A model-based sustainable productivity concept for the best decision-making in rough milling operations

[EN]There is a need in manufacturing as in machining of being more productive. However, at the same time, workshops are also urged for lesser energy waste in cutting operations. Specially, rough milling of impellers and bladed integrated disks of aircraft engines need an efficient use of energy due to the long cycle times. Indeed, to avoid dramatic tool failures and idle times, cutting conditions and operations tend to be very conservative. This is a multivariable problem, where process engineers need to handle several aspects such as milling operation type, toolpath strategies, cutting conditions, or clamping systems. There is no criterion embracing productivity and power consumption. In this sense, this work proposes a methodology that meets productivity and sustainability by using a specific cutting energy or sustainable productivity gain (SPG) factor. Three rough milling operations-slot, plunge nad trochoidal milling-were modelled and verified. A bottom-up approach based on data from developed mechanistic force models evaluated and compared different alternatives for making a slot, which is a common operation in that king of workpieces. Experimental data confirmed that serrated end milling with the highest SPG value of 1 is the best milling operation in terms of power consumption and mass removal rate (MRR). In the case of plunge milling technique achieve an SPG < 0.51 while trochoidal milling produces a very low SPG value.The authors acknowledge the support from the Spanish Government (JANO, CIEN Project, 2019.0760) and Basque Government (ELKARTEK19/46, KK-2019/00004). This research was funded by Tecnologico de Monterrey through the Research Group of Nanotechnology for Devices Design, and by the Consejo Nacional de Ciencia y Tecnologia de Mexico (Conacyt), Project Number 296176, and National Lab in Additive Manufacturing, 3D Digitizing and Computed Tomography (MADiT) LN299129. The authors also acknowledge the support from Garikoitz Goikoetxea and fruitful discussions with Mr. Jon Mendez (Guhring (c)) and Endika Monge (Hoffmann Group (c))

Computer Numerical Controlled (CNC) machining for Rapid Manufacturing Processes

The trends of rapid manufacturing (RM) have influenced numerous developments of technologies mainly in additive processes. However, the material compatibility and accuracy problems of additive techniques have limited the ability to manufacture end-user products. More established manufacturing methods such as Computer Numerical Controlled (CNC) machining can be adapted for RM under some circumstances. The use of a 3-axis CNC milling machine with an indexing device increases tool accessibility and overcomes most of the process constraints. However, more work is required to enhance the application of CNC for RM, and this thesis focuses on the improvement of roughing and finishing operations and the integration of cutting tools in CNC machining to make it viable for RM applications. The purpose of this research is to further adapt CNC machining to rapid manufacturing, and it is believed that implementing the suggested approaches will speed up production, enhance part quality and make the process more suitable for RM. A feasible approach to improving roughing operations is investigated through the adoption of different cutting orientations. Simulation analyses are performed to manipulate the values of the orientations and to generate estimated cutting times. An orientations set with minimum machining time is selected to execute roughing processes. Further development is carried out to integrate different tool geometries; flat and ball nose end mill in the finishing processes. A surface classification method is formulated to assist the integration and to define the cutting regions. To realise a rapid machining system, the advancement of Computer Aided Manufacturing (CAM) is exploited. This allows CNC process planning to be handled through customised programming codes. The findings from simulation studies are supported by the machining experiment results. First, roughing through four independent orientations minimized the cutting time and prevents any susceptibility to tool failure. Secondly, the integration of end mill tools improves surface quality of the machined parts. Lastly, the process planning programs manage to control the simulation analyses and construct machining operations effectively

Manufacturability analysis for non-feature-based objects

This dissertation presents a general methodology for evaluating key manufacturability indicators using an approach that does not require feature recognition, or feature-based design input. The contributions involve methods for computing three manufacturability indicators that can be applied in a hierarchical manner. The analysis begins with the computation of visibility, which determines the potential manufacturability of a part using material removal processes such as CNC machining. This manufacturability indicator is purely based on accessibility, without considering the actual machine setup and tooling. Then, the analysis becomes more specific by analyzing the complexity in setup planning for the part; i.e. how the part geometry can be oriented to a cutting tool in an accessible manner. This indicator establishes if the part geometry is accessible about an axis of rotation, namely, whether it can be manufactured on a 4th-axis indexed machining system. The third indicator is geometric machinability, which is computed for each machining operation to indicate the actual manufacturability when employing a cutting tool with specific shape and size. The three manufacturability indicators presented in this dissertation are usable as steps in a process; however they can be executed alone or hierarchically in order to render manufacturability information. At the end of this dissertation, a Multi-Layered Visibility Map is proposed, which would serve as a re-design mechanism that can guide a part design toward increased manufacturability

