INTRODUCTION TO PROJECTION WELDING

INTRODUCTION TO PROJECTION WELDING

Introduction to Projection Welding Machine Training (SA & ST Type) program provides participants with a comprehensive understanding of the principles, operation, quality control, and maintenance of SA and ST type projection welding machines. This course is based on the “Practical Manual of Welding Work: Projection Manual Edition” and is designed to equip trainees with both theoretical knowledge and hands-on technical skills to perform projection welding operations safely and effectively.

Projection welding is an essential process in manufacturing, particularly in the automotive and precision component industries, where high-quality welds are critical for product reliability and structural integrity. Through this program, participants will learn how to manage welding parameters, ensure consistent quality, and maintain optimal machine performance to meet production standards.

LEARNING OBJECTIVES

To provide trainees with a foundational understanding of the principles,  operation, quality control, and maintenance of SA and ST type projection welding machines  as detailed in the “Practical Manual of Welding Work: Projection Manual Edition”. 

COURSE CONTENT

MODULE 1: FUNDAMENTALS OF PROJECTION WELDING 

• Topic 1.1: Introduction to Projection Welding 
  • Definition: A specialized resistance welding method using pressure and  current. 
  • Core Principle: Concentrating current and pressure at specific projections to  generate heat and form a weld, known as the “press connection method”.
  • How it Works: Converting high primary voltage (e.g., 440V) to low voltage  
  • (10-30V) and high current (approx. 20,000A) to melt and fuse workpieces.
• Topic 1.2: The Four Pillars of Weld Quality 
  • A discussion of the four critical factors for a good weld:  

1. 1. 1. Current Flow Area: How smaller areas increase current density for  effective melting. 
      2. Welding Current (KA): The volume of current needed to melt the  connection area. 
      3. Current-Carrying Time (Cycle): The heating time required to reach  the melting point. 
      4. Welding Pressure: The force applied to suppress the molten pool and  prevent material from flying apart. 

• • Nugget Formation: Understanding the fused area and what constitutes a poor  weld. 

MODULE 2: MACHINE COMPONENTS AND SYSTEMS 

• Topic 2.1: Overview of Machine Types 
  • Introduction to the SA Piston Rod, SA Lower, and ST Hose Bracket welding  machines. 
  • Highlighting structural similarities and differences between the models.

• Topic 2.2: Key Components and Their Functions 
  • Electrical System: Timers, contactors, CT (Toroidal) Coils for current  detection, and transformers. 
  • Pressure System: Booster, pressure accumulator, press head, and pressure  cylinder. 
  • Current Path: Secondary conductor, OWNS Copper Plate, upper and lower  electrodes (middle/split). 
  • Cooling System: The importance of water cooling cables and flow meters to  manage heat in conductors and electrodes.

MODULE 3: MACHINE OPERATION AND QUALITY CONTROL 

• Topic 3.1: SA Machine Operation 
  • Step-by-step operational flow from parts conveyance to welding and part  ejection. 
  • Understanding the welding cycle: early applying pressure, welding current,  and retain applying pressure. 

• Topic 3.2: ST Machine Operation 
  • Unique operational steps: setting the bracket positioner, using magnets for part  retention, and the function of the Reject Device. 
  • Role of the “KOBAM” air intake sensor in detecting improper part  positioning. 

• Topic 3.3: Quality Control & S Process Management 
  • Defining “S Process”: Understanding security processes for critically  important parts (S classification). 
  • Worker Requirements: Education and identification for staff working on S  processes. 
  • Initial Quality Checks: Performing visual, hammering, and dimension  checks. 
  • Projection Fit Check: The critical process of using carbon paper to confirm  the contact area balance is >80% for ensuring weld strength. 

MODULE 4: MAINTENANCE AND TROUBLESHOOTING 

• Topic 4.1: Routine Maintenance Procedures 
  • Importance of daily and periodic checks. 
  • Cleanliness: Removing spatter and dirt from electrodes and machine  attachments during implement changes to prevent sparks and abnormal heat.

Component Inspection: 

• OWNS Copper Plate: Inspecting for wear and tear, with a mandatory  replacement when the tear limit reaches 25%. 
• Pipes and Hoses: Checking for abrasion, holes, or tears from spatter  and heat. 
• Cooling System: Visually checking the flow meter to ensure proper  cooling water volume. 
• Topic 4.2: Electrode Care 
  • Split Electrodes: Cleaning spatter, checking for abrasion, and correcting  oxide skin with a brass brush or sandpaper. 
  • Usage Limits: Emphasizing that electrodes should not be used beyond their  defined usage limit line. 

• Topic 4.3: Common Failures and Countermeasures 
  • SA Machines: Troubleshooting issues like Burrs, Burn Marks, Deformation,  and Insufficient Strength by verifying current, pressure, time, and electrode  condition. 
  • ST Machines: Addressing failures such as Lean, Dislocation, and Float by  checking electrode abrasion, guide plates, and welding pressure. 
  • Failure Protocol: The rule for stopping the line after 3 consecutive or 5  intermittent failures and contacting a Group Leader.