Glossary of Micro-Pulse Welding: Key Terms Explained
Many technical terms are associated with micro-TIG welding: TIG, pulse duration, heat-affected zone, inert gas, and build-up welding. This glossary explains the most important terms briefly and clearly, organized into five sections: Methods and Synonyms, Process Flow, Parameters and Control Variables, Materials and Joints, and Applications and Practical Terms. It is intended for beginners who are learning about the process and for users who want to quickly look up a term. The Lampert welding principle provides additional insight into how the welding pulse is generated in detail.
Procedures and Synonyms
This same process goes by several names. The following terms all refer to the pulsed TIG fine welding system that Lampert has been manufacturing since 2001.
| Term | Meaning |
|---|---|
| Micro TIG Welding | A TIG-based precision welding process that uses individual, precisely controlled current pulses instead of a steady arc. Developed by Lampert Werktechnik GmbH in Werneck, it has been in use since 2001. |
| Micro-TIG | The pulsed, precision variant of the TIG principle for material thicknesses starting at 0.1 mm. Lampert uses the terms “micro-TIG,” “precision welding,” and “micro-pulse welding” interchangeably. |
| TIG (Tungsten Inert Gas) | A welding process in which a non-consumable tungsten electrode conducts the current and the inert gas argon protects the weld zone from oxidation. English: TIG (Tungsten Inert Gas). |
| Pulse Arc Welding | English term for micro-pulse welding. “Micro TIG welding” is also used as a technical synonym. |
| Precision Welding | Synonym for micro-welding, micro-TIG welding, and micro-pulse welding. An umbrella term for the permanent joining of thin or delicate metal parts, typically with material thicknesses of less than 0.5 mm. |
| Conventional TIG Welding | Conventional TIG welding with a standing arc. It applies heat over a wider area, and the heat-affected zone extends to several millimeters to centimeters. Suitable for longer welds and thicker materials ranging from about 0.5 to 1 mm. |
The Welding Process, Step by Step
The process begins automatically once the electrodes make contact. These terms describe the individual stages of a welding pulse.
| Term | Meaning |
|---|---|
| Arc Ignition | The arc is initiated automatically the moment the electrode tip touches the workpiece. The electrode then retracts electronically into the handpiece, and the arc is established. |
| Welding pulse | The actual energy pulse: The arc remains active for a preselected duration and creates a weld spot of the desired intensity. After the pulse, the inert gas flows in to protect the solidifying weld, after which the next pulse can follow. |
| Pre-flow | The inert gas opens shortly before ignition and displaces the oxygen from the weld zone before the arc is formed. |
| Post-flow | The inert gas continues to flow after the pulse and protects the still-hot weld zone from oxidation during solidification. |
| Solidification | The molten metal solidifies in a matter of milliseconds under a continuous flow of shielding gas. The continuous flow of argon prevents oxidation. |
| Automatic Termination | As soon as the electrode is no longer in contact with the workpiece, the process stops immediately. This prevents uncontrolled welding. |
Parameters and Control Variables
Two control variables determine the result: the energy for peak power and the pulse duration for penetration depth. In addition, there are the inert gas, the electrode, and the preprogrammed welding curves.
| Term | Meaning |
|---|---|
| Pulse duration | The duration of a single current pulse, which ranges from 0.1 to 34 milliseconds in the Lampert method, primarily controls the penetration depth: longer pulses result in deeper penetration. |
| Energy | In Lampert machines, this is displayed as a percentage of the maximum amperage. It determines the peak power during the pulse and thus the diameter of the weld spot. Workshop rule of thumb for thin material (approx. 0.2–0.3 mm): start with 15 to 25% energy and 0.5 to 1.5 ms, then increase gradually. |
| Penetration depth | How deep the weld penetrates into the workpiece. This is primarily controlled by the pulse duration; the electrode angle also influences the direction of flow of the molten pool. |
| Heat-Affected Zone (HAZ) | The heat-affected zone around the weld point. In micro-TIG welding, it remains less than 1 mm, depending on the component, which is significantly smaller than in conventional TIG welding with a standing arc. |
| Welding point | The individual point where the pulse strikes. The diameter ranges from 0.2 to 4.0 mm, depending on the material and settings. Overlapping points result in dense seams. |
| Tungsten electrode | A non-consumable tungsten electrode, typically with added lanthanum oxide (WLa). It only transfers the energy pulse and does not melt itself; the weld metal comes from the workpiece or the welding wire. |
| Argon inert gas | An inert noble gas that displaces oxygen from the weld zone and prevents oxidation during the arc and solidification. Required for the Lampert process; flow rate approx. 2 l/min; no mixed gas and no CO₂. The inert gas also replaces the flux, eliminating the need for pickling. |
| Argon 4.6 | Argon with a purity of 99.996%, the standard for TIG and micro-TIG welding. |
| Welding Curves | Preprogrammed welding curves for improved weldability of common materials. The operator selects the metal type and welding situation; the curve automatically determines the optimal energy flow and controls the process without the need for manual fine-tuning. |
| Speed Function | This feature is designed for materials with high thermal conductivity, such as silver and copper. It supports rapid sequences of dots to prevent heat from dissipating too quickly. |
Materials and Joints
Micro-TIG welding produces a true metallurgical bond, not solder and not adhesive. These terms classify materials, filler material, and the distinction from brazing.
