Information Technology Reference
In-Depth Information
3.8 Approval
Upon completion of preceding steps, it is necessary that all design steps be controlled and
inspected by experienced SPM specialists to correct possible errors before sending the
machine design to the workshop for manufacturing. These points deserve special
consideration at this stage: a) control system and PLC programming, b) types and
specifications of machining and sliding units, c) motion diagrams, d) hydraulic and
pneumatic systems and servo-systems, e) performance of the machine, and g) possible
collision of the moving parts with other moving or fixed parts. As mentioned before,
sometimes it becomes necessary to repeat economic considerations of the feasibility of SPM
utilization before the machine is built. This is attributable to the fact that initial economic
analysis has been made based on the initial estimation. However, when detailed machine
design is available a more precise machine cost becomes available that could be different.
3.9 Manufacturing and testing
Chassis and table of the machine should be made and assembled considering technical
issues. These parts should be sufficiently rigid and equipped with special dampers in order
to minimize vibrations resulting from the operation of cutting tools. Generally, thick steel
plates and cast iron are used for machine table. Cast irons have good damping character,
and therefore, are used for making the machine table to reduce vibrations. Chip removal
could be a huge problem in SPMs that cannot be appreciated before the machine is made.
The volume of chips produced in SPMs is high and this could reduce effective machining
time by half or even less when a proper chip removal mechanism is not considered. In
addition, a properly designed coolant system should be used to enhance the lives of cutting
tools as frequent tool changes increase machining costs. Then, based on detailed engineering
drawings, installation of stands, supports, machining units, sliding units, indexing table and
coolant system are performed. Installation of hydraulic and pneumatic systems, wiring,
electric power supply to electro-motors, and finally, the control systems are all performed at
this stage.
Upon completion of previous steps, machine performance is measured considering required
product quality and production volume. Possible issues at this stage are detected and
resolved to bring the machine to a more productive state. Producing a reasonable number of
quality products is necessary before actual production begins.
4. Knowledge-Based Expert System (KBES)
KBESs use rules as the knowledge representation for knowledge coded into the system. The
definitions of KBES depend almost entirely on expert systems, which are system that mimic
the reasoning of human expert in solving a knowledge intensive problem. Instead of
representing knowledge in a declarative, static way as a set of things which are true, KBESs
represent knowledge in terms of a set of rules that tells what to do or what to conclude in
different situations (Grosan and Abraham, 2011). In this work a KBES has been developed
to perform the analysis of SPM utilization and determination of machine layout and its basic
components. Its development has been described in this Section.
