Laser Drilling Enables Advanced Drug Delivery Systems - Coherent

Laser Power
Usable
Cutting
Energy
Cutting
Threshold
Power
0 100 200 300 400
Time (microseconds)
Flowing Gas Laser
Laser Power
Usable
Cutting
Energy
Cutting
Threshold
Power
0 100 200 300 400
Time (microseconds)
Slab Discharge Laser
The fact that each square wave pulse delivers more useful cutting energy means that it takes
fewer of these pulses to perform a given processing task. Because of the interrelationship
between maximum possible pulse count and throughput speed in on the fly drilling, this
translates into a wider process window and greater flexibility. In addition, the reduction of waste
energy serves to further minimize any heat induced damage in the processed material.
Control Micro Systems utilizes Diamond K Series slab discharge CO2 lasers from Coherent for
many of its tablet drilling systems. In addition to the advantages of square wave pulsing, the
Diamond K Series also delivers several other benefits for on the fly processing. The ability of
these lasers to provide “power on demand” is probably the most important of these. This refers
to the capacity to control the laser’s pulsing characteristics, in real time, down to the single pulse
level if necessary. In contrast, many industrial lasers operate with a fixed or narrowly variable
pulse repetition rate. Moreover, in most other laser types, individual pulses cannot be relied
upon to produce consistent results because the laser takes several pulses to reach its steady state
performance level. However, the slab discharge design does not have this limitation and can be
perfectly pulsed instantaneously. Thus, power on demand is important because it allows the
laser to be slaved to any arbitrary (and even variable) feedrate in a real production line. This is
substantially simpler than attempting to adjust the mechanics of the conveyor system so that
tablets are supplied at exactly the right time to synchronize with a fixed pulse rate laser.
Conclusion
The development of more sophisticated drug delivery systems permits the use of a wider range
of chemical entities, but the complex structure of these devices often creates greater technical
difficulties in production. The laser has shown itself to be a reliable and cost effective tool that
Coherent Article for Pharmaceutical Manufacturing – – printed 01/18/07 Page 6