WOOD AND LEATHER PRODUCTS INDUSTRY

Wood products

Wood products

the branch of the wood industry that carries out the mechanical and chemical-mechanical treatment and processing of timber and that utilizes various woods for its raw materials. The industry produces sawn wood, sleepers, plywood, wood panels, and beams; it makes items needed for construction and rough-finished and finished parts for industries producing automobiles, as well as for agricultural machinery manufacturing; it produces matches, furniture, wooden packaging, wooden shoe lasts, boxes and cases for equipment, instruments, tools.

Furniture industry

The modern manufacture of furniture, as distinct from its design, is a major mass-production industry in Europe, the U.S., and other advanced regions. It is very largely a 20th-century industry, its development having awaited the growth of a mass consumer market as well as the development of the mass-production technique. Earlier furniture making was a handicraft, going back to the most ancient civilizations.

Modern methods of furniture construction are largely based on the availability of man-made materials such as reliable plywood, laminated board, chipboard, and hardboard as distinct from natural solid wood. It is not merely that manufacturers prefer the one to the other but rather that these substances are free from the great drawback fundamental to wood—movement. Natural wood shrinks as it dries or swells as it absorbs moisture from an atmosphere more humid than itself, and this movement must be allowed for in the method of construction. Unless this is done troubles may arise: splits along the grain or open joints on the one hand or jammed drawers or doors on the other. Over the years cabinetmakers have worked out ingenious systems to avoid these troubles in the use of solid wood, but today made-up materials may be regarded as inert if of good quality. To an extent solid wood has still to be used, notably for items that have to be turned, cut to shape, or molded, and for lippings to conceal the edges of manufactured boards; but virtually everything in the form of flat panels is made up.

NATURAL WOOD

The increase in the demand for reasonably priced furniture has placed a premium on the economical use of wood. Natural wood is extremely wasteful as a material. Hardly more than 25 percent of the natural substance of a tree actually goes into the furniture made of solid wood. When account is taken of the loss in sawdust in conversion from the tree trunk (taking off the outer slab portions and sapwood) and the further loss in bringing the lumber to usable size in the workshop (the offcuts, waste in sawing shapes, in turning, in planing, cutting joints, and final cleaning up), it becomes evident that much more wood is wasted than used.

PLYWOOD

In making plywood, the veneers are peeled rotary fashion from the log by a long knife fitted to a lathelike machine. The resulting veneer can be of unlimited width to be cut up as required. There is no loss in sawdust, and the peeling is continued until only a polelike centre is left. Much the same applies to laminated board in which both the core material and the outer plies are peeled. In the case of chipboard the timber is merely regarded as raw material to be reduced to fine chips that are dried, compressed, and assembled into boards, with resin glue as an adhesive. Where a natural wood grain is desired, a veneer is flat sliced from a flitch (longitudinal section) selected for the beauty of its grain.

Certain materials, notably chipboard, must be machined, because trimming at the edges by hand almost always shows as a deterioration. It cannot be planed; the plane merely forms dust rather than taking shavings and, owing to the abrasive nature of the material, the edge of the cutter is quickly lost. Consequently, when a panel of a certain size is required, it needs to be machine sawed to size, no further trimming being needed. This is only practicable with a precision saw capable of fine adjustment. Furthermore it requires a saw blade having tungsten teeth to resist abrasion. The same applies to any plywood or laminated board assembled with resin glue.

Another influence on the construction of furniture is the introduction of new types of adhesives in place of the traditional animal glue. Many are highly water resistant, some waterproof. Some can be applied cold, avoiding the complication of heating joints before assembly. They can be cured by heat in a matter of minutes, leaving presses and other apparatus free for other work.

Shoe lasts industry

Shoe Lasts come in many styles and sizes, depending on the exact job they are designed for. Common variations include simple one-size lasts used for repairing soles and heels, durable lasts used in modern mass production, and custom-made lasts used in the making of bespoke footwear. Though a last is made approximately in the shape of a human foot, the precise shape is tailored to the kind of footwear being made. For example, a boot last would be designed to hug the instep for a close fit. Modern last shapes are typically designed using dedicated computer-aided design software.

Historically, lasts were typically made from hardwoods and cast iron because these materials retain their shape, even when in contact with wet materials (like leather) and subjected to the mechanical stresses of stretching and shaping shoes on them. Today, wooden lasts are generally used only for bespoke shoemaking, particularly in Europe and North America.

The materials used in modern lasts must be strong enough to withstand the forces of mass production machinery, such as that applied by pullover machines when bottoming the shoe, and must also be able to hold tacks (known as "lasting tacks"), which are used to hold shoe parts together temporarily before the sole is added. Although hardwoods satisfy these criteria, modern lasts, especially those used by mass production factories in places such as China, are often made from high-density polyethylene plastic (HMW-HDPE), which allows for many tack holes before needing repair. Such plastics also have the benefit that they can be recycled and remoulded when they wear out.

Finisthing the leather production:

It 's the final stage and  the most complex process, which  includes all operations to be carried out on dried leather,   to change the surface effect,  both for aesthetic and functional aims. Finishing can be mechanical or chemical.

Mechanical finishing operations may include:

POLISHING : to create a shiny surface by rubbing it with a velvety wheel

IRONING and PLATING: to obtain a flat and smooth surface

EMBOSSING :to obtain a three-dimensional print

TUMBLING by rotating the drum quickly to create a more evident grain and a smooth   surface

Chemical Finishing involves the application of a film, natural or synthetic by using curtain coaters, roller coatings and spraying.