Types Of Cuttings Research Articles

Characterizing Rock-Breaking Performance of PDC Cutters via Stability Metrics and Energy consumption in FDEM Simulations

As oil production increasingly transitions from shallow to deep formation, the need for efficient PDC cutters to drill through deep hard rock becomes paramount. Currently, there is a lack of effective methods for optimizing cutter shapes and their cutting parameters. This study addresses this gap by developing a rock-breaking mechanism model for PDC cutters and proposing a Stability Index (SI) based on cutting force variations during the cutting process. Using the FDEM method, we simulated the rock-breaking processes of planar, stinger, and machete cutters under various cutting depths and angles. SI and Mechanical Specific Energy (MSE) were employed as evaluation metrics to analyze the rock-breaking characteristics and determine the optimal cutting parameters for each cutter type. The results indicate that at shallow cutting depths, cutting force changes are minimal, predominantly causing plastic damage to the rock, resulting in lower stress and reduced wear on the PDC cutters. Conversely, at greater cutting depths, significant fluctuations in cutting force occur, leading to brittle failure and the generation of large cuttings. This sudden increase in cutting force can accelerate rock breaking but also increases the risk of cutter wear. Our findings suggest that the planar cutter offers stable performance with high cutting force requirements, optimal at a cutting depth of 1.5 mm and an angle of less than 20°. The stinger cutter, requiring lower cutting forces, performs best at a cutting depth of 2 mm and an angle of 20°. The machete cutter exhibits characteristics similar to the stinger cutter at shallow depths and the planar cutter at deeper depths, making it suitable for drilling at a depth of 2 mm and an angle of less than 10°. By balancing SI and MSE, this study provides a comprehensive approach to optimizing PDC cutter performance, enhancing drilling efficiency while minimizing cutter wear.

Experimental investigation and theoretical modeling of cutting mechanics using serrated tines in drilling lunar regolith simulant

Drilling is a widely used method for exploring extra-terrestrial bodies and seeking information on astrobiology, material composition, and evolution of the universe. The bit cutter of the drill tool is the main component that is in intense contact with the regolith and is of great importance for guaranteeing the cutting performance during drilling. The tine is a special type of cutter, and currently, there is no theoretical model describing its interaction with a lunar regolith simulant during cutting. To address this gap, semi-tine and full-tine cutting tests were performed at different cutting speeds, cutting depths, regolith densities, and tip angles. The experimental results showed that the regolith failure zone has an elliptical shape in the top view and a logarithmic spiral shape in the side view. Based on the failure pattern, a tine cutting mechanics model was built, and its results were compared with those of the experiments. The model exhibited good prediction accuracy for the cutting force, with a maximum error not exceeding 30.96% and an average error of 13.81%. To apply the model to extra-terrestrial drilling, a conical drill bit with multi-row serrated tines was designed. By analyzing the error between the theoretical and experimental values of the rotational torque, the model was further refined to provide a better match with the actual cutting results. The proposed cutting mechanics model describing the tine-regolith interaction mechanism can provide a reference for predicting drilling loads during planetary exploration.

Analyze the effects of CNC machining parameters on the surface roughness (Rz) of Anatolian chestnut

The effect of processing parameters on the surface roughness parameter Rz (mean peak-to-valley height) in CNC machining of Anatolian chestnut (Castenia sativa Mill.) wood species used in the woodworking and furniture industry was investigated. The machining conditions were determined to obtain the lowest Rz value. The experi-ments were carried out at the speeds of 8000, 12000, and 16000 rpm and the feed rates of 1000, 1500, and 2000 mm/min with 3 and 4 machining layers by using two different cutters with a diameter of 8 mm. Rz measurements were made on the obtained surfaces using the needle scanning method according to TS EN ISO 21920-2 (2021). In the measurements perpendicular to the fibers, the lowest Rz values were obtained with cutter type 2 (the cutter of the three cutting edge straight end mill), at 16000 rpm speed, 1000/2000 mm/min feed rate, and four machining layers. In the measurements made parallel to the fibers, the lowest Rz values were obtained at the cutter type 2 (the cutter of the three cutting edge straight end mill), at the speed of 16000 rpm and the feed rate of 1000/2000 mm/min and 4th step-down. A smooth surface (lower Rz value) was obtained with fourth cuts (step down, cut layer) instead of third cuts.

