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56

TUBE PRODUCTS INTERNATIONAL May 2017

www.read-tpi.com

New tube cutting technology

meets next generation

production needs

By Geoff Shannon, Amada Miyachi America, and David Van de Wall, Amada Miyachi Europe

Replacing legacy cutting systems

The pulsed neodymium-doped yttrium aluminium garnet

(Nd:YAG) lasers used in the past two decades have definitely

been great workhorses. They have performed well and been

excellent manufacturing centres for many companies.

Unfortunately, the original integrated pulsed Nd:YAG

lasers that remain in operation are now obsolete and

difficult to service.

While many of these systems have been upgraded

to fibre lasers, they still have old stage sets that are

a number of generations behind current technology.

In addition, they are running on slow and ageing

controllers with legacy software.

Simply put, the laser, stages, controller, software,

water systems and automated tube loader technology

have all moved on.

Here is a brief overview of improvements in these

components that enable faster and better cuts with

higher production rates and less down time.

S

tents and tubes are used in countless medical

devices and new ones are being added every day,

fuelled in part by the growth of minimally invasive

surgery and the commonplace use of stents. The sheer

number and diversity of devices is rapidly increasing,

and with it the demand for more and more laser cut

stents: flexible tubing, cannulas and micro cannulas,

needles, biopsy devices and other minimally invasive

tools.

Figure 1

shows examples of common features in

modern stents.

While legacy stent and tube cutting systems have

performed well during recent decades, new cutting

technologies coming onto the market offer faster and

better cuts, with higher production rates and new and

unique cutting capabilities.

Laser

The pulsed Nd:YAG lasers used in the past have been

superseded by fibre lasers with better beam quality that

does not change with pulse energy and average power.

This provides a smaller and more consistent focused spot

size, which offers tighter cutting tolerances and, with spot

sizes down to 10 microns, the ability to cut much finer detail

features. These lasers provide pulse frequencies up to and

beyond 5 kHz and pulse widths down to 20 microseconds (µs)

to enable energy input optimisation for a wide variety of tube

materials and wall thicknesses.

Higher frequencies can be implemented to maximise

acceleration and speed for a range of part thicknesses. From

an operational standpoint, the fibre lasers have a number

of advantages. They are air cooled, run off single-phase

240V electrical power, and have diodes with lifetimes that

are greater than 70,000 hours, which equates to minimal

operational costs.

Figure 2

shows an example of a tube

produced by one of the new laser tube cutters on the market

(left) and a close-up of laser tube cutting (right).

Fibre lasers use microsecond pulses and offer a cutting speed

and edge quality that is sufficient for many applications. The

femtosecond (fs) laser offers laser pulses that are under

400x10

-15

seconds (s), or about one million times shorter than

the fibre laser. The very short pulse duration, combined with

Figure 1: Modern stents