| Term | Meaning |
|---|---|
| Metallurgical bond | A joint formed by melting both base materials, as opposed to the adhesive bond created by soldering. When the welding wire is of the same type, the joint matches the color of the base materials and is virtually invisible, requiring no flux and no etching. |
| welding wire | Separately supplied filler material for filling or building up. Basic rule: Choose an alloy that is as similar as possible to that of the workpiece; otherwise, there is a risk of color differences or mechanical weaknesses. Prices for precious metal wires fluctuate with the metals market. |
| Aluminum mode | A special operating mode on the Micro Arc Welder optimized for aluminum. Aluminum is considered more challenging than stainless steel because the oxide layer must be penetrated; furthermore, the choice of wire is critical. |
| Mu-metal | Soft magnetic nickel-iron alloy for magnetic shielding, sensors, and electronics; weldable using the Micro Arc Welder. After welding, annealing may be necessary to restore the magnetic permeability in the welded area. |
| Non-weldable metals | Metals with very low melting points, such as zinc, lead, and especially die-cast zinc (typically found in inexpensive costume jewelry). They spatter or melt uncontrollably. If the alloy is unclear, a test weld can help. |
Practical Applications and Terms
These terms describe typical tasks and procedures encountered in day-to-day work, ranging from repairs to seal welding to quality inspection.
| Term | Meaning |
|---|---|
| Build-up welding | Targeted material buildup on a surface for repair or extension. Typical examples: edge buildup in toolmaking or filling an engraving with wire of the same material for subsequent polishing. |
| Tacking | Placing individual spot welds to secure parts before proceeding to the next step in the process. This allows assemblies to be fully pre-assembled and then welded. |
| Spot Welding | A mode for tack welding small parts before the actual welding process to prevent them from shifting. The PUK features its own tack welding mode for this purpose (80 to 700 A at 1.5 ms); the tack welding kit (Item No. 100 845) is also available as a supplement. |
| Hermetic Sealing (Seal Welding) | Gas- and liquid-tight sealing of sensor housings, capsules, and components. A key area of application in electronics, medical technology, and laboratory settings. |
| Helium Leak Test | A test method used to verify the leak tightness of a hermetic seal. Can be performed after welding; the achievable leak rate depends on the geometry and preparation. |
| Welding Near Precious Stones | Thanks to the precise heat application, you can weld right next to set stones without damaging them. In practice, a damp piece of paper protects very delicate stones. |
| Welding Report | Welding documentation is important in medical technology and aviation. The Micro Arc Welder provides program memory and a Modbus TCP/IP interface for this purpose, including weld spot counting. |
| Sample Weld | Free test welding by Lampert Application Technology on workpieces you send in, including a written welding report. Recommended when the alloy is unclear or requirements are demanding. |
More in-depth information on the terms
This glossary provides a quick overview. The derivation of the process, including all process steps, can be found in the Lampert Welding Principle, and its classification within the family of processes is described in the article on micro-welding. If you’re looking for complete answers to the most frequently asked questions, you’ll find them in the Lampert FAQ.
There are separate guides for two specific applications: hermetic sealing using micro-TIG welding and the helium leak test.
If you have any questions about a term or a specific workpiece, simply send a brief description to [email protected], and we’ll be happy to provide a free sample weld upon request.