1. Field of Application and Purpose of the Manual
This manual is designed for qualified service technicians and welders operating TIG (Tungsten Inert Gas) welding machines. It provides clear, step-by-step instructions for key preventive maintenance procedures for TIG welding torches, including proper preparation of tungsten electrodes, effective cleaning of gas lenses and nozzles, and flushing and maintenance of the cooling system. Regular and high-quality performance of these tasks is critical to ensuring consistent weld quality, optimizing the life of consumables and welding equipment, and minimizing unplanned production downtime. Adherence to the procedures outlined here will help keep the equipment in working condition in accordance with DSTU, EN, ISO standards, which is a guarantee of the reliability of production processes.
2. Precautions
ОБЕРЕЖНО: Перед початком будь-яких робіт з обслуговування ОБОВ'ЯЗКОВО відключіть зварювальний апарат від електромережі та застосуйте процедуру блокування/маркування (LOTO) відповідно до внутрішніх стандартів безпеки підприємства та вимог ДСТУ EN 1032. Переконайтеся у відсутності електричної напруги.
РИЗИК ОПІКІВ: Компоненти пальника та навколишні деталі обладнання можуть бути надзвичайно гарячими після експлуатації. Дайте обладнанню охолонути до безпечної температури (<40°C) перед будь-яким контактом.
ЗАХИСТ ОРГАНІВ ДИХАННЯ: При роботі з очисними розчинами, зборі відпрацьованої охолоджуючої рідини або шліфуванні електродів (яке створює дрібний металевий пил), використовуйте відповідні засоби індивідуального захисту (ЗІЗ). Це включає захисні окуляри (ДСТУ EN 166), захисні рукавички (ДСТУ EN 388, мінімум 3121X) та респіратор (ДСТУ EN 149, FFP2 або FFP3) для захисту від вдихання частинок вольфраму та можливих хімічних випарів.
ЕЛЕКТРИЧНА БЕЗПЕКА: Завжди перевіряйте цілісність ізоляції кабелів та шлангів. Не працюйте з пошкодженим обладнанням. Будь-які маніпуляції з електричними компонентами повинні виконуватись лише кваліфікованим персоналом.
3. Necessary Tools and Materials
The following list of tools and consumables is required for the full scope of TIG torch maintenance work:
| Name of Tool/Material | Specification/Purpose | Quantity |
|---|---|---|
| A set of wrenches | The range is 8 mm - 22 mm | 1 set |
| Specialized grinding machine for tungsten | With diamond wheel, angle sharpening function (15-30°), dust extractor | 1 pc. |
| Micrometer/caliper | Measuring range 0-25 mm, accuracy 0.01 mm | 1 pc. |
| Multimeter | With resistance and voltage test function (up to 600V DC/AC) | 1 pc. |
| Manometer (for the cooling system) | Range 0-10 bar, accuracy class 1.5 | 1 pc. (if not built in) |
| A set of gauges for clearance (dipsticks) | The range is 0.05 mm - 1.0 mm | 1 set |
| Soft brushes for cleaning (nylon) | Different sizes for nozzle, gas lens and burner body | 3-5 pcs. |
| Compressed air (clean, dry) | For blowing, oil-free, filtered to 5 μm | As needed |
| Specialized liquid for the cooling system | Non-conductive, for welding machines, with anti-corrosion and anti-freeze additives (freezing temperature up to -20°C) | 5-10 liters |
| Distilled water | For system flushing, conductivity <5 μS/cm | 5-10 liters |
| Container for collecting waste liquid | Capacity of at least 10 liters, resistant to chemicals | 1 pc. |
| Napkins are lint-free | Industrial, for cleaning and wiping | 1 pack |
| Safety glasses | DSTU EN 166, marking F or B | 1 pc. |
| Protective gloves | DSTU EN 388, resistance to cuts and abrasion | 1 pair |
| Respirator | DSTU EN 149 FFP2/FFP3, with exhalation valve | 1 pc. |
4. Inspection Before Service
Before beginning detailed maintenance, perform an initial visual inspection and diagnosis to identify obvious faults.
| Item | Verification | Acceptance/Rejection Criteria | Notes |
|---|---|---|---|
| External inspection of cables and hoses | Visual inspection for insulation damage, cracks, bends, melts, abrasions on power cables, cooling hoses and gas lines. | Absence of visible damage (cuts, tears, punctures) of insulation and hoses. Cable connections must be tight, without traces of corrosion or overheating. | Damage may result in gas/coolant leaks, electrical breakdown, or loss of welding current. |
| The condition of the burner body | Inspection of the burner body for mechanical damage, deep cracks, significant melting, severe pollution, deformations. | Absence of deep cracks, significant melting (which affects functionality or safety), twisting. The case should be relatively clean. | Deformation or damage to the housing may affect the proper functioning of internal components, tightness or lead to contact with hot parts. |
| Overview of collet and collet body | Remove the electrode, check the collet and the collet body for wear, deformation, melting, corrosion or contamination from welding. | The collet must tightly hold the electrode along its entire length, without visible deformations, melting or excessive wear. Collet body without damage to threads and seats. | Unreliable attachment of the electrode leads to an unstable arc, poor current transmission and rapid wear of the electrode. |
| The condition of the nozzle (ceramic/glass) | A thorough visual inspection of the nozzle for cracks, chips, melting of the inner surface, heavy contamination from splashes or oxidation. | The nozzle is intact, without cracks or deep chips. The inner surface is clean, without significant melting that prevents the uniform flow of gas. | A damaged or contaminated nozzle leads to improper formation of the gas shield, turbulence of the gas flow and, as a result, porosity or oxidation of the weld. |
| Tungsten electrode | Assessment of the current state of the electrode: the presence of melting, contamination, incorrect sharpening, insufficient length. | Absence of significant melting, excessive pollution. The length of the electrode protrusion should be sufficient for re-sharpening. | A dirty or incorrectly sharpened electrode deteriorates welding quality, arc stability and can lead to inclusions in the weld metal. |
| Visual inspection of the cooling system | Inspect hoses and all connections for visible coolant leaks. Checking the liquid level in the cooler tank. | No visible leaks. The coolant level in the tank is within the limits specified by the device manufacturer (usually between the MIN and MAX marks). | Insufficient fluid level or leakage can lead to overheating of the torch and its critical damage, as well as a decrease in the productivity of the welding machine. |
5. Step-by-step Service Procedure
5.1. Preparation of Tungsten Electrode
- To remove the old electrode: Unscrew the back burner cap, loosen the collet and carefully remove the used tungsten electrode.
