Material Selection:
In broad strokes, instrumentation pinholes, apertures, collimators and air slits are fabricated from ultra thin metal foils. These metal foils vary from 25 microns (0.001") to 500 microns (0.020") thick.. Predominantly they are manufactured out of tantalum, tungsten or molybdenum since these metals are relatively homogeneous in morphology and exhibit the necessary durability for handling.
Although stainless steel (such ss 304 or 306) can be a material of choice for certain applications, its non-homogeneous nature does not make it a natural choice for utilizing laser micromachining technology. Therefore it is preferred that more homogeneous materials such as tantalum, tungsten and molybdenum are used for the fabrication of pinholes, apertures, collimators and air slits.
Photographs of micromachined metals can be found in the Application Material Guide to Metals.
1. Material Availability:
Resonetics provides a wide range of sizes of selected materials (refer to Section 3.0) in the thickness indicated. This one-stop solution allows the scientist or engineer to focus strictly on the specific pinhole, aperture, collimator, air slit or spatial filter design. Therefore Resonetics supplies a complete, finished component with accompanying quality control documentation and packaging.
PIVOTAL Laser Micromachining Technology:
In order to address the wide encompassing feature size range of the high precision instrumentation aperture market, Resonetics has developed the proprietary PIVOTAL laser micromachining technology which utilizes a hybrid of both high pulse energy solid-state lasers and the deep ultra-violet, nano-second pulsed lasers. This unique technology allows one to machine customized apertures, pinholes, collimators and air slits by alternating both laser sources "on-line" and maintain the stringent positioning and dimensional tolerances required.
Pivotal stands for:
- (Special) Packaging Considerations for specialized pinholes, apertures, collimators or air slits
- Inspection of components
- Verification of Inspection by SPC or other means
- Option of using one or two laser technologies on-line
- Proprietary Tooling fixtures to ensure repeatability
- A single source solution for both high and medium tolerance pinholes, apertures, collimators or air slits
- Laser micromachining technology from the largest independent laser micromachining company in the US.
As indicated by the acronym, PIVOTAL laser micromachining technology extends well beyond the actual drilling, cutting and milling.
Tooling
The technology incorporates unique tooling and fixturing techniques to handle delicate pinholes, apertures, collimators and air slits to allow a repeatable manufacturing process with minimal part handling. Since the diagnostic pinholes and slits may be very thin or small in size, it is critical that there is minimal human intervention from raw material quarantine to final product shipment.
Trays or cassettes are fabricated to allow batch processing with specially designed contoured air gaps below the parts to channel away the machined material. This technology is borrowed from Resonetics proprietary Precision Flow Device technology where flow dynamics contribute strongly to the ultimate design of nozzle device. PIVOTAL also incorporates proprietary post cleaning processes to ensure a quality-looking hole.
Optional Laser Sources
Since PIVOTAL incorporates both high speed solid-state laser technology and deep UV nano-second pulsed lasers in one machine, there is considerable flexibility in the manufacturing process. For medium precision devices, the solid-state laser can be used on its own, For high precision work requiring +/-1micron (0.00004") tolerances, the UV technology can be used for fine work while the solid-state laser can be used for excising.
As an added benefit, this unique configuration allows countersink holes to be drilled. For example, one type can drill at high speed through the majority of the aperture with relaxed dimensional tolerances. Then the ultra fine laser can be brought on-line and drill through the remaining material at much higher precision. This type of flexibility is a mainstay of PIVOTAL laser micromachining and is exemplified in Section 4.0
Verification
PIVOTAL laser micromachining technology is part of Resonetics in-house 25 laser micromachining contract manufacturing service. This job shop service runs in a three shift, 24 hour/day operation, incorporating first article, random on-line/off-line quality control and Statistical Process Control (SPC). This provides enormous benefit for customized pinholes, apertures, collimators and air slits since there exists a manufacturing framework to handle low quantities without sacrificing quality or workmanship.
Packaging
Since PIVOTAL can be as precise as 1micron (0.00004"), Resonetics has merged its semiconductor packaging technology with the fabrication of pinholes, apertures, collimators and air slits. If one can imagine fabricating a 5micron-diameter hole, any loose dust particle may accidentally block the hole. As a result, pinholes, apertures, collimators and air slits are manufactured in a Clean room facility, including final packaging of the components. These devices are packaged in specially developed pouches to avoid any direct physical contact. Again, another added benefit of Resonetics PIVOTAL technology.
Laser Micromachining Technology
To be fair, there are other manufacturing technologies to fabricate pinholes, apertures, collimators or air slits. Electroforming technology may be suited for high volume batch processing but it suffers from requiring lithographic step-ups, involving long lead-times and high front-end costs. The entrance taper angles tend to be wide. Due to the nature of the process, the resulting yields may vary. Micro Electro Discharge Machining (EDM) is another fabrication technology. It has similar advantages as lasers by being a direct process but it is notoriously slow, resulting in high component costs. It also a technology impediment of going below 5microns.
On the other hand, PIVOTAL laser micromachining technology attempts to address the spectrum of issues facing the fabrication of precision pinholes, apertures, collimators and air slits.
Direct Process: Since the laser beam is focussed on to the part, fabricating can begin immediately without involving complex setups or inherent process lead-times.
High Dimensional Tolerances: The technology can drill holes as small as 5microns diameter (or smaller), allowing very precise pinholes to be fabricated. Even if your specific application does not require such dimensions, utilizing a technology that offer such a precision without a cost penalty, can only improve the overall quality of the component.
Speed of the Process: By incorporating both a fine scalpel (deep UV pulsed lasers) and a medium scalpel (solid-state), one can optimize the fabrication process so that there is a balance between precision and drilling speed. This is one of the key unique features of PIVOTAL laser micromachining technology.
