Micro-welding and precision welding: processes, applications, and equipment selection
Micro welding is the collective term for welding processes that permanently join thin or delicate metal parts. Common synonyms include precision welding, micro TIG welding, micro pulse welding, pulse arc welding, and TIG welding. The most common cutoff is for material thicknesses under 0.5 mm; this is how the U.S. welding institute EWI defines the field of microjoining. The core of this field comprises five processes: micro-TIG/pulse arc welding, laser welding, micro-resistance welding, electron beam welding, and ultrasonic welding. The choice of technique depends on workpiece thickness, quantity, material, accessibility, and budget.
What is considered micro-welding?
There is no binding standard for the umbrella term. The American Welding Society does not list micro-welding as a separate process. Instead, experts use size limits, which vary depending on the source:
| Source | Delimitation |
|---|---|
| EWI (term “Microjoining”) | Material thickness less than 0.5 mm; includes welding, soldering, brazing, and bonding |
| Technical literature | Weld width less than 0.5 mm or heat-affected zone less than 100 µm; not listed as a separate process by the AWS |
| DVS technical Note 3224 | Laser welding: material thickness ≤ 100 µm for both workpieces; applies only to the laser process |
| Manufacturing practice | Pragmatically, everything below traditional welding methods, from approximately 5 mm down to 0.007 mm |
Microwelding, precision welding, …: one field, different names
Several terms for this kind of welding are used interchangeably and they are known as micro welding, pulse arc welding, micro TIG welding, or micro GTAW (U.S.: gas tungsten arc welding). Micro-TIG and micro-pulse welding refer to a specific process within this family: the pulsed arc.
People who search for one of these terms are usually looking for the same thing.
The five core processes
1. Micro-TIG welding / pulsed arc welding
A very short arc between a non-consumable tungsten electrode and the workpiece melts the material at specific points, under an inert gas. The general technical literature classifies the micro-TIG process category as having weld areas under 18 mm² and a current range of 5 to 300 A. This value describes the process class in the literature, not a device limit: industrial devices such as the Micro Arc Welder can reach up to 1,200 A. Lampert devices operate with pulse durations ranging from 0.1 to 34 ms and produce weld spots with diameters ranging from 0.2 to 4.0 mm; the welding process proceeds automatically upon contact with the tungsten electrode. The article on the Lampert welding principle explains how the pulse is generated.
2. Laser welding
A focused fiber or YAG laser beam performs contactless welding with a very narrow heat-affected zone and high cycle rates. However, this process requires radiation protection (laser safety class 4) and a significantly higher investment.
3. Micro-resistance welding
Electric current combined with electrode pressure creates the weld spot directly at the joint (spot or seam welding). The process is fast and cost-effective and is therefore often used as the standard in high-volume production. It generally requires access to the workpiece from both sides.
4. Electron beam micro-welding
Maximum precision in a vacuum, a special case for small-batch production with extreme requirements, such as when working with reactive specialty materials. Due to the vacuum chamber at the high end of the process family, the investment is often in the six-figure range.
5. Ultrasonic welding / wire bonding
A solid-state process without melting: ultrasound and pressure bond the joining partners together. In semiconductor manufacturing, wire bonding is the standard; nearly 90 percent of all chip connections are made this way.
In addition, some sources mention less common processes such as percussion welding, thermocompression, and micro-plasma. In practice, however, the five core processes are often the deciding factor in process selection.
Comparison of methods
| Procedure | Workpiece thickness | Suitability for small quantities | Range of materials | Investment | Mobility | Automation |
|---|---|---|---|---|---|---|
| Micro-TIG / pulsed arc | 0.1 mm and up; core range 0.1–1.0 mm | Single units, repairs, prototypes, and small-batch production | Very broad: steels, titanium, nickel-based alloys, precious metals, copper; aluminum with aluminum mode | low, Micro Arc Welder setup starting at approx. 7,000€ | High: handpiece moves toward the workpiece; workpiece size is unlimited | possible (i.e., program memory, Modbus TCP/IP) |
| Lasers (fiber/YAG) | Less than 0.1 mm possible; DVS 3224: ≤ 100 µm | Small-batch to mass production, high cycle rates | very wide; highly reflective precious metals are challenging | High, ranging from approximately 15,000€ to 500,000€, plus Class 4 laser safety requirements | Low: stationary, enclosure required | Very good, standard in production lines |
| Micro-resistance (spot/seam) | Films, thin sheets, wires, tabs | High-volume production, very short cycle times | Sheet metal, wire, and tab connections; access from both sides required | low, starting at approx. 4,000€ | low: asset-related | very good |
| electron beam | the finest textures | Small-batch production with extreme requirements | including reactive specialty materials (vacuum process) | high, starting at approx. 400,000€ | None: vacuum chamber | within the facility |
| Ultrasonics / wire bonding | Wires typically under 50 µm, foils | Mass production of semiconductors | Wire bonding; solid-state process without melting | Semiconductor production equipment | None: bonder system | fully automatic |
When to use which method?
