Computational Techniques in Statistical Analysis and Exploitation of CNC Machining Experimental Data

Author(s):  
N. A. Fountas ◽  
A. A. Krimpenis ◽  
N. M. Vaxevanidis

Extracting CNC machining data on- or off-line demands thorough and careful planning. Exploitation of this data can be carried out by statistical methods, in order to obtain the most influential parameters along with their respective level of significance. However, significance of machining parameters varies according to the posed Quality Characteristics at each machining phase. In actual experiments, measuring devices and assemblies are used, and data is recorded in computer archives. To shorten the production time and cost, machining processes are planned on CAM software, especially when complex part geometries, such as sculptured surfaces, are involved. Hence, planning machining experiments using CAM software modules is an efficient approach for experimentation on the actual CNC machine tools. Data extraction and statistical analysis methodologies are presented along with respective machining experimental examples.

Author(s):  
Xun Xu

The introduction of CNC machines has radically changed the manufacturing industry. Curves are as easy to cut as straight lines, complex 3-D structures are relatively easy to produce, and the number of machining steps that required human action has dramatically reduced. With the increased automation of manufacturing processes with CNC machining, considerable improvements in consistency and quality can be achieved. CNC automation reduced the frequency of errors and provided CNC operators with time to perform additional tasks. CNC automation also allows for more flexibility in the way parts are held in the manufacturing process and the time required to change the machine to produce different components. In a production environment, a series of CNC machines may be combined into one station, commonly called a “cell”, to progressively machine a part requiring several operations. CNC controller is the “brain” of a CNC machine, whereas the physical configuration of the machine tool is the “skeleton”. A thorough understanding of the physical configuration of a machine tool is always a priority for a CNC programmer as well as the CNC machine tool manufacturers. This chapter starts with a historical perspective of CNC machine tools. Two typical types of CNC machine tools (i.e. vertical and horizontal machining centres) are first discussed. Tooling systems for a CNC machine tool are integral part of a CNC system and are therefore elaborated. Also discussed are the four principal elements of a CNC machine tool. They are machine base, machine spindle, spindle drive, and slide drive. What letter should be assigned to a linear or rotary axis and what if a machine tool has two sets of linear axes? These questions are answered later in the chapter. In order for readers to better comprehend the axis and motion designations, a number of machine tool schematics are given.


2006 ◽  
Vol 315-316 ◽  
pp. 98-102 ◽  
Author(s):  
J.H. Shen ◽  
H.T. Zhang ◽  
Hong Tao Cao ◽  
Jian Guo Yang ◽  
C. Wang

The volumetric positioning precision of CNC machine tools is the key factor to get high machining precision, so the analysis, measurement and compensation of the volumetric error is becoming more and more important. In this paper, the modeling results of 3-axes CNC machine tools with four different configurations are given based on rigid body theory and homogeneous coordination transformation matrices. An improved sequential step diagonal measurement method is proposed and analyzed because the current laser measurement methods are complex and time cost. At the final section of the paper, the measurement data was applied into the error compensation and the sequential step diagonal measurement method was validated efficient and convenient.


Author(s):  
P Vichare ◽  
A Nassehi ◽  
S Newman

The capability of any manufacturing system primarily depends on its available machine tools. Thus machine tool representation is a vital part of modelling any manufacturing system. With the rapid advances in computerized numerically controlled (CNC) machines, machine tool representation has become a more challenging task than ever before. Today's CNC machine tools are more than just automated manufacturing machines, as they can be considered multi-purpose, multi-tasking, and hybrid machining centres. This paper presents a versatile methodology for representing such state-of-the-art CNC machining system resources. A machine tool model is a conceptual representation of the real machine tool and provides a logical framework for representing its functionality in the manufacturing system. There are several commercial modelling tools available in the market for modelling machine tools. However, there is no common methodology among them to represent the wide diversity of machine tool configurations. These modelling tools are either machine vendor specific or limited in their scope to represent machine tool capability. In addition, the current information models of STEP-NC, namely ISO 14649, can only describe machining operations, technologies, cutting tools, and product geometries. However, they do not support the representation of machine tools. The proposed unified manufacturing resource model (UMRM) has a data model which can fill this gap by providing machine specific data in the form of an EXPRESS schema and act as a complementary part to the STEP-NC standard to represent various machine tools in a standardized form. UMRM is flexible enough to represent any type of CNC machining centre. This machine tool representation can be utilized to represent machine tool functionality and consequential process capabilities for allocating resources for process planning and machining.


