Research : Micromanufacturing : Fabrication : Femtosecond Laser Machining

Femtosecond Laser Machining

Fabrication capabilities at ARRI include access to a Hurricane Femtosecond Ti:sapphire Laser by Spectra Physics for the micromachining of small parts. This rapid prototyping system can produce parts in as little as 20 to 30 minutes and is one of few available in academia and industry in the US for machining & manufacturing.

The revolutionary advances made in the field of semiconductors, information technology, biotechnology and medicine have led to an increased need for better and faster microfabrication technologies. In this respect, laser based micromachining is gaining recognition due to its numerous advantages over traditional microfabrication processes.

Laser Machining :

• Very high peak powers in the range of 1013W/cm² .
• Temperature increase is very localized. The extremely high energy density values result in instant plasma formation of the incident material.
• Selective materials removal without undercutting due to the highly localized heating.
• This is a subtractive manufacturing process with extremely clean cuts with no redeposited zone or recast layer.
• Creates sub micron feature resolution with good tolerances on the order of 20-30 microns but we are working towards submicron resolutions.
• The feature size depends on laser beam power and focusing lens used.
• Allows for machining on transparent materials by focusing laser light inside materials, to change the refractive properties of the material and can be used for creating waveguides and microfluidic channels.
• Another use of the system is for creating molds. Eg. Rapidly prototyping molds for hot embossing system (micro-molds).

Advantages:

• There is minimal thermal damage to surrounding material due to the absence of HAZ (heat affected zone).
• There is no redeposition, no resolidification, no recast layer and no melt zone. This eliminates the need for pre- or post- processing of the material.
• There are no microcracks, no shock waves and no detrimental by-products created.
• Makes it possible to machine micron sized features with good repeatability, well-defined shapes and complex features with high aspect ratios and good tolerances.
• This is a non-contact machining process with no tool wear or damage to the target material due to contact or material handling.
  It possible to machine a very wide variety of materials both transparent (glass, sapphire, PMMA ) and non-transparent hard to soft materials (Aluminum, Cobalt, Titanium, Shape Memory Alloys, Piezo Ceramics etc.) and fragile, ultra-thin and highly reflective surfaces.
  The system and processes can be automated.

Specs for Femtosecond Laser

• Pulse width: ~120 fs
• Wavelength range: 750 nm-850nm 
• Average energy: 1.0 mJ/pulse
• 1 Hz to 1 kHz pulsing rate (controlled)
• Beam profile: Gaussian
• Polarization: Linear, Horizontal

Process Parameters

• Wavelength
• Beam Shape
• Delivered Energy
• Pulse Width
• Lens Focal Length
• Depth of Focus
• Pulse Repetition Rate
• Air, Vacuum, Inert Gas Environment

Applications

• Surface and Interior Micromachining
• Mold Development
• Material Bonding
• Microfeature Machining
• Secondary Operations
• Medical Microinstruments
• Microneedles
• Micronozzles - Microfluidics
• Microoptics – Waveguides
• Refractive Index Modification
• Microactuators – Microcomponents
• Rapid Prototyping Environment.
• Interior machining.
• Bio-medical devices
• Machining of Stents for heart bypass.
• Controlled drug-delivery.

Materials Machined with the FLM System

metals

• Aluminum
• Brass
• Bronze
• Cobalt
• Copper
• Iron
• Nickel
• Silicon
• SMA
• Stainless Steel
• Titanium
• Tungsten

Non Metals

• Borosilicate Glass
• PLLA
• PMMA
• Polycarbonate
• PZT Ceramics

Publications:

Related Topics :
Control :
Femtosecond Laser Machining
PiezoMEMS