Low Speed Motion Control Experiments on a Single Point Diamond Turning Machine Using CMAC Learning Control Algorithm

1997 ◽  
Vol 119 (4) ◽  
pp. 775-781 ◽  
Author(s):  
G. Larsen ◽  
S. Cetinkunt
Keyword(s):  
Machine Tool ◽  
Control Algorithm ◽  
Single Point ◽  
Brittle Materials ◽  
Diamond Turning ◽  
Servo Control ◽  
Depth Of Cut ◽  
Positioning Accuracy ◽  
Tool Positioning ◽  
Highly Nonlinear

Diamond turning of brittle materials such as glass, ceramic, germanium, and zinc sulfide has been of considerable research interest in recent years due to applications in optics and precision engineering systems. When diamond turning brittle materials, material removal should be kept within the ductile regime to avoid subsurface damage (Evans, 1991; Nakasuji et al., 1990). It is generally accepted that ductile regime machining of brittle materials can be accomplished using extremely low depth of cut and feed rates. Furthermore, the tool positioning accuracy of the machine must be in the nanometer range to obtain optical quality machined parts with surface finish and profile accuracy on the order of 10 nm and 100 nm respectively (Nakasuji et al, 1990, Ueda et al., 1991). Nanometric level positioning accuracy of the machine tool axes is difficult particularly at low feed rates due to friction and backlash. Friction at extremely low feed rates is highly nonlinear due to the transition from stiction to Coulomb friction, and as such is very difficult to model. Standard proportional-integral-derivative (PID) type controllers are unable to deal with this large and erratic friction within the requirements of ultra precision machining. In order to compensate the effects of friction in the machine tool axes, a learning controller based on the Cerebellar Model Articulation Controller (CMAC) neural network is studied for servo-control. The learning controller was implemented using “C” language on a DSP based controller for a single point diamond turning machine. The CMAC servo control algorithm improved the positioning accuracy of the single point diamond turning machine by a factor of 10 compared to the standard PID algorithm run on the same machine and control system hardware.

Single Point Diamond Turning of Silicon by Using Micro-Laser Assisted Machining Technique

2014 ◽  
Author(s):  
Hossein Mohammadi ◽  
H. Bogac Poyraz ◽  
Deepak Ravindra ◽  
John A. Patten
Keyword(s):  
Fiber Laser ◽  
Cutting Tool ◽  
Single Point ◽  
Diamond Turning ◽  
Depth Of Cut ◽  
Beam Diameter ◽  
Diamond Cutting ◽  
Laser Assisted Machining ◽  
Diamond Cutting Tool ◽  
Si Wafer

In this study, single point diamond turning (SPDT) is coupled with the micro-laser assisted machining (μ-LAM) technique. The μ-LAM system is used to preferentially heat and thermally soften the work piece material in contact with a diamond cutting tool. In μ-LAM the laser and cutting tool are integrated into a single package, i.e. the laser energy is delivered by a single mode fiber laser to and through a diamond cutting tool. This hybrid method can potentially increase the critical depth of cut (DoC), i.e., a larger ductile-to-brittle transition (DBT) depth, in ductile regime machining, resulting in a higher material removal rate (MRR). An IR continuous wave (CW) fiber laser, wavelength of 1064nm and max power of 100W with a beam diameter of 10μm, is used in this investigation. In the current study SPDT tests were employed on single crystal silicon (Si) wafer which is very brittle and hard to machine by conventional methods. Different outputs such as surface roughness and depth of cut for different set of experiments were analyzed. Results show that an unpolished surface of a Si wafer can be machined in one pass to get a very good surface finish. The Ra was brought down from 1.2μm to 275nm only in one pass which is a very promising result for machining the Si wafer.

