OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
In case of mass production, there is an aim to have high productivity and interchangeability to facilitate easy
assembly. This necessitates production devices to increase the rate of manufacture and inspection devices to
speed up inspection procedure. For this purpose there is a need of Jigs and Fixtures. Jigs are provided with tool
guiding elements and fixtures hold the work piece securely in the correct position with respect to the machine or
robotic arm.
The jig and fixture is the basic equipment in the automobile industry for machining process and mechanical
assembly. Due to the advancement in the CAD/CAM and wide application of CNC machine forced to develop
automatic Jigs/Fixtures system. With the increase in the production system Computer Aided Fixture Design
(CAFD) is used to design the intelligent jig and fixtures. Fixture planning is an important part of any
manufacturing system because designing and fabricating of fixtures can take up to 10-20% of total cost of the
manufacturing system. Computer-Aided Fixture Planning (CAFP) has been used to improve the fixture
designing simultaneously used to reduce the lead-time and human interaction in fixture planning [5, 6].
Fig. 2. Jigs/Fixtures with Arc Welding Robotic Arm
3. CONTROL SYSTEM
A. The Control Circuit of Automatic Arc Welding System
The automatic arc welding system uses the PLC system for controlling the robotic arm, jigs/fixtures and other
devices like servo motor. A combined control panel is designed for controlling the system. The control panel
consists of power supply (24VDC, 4.5A), PLC (48 digital inputs/outputs), relay boards (8-channels), MCBs
(single and double pole), isolation transformer (3kVA, 415V, 2 Ph Input and 200V, 220V, 100V Outputs), servo
drives, bus duct, cooling fan, connectors etc. In this work, Control Techniques’ two Epsilon EP servo drives
(EP204-100-EN00) and servo motors (XV-13051) are used.
Motoman’s 6-axis vertically articulated arc welding robot (MA-1400) has been used, which has its own
dedicated controller for controlling the motion of different links, welding parameters and wire feed.
Fig. 3. Electrical Control Panel
Remote control panels are used where push buttons and selector switches are used for Hold, Cycle Ready,
emergency, Cycle start push buttons and also a selector switch for auto/manual selection. This system can be
operated either by the buttons on the panel or by HMI (touch screen). PLC receives the digital signal either from
HMI or from the buttons on the panel. According to the received signals and internal procedure (program),
output signals of the PLC controls the robot weld cycle, fixtures holding/un-holding, servo motor controlling
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