2021 ◽  
Author(s):  
◽  
Jonathan William Murdoch

<p>Throughout history the use of scale representations has been important in the process of creating architecture. In recent times the introduction of computer-aided design (CAD) has significantly altered traditional methods of conceptual design representation, mainly through a shift from the physical to the virtual. The aim of the research is to explore the relationship between computer aided manufacturing (CAM) and the methods for extracting and producing qualities of a conceptual nature from computer and numerically controlled (CNC) machine, and how this could advance conceptual creativity formulating in buildable form. The qualities that are inherently produced by CNC machining processes are then captured back into the three-dimensional environment (CAD), and then re-exported via CNC machining. The information that flows from the digital to the physical and then back again, creates new physical qualities that would not normally be produced, and allows for further investigation. Through the misrepresentation and reinterpretation of machine processes in this research, the output produces an object of an abstract nature created through identifying extraordinary expressions of tool paths. This 1:1 abstract object expresses qualities of craft produced by the CNC machine and creates a new form of craft that can be compared to the expression of the traditional craftsman and their trade. This simple movement between scales and formats begins to generate new design processes that in turn translate the conceptual expression of the object into a buildable form. On final completion of the object this project has proven that CAM conceptual creativity can be translated and formulated into built form. A key observation of this research is that identifying CAM production techniques can produce abstract representation through a new means of design representation.</p>


Manufacturing ◽  
2003 ◽  
Author(s):  
Donald Esterling ◽  
F. Donald Caulfield ◽  
Aaron Kiefer ◽  
Gregory Buckner ◽  
Pavan Jaju

The frequency response function (FRF) of a CNC machine tool is composed of tool/toolholder/spindle dynamics, and plays an important role in determining the stability of high speed machining processes. This paper details the design, development and operational verification of a non-contacting, controllable, electromechanical actuator (EMA) for measuring the FRFs of tools mounted in CNC milling machines. Although standard modal testing methods are available and provide similarly accurate results, these test procedures are difficult to perform in machine shop environments and can require expensive equipment. The EMA developed as part of this research extends the capabilities of the NIST “best speeds device” to provide controllable, non-contacting excitation for modal tests on machine tools. This EMA device offers the advantages of being accurate, easy to use, and applicable to a wide variety of tools and operating conditions.


2012 ◽  
Vol 163 ◽  
pp. 233-237
Author(s):  
Yan Zhong Wang ◽  
Liang Wei Hou ◽  
Yan Qiang Liu ◽  
Rong Shen ◽  
Can Hui Wu ◽  
...  

This paper describes the machining method of complex surface face gear used CNC machine tools and hob cutter, Based on surface characteristics and gear hob principle. A coordinate transformation process is explained in detail in the five axes CNC machining of complex parts. A CNC hob method is proposed about surface orthogonal gear. An experiment is done for validating the method.


2011 ◽  
Vol 418-420 ◽  
pp. 581-584
Author(s):  
Yan Ma ◽  
Wei Li ◽  
Dan Ping Li

CNC machining centers were analyzed by the failure mode, effect and criticality analysis (FMECA) method for identifying the weakest links of a CNC machining center and obtaining that the spindle system is the primary factor that affects the reliability of CNC machining centers. The spindle system was analyzed at different feed speed by the finite element method. The results have important guiding significance for the reliability research of CNC machine tools.


2012 ◽  
Vol 214 ◽  
pp. 939-943
Author(s):  
Jing Ping Liu ◽  
Yu Zhong Li

CNC machine tools and programming is a professional core curriculum of the vocational colleges in machinery manufacturing and automation, and CNC machining technology. This course involves teaching and professional practice, which requires us to improve teaching methods, improve the quality of teaching to promote students 'understanding of CNC machine tools and programming course and mastery, in order to develop students' practical capacity. In this paper, we use the conception, design, implementation, and operation of the CDIO model implementation of teaching reform, providing engineering teaching model with a new teaching ideas, and this also plays an active role in the training to cultivate innovative talents.


2011 ◽  
Vol 692 ◽  
pp. 112-119 ◽  
Author(s):  
Alfredo Sanz ◽  
Ignaciof González ◽  
Agustin Javier Castejón ◽  
Jose Leopoldo Casado

This paper presents a methodology for the incorporation of a Virtual Reality development applied to the teaching of manufacturing processes, namely the group of machining processes in numerical control of machine tools. The paper shows how it is possible to supplement the teaching practice through virtual machine-tools whose operation is similar to the 'real' machines while eliminating the risks of use for both users and the machines.


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