A Study of Cutting Strategy in Single-Point Diamond Turning of Micro V-Groove Patterns on Precision Roller Drums

2014 ◽  
Vol 625 ◽  
pp. 742-747
Author(s):  
C.H. Mak ◽  
C.F. Cheung ◽  
M.J. Ren ◽  
L.B. Kong ◽  
S. To
Keyword(s):  
Surface Quality ◽  
Single Point ◽  
Cutting Parameters ◽  
Diamond Turning ◽  
Surface Generation ◽  
Depth Of Cut ◽  
Tool Paths ◽  
Cutting Strategy ◽  
Groove Pattern

This paper presents a study of cutting strategies on the surface generation in single-point diamond turning of micro V-groove patterns on precision roller drums. An aluminium precision roller drum with a diameter 250mm and 100 long was diamond turned with a V-groove pattern. A series of cutting experiments were designed to study the effect of the variation of various cutting parameters and cutting tool paths on the surface quality in diamond turning of the precision roller drum. The parameters under investigation included the depth of cut, number of steps and the depth for each cut when diamond turning V-grooves on the cylindrical surface of a workpiece. The measurement result indicates that the surface quality of V-grooves machined on the precision roller drums is affected by cutting strategies. The optimal cutting strategy for machining a V-groove pattern on a precision drum with 5µm depth was obtained.

scholarly journals Development of an End-Toothed Disc-Based Quick-Change Fixture for Ultra-Precision Diamond Cutting

Machines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 257
Author(s):  
Xuesen Zhao ◽  
Xiangwu Cui ◽  
Zhenjiang Hu ◽  
Qiang Zhang ◽  
Tao Sun
Keyword(s):  
Finite Element ◽  
High Precision ◽  
High Efficiency ◽  
Small Diameter ◽  
Diamond Turning ◽  
Depth Of Cut ◽  
Diamond Cutting ◽  
Positioning Accuracy ◽  
Small Depth ◽  
Ultra Precision

With its standardized and unified interface, the quick-change fixture is an important part for maintaining high efficiency without compensation of precision in the metal-turning process because it can conveniently realize high-precision repeated clamping and multi-station conversion without complex positioning and adjustment steps. However, the existing quick-change fixture products and related research cannot fully meet the needs of repeatability and applicability raised from ultra-precision, single-point diamond turning with ultra-high accuracy and ultra-small depth of cut. In this paper, we develop a quick-change fixture for ultra-precision diamond turning, in which the end-toothed disc acts as the positioning element. Specifically, the main parameters of two key components of the end-toothed disc and slotted disc spring are calculated analytically to ensure the positioning accuracy of the designed fixture used in the rotation condition, which is further ensured by controlling the machining tolerance of the tooth profile of the end-toothed disc. Additionally, finite element simulations are performed to investigate the static and modal states of the quick-change fixture, which demonstrate a maximum deformation of about 0.9 μm and a minimum natural frequency of 5655.9 Hz for the designed fixture. Two high-precision sensors are used to detect the radial jump and end run-out values after repeated clamping actions, which are employed to verify the repetitive positioning accuracy of the fixture. Subsequent finite-element simulation of the clamping of small-diameter copper bar, as well as the diamond turning experiment, jointly demonstrate that the designed fixture can achieve a precision of 1 μm. Current work provides an effective quick-change fixture to reduce the deformation of a weak-stiffness workpiece caused by clamping deformation in ultra-precision diamond cutting.

Effects of Alpha-Cellulose Supply on the Working Life of MCF Slurry in MCF Polishing

2020 ◽  
Author(s):  
Yuta Nonaka ◽  
Mitsuyoshi Nomura ◽  
Tatsuya Fujii ◽  
Tsunehisa Suzuki ◽  
Yongbo Wu
Keyword(s):  
High Precision ◽  
Single Point ◽  
Brittle Materials ◽  
Surface Damage ◽  
Diamond Turning ◽  
Optical Systems ◽  
Smart Devices ◽  
Tool Marks ◽  
Hard And Brittle Materials ◽  
Inspection Systems