Analysis and Preventive Measures for an Abnormity of 220kV Isolating Switch

With the development of the power grid, the cutter brake is a kind of main equipment used cooperatively in the transmission and distribution line of the substations with the circuit breaker in the operation and maintenance of the electric power system. Its main role is to ensure the safety of the staff during the maintenance of high voltage equipment. The cutter brake forms a clear disconnection point to provide the staff with a sufficiently large insulation interval between the equipment in need of repair and other energized parts. In the long-term operation, various reasons may lead to various failures of the cutter brake, causing great security risks to the safe and stable operation of the power grid and personal safety. This paper is mainly focused on analyzing the abnormal phenomenon of the poor contact of the dynamic and static contact fingers of B phase of I cutter brake of Xinlang Line 1 in the 220kV substation, which causes most of the current to flow through the B phase of Xinlang Line 2. Future management and preventive measures for this type of cutter brake are also proposed in this paper.

Design and experimental verification of a new type of cutter for shield machine cutting underground plastic drainage boards

Design and experimental verification of a new type of cutter for shield machine cutting underground plastic drainage boards

Structure Design of Bionic PDC Cutter and the Characteristics of Rock Breaking Processes

The rational structural design of polycrystalline diamond compact (PDC) cutters effectively enhances the performance of drill bits in rock fragmentation and extends their service life. Inspired by bionics, a bionic PDC cutter was designed, taking the mole claw toe, shark tooth, and microscopic biomaterial structures as the bionic prototypes. To verify its rock-breaking effectiveness, the finite element method was employed to compare the rock-breaking processes of the bionic cutter, triangular prism cutter, and axe cutter. The study also investigated the influence of different back rake angles, cutting depths, arc radii, and hydrostatic pressures on rock breaking using the bionic cutter. Prior to this, the accuracy of the finite element model was validated through laboratory tests. Subsequently, a drill bit incorporating all three types of cutters was constructed, and simulations of rock breaking were conducted on a full-sized drill bit. The results demonstrate that the bionic cutter exhibits superior load concentration on the rock compared to the triangular prism cutter and the axe cutter. Additionally, its arc structure facilitates the “shoveling” of the rock, making it more susceptible to breakage under tensile stress. As a result, the efficiency of the bionic cutter surpasses that of the triangular prism and axe cutters. Similarly, it exhibits minimal fluctuations and values in cutting force. As the back rake angle and cutting depth increase, the MSE and cutting force of all three cutters also increase. However, the bionic cutter consistently maintains the lowest MSE and cutting force, confirming the superiority of its bionic structural design. The MSE and cutting force of the bionic cutter fluctuate with the increase of the arc radius, and the optimal arc radius falls within the simulation range, between 21 mm and 23 mm. Compared to the other two types of cutters, bionic cutters possess a unique structure that allows for better release of internal stress within the rock, thereby ensuring higher efficiency in rock-breaking, particularly in deep geological formations. The rock breaking simulation results of full-sized drill bits show that the use of a bionic cutter can improve the drill bit’s ability to penetrate the formation, reduce the possibility of drill bit bounce during the rock breaking process, prevent the occurrence of stick-slip, improve the drilling stability, effectively improve the efficiency and service life of the drill bit during the rock breaking process, and reduce the drilling cost. It is concluded that the research results of bionic PDC cutters are helpful to the development of high-performance drill bits and the reduction of drilling costs.

