Laser Material Processing

The mechanism of interaction between the laser beam and the processed material:

 Thermal Effects - Most of the applications of lasers in material processing were based on the absorption of the laser radiation inside the material, and the effects were thermal in nature. The absorption process transfers energy to the material. As a result, there is a rise in the temperature in that region to high temperatures.

 Photochemical Effects - Breaking the bonds between the molecules in the material. The Excimer laser emits in the Ultra-Violet (VU) part of the electromagnetic spectrum, and its photons are very energetic. It can be used to cut very delicate and accurate structures without causing thermal damage to surrounding areas.

The mostly used lasers for material processing are:

1. CO2 laser - which has high power and is highly absorbed in most materials. 2. Nd-YAG laser - which has high power and can be transmitted through optical fibers. 3. Fiber laser -

http://www.fiber-laser-systems.com/laser_applications.htm

1 The main advantages of lasers for material processing are:

 Close tolerance (± .001 inch)

 Excellent repeatability

 Unit cost reductions

 Material versatility

 Flame/fire polished edge cutting (acrylics)

 Minimal distortion in heat affected zones

 No tooling to wear out or change over

 Non-contact processing eliminates unwanted stress on materials

 Clean processing to eliminate debris (shavings, dust, etc.)

 Flexibility - fast setups achieved with computer controls

 Little or no burring can make secondary finishing unnecessary

 90% less heat input results in welds with minimal distortion

2 Laser Cutting

Laser cutting is the process of vaporizing material in a very small, well-defined area. The laser itself is a single point cutting source with a very small point, (0.001" to 0.020" / 0.025mm to 0.5mm) allowing for very small cut widths.

Laser Cutting Advantages

 There is almost no limit to the cutting path; the point can move in any direction unlike other processes that use knives or saws.

 The process is forceless allowing very fragile or flimsy parts to be laser cut with no support. Since the laser beam exerts no force on the part and is a very small spot, the technology is well suited to fabricating high accuracy parts, especially flexible materials. The part keeps its original shape from start to finish.

 The laser beam is always sharp and can cut very hard or abrasive materials.

 Sticky materials that would otherwise gum up a blade are not an obstacle for a laser.

 Lasers cut at high speeds. The speed at which the material can be processed is limited only by the power available from the laser.

 Cutting with lasers is a very cost effective process with low operating and maintenance costs and maximum flexibility.

3 4 5 Laser Drilling

Laser drilling is the process of repeatedly pulsing focused laser energy at a specific material.

The laser beam consistently drills holes down to 0.004" with little or no debris. Holes with length-to-diameter ratios of up to 50 can be drilled with reliable, high quality results.

With lasers it is possible to drill in very difficult locations using mirrors to bend the beam. Laser drilling at very high rates, 1000 pulses per second or greater, is also possible.

Laser Drilling Advantages

 Using laser system software, the operator instantly can control hole shape and size to produce round, oval or rectangular holes, or any shape imaginable. This eliminates downtime due to tool changes.

 Very small holes can be laser drilled in production. A focused spot can be as small as 0.1mm (0.004") in diameter.

 Since the tool is a beam of light, the tool never needs to be replaced eliminating downtime because of punch breakage.

6 Laser Micro Perforating

The laser can be pulsed on and off quickly so materials can be perforated at very high speeds and the perforation pattern changed at will.

Holes are drilled as fast as the laser beam is pulsed and moved from hole to hole. In some cases, the laser beam can drill as fast as 10,000 holes per second.

An example of this is laser perforated computer paper that is with a hole pattern so fine it is almost impossible to tell if it was sheared or torn apart. Laser micro perforating is also useful for package applications such as easy open and breathability.

Laser Micro Perforating Advantages

 Using laser system software, the operator can automatically control hole shape and size to produce round, oval, or rectangular holes or any shape imaginable. This eliminates down-time due to tool changes.

