scholarly journals Correlation Studies of Dimensional Accuracy with Temperature Changes of Selected Elements of a Machine Tool in the Machining Process

2022 ◽  
Vol 16 (1) ◽  
pp. 253-259
Author(s):  
Damian Basara ◽  
Leszek Skoczylas
Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 580
Author(s):  
Francisco J. G. Silva

Though new manufacturing processes that revolutionize the landscape regarding the rapid manufacture of parts have recently emerged, the machining process remains alive and up-to-date in this context, always presenting itself as a manufacturing process with several variants and allowing for high dimensional accuracy and high levels of surface finish [...]


Author(s):  
Andre D. L. Batako ◽  
Valery V. Kuzin ◽  
Brian Rowe

High Efficiency Deep Grinding (HEDG) has been known to secure high removal rates in grinding processes at high wheel speed, relatively large depth of cut and moderately high work speed. High removal rates in HEDG are associated with very efficient grinding and secure very low specific energy comparable to conventional cutting processes. Though there exist HEDG-enabled machine tools, the wide spread of HEDG has been very limited due to the requirement for the machine tool and process design to ensure workpiece surface integrity. HEDG is an aggressive machining process that requires an adequate selection of grinding parameters in order to be successful within a given machine tool and workpiece configuration. This paper presents progress made in the development of a specialised HEDG machine. Results of HEDG processes obtained from the designed machine tool are presented to illustrate achievable high specific removal rates. Specific grinding energies are shown alongside with measured contact arc temperatures. An enhanced single-pole thermocouple technique was used to measure the actual contact temperatures in deep cutting. The performance of conventional wheels is depicted together with the performance of a CBN wheel obtained from actual industrial tests.


Author(s):  
Hossein Ghorbani-Menghari ◽  
Mehrdad Azadipour ◽  
Mehran Ghasempour-Mouziraji ◽  
Young Hoon Moon ◽  
Ji Hoon Kim

The deformation machining process (DMP) involves machining and incremental forming of thin structures. It can be applied for manufacturing products such as curved-surface blades without using 5-axis computerised numerical control machines. This work presents the effect of tool diameter and forming temperature on spring-back and dimensional accuracy of a simple fabricated part. The results of the first phase of the study are utilised to design the fabrication process of a curved surface blade. A feature-based algorithm is used to design the tool path for the forming process. The dimensional accuracy of the final product is improved through warm forming, two-point incremental forming, and extension of the bending zone to the outside of the product edges. The results show that DMP can be used to fabricate complex curved-surface workpieces with acceptable dimensional accuracy.


Author(s):  
Andrzej Gessner ◽  
Roman Staniek

The publication demonstrates an accuracy assessment method for machine tool body casting utilizing an optical scanner and a reference design of the machine tool body. The process allows assessing the casting shape accuracy, as well as determining whether the size of the allowances of all work surfaces is sufficient for appropriate machining, corresponding to the construction design. The described method allows dispensing with the arduous manual operation - marking out. Marking out, depending on the size and complexity, might take several working shifts for prototype casting. In case of large and elaborate casts, as those of machine tool bodies, marking out is often restricted only to the first cast of the desired body produced in a given casting mold. Such course of action is based on an assumption that casting is reproducible; hence, no need to assess each and every individual cast. While this approach saves time, it often results in late detection of casting errors (allowance shifts or insufficiencies) during the actual machining process. That, in turn, results in considerable losses due to the disruption of the work process and often demands cast repair. The aim of the hereby presented study is to introduce a new technological premise dispensing with manual marking out as well as allowing fast verification of the cast shapes.


2021 ◽  
Vol 2066 (1) ◽  
pp. 012113
Author(s):  
Weiwen Ye

Abstract Multi axis CNC machine tool has good linkage processing effect. Through the application of integral impeller in CNC machine tools, to improve the adaptability of CNC machine tools to complex surface processing parts, to improve the accuracy of multi axis CNC machine tools. The first part of this paper introduces the integral impeller and its machining characteristics; the second part introduces the basic NC machining process of integral impeller; the third part discusses the application of impeller in multi axis CNC machine tools from the creation of guide track, the simulation of integral impeller, software processing and generation. The purpose is to provide some reference for the processing and production of integral impeller.


