To design the sanding system, it is necessary to understand the sanding process of different workpieces and the performance of the belt.
Categories of sanding processes
In the woodworking industry, sanding processes fall into the following categories:
(1) the plane thickness sanding, eliminate the workpiece shape and size deviation, ensure the equal, some can play the role of grinding instead of planing.
(2) the fine sanding of the surface is used to eliminate the traces of the fixed thickness sanding, the roughness and burr scar knot caused by the blade and texture.
(3) Further refine the sand before veneer veneer, dyeing, painting, printing and other processes to improve the surface quality and save dye and paint. Reduce product cost.
(4) the ultrafine sanding before and after the work, such as the polishing of the workpiece after the paint, in order to obtain a mirror bright paint film.
(5) the surface of the workpiece, used for the original surface is too smooth and need special roughness.
Relationship between belt performance and sanding system
The belt is composed of substrate, binder and abrasive. The substrate determines the flexibility, ductility, and tensile strength of the belt. The dry bonding agent makes the belt not cause sand particles to fall off under the conditions of strong grinding, the dry bonding strength is high, and is not sensitive to temperature change, and will not be sticky in high temperature grinding. Abrasives are composed of different materials and are divided into different granularity.
The quality of the sand and the joint of the belt has a lot to do with the joint strength is high, flexible, thickness tolerance of the sand belt, the surface quality of the workpiece after the sand is good, and will not produce a joint ripple. The thickness of the belt is uniform and the length of the two edges is the same, which can ensure good processing quality and easy to control the swing degree of the belt.
The thickness of abrasive belt can be coarse sand, fine sand and fine sanding of wood and wood-based panels, as well as polishing of lacquer surfaces.
Different sand heads in the wide band sander are equipped with different sand belts, which can meet the needs of different sanding processes.
Design of sand frame
According to different process requirements, sanding machine has three forms of sand frame:
(1) The upper sand frame, the feeding system is under the sand belt, and the lifting of the feeding table is used to complete the sanding of the workpiece with different thicknesses. Because the working height is not fixed, it is not conducive to the use of the production line.
(2) The lower sand frame and feeding system are located above the sand belt. Because of the fixed working height, they can be used in the production line.
(3) Mixed sand frame, composed of upper sand frame and lower sand frame, can complete the double-sided fixed thickness sanding of the workpiece, generally designed as heavy or semi-heavy sand frame, this sand frame is mainly used for wood-based panel production line.
The design of sand frame should mainly ensure its stiffness and seismic performance. The sand frame and the frame should be closely combined, so that it and the frame become a firm whole, only to meet the above two conditions, to ensure the stability of the sanding process and excellent sanding quality.