Rotary planing and moulding machining operations have been widely used within the
woodworking industry for many years. As a result of these machining processes, the
surface proftle of machined timber consists of cuttermarks which determine the
product quality. However, the presence of machine system variations does not
guarantee the quality requirements. Most of the rotary machining improvement
techniques applied to obtain an improved product quality focus on conventional
methods such as tooling and spindle system design. Tbe current state of the industry
indicates that the design of rotary planing machines has probably reached its
mechanical development limit, hence for an advanced machining process,
mechatronics based improvement techniques are necessary. Therefore, the focus of
this research work is directed towards the improvements on a mechatronics based
small scale wood planer. Firstly, the effects of machining variations on the resultant
surface form have been investigated. Especially, the effects of spindle vibrations and
tooling inaccuracies on the surface ftnish have been analysed through simulation and
further demonstrated through experimental work. With the introduced defect
generation tool (DGT), the effect of a speciftc disturbance could be made to order,
hence allowing generation of defects for quality investigations. This is not possible
on existing machinery. Secondly, for an enhanced machining environment, surface
proftle information is desirable. Various surface proftle measurement systems have
been evaluated in terms of in-process deployment. Most of the evaluated
measurement systems lack the measurement speed or exhibit other disadvantages
which limit their implementation for real-time measurement purposes. Therefore, a
novel in-process surface prof:tle monitoring system (ISMS) has been introduced that
is capable of extracting surface proftle features in real-time. Thirdly, active vibration
control has been implemented on the small scale planer. Unlike conventional design
improvement methods, with the active vibration control approach the dynamic
characteristics of the small scale planer were substantially improved, hence enabling a
higher degree of freedom in terms of machining operation. This improvement allows
machining operations beyond the limitations set by the mechanical properties of the
planing system, thus enabling higher product quality where additional machining
processes such as sanding could be obsolete.
History
School
Mechanical, Electrical and Manufacturing Engineering