SIS Manufacturing--Filament Repair Shops

A collection of some of the many filament styles repaired and manufactured by SIS

Filament Repair at SIS

In 1978 Scientific Instrument Services, Inc. began the business of mass spectrometer filament and heater repair. During the past 26 years, we have repaired tens of thousands of mass spectrometer filaments. Our repair staff has grown from one individual to its present number of ten with additional expansion anticipated. At the same time, we have added a wide variety of technical equipment for the manufacture, repair and alignment of the filaments. This new equipment and expanded facilities has enabled SIS to repair a greater quantity and variety of filaments for mass spectrometers and other scientific instruments. In addition we have been able to improve the quality of our repairs via the use of filament alignment and tensioning jigs which have been custom designed and manufactured by our highly skilled technical staff. We presently repair filaments for almost all manufacturers and models of mass spectrometers. In addition we also repair and manufacture filaments for other scientific instruments including X-Ray generators and other techniques which utilize a resistance wire or coil filament. Since 1978 we have been the leader in providing quality filaments for the mass spectrometer community. We have repaired hundreds of different types of filaments and this experience has been used to design and develop new filaments for a variety of instrument manufacturers. SIS manufactures a large number of filaments on an OEM basis for a number of scientific instrument companies in the US as well as worldwide.

For a complete list of all the filaments repaired by SIS along with pictures of all the filaments, see the SIS service section SIS Filament / Heater Repairs. For a listing of all the filaments manufactured by SIS see the product section - New Mass Spectrometer Filaments From SIS.

Filament Manufacture at SIS

SIS Redesigned Finnigan-MAT 4000 Filament and Finnigan-MAT Incos 50B Filament

Utilizing the knowledge and experience gained from repairing thousands of filaments from a wide variety of manufacturers and models of instruments, SIS began to design and redesign filaments for mass spectrometers about 10 years ago. We learned from the various types of filaments we repaired, which designs worked best and what could be done to increase filament life and performance. Our goal in producing new filaments is to improve the design, increase filament life, reduce the cost and improve the filament and mass spectrometer performance.

We presently manufacture filaments and heaters for more than 25 models of mass spectrometers and related equipment. In addition we custom manufacture filaments on an exclusive OEM basis for several instrument companies. If you have a need for a custom design filament, SIS can help you with the design and can manufacture the filament for you. If you are an Original Equipment Manufacturer (OEM), SIS can aid you in the design of your filaments, produce prototypes and provide you with high quality filaments with timely delivery.

A complete description of the techniques used to clean and repair mass spectrometer filaments at SIS is described in the accompanying article entitled "Mass Spec Source Cleaning Procedure".

SIS manufacturers a wide variety of filaments from many different materials. Materials such as tungsten, rhenium, platinum and others are routinely formed into coils and other shapes for use as filaments. These filaments are then accurately welded on to various assemblies.

Precision spot-welders are combined with custom designed and manufactured electrodes and fixtures to maintain accuracy and precision on all the filaments we manufacture. Microscopes are mounted over all of the spot-welders to provide additional accuracy. In some cases video systems are utilized to assure accurate manufacture of our filaments. These tools combined with the most experienced personnel in filament manufacture insure quality filaments from prototypes to quantities of 10,000 or more per year.

Unitek Model DP125 Dual Pulse Spotwelder (6) Equipped with microscope viewing system.

Filament Cleaning

At SIS a wide variety of equipment and techniques are used to clean filaments before they are repaired. Probably the most useful cleaning technique is sandblasting using the Miniblaster. Glass beads abrasive is normally used to clean metal parts and aluminum oxide abrasives are used to clean the harder ceramics. Other techniques used to clean filaments such as micromesh abrasives are described in the Mass Spec Source Cleaning Procedure Article.

Sandblaster used to clean mass spectrometer filaments. It will remove all residues and contamination from metal and ceramic.

After sandblasting all metal parts are polished using a variety of buffing wheels, Dremel and Foredom tools to thoroughly clean and polish these metal surfaces to a bright finish. These highly polished metal surfaces contain minimal scratches and will therefore remain cleaner longer while in use in the mass spectrometer.

The small buffing wheel is used to polish metal filament parts to a high luster.

Precision Spotwelding

Seven spotwelder systems are used for various filament repairs and for manufacturing mass spec filaments. Depending on the filament, unique jigs have been custom designed and manufactured at SIS for the accurate alignment and tensioning of the filament wire on the filament support bracket during the spotwelding process. Shown below are two of these spotwelders with close-up pictures of the actual spotwelding of rhenium wire to the filament supports.

Unitek Model 125 Spotwelder (2) Equipped with microscope viewing system and Unitek Model UB25 Linear DC Spotwelder Equipped with microscope viewing system.

Mass Spectrometer Filament Quality Control and Inspection

After all filaments are repaired we conduct a quality control procedure to assure the accurate alignment of the filament wire. Using a video microscope enables us to accurately align the filament wire over the mass spec source ion entrance hole as well as perform quality control inspections of the filament and the welding process. The Video Inspection equipment has proven to be a valuable tool, not only for the repair of mass spectrometer filaments, but for high quality manufacturing as well.

Quality Assurance is the over riding aspect of all that we do. From design and manufacturing, to assembly and packaging, quality is built into every part that we manufacture and assemble. Optical measurement systems, lasers, microscopes and other equipment are used to assure that you get the parts that you need.

RAM Optical measuring system to check accurate alignment of filaments - Filament accurately aligned over ion entrance hole.

Werth Video Check IP System Equipped with Optical, Laser and Touch Probe options.

Filament Research and Development

Over the last fifteen years SIS has conducted an intensive program on filament testing and design for mass spectrometers. Most of the data has been published in previous editions of our newsletter, "The Mass Spec Source". SIS has developed a PC controlled multiple filament testing station. This system enables us to do lifetime studies and cycle ON-OFF studies for up to 12 filaments at a time in order to study the design of the filaments we manufacture. The equipment shown below was constructed by our staff for some of our studies to analyze various filament operating parameters. It consists of a vacuum chamber with a Bayard-Alpert ion gauge meter, filament and accelerating voltage power supplies, and a wide assortment of voltage, current and oscilloscope meters to measure the filament performance.

Hewlett Packard filament burned out after 30 hours continuous operation at high current.

The work at SIS on filament design and performance is a continuing project. Custom research projects can be contracted with S.I.S.