Reductions in Energy Consumption and Emission of Harmful Exhaust Gases by Fishing Vessels

This article presents an analysis of the influence of engine types, fuel types and selected methods of fuel treatment before injection on reductions in fuel consumption and exhaust emission components. This is the first of such studies, the continuation of which will allow a comprehensive assessment of the impact of cutter operations on environmental pollution. For the selected type of cutter, EEOIs (Energy Efficiency Operational Indicators) were determined to be a measure that takes into account both fuel consumption and harmful gas compound emissions depending on the type of engine used and the type of fuel. The data necessary to prepare this analysis were obtained during operational tests carried out on selected cutters with various types of engines fuelled with liquid fuel and a new catalytic fuel treatment method developed by the authors, while for the case of using gas fuel and a common rail engine, possible effects were forecasted. The effects of engine type, years of manufacture and fuel type (liquid and gas) on fuel consumption and emissions of selected exhaust components are demonstrated. The positive effects on fuel consumption and emissions of harmful exhaust constituents obtained, under laboratory test conditions, for an engine fuelled with catalytically treated fuel have allowed further research directions to be set for cutter engines equipped with injection equipment with applied catalytic coatings.

Numerical Simulation and Field Test of a PDC Bit with Mixed Cutter Arrangement to Break Non-Homogeneous Granite

As the depth of petroleum drilling increases, the strata environment becomes more complex. The efficiency and lifespan of Polycrystalline Diamond Compact (PDC) drill bits fail to meet current drilling demands. However, the structure and arrangement of PDC cutters are valuable determinants of drilling efficiency, although related research still has gaps and deficiencies. This study focuses on PDC cutters in axe, triangular prism, and circular forms. It establishes an inhomogeneous granite model based on the actual measurements of granite and verifies the accuracy of this model through uniaxial compression simulation. Finite element models of three types of cutters in various combination schemes are constructed to examine rock-breaking effects, with the best scheme optimized using Box-Behnken response surface methodology. The rock-breaking process of the optimal PDC drill bit layout has been compared to that of a single cutter bit. Field drilling has demonstrated the effectiveness of a mixed cutter arrangement. The results show that the inhomogeneous granite model can be trusted. The optimal arrangement involves axe cutters in the front row and an alternate arrangement of triangular prism cutters and axe cutters in the back row. The optimal lateral and longitudinal distances for the triangular cutters from the front row of axe cutters are 10 mm and 7 mm, respectively, while those for the back row of axe cutters from the front row are 10.06 mm and 7 mm, respectively. The ROP standard deviation in the drilling process of mixed cutter bits decreases by 53.06% and 43.08% compared to axe and triangular prism cutter bits, respectively. The drilling efficiency increases by 16.8% and 16.6%, respectively, demonstrating higher efficiency and stability. Field drilling results indicate that a mixed cutter bit increases efficiency by 23.5% compared to a bit with only triangular prism cutters. This study posits that research on the combination schemes and parameters of PDC cutters can significantly enhance drilling efficiency, thereby reducing the drilling cycle and costs.

Comparative Study of the Rock-breaking Mechanism of a Disc Cutter and Wedge Tooth Cutter by Discrete Element Modelling

The operation of a shield tunnel boring machine (TBM) in a high-strength hard rock stratum results in significant cutter damage, adversely affecting the thrust and torque of the cutter head. Therefore, it is very important to carry out the research on the stress characteristics and optimize the cutter parameters of cutters break high-strength hard rock. In this paper, the rock-breaking performance of cutters in an andesite stratum in the tunnel of Qingdao Metro Line No. 8 was investigated using the discrete element method and theoretical analysis. The rock-breaking processes of a disc cutter and wedge tooth cutter were simulated by software particle flow code PFC3D, and the rock-breaking degree, stress of the cutter, and rock-breaking specific energy were analyzed. The rock damage caused by the cutter in a specific section was divided into three stages: the advanced influence, crushing, and stabilizing stages. The rock-breaking degree and the tangential and normal forces of the wedge tooth cutter are larger than that of the disc cutter under the same conditions. The disc cutter (wedge tooth cutter) has the highest rock-breaking efficiency at a cutter spacing of 100 mm (110 mm) and a penetration depth of 8 mm (10 mm), and the rock-breaking specific energy is 11.48 MJ/m3 (12.05 MJ/m3). Therefore, two types of cutters with different penetration depths or cutter spacing should be considered. The number of teeth of wedge tooth cutters can be increased in hard strata to improve the rock-breaking efficiency of the shield. The research results provide a reference for shield cutterhead selection and cutter layout in similar projects.

