FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10; RULE 13)
"SYSTEM FOR SCHEDULING TIP REPLACEMENT OF SPOT WELDING
GUN"
MAHINDRA & MAHINDRA LIMITED A COMPANY REGISTERED UNDER THE PROVISIONS OF COMPANIES ACT, 1956 HAVING ADDRESS AT R & D CENTER, AUTOMOTIVE SECTOR, 89, M.I.D.C, SATPUR, NASHIK - 422 007, MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THE INVENTION AND MANNER IN WHICH IT IS TO BE PERFORMED

FIELD OF THE INVENTION:
The present invention is related to spot welding gun used in body shops of automobile manufacturing units. More particularly the present invention is related to proactive system for scheduling tip replacement of spot welding gun and data management of tip replacement.
BACKGROUND OF THE PRESENT INVENTION:
In today's high speed process of vehicle assembly, precise equipment, people and using them play a critical role in defining quality and delivery of work. Thus keeping pace with requirements, use of spot welding gun is very common in body assembly shop. These spot welding guns are used to assemble/weld a huge quantity of metal sheets on vehicle body. These guns consist of electric rods, welding tip, water bag & pneumatic cylinder assembly. Separate microcontroller unit is provided to supply the precise current & to display the all parameters of welded spot (strength, taken spot numbers). LED indicators are provided on controllers of these guns to display various information like, spot taken, current flow, water status, air status etc. For changing the welding gun tip, a common practice is to observe an LED indicator glow on controller unit. On observing the need for tip replacement, stage operator puts a call for maintenance operators, who then replace the tip to close the call.
The drawbacks of this conventional system are as under:
- Poor adherence to welding gun tip replacement results in loss of spot integrity. It further leads to quality defects like-spot burr, spot burn etc.
- Spot welding guns do not provide any solution to discontinue the welding spot operation after utilization of welding copper tips.
- Size of LED is very small & difficult to observe as the position of the controller unit is far away from the operation stage.
- Valuable manpower resources are wasted/ underutilized for conventional system.
- It further leads to rework.

- All this results in poor quality and late delivery.
To take care of all these drawbacks and address the issues therein, the present invention is proposed.
OBJECTIVES OF THE PRESENT INVENTION:
The main object of the present invention is to provide a proactive system for scheduling tip replacement of spot welding gun and data management of tip replacement.
STATEMENT OF INVENTION:
Accordingly the invention provides a system for scheduling tip replacement of spot welding gun comprises a CPU/ PLC(programmable logic controller) connected to number input modules to receive welding spots count; a control system provided in the said CPU/PLC to send command for fixture clamping and unclamping; the data output of spot count from the said CPU/PLC connected to a SCADA (supervisory control and data acquisition) unit provided with tip replacement software and controlling system functions in such way that:
a. all the configured welding gun spot counts data received from CPU
(Programmable device) and calculates the actual welding spot counts
of individual welding gun and compare with alarm level & maximum
programmed welding spot counts to display the critical welding gun tip
to be replaced;
b. further, generates the critical level gun tip report and sends calculated
critical welding gun numbers/names/stage nos. to ANDON display
connected to the said SCADA unit;
c. also it sends resulted feedback to CPU (Programmable Device) for
controlling the critical welding gun stage fixture clamping & unclamping
operation.

BRIEF DESCRIPTION OF THE FIGURES:
The present invention and its advantages derived out it will be clearly understood for the following specifications when read in conjunction with the accompanying figures wherein,
Figure 1 shows block diagram of the tip replacement scheduling system in accordance with the present invention.
Figure 2 shows the display of data management in the system on the tip replacement history of the spot welding gun in accordance with the present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION:
The system of the present invention comprises of Input module, Central Processing unit, Central Unit, Output module and Display and alert units.
The input module has a facility to count the welding spots and it sends welding spot counts data to programmable device (CPU / PLC). The central processing unit is the controlling unit of the body shop (existing). It receives all welding gun spot count data from welding gun controller and sends all spot welding counts data to Tip Replacement system (SCADA). It also sends command/controlling signals to welding gun stage to control fixture clamping & un-clamping operation. The central unit receives all configured welding gun spot counts data from CPU (Programmable device) and calculates the actual welding spot counts of individual welding gun and compare with alarm level & maximum programmed welding spot counts to display the critical welding gun tip to be replaced. It further, generates the critical level gun tip report and sends calculated critical welding gun numbers/names/stage nos. to ANDON display. Also it sends resulted feedback to CPU (Programmable Device) for controlling the critical welding gun stage fixture clamping & unclamping operation.

The output module receives data from Tip replacement system & shows the all critical welding guns. Shows the Tip replacement system is not working error message on display board. If system power is off or communication problem between and on & tip replacement system. CPU receives critical welding gun stage data from Tip replacement system & sends to welding gun fixture control unit and Controls the fixture clamping & unclamping operation with respect to critical welding gun received data.
The said system uses momentary signal produced by controller unit by welding spot gun operation and gives graphical representation of welding gun location on screen. The system proactively provides real time schedule for welding gun tip replacement when the number of spot taken by each welding gun equals safe working life of welding tip. The unskilled operator can operate system very easily. The system also provides machine maintenance schedule e.g Lubrication of ROBOT, CBM check of motor etc. It is a safe system with password protection security.
The system provides a simple solution to prevent / eliminate human errors involved during operation. It is a low cost solution adding to operational effectiveness of spot welding guns. Further, this system provides operator wise traceability for tip replacement data for one year. System provides ease of installation and is easily adaptable system for spot welding guns by any body assembly shop. It provides complete confirmation of blind operations.

WE CLAIM:
1. A system for scheduling tip replacement of spot welding gun comprises a CPU/ PLC(programmable logic controller) connected to number input modules to receive welding spots count; a control system provided in the said CPU/PLC to send command for fixture clamping and unclamping; the data output of spot count from the said CPU/PLC connected to a SCADA (supervisory control and data acquisition) unit provided with tip replacement software and controlling system functions in such way that:
a. all the configured welding gun spot counts data received from CPU
(Programmable device) and calculates the actual welding spot counts
of individual welding gun and compare with alarm level & maximum
programmed welding spot counts to display the critical welding gun tip
to be replaced;
b. further, generates the critical level gun tip report and sends calculated
critical welding gun numbers/names/stage nos. to ANDON display
connected to the said SCADA unit;
c. also it sends resulted feedback to CPU (Programmable Device) for
controlling the critical welding gun stage fixture clamping & unclamping
operation.