Manufacturing Engineering Magazine June 2018
Today, laser technology in manufacturing touches all of our lives on a daily basis; lasers cut air bag material and weld air bag detonators for our in-car safety; lasers weld the batteries in many of our mobile devices; lasers drill aero-engine components for planes; lasers cut the glass for our smart phones and tablets screens; lasers weld the drivetrains in our cars and trucks; lasers cut medical stents that increase and enhance our lives, just to name a few.
The proliferation and key revenue stream driver of laser technology in the manufacturing sector started with the laser cutting of sheet metal. The adoption of this technology serves as the blueprint for why laser technology has grown steadily with an almost 10% CAGR. The cuts produced by the laser were more accurate, more precise, which led to many advantages in downstream processes. An interesting example of this was in the shipbuilding industry where previously plasma-cut parts needed rework to fit correctly, with the shipyard reverberating to the sound of a thousand hammers. The capability for precision, flexibility and unique processing are really the cornerstone of why laser technology is selected for a manufacturing process.
Looking at present day where laser technology is currently at, there is nearly a laser for every process a manufacturing or design engineer can imagine: cutting, welding, marking, machining, cladding, additive building, roughening, stripping – the list goes on. Looking more closely at the manufacturing sectors that are currently trending:
High-Volume Laser Welding
Maximizing weld time and minimizing non-weld time is of course the goal. As laser welding is a noncontact process, and the laser can be directed very quickly by moving mirror systems known as scan heads, making welding almost instantaneous. A great example of this is welding car seat assemblies—a robot carrying a scan head moves above the assembly without stopping, making all the welds on the fly. A job that previously took minutes is now seconds. Another example is battery welding for electric vehicles—ultimately the cost of the batteries will determine the success of this sector. The need to drive battery pack manufacturing costs down means high-speed welding. Laser technology is the only viable process to enable this.
Laser Part Making
The fastest-growing laser market in recent years continues to expand as the need for tracking and traceability for parts increases. Laser marking provides a permanent direct mark for a wide variety of materials, with any feature—text, graphics, barcodes. The markers can be linked to databases for mark serialization or operate in standalone capacity. The laser marker offers a truly impressive package for a commodity price that reflects the tens of thousands that are sold every year.
Laser Additive Manufacturing
Additive manufacturing is finally hitting the big time, having been around for almost 30 years, with price, capability and demand aligning. Laser additive manufacturing can be split into part repair and part creation. Part creation enables fabrication of parts not possible by any other process: custom parts for medical implants, lighter, single-piece complex aero-engine components, fast component prototyping, parts with graded material compositions. Part repair is targeted at expensive components or tooling that wear over time; two key examples of this are molds and aero-engine turbine blades. Metal layers are deposited in the region of repair with the slight excess machined back to specification. The key to the success of laser additive manufacturing, particularly for part creation, will be continued reduction in cycle times
Ultrashort, Pulse Laser Micromachining
With pulse durations of 10-12s and 10-15s, the picosecond and femtosecond lasers are defining a new regime in laser micromachining—the ability to process metals, with no or negligible heat-affected zones, machine plastics, brittle materials, such as glass and ceramics, and virtually any material. The laser removes material by a sublimation method, solid to vapor. The machined edges are of the highest quality; clean, precise with no burring. This provides extreme precision with feature tolerances down to micron levels, which is being leveraged in production using femtosecond lasers to drill holes into gas injectors that must have a precise geometry to maximize efficiency. The medical device industry has many requirements for plastic and metal machining that align with the ultrashort-pulse laser capabilities. Even by laser cost standards, these lasers are not cheap, but prices are now coming down from demand and can provide either a means to create unique part design or dramatically reduce post processing operations.
Flatbed Laser Cutting
Coming full circle to what started the laser processing industry, and what is still by far the highest revenue sector, laser cutting continues to move forward. The latest step change occurred with the development of the fiber and disk lasers that have significantly pushed the envelope for cutting speeds. A 2-kW fiber or disk laser can now cut faster than a 4-kW CO2 laser. To keep up, motion systems require 5G accelerations with cutting speeds through the roof. More recently, these lasers can be externally controlled to optimally cut both thin and thick sections on the fly. The diode laser is newer to the scene and is starting to create a lot of interest for aluminum cutting.
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