Abstract High precision surfaces exhibit prominent capabilities for enhancing the imaging quality, expanding the visibility of equipment, simplifying structures, and reducing total costs of optical systems. Hence, they are regarded as essential optical surfaces for replacing traditional elements to modify optical systems, including space systems, optical inspection systems, and smart devices. Single point diamond turning (SPDT) and ultra-precision grinding have been adopted preliminarily to manufacture high-quality elements. However, these processes create sub-surface damage and tool marks on the work surface. To meet performance requirements, polishing is critical for post-processing to improve the quality of the products. MCF (Magnetic Compound Fluid) polishing, which is one of polishing methods using magnetic fields, is a processing method for finishing hard and brittle materials with high accuracy. Previous research has shown that MCF polishing is effective for hard and brittle materials. However, despite the high cost of the magnetic fluid that is a component of the MCF slurry, the MCF slurry used for polishing has been discarded. Another major issue was that unused MCF slurry could not be used due to drying. The purpose of this study is to recycle MCF slurry to solve this problem, and to develop high precision finishing technology. Therefore, in this study, a novel MCF polishing method using ultrasonic atomization is proposed, and the effects of α-cellulose on the MCF polishing are investigated. In addition, in order to make it possible to reuse the MCF slurry, In addition, experiments are conducted to enable reuse of MCF slurry.

The Control System Construction of the Multifunctional Combined CNC Machine

2006 ◽  
Vol 315-316 ◽  
pp. 566-570
Author(s):  
Meng You Huo ◽  
Qin He Zhang ◽  
Jian Hua Zhang ◽  
Xing Ai
Keyword(s):  
Control System ◽  
Machine Tool ◽  
Ultrasonic Vibration ◽  
Brittle Materials ◽  
State Inspection ◽  
Servo Control ◽  
System Construction ◽  
Cnc Machine ◽  
Hard And Brittle Materials ◽  
The Stability

In this paper we present a multifunctional combined CNC machine that integrates the technology of USM, EDM and grinding. For non-conductive hard and brittle materials, the machine tool could perform ultrasonic machining and grinding machining combined ultrasonic vibration; for conductive hard and brittle materials, electrical discharge with or without ultrasonic vibration could be implemented. Conductive engineering ceramics have been used for elementary experiments, the results show that it is more efficient and more stable for processing this kind of materials by using the multifunctional combined CNC machine. On the basis of brief introduction about the structure of the machine tool, this paper emphasizes the form of control system, the gap state inspection that can be used to ensure the stability in processing and the principle for servo control.

Finite Element Analysis of Ultrasonic Vibration Assisted Turning of Ferrous Metals

2013 ◽  
Vol 567 ◽  
pp. 33-38 ◽  
Author(s):  
Lai Zou ◽  
Ming Zhou
Keyword(s):  
Finite Element ◽  
Tool Wear ◽  
Ultrasonic Vibration ◽  
Single Point ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Diamond Turning ◽  
Depth Of Cut ◽  
Technological Parameters ◽  
Ferrous Metals

Ultrasonic vibration assisted turning has significant improvements in processing of intractable materials compared to conventional turning. This paper presents a theoretical investigation of tool wear in single point diamond turning of ferrous metals based on numerical simulation. Finite element modeling and simulation of ultrasonic vibration turning process were performed, aimed at optimizing a series of technological parameters in the process of machining, reducing tool wear and improving surface quality as much as possible. The results revealed that the cutting speed and depth of cut are two crucial factors for tool wear, unlike the other parameters of vibration frequency, amplitude and flank angle. Moreover, this technological measure has observably decreased the cutting force and cutting temperature, so as to obtain superior surface finish.

