The Center for Drug Evaluation (CDER) within the U.S. Food and Drug Administration (USFDA), invited Lenox Laser to participate in a conference in October of 2012 in recognition of the calibrated leak standard maintained by Lenox Laser in the pharmaceutical, medical, and food industries.
Joseph d'Entremont and Gregory Solyar presented the following presentation at this conference, securing the foundation of Lenox Laser Medical, LLC as an organization born out of Lenox Laser Inc. that is dedicated to precision, accuracy, and service in the most dynamic health industries.
Producing
a Calibrated Leak Standard with Laser Technology
by
Gregory Solyar
Scientist, Lenox Laser
by
Gregory Solyar
Scientist, Lenox Laser
OCBQ seminar: Current Technology in
Container/Closure Testing
Three Parts of Integrity
Testing by Calibrated Orifice
•
Manufacturing the leak
•
Calibrating the leak
• Cross calibrating the leak test methods
Sealed and Filled
Containers
Open Containers
Glossary
•
Calibrating the leak – measuring the flow
and flow effective diameter
•
Flow effective diameter – the diameter of the
round orifice with the area equivalent to a leak
•
Positive, negative, volumetric flow meters
•
Aspect ratio – length of the
channel divided by its diameter
•
Laser parameters – wavelength, energy
per pulse, repetition rate, pulse width
•
SEM – (Electron Scanning
Microscope)
Two Major Parts of Manufacturing the Leak
•
Laser drill the orifice with post measurement
(non-destructive and destructive)
•
Laser drill the orifice with in-process test
Pre-qualification of Containers: Syringes,
Ampoules and Vials for Laser Drilling
•
Measurement of the wall thickness deviation
•
Selecting the methods of preprocessing (mechanical, laser
beam)
•
Optimizing the laser parameters for material composition
•
Selecting the metrology methods for different contents of
the containers (developing the repeatability, non-destructive and destructive
methods)
•
Selecting the correct methods and ways of handling: mechanical
fixtures for drilling, marking, testing, storing, shipping
Measurement of the Wall Thickness Deviation (Fig.1)
•
The thickness of the material (glass, plastic) varies in
different parts of the given container such as ampoule, syringe and bottle.
•
Although this
thickness is defined on the drawings of the manufacturer of the given
containers, it may vary by 50%.
•
The diameter of the microhole is effected by this thickness
variation.
•
Therefore, Lenox Laser performs its own study of the
thickness in the areas selected for drilling by customer. Sometimes these
methods are destructive.
Measurement of the Wall Thickness Deviation (Fig.2)
Measurement with OGP
Selecting the Methods of Preprocessing
•
Due to high precision and aspect ratios, (ratio of a wall
thickness to an orifice diameter), application of more than one laser beam is
required. This step may also include some mechanical drilling before the
application of the final laser beam for the calibrated orifice is done.
Optimizing the Laser Parameters for Material
Composition
•
Different types of glass or plastic have different thermal,
mechanical and optical properties. Some of those types are very sensitive to
changes of the laser parameters such as wavelength, energy per pulse,
repetition rate, pulse width etc.
•
Choice of the correct combination of the laser parameters
may lead to cracking, melting, carbonization, separation of the composite
materials, or the presence of micro-particles in a channel.
Methods for Different
Contents of the Containers
The containers supplied for the orifice manufacturing may be
empty or filled with liquid. The containers also may be open to the ambient
atmosphere or sealed, having the internal pressure above or below ambient.
•
In each particular case, one or more hole calibration
methods may be used.
•
The methods include:
•
1. Mass flow, volumetric methods (volume vrc. time).
•
Standard: leak standard.
•
2. Optical microscope method (geometrical size and shape).
•
Standard: optical standard.
•
3. SEM method (geometrical size and shape on nano scale).
Standard: nano sphere.
•
4. Bubble detection. Qualitative method.
Mass Flow Methods
Flow Measuring Method by Water Displacement
Vacuum Gauges Calibration Station
Flow Measurement by
Vacuum Gauges
Measurement by SEM
(Fig.1)
Measurement by Electron
Scanning Microscope
(Fig.2)
Diffraction by the
Orifices
Mechanical Fixtures for Laser Drilling under Flow Testing
Selecting the Correct
Methods and Ways of Handling
•
Due to a small diameter of the orifice, specific methods
preventing the drilled channel from being clogged are applied.
•
During processing, a presence of the assist gas or clean air
and a method assuring the transport of the laser-created material particles
away from a drilled sample may be necessary.
•
The samples have individual reports indicating the effective
flow diameter, or optical diameter, flow rate and test conditions. So correct
identification of each sample container becomes very important. No marking on a
sample itself is usually allowed.
•
In case the containers are filled, Lenox Laser develops a
specific method of packing with each customer to preserve the contents from
contamination and the drilled channel from clogging.
Goals and Vision
•
Zero defects practice (aerospace philosophy)
•
Use of the simplest possible methods and “transparent” physics for manufacturing.
•
Use “optical signature” methods such as photography and videography on macro- and micro-
scale for quality control and manufacturing.
•
Develop new “Object oriented” methods and techniques for metrology.