The use of an artificial neural network for predicting the machining characterizing of wood materials densified by compressing

In this study, an approach for artificial neural network (ANN) was presented to predict and control arithmetical mean surface roughness value (Ra), machining properties of wood materials densified by compressing in a computer numerical control (CNC) machine. Black poplar (Populus nigra L.) tree species were used as the experimental material. After specimens were densified by Thermo-Mechanical (TM) method at 0%, 20%, and 40% ratios, machining process of specimens were performed at 1000, 1500, and 2000 mm/min feed speeds and in 12000, 15000, 18000 rpm rotation speed on a CNC vertical wood machining center by using two different cutters. Data used for the training and testing of an ANN. Cutter type, compression ratio, feed rate, and spindle speed were selected as Four parameters. While hidden layer of the Ra model has ten neurons, one hidden layer was used, Compression ratio is the most significant parameter, followed by feed speed for Ra values. surface roughness increases with increased feed rate. Ra values in training, validation, and testing the data set for Ra were 0.97122, 0.8538, and 0.76685, respectively. The Mean Square Error (MSE) value was determined as 0.0019914 test of the network. The proposed ANN model came to agreement with the measured values in predicting surface roughness Ra values of MAPE. The MAPE value was calculated as 6.61, which can be considered a very good prediction (MAPE< 10 % = very good prediction). The study showed that obtained ANN prediction model is a practical and efficient tool to model the Ra of wood. For reducing energy, time and cost in the wood industry (densification and CNC wood machining), current research results can be implemented.

Small‐diameter tunneling in difficult ground – Analysis of TBM performance in hard rock

AbstractSmall‐diameter tunneling in hard rock is increasingly widespread due to the need for new and longer utility tunnels comprising sewer, stormwater, freshwater, or hydropower as well as cable tunnels and casings for pipelines transporting gas or hydrogen. Utility tunnels have to deal with a wide range of geological settings, like small overburden, weathered rock, rock–soil transitions, as well as fractured or intact hard rock with high strength and abrasivity. A database has been created including 35 hard rock projects with diameters between 1 and 5 m as well as more than 70,000 m of tunnel alignments, with a median drive length of less than 500 m. Challenges in creating it and some early interpretations based on the contents of the database are presented. Details about an exemplary pipe jacking project in basement rocks in Brittany, France, are given. The large variety in this small‐diameter range in hard rock includes different TBM types, cutterhead designs, cutter types, and geotechnical conditions. Potential pitfalls in small‐diameter TBM data analysis are shown and general drive parameter trends and penetration prediction approaches are presented and set in relation to the geotechnical conditions. Our analysis shows that difficult ground conditions do not only incorporate rocks with very high strength, but also generally weak rocks like schist or limestone could be responsible for low penetration rates and high thrust forces.

Prediction of geology condition for slurry pressure balanced shield tunnel with super-large diameter by machine learning algorithms

Real-time and precise prediction of geological conditions is extremely beneficial to the safe and efficient construction of slurry pressure balanced shield machines (SPBMs), especially for super-large diameter tunnels. Machine learning algorithms provide an effective way to predict geological conditions and have been successful in hard-rock tunnel boring machine (hard-rock TBM) tunnels or earth pressure balance shield machine (EPBM) tunnels. However, the effectiveness of machine learning in predicting geological conditions for super-large diameter SPBM tunnels is still unknown. This study systematically demonstrated the application of machine learning algorithms to the prediction of geological conditions in super-large diameter SPBM tunnels based on field data from the Heyan Road crossing river tunnel. The relationship between SPBM parameters and geological conditions was first evaluated, and subsequently, an adaptive model was proposed to determine the number of input variables. The performance of three algorithms, random forest (RF), AdaBoost, and support vector machine (SVM), in rock mass classification, and seven algorithms, multi-objective random forest (MORF), single-target-RF, regressor chain-RF, single-target-AdaBoost, regressor chain-AdaBoost, single-target-SVM, and regressor chain-SVM, in formation percentage prediction, were compared. The results showed that machine learning algorithms can effectively predict the geological conditions in super-large diameter SPBM tunnels. Specifically, RF had the best performance in rock classification compared with AdaBoost and SVM. MORF outperforms the other six algorithms in terms of formation percentage prediction. Additionally, sensitivity analysis indicates that the newly proposed parameters, including slurry system parameters and cutter type, have a clear positive effect on the performance of geological condition prediction.

