Virtually any type of industrial laser can easily produce holes with the sizes and tolerances required for tablet drilling. Therefore, the primary selection criterion for the laser source is the throughput speed it can support. Secondary to this are considerations such as operating costs and uptime.

1. Use of CO2 Laser for Tablet Drilling
Virtually any type of industrial laser can easily produce holes with the sizes and tolerances required for tablet
drilling. Therefore, the primary selection criterion for the laser source is the throughput speed it can support.
Secondary to this are considerations such as operating costs and uptime.
The maximum achievable throughput speed for tablet drilling is influenced by several laser characteristics. For
example, if all other factors are equal, throughput increases when using a laser whose output wavelength is well
absorbed by the material to be processed. Also, high absorption in the processed material ensures that no
significant laser power penetrates through to other layers in the delivery system, where it might cause damage.
The organic materials used in drug delivery systems nearly all display strong absorption in the infrared, so the
carbon dioxide (CO2) laser, with nominal output at a wavelength of 10.6 μm, is well matched for this task. In
contrast, many organics are transparent at the near infrared output wavelength (1.06 μm) of industrial lasers.
From a practical standpoint, industrial CO2 lasers represent a very mature technology offering excellent
reliability characteristics and low consumables costs. In fact, they offer lower overall cost per watt than any
other type of industrial laser.
Most organics are also strongly absorptive in the deep ultraviolet, and could therefore be
processed using excimer lasers. Currently, there is quite a diverse range of commercially available CO2 lasers,
offering output powers from a few watts to multi-kilowatts. Furthermore, some CO2 lasers operate in
continuous wave (CW) mode, while others are pulsed. A CW laser produces an uninterrupted beam of light,
while a pulsed laser emits a stream of very short duration (<1 millisecond) bursts of light at high repetition rates
(up to 100 kHz). Pulsed lasers exhibit very high peak power, which is the instantaneous power level at the most
intense part of the output pulse, even if the total average power is relatively modest.
The high peak power of pulsed lasers enables processing of a wide range of materials, even including metals,
with relatively low average power. This is advantageous because laser cost goes up with increasing power.
Furthermore, the short duration of a pulsed laser means that the material being processed is only heated for a
very brief period. This allows for very precise process control and minimizes any heat induced effects, such as
discoloration or debris formation. As a result, pulsed lasers are favored for processing applications where heat
damage of surrounding or underlying material is a concern, or for structuring of high melting point materials. In
contrast, CW lasers are typically employed with materials, such as plastics or textiles, where bulk heating is not
a concern, or for applications where it is actually desirable (e.g. heat treating and annealing).
Established in 1983, Control Micro Systems is an industry leading provider of turnkey industrial laser
markingsystems (including part handling and vision) for solving unique manufacturing material processing
challenges. Our engineers are among the brightest in the laser industry and keep Control Micro Systems on the
leading edge of turnkey solutions designed to meet specific production demands.