Vacuum News

ultimate vacuum, fast pump-down, and virtual elimination of sources of gas bursts. Installation is also much simplified. This efficiency is coupled with zero backstreaming and at least the same freedom from hydrocarbon contamination as turbomolecular pumps for about a third of the cost and with no need for liquid nitrogen trapping. Pumping speed for light gases is significantly faster.

The Diffstak’s integral valve contributes to high overall pumping speed by virtue of its high installed conductance and the elimination of associated seals. However, valveless Diffstaks can be supplied on request, typically for use in systems where standard diffusion pump accessories are to be retained. In these cases there will be some reduction in overall system pumping speed due to the impedance of the retained accessories. The range provides air-pumping speeds from 150 I s-l up to 2000 I s-1 and ultimate vacuum for all models of 1.3 x 1 O-10 mbar, achievable without cryo-trapping.

Edwards High Vacuum, Manor Royal, Crawley, West Sussex RHIO 2LW, UK

The Mark I/ range of Edwards Diffstak integrated pumping systems for high vacuum applications is now available incorporating a number of new features.

Balzers dry operation leak detector A new leak detector for production testing, the LSA 100, introduced by Balzers, features dry operatien-eliminating the need to pressurize and immerse in liquid the piece to be tested. Tests are carried out at atmospheric pressure ensuring short batch times. Test pieces are filled with a halogen-containing test gas. The sensor will detect any traces of halogen which escape from the test piece and the ionic emission will increase. This current is

processed in the electronics of the system and triggers a relay when a certain level is reached. The detection limit (depending on the surface area to be tested) is 1 O-3-1 O-4 mbar I s-1, detection time 2-l 0 s, and the maximum surface area which can be tested is 1 m2.

Some fields of application include car accessories : testing tyres, inner tubes, petrol tanks, fire extinguishers, etc; the plastic industry : containers, stoppers and plugs, etc ; the cosmetic industry : sprays and atomizers.

Balzers High Vacuum Ltd, Northbridge Road, Berkhamsted, Herts, UK

New Anavac diagnostic vacuum gauge The latest addition to Anavac’s range of uhv measuring and gas analysis devices is the new Anavac II duadrupole Mass Spectrometer. This new device will give you a cost effective convenient method of dealing with everyday procedures including leak detection and both total and partial pressure measurement and can even give process control facilities when linked with RUl. Clean construction ensures total compatibility with any uhv system, quadrupole heads are interchangeable so that only one controller is necessary for all systems and to ensure trouble-free operation it has a very straightforward construction principle which makes repair and replacement simple.

Vacuum Generators Ltd, Menzies Road, Hastings, Sussex TN34 1 YQ, UK

A cleaning process for electronic equipment using a vacuum drying oven Due to the effects of static, heating, cooling and circulation of air electronic equipment becomes dirty and this can lead to malfunction and to eventual breakdown. Periodic cleaning helps to ensure operating efficiency. The Craswell Scientific vacuum ovens illustrated form part of a process used by the Royal Navy for the cleaning of such equipment. In this process the equipment is hand scrub-washed with warm water and solvent to remove dust and dirt and, after a series of rinsings, is transferred to the vacuum oven. The oven chamber is evacuated to a point just below the vapour pressure of water and the chamber heated. In this way the equipment is dried quickly and thoroughly, without risk of detriment even to the most sensitive component.

The vacuum ovens have been supplied to the Ministry of Defence for drying, after cleaning, the complex electronic equipment of the Polaris navigation system. The oven is of industrial proportions, 1.2 x 0.9 x 0.46 m, has an ultimate vacuum clean dry and empty of better than 5 mm Hg obtainable within 30 min and a temperature range, with pre-set facility, of 38-82°C. The rotary mechanical vacuum is protected from ingress of water vapour by a refrigerated cold trap which condenses the vapour before it reaches the pump.

These vacuum ovens can also be used for industrial and research applications where metallic and non-metallic components or assemblies are required to be dried after cleaning. There are applications in the electronics, metallurgical, electroplating and chemical industries, etc. where a very high degree of dryness iS

required. Craswell Scientific Ltd,

High Vacuum Division, Fairview Road, Cheltenham, Glos GL52 2EH UK

Sputtering target silver-filled epoxy bonding cement CERAC offers a plastic cement which consists of a special silver-filled epoxy composition. It is used for making electrical

135

Vacuum News

CLS vacuum drying ovens for computers and electronic components.

connections in various electronic applications or in bonding metallic and non-metallic sputtering targets to various substrates.

CERAC silver-epoxy cement is silver coloured and comes as a thick paste. If thinning is desired, not more than 20% by weight of toluene can be used. Typical properties are : thermal conductivity 40 Btu ft-2 h-l F-l in., volume resistivity 2 x lo-“ G cm, use temperature -70 to +350 F, shear strength 450 psi at room temperature, bending strength 12,000 psi.

The instructions for use are the following.

(1) The substrate should be degreased and preferably roughened by mild sandblasting or some such technique.

(2) Weigh out an amount of cement to be used.

(3) Mix one part by weight of the catalyst to 40 parts of cement. Conveniently, from a medicine dropper, use one drop of catalyst to one gram of cement.

(4) Apply the mixture of catalyst and cement to the surface to be bonded. No pressure is required.

(5) The bond will form at room temperature overnight, in about 2 h at 120 F, or in a few minutes at 150 F. The lowest resistivity occurs with the higher temperature cure.

Testbourne Ltd, 9 Sheppard Road, Basingstoke, Hants RGI 3HT, UK

Substrate cleaning and thin film deposition source Testbourne introduces the new PLASMAX thin film deposition source, which can be fitted to existing coating units. It can operate as a substrate cleaning high intensity ion source with ion currents of up to 300 mA and ion energies from 100 to 1000 eV, as well as a high rate sputter deposition gun. The unique triode

136

configuration employs mechanical confinement of the plasma inside the source and can sputter deposit magnetic, non-magnetic electrically conducting and insulating materials from targets as small as a few millimeters to 50 mm dia. Larger sources having targets of up to 150 mm are also available. The Plasmax can be supplied as both ultra high vacuum and high vacuum versions. It can produce reactive gas deposited thin films of accurately reproduced stoichiometry.

Testbourne Ltd. 9 Sheppard Road, Basingstoke, Hants RG21 3HT, UK

New pressing technique produces shims and gaskets quickly and cheaply Quicker and cheaper manufacture of shims, gaskets, washers and other flat thin-metal components is claimed for a new pressing process developed by Ford Et Co (South Shields) Ltd. Even components of complex shape can now be supplied in seven to ten days from receipt of drawings (or faster in urgent cases), compared with normal times of between six and eight weeks for conventional methods. Tooling costs are often reduced by more than 9096, so that small and mddium-size batches (from one to 20.000 parts) can be made significantly more cheaply, although any quantity can be supplied. Thickness range is from 0.025 to 1.5 mm and any size and shape of component up to a maximum diameter of 560 mm can be made.

For commercial reasons precise details of the manufacturing process are not being disclosed, but basically it involves the use of simplified tooling. Conventional processes require the use of precisely-matched punch and die sets which must often be machined to yvithin 0.0025 mm. Parts can be made in all ferrous and non-ferrous metals of hardness up to Brinell Hardness