Design and Simulation Analysis of a Flexible Clamping and Conveying Device of a Green Leafy Vegetable Cutting and Bundling Integrated Machine

In order to improve the harvesting production efficiency of green leafy vegetables, this paper designs and simulates the flexible clamping and conveying device of the green leafy vegetable cutting and bundling integrated machine. Through theoretical calculation and 3D modeling, the design optimization of key components is carried out in this paper. The cutter head of the guillotine cutting and throwing device is a wheel cutter type. The throwing blades are axially symmetrically distributed on the cutter head, and the movable blades are radially distributed at equal angles and are located in the middle of the two throwing blades. The electronic control system of the wrapping device uses a pressure sensor to cooperate with the baling device to realize automatic wrapping after baling. In addition, the drive chassis of the machine is a hydrostatic drive system, which is convenient for step-less speed change and automatic control within a certain range. Through the simulation study, it can be seen that the flexible clamping and conveying device of the green leafy vegetable cutting and bundling integrated machine proposed in this paper can meet the industrialization needs of green leafy vegetables.

Development and application of a full-scale mechanical rock-cutting platform for measuring the cutting performance of TBM cutter

With the massive development of mechanical equipment for underground space construction, understanding the cutting mechanism and measuring the cutting performance of various cutters used in tunnelling boring machine prior to the construction is vital for increasing tunnelling efficiency and reducing cost. Mechanical rock-cutting tests have been an indispensable method for investigating the cutting characteristics, which can be effectively used for guiding the mechanical excavation of underground engineering. In this paper, a novel full-scale cutting platform developed by Shanghai Shield Design and Experimental Research Center Co., Ltd is introduced. The rock types, rock structure types, cutter types, cutting radius, rotation speed, penetration depth, cutting modes, cutter spacing and cutter installation angle are considered and integrated into the design of cutting platform. Specifically, different cutters, including disc cutters, scraper cutters, shell cutters and pick cutters, can be considered in this platform. Moreover, the circular cutting mode can be conducted with cutting diameter ranging from 0 to 6.2 m, and the arc cutting method is originally proposed to perform a rotary cutting test with cutting diameter above 6. 2 m. Notably, a laser measurement method is newly performed to measure the rock surface profile and calculate the rock cutting volume in the rotary cutting mode. The rock-cutting platform consists of mechanical system, hydraulic system, cutterhead system, control system, data sensing and acquisition system. The measuring reliability and accuracy of the newly designed rock-cutting platform and laser measurement is experimentally verified by the rotary cutting tests on granite and mortar using disc cutter and scraper cutter. A critical cutting radius of 1000 mm for side force is acquired, and the effects of cutting radius and cutting depth are initially investigated. The development of the full-scale rock-cutting platform is an effective measurement method for cutting performance, which can provide data support for optimization of cutterhead layout and determination of working parameters.

