Abstract: Soda-lime glass is a typical brittle material, which is difficult to realize ductile-regime
machining by using conventional cutting technology due to the extremely small critical depth of cut.
In this work, the micro-deformation characteristics of this kind of materials were analyzed by micro
indentation. Ultrasonic vibration assisted diamond cutting was performed in order to investigate the
effect of tool vibration on material removal process and surface quality. The profiles of cut surfaces
were measured and compared with those obtained by conventional diamond cutting. Real depths of
cut in ultrasonic vibration cutting correspond well with the nominal ones. The change in the tribology
of the cutting process as well as the alteration of the deformation mechanism of the work material
might be responsible for the reduction in tool wear in vibration cutting.
Abstract: Ultra-precision raster milling is an emerging manufacturing technology for the fabrication
of high precision and high quality components with a surface roughness of less than 10 nm and a form
error of less than 0.2 μm without the need for any subsequent post polishing. Surface quality of a
raster milled surface is affected by process factors and material factors, respectively. The process
factors involve cutting conditions, cutting strategies, and relative vibration between the tool and the
workpiece which are related to the cutting geometry and the dynamic characteristics of the cutting
process. The material factors considered are material property and swelling of the work materials.
Due to different cutting mechanics, the process factors affecting the surface quality are more
complicated, as compared with ultra-precision diamond turning, such as swing distance and step
distance. This paper presents an experimental investigation of the distinctive process factors affecting
the surface roughness in ultra-precision multi-axis raster milling. Experimental results indicate that
the influence due to the process factors can be minimized through a proper selection of operational
settings and better control of dynamic characteristics of the machine.
Abstract: The fabrication of high-quality optical microstructural surfaces is based on fast tool servo
(FTS) machining. It makes use of auxiliary piezo-electric driven servos to rapidly actuate the
diamond tool with a fine resolution and a sufficiently high bandwidth for machining optical
microstructures with submicrometer form accuracy and a nanometric surface finish without the need
for any subsequent post processing. However, the achievement of a superior mirror finish and form
accuracy still depends largely on the experience and skills of the machine operators, acquired through
an expensive trial-and-error approach to using new materials, new mircostructural surface designs, or
new machine tools. As a result, this paper, a model-based simulation system is presented for the
optimization of surface quality in the FTS machining of optical microstructures. Preliminary
experimental work and the results are also presented.
Abstract: Recently, the high quality and high productivity in fabrication of freeform optics has been
of primary interest in manufacturing industries, such as die and mould manufacturing, aerospace part
manufacturing, and so forth. However, the fabrication of freeform optics is currently expensive and
vastly complex. Ultra-precision raster milling can produce non-rotational symmetric surfaces with
sub-micrometric form accuracy and nanometric surface finish without the need for any subsequent
post polishing. While, there is little research work focus on this kind of machining method. This paper
presents a framework of a tool path generation system for freeform surface ultra-precision raster
milling. This system includes model of freeform optics, tool path generator, interference monitor and
an optimization model of machining parameters. The tool path generation system can generate
interference free and optimal tool path for machining freeform surfaces. Some simulation results have
been presented to illustrate the performance of the system.
Abstract: Ultra-precision freeform surfaces have become widely used in advanced optics
manufacture. Although these surfaces can be fabricated by ultra-precision freeform machining
technology with sub-micrometer form accuracy and surface finish in nanometer range, our current
understanding on the evaluation of surface quality of these surfaces is still far from perfect. In this
paper, a study of measurement technology for ultra-precision freeform surfaces is presented.
Abstract: This paper presents an integrated platform for modelling and measurement of freeform
surface generation in ultra-precision raster milling. It is composed of several components which are
optics design component, tool path generator, modelling system, measurement system, evaluation
component, compensation component and optimization component, respectively. The research
emphasizes on modelling and simulation of freeform surface generation, the prediction of the cutting
performance and hence the optimization of cutting strategy in the ultra-precision raster milling of
freeform surfaces. A measurement system is also proposed to carry out a fast and efficient
measurement plan of freeform surfaces. Non-uniform Rational B-Spline (NURBS) will be employed
for the development of the integrated platform which will meet Standard for the Exchange of Product
model data (STEP).
Abstract: An active cooling approach for coolant during ductile material grinding is proposed and
examined. The aim is to enhance surface quality and to enhance productivity. The problem associated
with the cryogenic cooling approach and the one with the chilled air approach are addressed. An
active cooling prototype was developed utilizing a compact heat pump design, which is easy to use,
movable, and can be easily fitted into different type of machine designs with relatively low costs. The
system is based on the use of forced convection of the heat generated during the machining process.
Experimental and computational studies of the effects of actively cooled coolant for grinding ductile
materials are carried out. The experimental results show that the use of actively cooled coolant is able
to improve surface quality by up to 29.95% on average in terms of surface roughness Ra.
Computational testing results show that the heat can be taken away more effectively by using the
proposed approach. The results of optical and SEM examinations also confirmed that the proposed
approach is advantageous.
Abstract: For nano-positioning systems with piezoelectric actuators used for dynamic grinding
control, sinusoidal command signals will used and will give additional problems compared with the
commonly used step signals because of the hysteresis effects, which require a good modeling
approach. The proposed approach of multiple polynomial regression with first order continuity gives
a relative modeling error of 2.65%. The method reduces the error by 26.3-80.2% in comparison with
the methods using the single, dual, and multiple polynomial regression with zero order continuity.
Abstract: PC-based software computer numerical control (CNC) system is the ideal for open CNC
system, but there are some problems about the current open CNC system, such as the limitation of
interpolation cycle, demanding on high-speed and high precision machining and the limitation of
operation system (OS). So advances a novel PC-based architecture for compiled-type software CNC
system, in the architecture, the general Windows is adopted as CNC platform and adopts two huge
memories acting as data buffer to solve real time problem. And then analyzes the structure and basic
principle of compiling system. The hardware has been developed based on this architecture and
applied in the CNC system.
Abstract: Virtual manufacturing (VM), which primarily aimed at reducing the lead times to market
and costs associated with new product development, offers various test-beds for the time-consuming
and expensive physical experimentation. Since surface roughness and form accuracy play essential
roles in the functional performance of the products machined with ultra-precision machining
technology. An optimizer, VSPDT (virtual single point diamond turning) system was developed for
the purpose of form error compensation and optimal cutting parameters selection. In this paper, the
keys issues for developing VSPDT using virtual manufacturing technology were highlighted such as
framework of system, virtual workpiece, virtual machining and inspection, etc. At the end of the
paper, A VSPDT was developed and applied to predict and compensate the form error, select optimal
cutting parameters by using a 2-axis CNC ultra-precision turning machine.