Experimental investigation of cutting vibration during micro-end-milling of the straight groove

Micro-end-milling is a cutting technology that removes redundant material from machined workpieces by small-diameter end mills, and is widely used to manufacture miniature complex parts. During micro-end-milling, the cutting vibration caused by weak tool rigidity and high spindle speed is known as a key factor for decreasing machined quality and accelerating tool failure. This study reports on experiments of micro-end-milling of the straight groove for AISI 1045 steel. The waveform characteristics of acceleration vibration were revealed, the relationship between acceleration and milling parameters were analyzed and two types of relationship models were developed. The results show that, during micro-end-milling of the straight groove, the components of acceleration vibration from largest to smallest are in turn the transverse acceleration αY, the feed acceleration αX and the axial acceleration αZ. Compared with feed velocity vf and axial depth of cut ap, the spindle speed n has the highest influence on cutting vibration. The response surface model of acceleration vibration was shown to have a higher prediction accuracy compared to the power function model and is more suitable for the prediction and control of cutting vibration during micro-end-milling

Development of the reduction gear case 3411040-8902286-00 production process and the study of surface milling process

У кваліфікаційній роботі розроблено технологію виготовлення деталі корпус редуктора 3411040-8902286-00 з дослідженням процесу фрезерування поверхонь. Прийняті в кваліфікаційній роботі інженерні рішення дали змогу підвищити якість виготовлення деталі і зменшити підготовчо-заключний час на операціях, забезпечили концентрацію операцій а також скорочення затрат на виготовлення деталі. Для забезпечення безпечних умов роботи персоналу розроблено питання охорони праці і безпеки у надзвичайних ситуаціях. Наведено теоретичне узагальнення і вирішення наукової задачі, що полягає в дослідженні процесу фрезерування поверхонь.In qualification work the technology of manufacturing of a detail of the case of a reducer 3411040-8902286-00 with research of process of milling of surfaces is developed. The engineering decisions made in the qualification work made it possible to improve the quality of part manufacturing and reduce the preparatory and final time for operations, ensure the concentration of operations and reduce the cost of manufacturing parts. To ensure safe working conditions for staff, issues of labor protection and safety in emergencies have been developed. The theoretical generalization and the decision of a scientific problem consisting in research of process of milling of surfaces is resulted.Вступ 1 Аналітична частина 1.1. Аналіз стану питання 1.2. Службове призначення деталі 1.3. Висновки та постановка задач 2 Науково-дослідна частина 2.1 Характеристика об’єкту або предмету дослідження 2.2. Оброблення результатів досліджень 2.3. Висновки 3 Технологічно-конструкторська частина 3.1. Аналіз технологічності деталі 3.2. Вибір способу одержання заготовки 3.3. Формування технологічного процесу 3.4. Визначення припусків на оброблення 3.5. Визначення режимів різання 3.6. Розрахунок пристосування 4. Проектна частина 4.1. Визначення основних і допоміжних площ цеху 4.2. Розробка планів компонування цеху та розміщення обладнання на дільниці 5. Охорона праці та безпека в надзвичайних ситуаціях 5.1 Структура цивільної оборони об’єкту господарської діяльності машинобудівного профілю та виконання завдань по ліквідації аварійних ситуацій 5.3 Розрахунок вiброопор типу ОВ-30 для верстату моделi 1М61 Висновки Перелік посилань Додатк

Development of the reduction gear case 3411040-8902286-00 production process and the study of surface milling process

У кваліфікаційній роботі розроблено технологію виготовлення деталі корпус редуктора 3411040-8902286-00 з дослідженням процесу фрезерування поверхонь. Прийняті в кваліфікаційній роботі інженерні рішення дали змогу підвищити якість виготовлення деталі і зменшити підготовчо-заключний час на операціях, забезпечили концентрацію операцій а також скорочення затрат на виготовлення деталі. Для забезпечення безпечних умов роботи персоналу розроблено питання охорони праці і безпеки у надзвичайних ситуаціях. Наведено теоретичне узагальнення і вирішення наукової задачі, що полягає в дослідженні процесу фрезерування поверхонь.In qualification work the technology of manufacturing of a detail of the case of a reducer 3411040-8902286-00 with research of process of milling of surfaces is developed. The engineering decisions made in the qualification work made it possible to improve the quality of part manufacturing and reduce the preparatory and final time for operations, ensure the concentration of operations and reduce the cost of manufacturing parts. To ensure safe working conditions for staff, issues of labor protection and safety in emergencies have been developed. The theoretical generalization and the decision of a scientific problem consisting in research of process of milling of surfaces is resulted.Вступ 1 Аналітична частина 1.1. Аналіз стану питання 1.2. Службове призначення деталі 1.3. Висновки та постановка задач 2 Науково-дослідна частина 2.1 Характеристика об’єкту або предмету дослідження 2.2. Оброблення результатів досліджень 2.3. Висновки 3 Технологічно-конструкторська частина 3.1. Аналіз технологічності деталі 3.2. Вибір способу одержання заготовки 3.3. Формування технологічного процесу 3.4. Визначення припусків на оброблення 3.5. Визначення режимів різання 3.6. Розрахунок пристосування 4. Проектна частина 4.1. Визначення основних і допоміжних площ цеху 4.2. Розробка планів компонування цеху та розміщення обладнання на дільниці 5. Охорона праці та безпека в надзвичайних ситуаціях 5.1 Структура цивільної оборони об’єкту господарської діяльності машинобудівного профілю та виконання завдань по ліквідації аварійних ситуацій 5.3 Розрахунок вiброопор типу ОВ-30 для верстату моделi 1М61 Висновки Перелік посилань Додатк