СОЗДАНИЕ КАНАВОЧНОГО И ОТРЕЗНОГО ИНСТРУМЕНТА С КАНАЛАМИ ДЛЯ ОХЛАЖДЕНИЯ, ИЗГОТОВЛЕННЫМИ С ПОМОЩЬЮ АДДИТИВНЫХ ТЕХНОЛОГИЙ

The study objective is to develop the design and technology of manufacturing grooving and cutting tools with internal channels for supplying coolants under high pressure. The design assumes the use of conventional replaceable cutting carbide plates (CCP) offered by many manufacturers. Due to the fact that drilling of narrow channels in the cutter is very problematic, it is proposed to manufacture the front part of the cutter, which secures the replaceable cutting carbide plate, in an additive way. The back of the cutter (holder) can be made by traditional methods. At the same time, the options for fixing the replaceable cutting carbide plates (CCP) are analysed, as well as basing it in the holder and the method of coolant supply. The variants of the design of grooving and cutting tools according to the criterion of treatment features are considered. Special attention is paid to the design of cutters for the surface treatment of narrow deep grooves. The novelty of the work is in carrying out research related to the development of a new design of cutting tools with channels for coolant supply and the method of its manufacture. The research method is 3D modeling of the tool and computer analysis of the stress state on the support surface of the tool head. The development of designs of grooving and cutting tools with cooling channels made with the help of additive technologies is currently not described in the scientific literature. Study result: 3D models, drawings of tools for cutting radial and axial grooves and tools for cutting the edges are obtained. Studies of the stressed state of the support surfaces for CCP are carried out. Prototypes of the corresponding three types of cutters are made. Conclusions: the conducted research proves the prospects of using the method. Thanks to the use of the developed tool, it is possible to increase the productivity of machining parts made of hard-to-machine material, including titanium alloys and heat-resistant steels. As a result, the task of creating a domestic cutting tool that surpasses imported analogues in its properties can be solved.

Determination of Optimal Drilling Parameters of Massive Wooden Edge Glued Panels (EGP) and Medium Density Fiberboard using Taguchi Design Method

In this paper, the optimization of computer numerical control (CNC) drilling parameters was conducted using the Taguchi design method on the drilling holes’ inner surfaces roughness (Ra) massive wooden edge-glued panels (EGP) made of spruce (Picea Orientalis Link.), beech (Fagus Orientalis Lipsky), Iroko (Chlorophora excelsa) and Medium Density Fiberboard surfaced with synthetic resin sheet (MDFlam). Three drilling parameters and their effects on Ra were evaluated. These parameters included spindle speed, feed rate, and cutter type. Surface roughness measurements according to ISO 4287 were performed on the inner surfaces of the holes, and Ra values were obtained. An analysis of variance (ANOVA) was performed to identify the significant factors affecting the Ra. Optimum drilling parameter combinations were acquired by analyzing the signal-to-noise (S/N) ratio. It is shown that the most ideal result was obtained with a two flutes cutter (cutter number 2) at 18000 rpm and feed of 1750 mm/minute for in-hole roughness values of the MDFlam test sample. In the drilling operations performed with a double-entry cutter, the lowest roughness values were obtained in all materials.

Performance Test of Cassava Cutting Machine Type of Double Block Cutter

Preparation of cassava seeds using a machete or hand saw takes a long time, the results are not uniform, and there is a potential for damage to cassava seedlings. The double block cutter type cassava stem cutting machine has been designed to produce high capacity and good quality cassava seeds. This study aims to test the performance of the cassava stem cutting machine with the double block cutter type. Performance tests include measuring machine working capacity, fuel consumption, seed uniformity, and planting test. The cutting test was carried out using 3 varieties of cassava seedlings. The machine works at a rotational speed of 3800 rpm and the test was carried out with various feeding loads, namely 3 rods, 4 rods, and 5 rods with. Each test was repeated 3 times. Cassava stem cutting machine (Petokong) is suitable for producing cassava stems with an average working capacity of 16275 seeds/hour. The results of the Anova test showed that the number of baits and varieties of cassava seeds and their interaction had a significant effect on the working capacity of the Petokong machine. Variations in fuel consumption are thought to be influenced by the variety of cassava stem used, which is influenced by the stem diameter of each variety. The Petokong machine is far superior to manual cutting using a machete or saw which can only produce 815 and 3005 seeds/hour per hour. The average fuel consumption is 1.82 liters per hour. Seed uniformity is about 98% and seedling damage can be minimized to 2%. The seeds produced by the Petokong machine can grow well, which is indicated by the appearance of shoots and an even distribution of roots. Keywords: Cassava seeds, Cassava stem cutter, Double block cutter, Petokong

