Moulded or curved, cut?to size hardwood plywood is playing an important part in the manufacture of upholstered furniture today because of the expansion of design possibilities with this product. Its many uses have proved it to be a versatile yet stable material in furniture production.
Curved plywood has been utilized by furniture manufacturers for table and chair legs, chair backs, seats and arms, sofa frame parts, goose neck chair and bar stool back supports, chair stretchers bench seats and body form pew seats.
The radius of moulded plywood is normally limited by the thickness of the face, core and back plies and the construction and thickness of the plywood it can be ordered with an inside radius as small as 1/2″ Thickness of construction can be readily varied with dimensions available from 1/8″ to as much as 2″ in graceful, flowing, simple or compound curves.
The furniture manufacturer needs only to send a drawing or accurate description of the shape he wants, dimensions, grade, species of face veneers and probable quantities and the hardwood plywood manufacturer will be able to complete the engineering and give a fast quotation. The hardwood plywood manufacturer will be able to complete the engineering and give a fast quotation. The hardwood plywood manufacturer has hundreds of stock moulds or he will build moulds for the upholstery’s exclusive use. Many furniture manufacturers are now buying segment plywood stock which the manufacturer will saw into 1 1/2″ or 2″ strips and use in place of bent solid wood in overstuffed furniture. The old process is slow because of the problem of trying to make curves out of straight pieces of wood. This results in heavy but weak frames.
Some furniture manufacturers buy veneer from veneer mills and manufacture their own plywood, however the Hardwood Plywood Manufacturers Association member mills are making hardwood plywood every day to the user’s exact specifications and quantities required and the upholsterer will know his exact cost for hardwood plywood.
The trend in the future for the furniture manufacturer is to be an assembler of parts. Let the hardwood plywood manufacturer be the furniture manufacturer’s machinery investment. Veneer cutting lathes, splicers, dryers and hot presses are expensive to own and operate.
Let the hardwood plywood manufacturer be the furniture industry’s inventory of logs, face veneer core stock and adhesive and let him solve part of the waste problem, so the furniture manufacturer doesn’t have to sell or chip cores dropped at the lathe and worry about sawdust. The hardwood plywood manufacturer can furnish the upholsterer with precision?made cut?to?exact?size products and conserve space in his factory for the principal function of manufacturing furniture. Panels can be furnished completely. cut to size with edges bevelled or shaped, routed, bored, cut?out and grooved to meet the upholsterers’ specifications.
Hardwood plywood is a product based on the concept of cross?lamination. The effect of cross?grain orientation is to minimize dimensional change, which means that shrinking and swelling are reduced to a minimum. Because of hardwood plywood’s cross?layer construction, the optimum properties of wood are realized. Screws, nails, tacks, staples and other fasteners can be placed near the edge of hardwood plywood without danger of splitting the panel. Preboring for screws and nails frequently can be eliminated. The porous nature of the wood is obviously compatible with adhesives.
Due to hardwood plywood’s unique properties stresses from impact are dissipated through the panel and the strength is distributed in both directions. It can withstand a great deal of strain, twist and vibration and yet retain enough flexibility to avoid splitting. Since moulded panels have fewer parts and joints, the curved blanks naturally provide a stronger more durable practically indestructible frame with no loose edges at the corner. Another areas of conflict between designers and production men is being resolved. Designers like to use curves; production men, however know that curved upholstery frames are costly as far as labour and materials are concerned. Barrel backs, kidney shapes, rounded fronts, curved top rails and arms, in particular are expensive. These frame styles formerly had curves made from heavy bandsawn blocks of wood held together tenuously by dozen dowels. The frames were heavy, weak and high priced. Now there is a breakthrough that will have a big influence on the design and production of traditional upholstery styles.
The new concept is very simple The curved portions of the base arms, centre rails and top rails are made of thin concentric pieces of curved plywood. The unique construction feature is the use of bridging blocks between the parallel pieces of curved plywood. The bridging serves two functions the thin three ply plywood arches take on a strength and rigidity similar to that of a bar joist used in building constructions and the spacing blocks are located to serve mechanical purposes for attachment of springs and as locators for exact positioning of stumps, posts, legs and wings.
The base of the chair : The base of the chair or sofa holds the key to the new design. The two concentric hands of plywood are formed so that there is a uniform gap (about 7/8″ wide) between them. Short blocks of wood (7/8″ square x 22″ to 4″ long) are glued and stapled between the bands to form a light weight but extremely strong subassembly. The same concept is used in arms, top back rails and other parts of the chair or sofa.
The resulting frames show some remarkable characteristics. Firstly initial strength tests reveal the new frame to be more than twice as strong as a conventional frame and a reduction in overall weight between 30 to 45 per cent, depending on the style of the chair. Secondly, frame cost reductions have ranged from 25 to 44 per cent (based on detailed standard costs comparisons by a leading furniture manufacturer).
Frame assemble time can be cut more than 50 per cent. Lastly, the use of 7/8″ tick tension on the lower ends of arms and inside backs will allow many styles to be upholstered as components for final assembly at the inspection area. The tenons are inserted through cuts in the desk and securely fastened between the bridging in the plywood base rims. Reductions in upholstering costs may approach the savings in frame costs on such styles. The elimination of dowels and the reduction in the number of parts required will cause many changes in the machining and assembly departments. For these types of frames, the board footage needed from the rough end will be 1/3 to 1/2 of the previous need. Shorter lengths and narrower widths will increase yields. Double end mitering, boring and doweling will increase along with most of the marking?out and band sawing.
Moreover, standardization of widths and tenon cuts will make it practical for frame makers to own small tenon machines and other high?speed production equipment. The frame maker will need curved plywood parts especially the prototype frame of 1/10″ thick veneer laid up in three piles. The curves are simple and many customs plywood makers will come up to supply the frame makers with their individual requirements.
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