Membrane Seam Welding - Drawings

Contents

CONTENTS

INTRODUCTION

1.SEAM WELDING TECHNOLOGY

1.1Performance of the article

1.2 Properties and weldability of workpiece material

1.3 Welding mode parameters. Welding cyclogram

1.3.1 Determination of welding mode parameters

1.3.2 Welding cyclogram

1.4 Welding Process

1.4.1 Preparation of workpiece surface

1.4.2 Assembly

1.4.3 Welding

1.4.4 Quality Control

2. CALCULATION OF TRANSFORMER PARAMETERS

2.1 Initial data for transformer calculation

2.2 Calculation of secondary circuit resistance and contact machine impedance

2.3 Transformer primary winding diagram

2.4 Core section

2.5 Geometric dimensions of transformer

2.6 External characteristics of the machine

3. DESCRIPTION OF DEVICE STRUCTURE

4. MACHINE INSTALLATION

5. OCCUPATIONAL SAFETY

6. TECHNICAL AND ECONOMIC INDICATORS

BIBLIOGRAPHIC LIST

SPECIFICATION

Introduction

For welding of this article (welding of membranes), seam welding is used.

Seam welding is the process of forming non-detachable joints of structural materials as a result of their short-term heating by electric current and plastic deformation by compression force.

Seam welding is a method of obtaining a sealed joint (seam) by forming a series of overlapping points.

The size of each point depends on the diameter of the electrode, the amount of welding current, the compressive force and the electrical resistance of the welding zone.

The welding process is characterized by a very short welding time with large welding currents and forces that ensure local melting of the metal.

The process of forming a weld point takes place in 3 stages:

Compression of blanks with a certain force is increased. Contact resistance is formed between blanks.

It is characterized by the melting of the metal by an electric current and the formation of a nucleus.

It starts from the moment the current is turned off, accompanied by cooling and crystallization of the metal. When cooling the metal, residual stresses arise. In order to reduce the level of these stresses and prevent shrinkage cracks and shells, the compression force at this stage is increased.

The electrodes of the contact machine are then moved apart and the article is released.

It is also possible to heat treat the welded point directly in the machine electrodes by flowing an additional current pulse of less, but greater length.

Seam welding is a high-performance welding method that has great process automation capabilities. [1. p. 6]

Seam welding technology

1.1 Characteristic of the article

This article is two stamped halves 0.8 mm thick. This article is of an open type, which makes it convenient to bring the rollers to the welding site. Allows welding on standard equipment.

1.4 Welding Process

The welding process consists of the following operations:

Preparation of workpiece surfaces;

Assembly;

Welding;

Product quality control.

1.4.1 Preparation of workpiece surface

The quality of the weld joint and the resistance of the electrodes depend on the surface condition of the blanks. The welded surface must be cleaned from the initial thick, non-uniform surface films. Order of operations: chemical etching, neutralization, drying.

Drying is carried out in an insulated room with enhanced plenum ventilation.

1.4.2 Assembly

The assembly shall ensure the precise arrangement of the parts (in accordance with the drawing) and the minimum gaps between them. During assembly, it is necessary to ensure that dirt, metal chips and the like do not fall on the mating surfaces. Welding shall be performed in special welding and assembly devices. The accessory shall ensure free access of the electrodes to the welding site, with the necessary accuracy mutual arrangement of the assembled parts, quick and reliable fastening of the parts. [The 5th p. 59]

1.4.3 Welding

Welding is performed on MT type machine. The product is placed between two rollers. The lower roller is not movable, and the upper roller has a vertical movement (50 mm). Welding is performed at specified modes.

1.4.4 Quality control.

This design is responsible. Perform visual inspection of welded article for burning, non-blasting and excessive deformations.

All process operations are recorded in the roadmap.

Description of accessory structure

The seam welding process includes a welding operation itself and a number of auxiliary operations for maintaining and moving the weld assembly.

The welding tool is used to increase assembly accuracy, welding quality and efficiency.

This accessory consists of two main elements:

The table.

A rotary device that rotates the table around the perimeter of the article to be welded.

The welder places the product on the table using any lifting device (for example: a telfer). The welder moves the table under the electrodes of the machine on his own. Adjusts the article relative to the machine electrodes so that the future welded assembly fits tightly to the machine lower electrode. And making sure that there is no skew.

To ensure the operation of the rotary device, the drive of the rollers of the seam machine.

Then the product is taken out and after that the product is ready. You can install the following welding products:

Machine device

Preparing the machine for operation.

After actuation of water and pneumatic system, supply power voltage with Q1 automatic machine. Energize step-down transformer T2 of control circuits by switching on Q2 "Voltage" packet switch. Actuators S2 "roller up - down" and S3 "welding current" in the operating position shall be switched on. When testing the machine at idle, set switch S3to "ON" position.

First press on the pedal button S1

Contact S1.1. closes the circuit of relay coils K1 and electro-pneumatic valve Y along path S1.1. - K3.2 – K2.4 – K3.1 – K1,Y . When the valve Y is actuated, the rollers compress the blanks. As a result of closing of contacts K1.1, K1.2, K1.3, the motor M starts, but the electrodes do not yet rotate, since the EMC electromagnetic clutch does not work. Contact K1.4 sets relay K1 and valve Y to power, independent of pedal button S1. relay K2 is not started because the second contact of the pedal button S1.2 breaks the circuit of its coil.

Release of pedal button S1

When S1.2 contacts are returned to the initial closed state, relay K2 is powered. Its contact K2.1 includes EMC clutch, rotation of rollers and movement of parts begins. Simultaneously with contact K2.2 the FL breaker is started. Control pulses formed by its control unit are supplied through pulse transformer T3 to control electrodes of thyristors V1 and V2. The latter are brought into conduction state and voltage is supplied to primary winding of welding transformer T1. welding is in progress. Contact K2.3 prepares relay K3 for operation, and contact K2.5 provides power to relay K2.

Second pressing of pedal button S1

When the welding is completed, the relay K3 is switched on by re-closing the contact S1.1. Its contact K3.1 breaks off a power-supply circuit of K1 and valve Y. disconnection of contacts of K1.1, K1.2, K1.3 leads to a stop of engine M and the termination of rotation of rollers. Contact K1.4 de-energizes relay K2; welding current is cut off by contact break K2.2. When valve Y is switched off, the electrodes are expanded. Welding finished.

Release of pedal button S1

Coil K3 is de-energized. Since all relays and actuators are now de-energized, the circuit is reset.