Active vibration control and real-time surface profile monitoring system for a high performance machining process
thesisposted on 03.02.2014, 14:19 by Sedat Elmas
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.
- Mechanical, Electrical and Manufacturing Engineering