (Illustrations)

    Glue application

    Glue is applied by feeding the boards through a glue curtain.

    Machines:
    Glue application line

  • Pressing

    Glued wood after pressing (Illustration)

    Pressing

    The glued boards are layered on top of each other in a pressing jig and pressed together. At least two grain parallel boards must be pressed to each other. The pressing jig can be straght, curved, standing or horizontal. 

    Machines:
    Press, Conveying technology

  • Final processing

    Glued laminated timber beam

    Calibrating

    After the glue has hardened the raw part is planed and chamfered.

    Machines:
    Moulder

    Tools:
    Planing knife

    Cutting to length

    Straight beams are cross-cut to the desired finished measure. 

    Machines:
    Cross-cutting saw

    Tools:
    Circular saw blade

Production process:Glued laminated timber

Tools for production process Glued laminated timber3

Besides machinery, also additional devices and gadgets are used in woodworking. Machine tools for Glued laminated timber production are listed here.

  • Circular saw blades, HW-tipped

    E.g. used in:Glued laminated timber

  • Circular saw blades, all-steel

    E.g. used in:Glued laminated timber

  • Circular saw blades, tipped with cobalt alloy

    E.g. used in:Glued laminated timber

Necessary peripheral devices for Glued laminated timber2

  • Conveyors for sawn timber (roller conveyors / tracks, cross-transfer units, etc.)

    E.g. used in:Glued laminated timber, Cross laminated timber

  • Infeed units

    E.g. used in:Carcass furniture, Furniture front, Flooring, Glued laminated timber, Cross laminated timber

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