Process dependent path planning for machining with industrial robots

The use of industrial robots in machining operations, such as milling, is an area of growing interest due to potential workflow and efficiency benefits. However, the inherent mechanical design of robot manipulators results in low stiffness and easy-to-excite dynamics when compared to the traditionally used \gls{cnc} machines. While research exists to compensate for deficiencies in robot manipulators, such as trajectory planning, online and offline error compensation, no integrated solution combining process-force compensation, robotic trajectory planning, and online error compensation exists, as would be required for industrial settings. This thesis introduces a deflection-limited trajectory planning algorithm for curvilinear slotting and linear peripheral milling cuts. The research purpose is to develop a solution involving a variable feed rate trajectory that limits the deflection-induced part errors when milling with an industrial robot. Thus, given a set of points to be approximated into a path, the methodology in this thesis generates a process-aware trajectory in which feed-rate has been adjusted to meet a user-specified deflection limit. The trajectory is formatted to be compatible with a closed-loop feedback and communication system with the industrial robot. Experiments are conducted using a large (range of 2855 mm), industrial robot milling system controlled by a closed-loop, laser tracker feedback system. Experimental data supports that the deflection-limited variable feed rate trajectory provides better part accuracy and surface roughness than the constant feed rate case. Furthermore, the variable feed rate trajectory executed by the closed-loop system maintains better positional accuracy than the open-loop, native robot controller using native motion types. Thus, the merit of a process dependent trajectory planner is argued, and future work for improvements and use-case generalization is suggested.M.S

A new CAD/CAM/CAE integration approach to modelling flutes of solid end-mills

Milling is used widely as an efficient machining process in a variety of industrial applications, such as the complex surface machining and removing large amounts of material. Flutes make up the main part of the solid end-mill, which can significantly affect the tool’s life and machining quality in milling processes. The traditional method for end-mill flutes design is using try-errors based on cutting experiments with various flute parameters which is time- and resources-consuming. Hence, modeling the flutes of end-mill and simulating the cutting processes are crucial to improve the efficiency of end-mill design. Generally, in industry, the flutes are ground by CNC grinding machines via setting the position and orientation of grinding wheel to guarantee the designed flute parameters including rake angle, relief angle, flute angle and core radius. However, in previous researches, the designed flute profile was ground via building a specific grinding wheel with a free-form profile in in the grinding processes. And the free-form grinding wheel will greatly increase the manufacturing cost, which is too complicated to implement in practice. In this research, the flute-grinding processes were developed with standard grinding wheel via 2-axis or 5-axis CNC grinding operations. For the 2-axis CNC flute-grinding processes, the flute was modelled via calculating the contact line between the grinding wheel and cutters. The flute parameters in terms of the dimension and configuration of grinding wheel were expressed explicitly, which can be used to planning the CNC programming. For the 5-axis CNC flute-grinding processes, the flute was obtained with a cylinder grinding wheel via setting the wheel’s position and orientation rather than dressing the dimension of grinding wheel. In this processes, optimization method was used to determine the wheel’s position and orientation and evaluating the machined flute parameters. Beside, based on the proposed flute model, various conditions for grinding wheel’s setting were discussed to avoid interference of flute profile. A free-form flute profile is consequently generated in its grinding processes. However, in the end-mill design, the flute profile is simplified with some arcs and lines to approximate the CAD model of end-mills, which would introduce errors in the simulation of cutting processes. Based on the proposed flute-grinding methods, a solid flute CAD model was built and a CAD/CAM/CAE integration approach for the end-mill was carried out to predict the cutting forces and tool deflection. And also, the prediction results with various methods are verified to demonstrate the advantage of proposed approach. This work lays a foundation of integration of CAD/CAM/CAE for the end-mill design and would benefit the industry efficiently