For making curved parts from wood apply two basic ways: cutting out the pattern and bending the pre-steaming of wood using the template on a special machine. The first method leads to cutting of fibers and loss of strength of parts. The bending also provides a high percentage of useful output parts and considerable strength. Bent parts can be finished with high quality and subjected to various mechanical processing (profiling, forming spikes, lugs, etc.).
The ability of wooden Board to the bending is determined by the plasticity of the wood depends on the wood. Beech, birch, oak, pine and spruce have the highest plasticity. But you can control the plastic properties of the workpiece, and its hydrothermal treatment.
At 100 ° C and a humidity of 30% of the substances included in the composition of the cell material enters the gel state, while the walls of cells and fibers of the wood becomes elastic and soft. Such wood is easy to bend. After drying, the bent Board retains the shape given to it, because the colloidal substances harden.
Machining consists in boiling it in hot water or steaming with saturated steam of low pressure. Steaming is more common, since this treatment the wood is heated evenly, does not occur excessive moisture of the wood.
When thus treated Board is bent on a curve or in a special clamping device, material having internal stress. The wood stretched on the convex side and compressed on the concave. In the middle of the neutral layer voltage is equal to zero.
The outer layer is under tensile stress will have the elongation, and the inside will be shorter. The magnitude of deformation depends on the thickness of the docks and bend radius. To limit the elongation of the grain of the wood and to prevent their possible rupture on the convex side of the bent parts impose a splint of steel with a thickness of 2.5 mm Billet Flex with the tire. In this case the neutral line goes to the side of the stretched fibers off the Board, and bending only occurs due to the compression.
Advice 2: How to bend plastic pipe
In the manufacture of structures of plastic products often have to bend the elements, giving them a desired configuration. In bending of such products there are several ways. The choice of a particular method depends on the available tools and the required accuracy. To bend, for example, a plastic pipe, you will need to work at it thermally.
You will need
- forming machine;
- - fibreboard;
- - silicone;
- - gas burner;
- construction Hairdryer.
To give the desired shape tube is made of polystyrene pre-manufactured frame made of fibreboard. Collect the form, in accordance with the length of the pipe and its diameter. After fitting the rims carefully apply it with sandpaper.
Molding machine manufacture of silicone shell for the plastic part. She will need to secure the tube on the rim and surface protection of plastic against scratches, chips and dents.
Insert the plastic pipe into the shell. Secure the item in the frame of hardboard. Place the entire design on the moulding machine. After heating the plastic will soften and begin to okazyvatsya to the frame. The product will take the necessary curved shape. Wait about ten minutes before they could release the pipe. Now the product can be removed from the mandrel and leave to cool.
In the absence of molding machines use a heat gun or gas burner. Pre-fabricated template that will match the shape of the future bent tube. It is desirable to avoid bending the plastic with sharp turns, so the template should have a smooth curve across its surface.
Mark the bend pipe. Move the heating device in place of the intended bend. In doing so, ensure the distance from the source of high temperature to the products was not too small to prevent ignition of the plastic.
Continuing to work on the pipe with a Hairdryer or torch, slowly roll the tube along the axis. When plastic becomes soft and pliable, place it on a prepared template and bend, bringing the bend to the desired angle. Comply with patience and accuracy, not to get tear of the product. Hold the curved pipe in the template to until it cools off. The hardened plastic off of the template and use as directed.