Analysis and Application of a New Hybrid Drill Bit for Use in Hard Rocks

Abstract A polycrystalline diamond compact (PDC) bit has advantages, such as a fast drilling rate and long drilling footage, but its abrasive resistance is low. Although an impregnated diamond bit has a high abrasive resistance, the corresponding rate of penetration (ROP) is low. In view of the difficulties of rock breaking in hard rocks and the characteristics of each cutter type, it is necessary to design a new hybrid drill bit with multiple cutting functions. Through laboratory experimentation and analysis, this study investigated a conical PDC cutter with a strong penetration capacity, abrasive resistance, and impact resistance, and developed a new diamond-impregnated block embedded with natural diamonds, with consideration of its matrix formulation and diamond grades, sizes, and concentrations. Moreover, this research optimized the crown shape, blades, cutters’ position, and number with a reinforced hydraulic structure. The combination of three cutters with different structures enables the drill bit to adapt to drilling in hard rocks and greatly improves the rock-breaking efficiency and service life of the drill bit. The drilling test was conducted of the well Jingu 1-1HF in the Jinshan gas field and drill bit demonstrated excellent performance.

Determination of the machining characteristics of Uludağ fir (Abies nordmanniana Mattf.) densified by compressing

ABSTRACT The main objective of this study is to determine optimum machining parameters to specify the effect of densification by compressing the processing properties of wood material and to achieve the best surface quality in materials densified at different rates. In line with this goal, low-density Uludag fir (Abies nordmanniana Mattf.) tree species,widely grown in Turkey, were selected as the experimental material. Samples, which were compressed and densified by the thermo-mechanical method at 0%, 20% and 40% ratios, were processed at 1000, 1500 and 2000 mm/min feed speeds and in 12,000, 15,000, 18,000 rpm rotation speeds on a CNC machine by using two different cutters. Ra and Rz surface roughness values were measured to evaluate the surfaces obtained. With the increase in the compression ratio (from 0% to 40%), roughness values decreased. Roughness values increased with the increase of the feed rate. The lowest roughness value for Ra occurred in the cutter type 2 at 40% compression ratio, 1000 mm/min feed rate and 18,000 rpm speed. The lowest roughness value for Rz occurred in the cutter type 1 at 40% compression ratio, 1500 mm/min feed rate and 18,000 rpm speed.

Bionic Optimization Design and Experiment of Reciprocating Cutting System on Single-Row Tea Harvester

The reciprocating cutting system is one of the key parts of a tea harvester; and its cutting performance directly determines the cutting power consumption and harvesting quality of the machine. Because the structural parameters of reciprocating cutting systems do not match the tea cut; resulting in larger cutting resistance, it is necessary to optimize the structural parameters. The cricket mouth part has outstanding performance in tea tree fiber cutting; and the curved structural characteristics of the upper jaw of the cricket have been useful to improve the cutting efficiency of cutting system. Quantitative analysis of the structure of the upper jaw revealed that the arc-shaped structure of the incisor lobe would inspire new bionic blades and bionic cutters to solve the above problems. The cutting performance experiment of the cutting blade was designed for investigating the effects of inter-node number; tea variety and blade type (ordinary blade; bionic blade e and bionic blade f) on the cutting force and cutting power consumption. Experimental results of cutting performance have shown that the bionic blade could reduce cutting resistance and cutting power consumption. Tea varieties had little effect on cutting force and cutting power consumption. In addition, the orthogonal test was carried out to study the influence of cutter type with the cutting speed ratio and cutting angle on the integrity rate and missing rate of tea shoot. The field cutting experiment showed that the cutting angle was the most important for the integrity rate and missing rate of tea shoot; followed by the cutter speed ratio; and finally, the cutter type. The optimum combination of parameters was a cutting speed of 0.8 m/s; a forward speed of 1.0 m/s; a cutting angle of −3°, and using the bionic cutter e. With the optimal parameter combination, the integrity rate and missing rate of the tea shoot were 92.7% and 3.9%, which were increased by 13.2% and decreased by 6.4% compared to those under the condition of the 0° cutting angle and an ordinary cutter. As a result, the bionic cutter could obviously reduce cutting resistance; reduce cutting power consumption and improve the harvesting quality. These results would provide guidance for the design of the reciprocating cutting system of tea harvesters and other stalk cutting machinery.