| dc.description.abstract | Rubber tree tapping is usually done using a manual type tapping knife. By using this knife, bark consumption and cutting depth can not be controlled. To solve the problem, it is important to develop a mechanized or electric tapping knife which can control bark consumption and cutting depth. The objectives of this study were to design and to test the working performance of an electric tapping knife. For determining the cutting power, bark cutting resistance of 5-17 years old rubber trees were measured using a tapping knife which is equipped with a ring transducer. A reciprocating chisel mechanism was chosen for cutting the bark, and was driven by an electric DC motor. The electric tapping knife was designed for downward tapping system, and equipped with rolls for controlling bark consumption and cutting depth. It was powered by a 66 Watt electric DC motor, and operated by a tapper. The prototype was tested on 5, 6 and 8 years old rubber trees. The test result showed that the bark consumption could be controlled in the range of 1.8-2.1 mm. Bark cutting depth was 0.9-1.2 mm, which was shallower than the normal cutting depth (1.5 mm from cambium). However, the bark cutting by the prototype was smooth and did not wound cambium layer and wood. The shallower cutting depth caused a lower latex yields in the range of 45- 66% lower than normal yield. Cutting duration using the prototype was 14-22 second per tree, which was longer than manual tapping duration (6-8 second). Tapping groove resulted by the electric tapping knife was tidy, uniform, and halfspiral shaped. | en |