Error: Applying excessive force can damage the collet or the collet body, as well as deform the thin part of the torch. - Electrode selection: Make sure that the diameter of the new electrode exactly matches the size of the collet and the expected welding current. Typical diameters: 1.0 mm, 1.6 mm, 2.4 mm, 3.2 mm, 4.0 mm. For most direct current (DC) welding applications, electrodes with 2% lanthanum (WL20, blue marking) or 2% cerium (WC20, gray marking) are recommended according to DSTU EN ISO 6848. For alternating current (AC) welding, electrodes with 1.5% lanthanum (WL15, gold marking) or pure tungsten (WP, green marking) are more often used.
- Electrode sharpening:
CAUTION: Use a specialized grinding machine designed exclusively for tungsten electrodes, equipped with a diamond wheel and a dust extraction system. Sharpen the electrode longitudinally, along its axis, not across. This ensures optimum arc stability, minimizes spatter and prevents contamination of the weld seam.
Mistake: Using a common grinding wheel that has been used for other metals leads to contamination of the tungsten electrode with foreign impurities and a significant deterioration of the welding quality, as well as rapid destruction of the electrode.- Sharpening angle: For DC TIG welding, the recommended sharpening angle is 15° to 30° relative to axis of the electrode. For low currents (up to 50A), the preferred angle is 15-20°, for medium currents (50-150A) - 20-25°, for high currents (over 150A) - 25-30°. Use the sander's built-in template or a precision protractor to follow the geometry.
- Cone length: The sharpened part should be approximately 2.5 to 3 times longer than the diameter of the electrode. For example, for an electrode with a diameter of 2.4 mm, the recommended length of the cone is about 6-7.2 mm.
- Tip blunting (if necessary): To stabilize the arc at high currents or when welding with alternating current (AC TIG), the tip of the electrode after sharpening can be slightly blunted, creating a small plane with a diameter of about 0.1-0.2 mm. This helps prevent beading at the tip of the electrode and provides a more controlled arc.
Visual control: The tip of the electrode should be sharp and symmetrical, without radial scratches passing across the axis. The surface must be smooth.
- Electrode installation: Carefully insert the sharpened electrode into the corresponding collet, then assemble the collet with the collet body. The length of the electrode protrusion from the nozzle should be 3-6 mm for standard welding. For corner seams or work in deep joints, a larger protrusion (up to 10-12 mm) may be required, but this requires a corresponding increase in the consumption of shielding gas. Tighten the rear burner cap. The tightening should be tight, but without excessive force, which can deform the collet or damage the thread.
5.2. Cleaning the Gas Lens and Nozzle
This procedure is critical to ensure laminar shielding gas flow and prevent weld porosity.
- Dismantling the components: Unscrew the ceramic or glass nozzle. Carefully remove the gas lens, which usually consists of a mesh (or filter) and its housing. If the gas lens is not used, clean the standard collet body.
- Visual Inspection: Carefully inspect the nozzle and gas lens for the accumulation of metal spatter, soot, melts, cracks, or blockages in the fine mesh openings. Look for discoloration, which may indicate overheating or oxidation.
- Mechanical cleaning:
CAUTION: Use only soft nylon or natural brushes to remove dirt. Never use metal brushes, abrasive materials or sharp metal objects that can damage the delicate surface of the gas lens, leaving metal particles that will contaminate the shielding gas and the welding bath.
Error: Rough cleaning with metal tools irreversibly damages the porous structure of the gas lens, which leads to turbulent gas flow and loss of effectiveness of the protection of the welding zone. - Blowing: Blow the gas lens and nozzle with clean, dry compressed air under low pressure (max. 2-3 bar). This removes fine particles, dust and debris that cannot be removed with a brush. Make sure the air is free of oil or moisture by using an air filter-dehumidifier.
Visual control: All channels of the gas lens must be completely transparent, without any obstruction. The inner and outer surfaces of the nozzle are clean.
- Assembly: Install the cleaned gas lens (if removed) and nozzle onto the burner. Tighten them by hand until they are snug. Do not use excessive force. Make sure the O-rings (if any) are in place and undamaged.
5.3. Flushing and Maintenance of the Cooling System
Regular flushing of the cooling system is mandatory to prevent overheating of the burner and the welding machine. This ensures stable operation of the equipment and prevents costly repairs. The recommended flushing interval is every 3-6 months of intensive use or when the coolant changes color visually.
- Draining the old cooler:
CAUTION: Prepare a suitable container for collecting the used liquid (minimum 10 liters). Drain the old coolant from the system by disconnecting the corresponding hose (usually
