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Laser Micro Welding Solutions

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Laser Welding

Technology

Technology

Laser micro welding has been a hot R&D topic at several public research institutions in the past decade to accompany the miniature trend of components and devices in the electronics, medical, photonic and precision instrument industries. These applications require a rapid, precisely controlled and individually adjustable energy delivery to the weld spot. Recently, a number of industrial laser micro welding applications has been successfully carried out at various laser job shops.

The unique ability of the laser beam to be focused to a very small spot size and cause rapid but minimal heat transfer makes it just the right tool for micro-welding. Laser intensity is scalable in great ranges both locally, as well as, temporally. Laser micro welding has become the most suitable and preferred method for the automated production of high valued miniature devices, when compared to conventional resistance welding and brazing.

Laser micro welding is recognized as a high-speed, repeatable process that offers numerous advantages, including:

  • high quality weld (e.g. smooth seam surface, no oxidation, no part distortion)
  • no need of using filler materials
  • minimum heat-affected zone, which minimizes damage to the workpiece
  • non-contact process with great accessibility of the hard-to-reach welding areas
  • simple integration with viewing systems for micro precision material positioning and handling
  • no need of a vacuum chamber, as required by electron beam welding

Laser micro welding has been used to perform delicate welding of thin foils of 1 – 5 mil (0.025 – 0.125mm) thickness, tiny wires of 3 – 10 mil (0.075 – 0.250 mm) diameter as well as small tubular or intricate parts. In other cases, its unique and precision manufacture process is applied to avoid part distortion and thus to maintain tight tolerances and minimum interference with the surrounding components.

Materials, frequently used for laser micro welding, are aluminium, copper, gold, nickel, platinum, steel and titanium alloys. Depending on the application, CO2-, pulsed solid-state lasers or fiber lasers can be used. Average output power ranges from 10 up to 200 W. In general, pulsed lasers generate less heat in the workpiece than continuous wave lasers.

For joining micro parts, the air gap distance between two sheets or a sheet and a solid body has to be less than 5% of the thickness of the sheet. In some cases, an intimate contact is essential to produce a hermetic seam joint. Small focus diameters are preferred to minimize the impact of air gap. Typical spot size (weld width) varies from 25 to 400 µm (.001” to .016”). Typical laser micro welding penetration depths range from 50 to 500 µm (.002” to .020”).

Tack (spot) welding is usually required to fix the parts in the defined position prior to seam welding. A strong weld is achievable if the weld pool is deeper than the thickness of the thinner part. Often, welding of dissimilar metals or fillet welding of small rod to a housing could only be realized with the help of additive materials. The weld can be made smoother and stronger by performing more than one pass (multiple pass) at a pulse overlap rate of approximately 70 – 85%. A laminar flow of inert shielding gas, such as argon, is desirable to avoid oxidation of the weld and thus, to achieve a shiny finish of the weld seam.

Proper part geometry design, precision part fabrication, correct tooling and fixturing as well as applying optimum process parameters are all critical to create intimate contact between the materials at the weld joint and to ensure a crack-, porosity- and distortion-free weld.

Following examples can be found in Laser Welding Gallery:

  • Laser micro welding of corrugated CuBe membranes (0.005” thick) to CuBe buttons
  • Laser micro welding of mirror shaft (dia. 0.125”) of scanning mirrors
  • Laser micro welding of Cobalt wires (dia. 0.004”) to PCB pads
  • Laser micro welding of thin stainless steel disk (0.010” thick) to thin stainless steel tubes (0.005” and 0.010” thick)
  • Laser micro welding of stainless steel foil (0.002” thick) onto steel tube
Area of expertise

Area of expertise

KJ Laser Micromachining is a leading specialist in handling and positioning micro components, in providing innovative laser micro welding services with or without using additional filler material, in micro welding of extremely thin foils or tiny tubes. We have are experienced in process customization to avoid air gap between overlap joining partners, to minimize surface oxidation and to obtain consistent and sound micro welds.

Further information can be found under “laser precision welding”

Materials

Materials

An extended matrix of weldability (welding compatibility chart) is available in our database. For further information, please see “laser precision welding”.

Sub-contract micromachining and R&D

Sub-contract micromachining and R&D

Our laser welding services include samples testing, feasibility study, prototyping and contract manufacturing. We can also play a vital role during your product design and development period by conducting welding and metallurgical investigations in laser micro welding.

System development and process automation

System development and process automation

KJ Laser Micromachining has the capability to design and develop customized laser welding systems for the high-volume and automated manufacture of parts or components