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

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.

      Selecting the Metrology

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.