Compound Micro/Nano Machining – A Tool-Based Innovative and Integrated Approach

2010 ◽  
Vol 447-448 ◽  
pp. 9-15 ◽  
Author(s):  
Mustafizur Rahman ◽  
A.B.M.A. Asad ◽  
T. Masaki ◽  
Yoke San Wong ◽  
A. Senthil Kumar
Keyword(s):  
Machine Tool ◽  
Surface Finish ◽  
Process Development ◽  
Single Point ◽  
Dimensional Accuracy ◽  
Integrated Approach ◽  
Diamond Turning ◽  
Micro Machining ◽  
Hard And Brittle Materials ◽  
Ultra Precision

Compound micro-machining is the most promising technology for the production of miniaturized parts and this technology is becoming more and more important and popular because of growing demand for industrial products with not only increased number of functions but also of reduced dimensions, higher dimensional accuracy and better surface finish. In this paper, the development efforts in micro/nano-machining based on solid tools (tool-based micro/nano-machining) in NUS are introduced. In order to achieve meaningful implementation of micro-machining techniques, this research seeks to address four important areas; namely (a) development of machine tool capable to do both conventional micro-machining, (b) process control, (c) process development to achieve necessary accuracy and quality, and (d) on-machine measurement and inspection. An integrated effort in these areas has resulted in successful fabrication of micro-structures that is able to meet the miniaturization demands of the industry. In the area of nano-machining machine tool and process developments have also been carried out for electrolytic in-process dressing (ELID) grinding and ultra precision machining using single point and poly crystalline diamond tools to produce nano surface finish on hard and brittle materials. An ultra-precision diamond turning machine has been developed which incorporates a fast and fine tool servo system to produce nano-precision surfaces and features.

Forecasting of Surface Roughness and Cutting Force in Single Point Diamond Turning for KDP Crystal

2007 ◽  
Vol 339 ◽  
pp. 78-83 ◽  
Author(s):  
Jing He Wang ◽  
Shen Dong ◽  
H.X. Wang ◽  
Ming Jun Chen ◽  
Wen Jun Zong ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Prediction Model ◽  
Cutting Force ◽  
Single Point ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Diamond Turning ◽  
Depth Of Cut ◽  
Kdp Crystal ◽  
Optimal Cutting Parameters

The method of single point diamond turning is used to machine KDP crystal. A regression analysis is adopted to construct a prediction model for surface roughness and cutting force, which realizes the purposes of pre-machining design, prediction and control of surface roughness and cutting force. The prediction model is utilized to analyze the influences of feed, cutting speed and depth of cut on the surface roughness and cutting force. And the optimal cutting parameters of KDP crystal on such condition are acquired by optimum design. The optimum estimated values of surface roughness and cutting force are 7.369nm and 0.15N, respectively .Using the optimal cutting parameters, the surface roughness Ra, 7.927nm, and cutting force, 0.19N, are obatained.

Machinability Investigation of Reaction-Bonded Silicon Carbide by Single-Point Diamond Turning

2008 ◽  
Vol 389-390 ◽  
pp. 151-156 ◽  
Author(s):  
Zhi Yu Zhang ◽  
Ji Wang Yan ◽  
Tsunemoto Kuriyagawa
Keyword(s):  
Surface Roughness ◽  
Silicon Carbide ◽  
Large Scale ◽  
High Efficiency ◽  
Low Cost ◽  
Single Point ◽  
Diamond Turning ◽  
Machining Process ◽  
Depth Of Cut ◽  
Material Microstructure

Reaction-bonded silicon carbide (RB-SiC) is a recently developed ceramic material with many merits such as low manufacturing temperature, dense structure, high purity and low cost. In the present paper, the precision machinability of RB-SiC was studied by microindentation and single-point diamond turning (SPDT) tests. The influence of depth of cut and tool feed rate on surface roughness and cutting force was investigated. Results showed that there was no clear ductile-brittle transition in machining behavior. The material removal mechanism involves falling of the SiC grains and intergranular microfractures of the bonding silicon, which prevents from large-scale cleavage fractures. The minimum surface roughness depends on the initial material microstructure in terms of sizes of the SiC grains and micro pores. This work preliminarily indicates that SPDT can be used as a high-efficiency machining process for RB-SiC.

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