1. Cooling & Mechanical Systems

2. Lesson Objectives When you finish this lesson you will understand: System for cooling critical components Systems for exerting electrode Force Typical Applications Learning Activities 1.View Slides; 2.Read Notes, 3.Listen to lecture 4.Do on-line workbook 5.Do Homework Keywords Cooling System, Mechanical System, Fixed Stroke, Adjustable Stroke, Retractable Stroke, Valves, Rocker Arm, Press Type Welder, Servo Gun

3. Machines and Equipment Cooling System Mechanical System –Force generation system Pneumatic/Hydraulic system Motor or foot-operated system –Electrode application system Rocker arm or pinch type Press or direct action type Portable system Electrical System –Single-phase system –Single-phase rectified system –Three-phase rectified system –Frequency changer system –Frequency inverter system

4. Cooling System Function: –Prevent overheating of the components of the welding machine Components requiring cooling include: –The welding contactor (ignitron tubes or SCRs) –The welding transformer –The welding electrodes –Power cables (portable welding gun only)

5. A. Saabria, WE651 Lab Report 1999

6. Machines and Equipment Cooling System Mechanical System –Force generation system Pneumatic/Hydraulic system Motor or foot-operated system –Electrode application system Rocker arm or pinch type Press or direct action type Portable system Servo System Electrical System –Single-phase system –Single-phase rectified system –Three-phase rectified system –Frequency changer system –Frequency inverter system

7. Pneumatic/Hydraulic System K X A A A L P B RPRP B CBCB RPRP HLMHLM (a) Fixed Stroke(b) Adjustable Stroke (c) Adjustable, Retractable Stroke Electrode Force: F=AP

8. Pneumatic Cylinder Valves Symbol Physical (a) Two-Way Valve (b) Three-Way Valve with Single Acting Cylinder

9. Pneumatic Cylinder Valves (CONT.) P1P1 P1P1 P2P2 P2P2 (c) Four-Way Valve with Double- Acting Cylinder (d) Four-Way, Five Port Valve with Double-Acting Cylinder

10. Hirsch, R & Leibovitz, R, “Improved Weld Quality and Electrode Life in Resistance Welding” Practical Welding Today, Nov-Dec, 1997 Electronic Pressure System

11. Motor or Foot-Operated System F Rocker Arm Anvil x Spring Assembly Pivot Point X Y

12. Rocker Arm Machines Air in [Reference: Resistance Welding Manual, p.16-2, RWMA] X Y

13. Press Type Welding Machines [Reference: Resistance Welding Manual, p.16-5, RWMA]

14. C - Type Servo Spot Gun Slavick, “Overview of Servo-Driven Weldguns..” AWS Sheet Metal Conf. VIII, 1998

15. Slavick, “Overview of Servo-Driven Weldguns..” AWS Sheet Metal Conf. VIII, 1998 X - Type Servo Spot Gun

16. Slavick, “Overview of Servo-Driven Weldguns..” AWS Sheet Metal Conf. VIII, 1998

17. Portable System [Reference: Automotive Manufacturing, April 1996, p.5, SAE]

18. Mechanical Systems