The decision-making logic as an “if-then” list:
- Films or wires thinner than 0.1 mm: test using laser, micro-resistance, or ultrasonic methods. This marks the end of the core application area for the pulsed arc.
- Material thickness between 0.1 and 1.0 mm: the core range for micro-TIG and pulsed arc welding. Lampert machines can weld materials as thin as 0.1 mm, producing weld spots ranging from 0.2 to 4.0 mm.
- Individual parts, repairs, prototypes: manual micro-TIG welding under a microscope. No setup required; no fixture necessary.
- High-volume production with tight cycle times: automated laser or resistance welding.
- Chip and semiconductor contacts in volume: wire bonding.
- Highly reflective precious metals (gold, silver, platinum): pulsed arc. These materials pose a challenge for the laser due to their reflectivity.
- Aluminum: check for aluminum compatibility. Aluminum is considered difficult to weld using DC micro-TIG; the Lampert MAW addresses this with a dedicated aluminum mode, and laser welding is also possible.
- Accessible from only one side (inner edges, undercuts, fully assembled subassemblies): manual electrode in pulse arc welding. Resistance welding requires access from both sides, while laser welding requires a line of sight and an enclosure.
- Budget is the main factor: resistance and micro-TIG are the most affordable; lasers start at around 15,000 EUR plus laser safety requirements; electron beam is at the high end.
- Documentation requirements (medical technology, aviation): ensure program memory and interface capabilities. The MAW provides both via Modbus TCP/IP, including weld spot counting for the weld report.
The most common purchasing decision, between pulsed arc and laser, is examined in detail in the comparison of micro-TIG welding versus fiber laser welding.
Cost-effectiveness: guidelines for assessment
The following figures are rough guidelines for estimating investment thresholds; they are not quoted prices. They vary depending on the configuration, level of automation, and vendor.
| Process / equipment category | Purchase (order of magnitude, net) |
|---|---|
| Micro-TIG for jewelry making (PUK complete setup) | Starting at approx. €4,400 |
| Micro TIG for industry and laboratories (Micro Arc Welder) | Starting at approx. €7,000 |
| Laser micro-welding | Starting at approx. 15,000 €, plus Class 4 laser safety requirements |
| Micro-resistance welding | Starting at approx. €4,000, equipment-dependent |
| Electron beam micro-welding | Starting at approx. €400,000 (industry estimate), plus vacuum chamber |
| Ultrasonics / wire bonding | Semiconductor production equipment, depending on the project |
A rule of thumb for cost-effectiveness: it’s not the price of the equipment that matters, but the production volume profile. For those manufacturing one-off parts, performing repairs, or producing small batches, micro-TIG is usually the most cost-effective option; for those producing in the millions with defined geometries, the higher investment in lasers or equipment pays for itself through cycle time savings.
Areas of application
Micro-welding is a major topic: wherever components are too delicate for conventional welding techniques, one of the five processes is used:
- Medical technology: catheters, guide wires, surgical instruments, implant housings
- Electronics and sensors: contacts, thermocouples, battery tabs, sensor housings
- Laboratory and research: prototypes, specialty materials such as tantalum, niobium, or zirconium
- Repair and maintenance: tool edges, surface defects, thin-walled components
- Jewelry: soldering on stud earrings, settings, repairs to finished pieces, including permanent jewelry
- Dental: braces, bridges, cast-metal repairs
- Model making and restoration: brass, nickel silver, filigree assemblies
- Aviation: thin-walled components, repairs, documentation requirements
A key area of application spanning medical technology, sensor technology, and laboratory work is the hermetic sealing of capsules and housings, as discussed in greater detail in the article “Hermetic Sealing with micro-TIG welding.”
Micro-welding and precision welding at Lampert
Lampert Werktechnik (Werneck, since 2001) manufactures equipment for exactly one of the five core processes: TIG micro-pulse welding, i.e., the pulsed micro-TIG arc. Lampert itself uses the terms “precision welding,” “micro-TIG welding,” and “micro-pulse welding” interchangeably.
