The Manufacturing of Plywood

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Eng: Erasmo Reyes Perez.

StepsSelecting the Log Stripping the Bark Peeling the Log Making a Continuous Ribbon of Wood Cutting and Stacking Gluing the Wood Pressing the Wood Trimming, Sanding, and Finishing Conclusion to the Manufacturing of

Plywood

Selecting the long

• Plywood is made from several different species of trees. 

• The first step in the manufacturing process of plywood is the selecting of the logs.  The logs that are selected are chosen for their straightness and roundness. 

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Stripping the Bark

• The selected logs are then stripped of their bark.  According to the following picture, the logs are fed in from the right by chain conveyors.  The logs are going to be stripped so therefore, they are rotated by ridged wheels as the cutting head on the track reverses the log from end to end.

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PEELING THE LOG

• The next step of the manufacturing process is peeling the log.  The log sections, which show the marks of the debarking knives, are fed into the lathe loader where the log revolves around on a huge lathe against a long cutter blade which is reduced to a 6-inch core or sawed into lumber or chipped (44).  The following illustration shows the operation of the peeler.

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MAKING A CONTINUOUS RIBBON OF WOOD

• Following the peeler process, the next step in the manufacturing process of plywood is taking the logs and making them into a continuous ribbon of wood.  The cutting edge of the lathe is forced against the spinning log.  The wood is unwound in a continuous ribbon varying in thickness depending on how its used

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CUTTING AND STACKING

• The standard size for the pieces of wood to be cut is 4’ X 8’.  The thickness of the plywood will be determined later when the sheets are glued and pressed together to a varying thickness of which ¼” to ¾” is the most common.  As the sheet emerges from the peeler it is scanned automatically and then it is stacked green and is prepared for the transferring to the drying ovens

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GLUING THE WOOD

•      The next step in making plywood is the gluing of the plies together in order to determine the desirable thickness of the plywood sheet.  Modern methods of manufacturing use synthetic plastics such as urea resins or phenol-formaldehyde for bonding the plies together.  These glues are mixed mechanically and then spread on alternate layers of lumber by passing between pairs of grooved metal or hard rubber rollers

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PRESSING THE WOOD

• The following step in manufacturing process is the procedure of pressing the glued sheets together to a desired thickness.  One example of a hot press machine.

• Hydraulic or pneumatic presses squeeze the plies together with heat and pressure or with just pressure only.  When heat is used the glue hardens within a few minutes.  The glue solidifies as the plies are pressed together; and once the pressure is released, the boards are considered dry .

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TRIMMING, SANDING, AND FINISHING

• Lastly the sheets have to go through a process that gets them ready to be shipped out for market.  This processes involves trimming, sanding and finishing the sheets.  This process also takes the sheets down to the proper size that is desirable to the consumer.  This is what makes the final smooth edges that are seen in the modern lumberyard.  The finished panels of plywood are then divided into two groups indicating whether they are for interior or exterior use.  Plywood may carry a quality grade, which is indicated with the letters A through C, with A being the highest quality.  This grade is based on requirements set by U.S. Commercial Standard CS - (35-36) (Wood 468).   

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CONCLUSION TO THE MANUFACTURING OF

PLYWOOD• These are the steps of the manufacturing process of

plywood from the original type of tree chosen, clear to the completed sheets of plywood stamped and ready to be shipped to your local hardware stores and lumber yards.  This process shows how the plywood, which the customer buys, comes from a variety of different tree species.  It also shows the mechanics of how the plywood you buy is made into widths, lengths and a variety of different thicknesses depending on the use of the material.  Hopefully, this illustrates the process of how a tree is manufactured into the plywood that is found in a local lumberyard.

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