# The Development of Rubber Tapping Machines in Intelligent Agriculture: A Review
## 4 Rubber Tapping Technology
### Manual Tapping  
[PERSON] et al. [61] optimized the use of a rubber knife to control tapping depth and used software to select component materials and conduct manufacturing tests on nine rubber trees. The treatment was carried out according to the design plan, keeping the depth between 1 and 1.5 mm of the cambium, the tapping thickness between 1.5 and 2 mm, and tilting angles between 35\({}^{\circ}\) and 60\({}^{\circ}\). The results of the functional testing showed that rubber tapping can function properly and using intervals of 09:00-10:00 WIB for slopes 60\({}^{\circ}\), 45\({}^{\circ}\), and 35\({}^{\circ}\), they obtained average latex amounts of 1.83 g, 1.11 g, and 0.74 g. The rubber tapping capacity of 5-6 s per tree was an improvement upon conventional rubber tapping, which required between 6-8 s with 5.32 cm\({}^{3}\) rubber bark consumption. Their blades were connected by means of bolt joints so that they could be easily replaced if a blunt force was encountered.  
[PERSON] et al. [51] designed a portable electric tapping machine. The experimental results showed that in addition to individual data, the difference in bark consumption at each cut was less than 0.2 mm, and the average bark consumption of each group was also less than 0.2 mm. This showed that the bark consumption was uniform and could meet the requirements of the design. Furthermore, the knife body had no extrusion on the tapping line, which was conducive to rubber discharge. The design's symmetrical blade structure can be used to tap rubber with an upside and a downside, greatly reducing the technical difficulty and labor intensity of rubber workers, and changing the rubber tapping operation from a professional task to a more accessible one. [PERSON] et al. [66] designed a series of electric rubber tapping knives called 4 GXJ. By adjusting the relative position of the guide and the circular edge of the blade, precise control of the tapping depth was realized at a millimeter level. Furthermore, by moving the guide up and down and adjusting its relative position with the horizontal edge, precise control of the millimeter thickness of bark consumption was realized. The results showed that under the conditions of torques of 0.2 N-m, 0.22 N-m, and 0.25 N-m, the movement curve of the transmission mechanism changed smoothly and periodically, and the maximum stress generated by the key components was 5.147 \(\times\) 10\({}^{3}\) MPa, which was much smaller than the yield strength of the material, 2.206 \(\times\) 10\({}^{8}\) MPa, and there was no obvious change in deformation. A performance comparison between a traditional tapping knife and an electrical tapping knife is shown in Table 3. Because of the need for a motor, a lithium battery, transmission components, and precision requirements, the cost of an electrical rubber cutter is higher than that of a traditional one. With the same operation time or labor intensity, the tapping area can be increased by 20-30%. At the same time, the use of an electrical cutter can reduce bark consumption and the damage to trees, which can make up for the higher cost.