Device classification:
- Micro Arc Welder (MAW), industrial and laboratory use: 5 to 1,200 A, material thicknesses starting at 0.1 mm, weld spot sizes 0.2 to 4.0 mm, 12 material programs, aluminum mode, Modbus TCP/IP interface for automation and welding reports. Fully functional complete setup starting at €7,000 net.
- PUK, jewelry: spot welds from 0.2 to 3.0 mm, PIN mode for stud earrings, welding near gemstones. Base unit starting at €3,699 net.
- PUK D, dental: welding curves optimized for dental alloys.
- M280, model building: the same technology in an entry-level format.
The Micro Arc Welder comes with a 1-year warranty; the PUK, PUK D, and M280 each come with a 3-year warranty; all are designed and manufactured in Germany.
Honestly acknowledging when other methods are a better fit:
- For material thicknesses under 0.1 mm, the laser has the advantage.
- For large-scale production runs where cycle times are critical, automated laser or resistance welding is usually more cost-effective. Many Lampert customers use both technologies in parallel: micro-TIG for repairs, one-off items and mobile applications, and laser for high-volume production runs.
- Semiconductor wire bonding remains the field of wire bonding.
- Aluminum can be welded in aluminum mode; for critical applications (pressure-tightness, high-stress parts), weld test pieces first.
If you’re unsure, send us sample parts: Lampert application engineering will produce free sample welds along with a written welding report.
In-depth pages
This overview provides a summary of the topic; the individual pages go into greater depth:
Processes and technology
- The Lampert welding principle: how micro-TIG welding works
- Micro-TIG welding vs. Fiber laser: a comparison
- Hermetic sealing using micro-TIG welding
Materials tutorials
Products
- Micro Arc Welder (MAW) for industry and laboratories
- PUK for jewelry and goldsmiths
Frequently asked questions about micro-welding
Microwelding is the umbrella term for welding processes that permanently join thin or delicate metal parts, typically with material thicknesses of less than 0.5 mm. It is not a single standardized process, but rather a family of processes: micro-TIG/pulsed arc, laser, resistance, electron beam, and ultrasonic.
None; the terms mean the same thing. Lampert uses the terms “fine welding,” “micro-TIG welding,” and “micro-pulse welding” interchangeably; in English, this field is known as “micro welding” or “pulse arc welding.”
There is no established standard. A common threshold is a material thickness of less than 0.5 mm; this is how the U.S.-based EWI institute defines the field of microjoining. DVS information sheet 3224 sets the threshold for laser micro-welding at 100 µm, while some manufacturers interpret the term more broadly, extending it to approximately 5 mm.
Micro-resistance welding requires the lowest initial investment; pulsed arc welding falls in the mid-range; laser systems start at approximately 12,000 EUR, which is significantly more than micro-TIG equipment, and also require additional laser safety measures. Electron beam welding is at the high end of the spectrum due to the vacuum chamber.
Yes, but not all methods work equally well. With traditional DC micro-TIG welding, aluminum is considered difficult to weld; the Lampert Micro Arc Welder has a dedicated aluminum mode for this, and laser welding is also an option. The choice of welding wire is crucial. Step by step: welding aluminum.
Not with micro-TIG welding. The welding process begins automatically once the electrode makes contact and can be learned in just a few hours, even by non-welders. Laser systems require more training and the implementation of laser safety procedures.
Yes. Hermetic sealing of sensor housings, capsules, and implant housings is a core application area; validation is performed using a helium leak test. Details: hermetic sealing using micro-TIG welding.
The Micro Arc Welder (MAW) for industrial, laboratory, and repair applications (5 to 1,200 A, starting at 0.1 mm), the PUK for jewelry, the PUK D for dental applications, and the M280 for model making. If you’re unsure about the application, a free sample weld can help: [email protected].
Conclusion: the task determines the procedure
The selection is based on six criteria: workpiece thickness, quantity, material, accessibility, investment, and automation requirements. The pulsed micro-TIG arc, known as the Lampert process, is the first choice for material thicknesses of 0.1 mm or greater, single pieces, repairs, precious metals, and jobs with access from only one side; the appropriate device for this is the Micro Arc Welder. For thicknesses below 0.1 mm, in high-volume production, and for semiconductor bonding, lasers, resistance welding, or wire bonding are the more suitable methods.
If you would like to have your specific case evaluated, please send sample parts to Lampert application engineering: [email protected]. Each sample weld will be returned with a written welding report.