Author(s):  
TJ Li ◽  
XH Ding ◽  
K Cheng ◽  
T Wu

Natural frequencies and modal shapes of machine tools have position-dependent characteristics owing to their dynamic behaviors changing with the positions of moving parts. It is time-consuming and difficult to evaluate the dynamic behaviors of machine tools and their machining accuracy at different positions. In this paper, a Kriging approximation model coupled with finite element method is proposed to substitute the dynamic equations for obtaining the position-dependent natural frequencies of a machine tool, as well as relative positions between the tool and the workpiece during the machining process. Based on the proposed method, dynamic performance optimization design of the machine tool is conducted under the condition of minimum relative positions. Three case studies are illustrated to demonstrate the implementation of the proposed method.


2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774843 ◽  
Author(s):  
Ahmed Nassef ◽  
Ahmed Elkaseer ◽  
El Shimaa Abdelnasser ◽  
Mohamed Negm ◽  
Jaber Abu Qudeiri

This article reports an investigation of the influence of process parameters on the obtainable dimensional accuracy when drilling glass using abrasive jet machining. In particular, holes were drilled out of glass sheets, and the effects of standoff distance, nozzle diameter, particle grain size and applied pressure on the kerf taper were examined. An artificial neural network technique was used to establish a precise model of kerf taper as a function of the process parameters. The proposed model was then optimised, and the conditions to minimise the kerf taper were identified using a genetic algorithm. The results revealed that standoff distance has a major effect on kerf taper, and it proved possible to substantially reduce the kerf taper by applying an axial feed to the nozzle so that the standoff distance is kept constant during the machining process.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
M. Balasubramanian ◽  
S. Madhu

Purpose The purpose of the study is to machine the composites at lower machining time with higher accuracy without causing delamination. Design/methodology/approach Abrasive jet machining is the technology appropriate for machining composite materials to obtain good dimensional accuracy without causing de-lamination. The central composite design was followed in deciding the number of experiments to be carried out. Findings The influence of abrasive jet machining process parameters on machining time, material removal rate (MRR) and kerf characteristics were investigated. The experimental results proved the newly designed internal threaded nozzle increased MRR, thereby reducing the machining time. Originality/value Machining of glass fibre reinforced polymer (GFRP) is one of the challenging tasks given its non-linear and in-homogeneous properties. In this investigation, newly developed threaded and unthreaded nozzles in machining were used for making holes on the GFRP composites.


1999 ◽  
Author(s):  
Alex O. Gibson ◽  
Jeffrey L. Stein

Abstract Machine tool spindle bearings are subjected to a large range of axial and radial loads due to the machining process. Further the rotating spindle must be extremely stiff to minimize the cutting tool’s deflection. The high spindle stiffness is achieved by applying a mechanical load to the bearings, the preload. In fixed preload spindles the bearing loads tend to increase with increasing spindle speed due to thermal expansion and it is well established that these thermally induced loads can lead to premature bearing failure. A model of thermally induced bearing load in angular contact bearing spindles is developed that includes an axis-symmetric reduced order finite element model of the heat transfer and thermal expansion within the spindle’s housing and shaft and the bearing and shaft dynamics. Nodal reduction is used in the reduced order model to minimize the number of temperature states and the computational load. The reduced order model’s calculated temperature and bearing load values are shown to closely match experimentally measured values over a wide range of spindle speeds. The paper ends with a parameter variation study which predicts a dramatic decrease in the thermally induced bearing load when silicon nitride balls are substituted for steel balls.


2018 ◽  
Vol 779 ◽  
pp. 149-152 ◽  
Author(s):  
Ashwin Polishetty ◽  
Basil Raju ◽  
Guy Littlefair

Titanium alloy, Ti-6Al-4V is a popular alloy used in wide range of design applications mostly in aerospace and biomedical industry due to its advantageous material properties. This research is based on threading operation in a cylindrical workpiece of Ti-6Al-4V additive manufactured by Selective Laser Melting (SLM) technique. Secondary machining is described as the operations that are performed on the workpiece after a primary machining in order to achieve a required finish and form. Common secondary operations after drilling includes threading, reaming and knurling. Threading is a significant machining process in almost all applications of Titanium alloys. The development of an efficient threading process for Titanium alloys and enhancing existing methods may lead to a wider application of additive manufactured Titanium alloys. The aim of this research is to find out favorable threading conditions for Titanium alloy Ti-6Al-4V to obtain better machinability. Threads are tapped into the workpiece using variable machining parameters such as spindle speed and depth of cut. Statistical data are collected and analyzed by qualitative and quantitative evaluation of the threads. The outputs under consideration to evaluate efficiency of the secondary machining include surface texture (roughness (Ra)), dimensional accuracy (thread geometry) and power required (cutting force).


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