 Very small holes can be drilled in production. A focused spot can be as small as 0.1mm (0.004") in diameter.

 Since the tool is a beam of light, the tool never needs to be replaced eliminating down time because of punch breakage.

7 Laser Heat Treating

Laser heat treating is a surface modification process designed to change the microstructure of metals by controlled heating and cooling. Lasers have the advantage of being able to heat treat precise areas of metals without involving the entire workpiece. The mass of the material being processed is generally sufficient for rapid heat removal or "quenching ".

The enhanced mechanical properties resulting from laser heat treating depend upon the specific composition of the metal or alloy. Laser case hardening of transformation hardenable metals provides high wear and abrasion resistance with a minimum of distortion and cracking. Laser spot annealing of precipitation and work hardened metals (i.e., 300 series stainless steel and copper alloys) restores ductility and improves formability and fatigue resistance in critical areas. Laser Heat Treating Advantages

 Precision control of heat input to localized areas  Minimum distortion  Minimum stress and cracking  Self-quenching, requires no quenching medium  Inherently time efficient process  Line-of-sight access for hard to reach areas

8 Laser Welding Laser welding uses an intense energy beam as its heat source. Laser welding is accomplished at very high speeds with low heat generation and little or no distortion. Since no filler material is required, laser welds are less bulky and more precise. Laser welds are also very repeatable because they eliminate the human error. No physical material such as electrodes or contacts is needed to apply heat to the part. With their well defined beams, lasers are excellent tools for welding thin materials, hermetic welds or in close proximity to heat-sensitive components. Even hard to reach areas can be laser welded if a line-of-site exists.All materials which are commonly welded can be easily laser welded. In addition, difficult to join materials such as high carbon stainless steels and titanium may be successfully laser welded. Lasers are also used to weld many dissimilar materials which may otherwise be incompatible. http://tw.youtube.com/watch?v=1-J_EzKm_70&feature=related

Laser Welding Advantages

 Low heat input/minimal heat affect  Fine grain structure/excellent weld quality  High energy density/high weld speeds  No filler material  Line of sight access for hard to reach areas 

9 Laser Scribing / Etching

Laser scribing is a process in which lines and characters of different fonts can be produced on materials.

Unlike laser engraving, the line being laser scribed is only as wide as a single laser beam and is set to a specific tolerance depth. The line consists of a series of small, closely spaced holes in the substrate that is produced by laser energy pulses.

Laser scribing is a process in which lines and characters of different fonts can be produced on materials.

Ceramics, glass and wood are common laser scribed products. Laser scribing is a process in which lines and characters of different fonts can be produced on materials.

Ceramics, glass and wood are common laser scribed products.

10 Laser marking and engraving

Laser marking or engraving is very much as it sounds. A PC controlled laser beam is used to either discolour the surface of a component or to actually engrave it by vaporising material. The laser and its position can be very accurately controlled and this allows a variety of effects to be achieved from putting barcodes onto stainless steel to putting company logos onto plastic pens.

 All metals, most plastics and ceramics. Marking anodised aluminium or coated components with barcodes and serial numbers.  Marking of CE marks on safety and electrical equipment.  Marking of batch numbers and serial numbers for ISO 9000 compliance.  Marking of wiring diagrams and symbols directly onto components.  Very precise engraving on fragile components.  Medical instruments can be marked without creating a rough surface which would have hygiene implications.  Logos can be applied to promotional items.  Removing coatings.

11  Medical  Electronic  Automotive  Aerospace

Tooling Item Marked for Product Pen Engraved with Company Name & Logo Identification

12 Promotional Item Engraved with Company Engraved Machine Dials Name

Part Number Engraved on Wooden Mirror Marked with Graphic Drill Bit

13 Smoked Glass Engraved with Custom Graphic Wood Marked with Custom Fonts

Product Tags Engraved with Photograph Engraved on Coated Aluminum Part Numbers / Serial Numbers