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Drew... You are one lucky guy! During one of my rare lucid moments I found 4 of the rotary actuators I mentioned yesterday. These would be very easily modified by the addition of a vane (or flag) to cover the opening of your evap box during the initial heating of the material. I would position the flag in a fail-safe manner i.e. with the opening covered unless the actuator is powered up. I believe these are 24VAC movements but should be fairly easy to figure out. If you have a variable power supply (XMS?) you could ramp up the voltage until they move then measure the voltage and add a bit for reliability sake. I can't remember if the XMS had 120vac outputs for the switched devices or not but a doorbell transformer (or voltage dropping resistor) might just be the ticket if so. Not sure about how they would behave in a vacuum re: outgassing, oils etc. They seem to be "dry" but any mechanism is likely to outgass for a while in vacuum. Already addressed in a box and will be on your way this weekend. Ken

Greetings, I am looking for some reasonably priced crystal holders and oscillators for a deposition controller. I see some good info in the files section on crystal holders and oscillators, and while I can machine housings and such pretty easily, I would prefer to just purchase something that already works. If anyone has working sensor heads or oscillators they would part with for a reasonable price, it would save me a lot of time and trial & error. I have been looking on Ebay for awhile now, and I can find the odd oscillator for $100.00 USD (pricey IMO) and I can find deposition crystals cheap, but I have yet to stumble upon any crystal holders. I recently picked up a nice Leybold IC6000 4 channel deposition controller and it will be arriving soon, so I want to come up with some sensors to try it out - any ideas? -Achro

Dear ALL Hoe measure the thin film thickness by refelction and transmitted light using monochoromator. I need basic information for this methode

Hi All, I've been interrested in learning about E-Gun evaporators and have added a link to a patent that describes such an E-Gun for those interrested. Regards, Alfredo

Hi All, I've placed some more links to patents on E-Guns, but I was wondering if any other member that has pratical experience with these could help me (and others) with some more detailed info or links. Regards, Alfredo

Does anyone have any information on a Dynavac CS300 Coating Unit - or know where I might get some information ? It uses an ULVAC diffusion pump. ULK-04 (B1) When I originally acquired the unit, the intention was to rebuild it as necessary or reuse some of the parts. Like using baseplate, chamber, isolation valve etc. which would shortcut the process of building up a system. So I tried to figure out how the controller worked. Because of various interlocks, it became clear that trying to test the controller as seperate modules would be difficult or impossible without a schematic. Gave up trying to draw out the circuit although I now understand it a little more. The main isolation valve was 'stuck'. But, after realizing it was being held shut because of a vacuum (heaven only knows when it was last used - years ago ?), decided the whole unit may be a goer, so gave it water flow and power and it pumped down to 2 x 10^-5 torr which floored me. I had intended to change the diff pump oil but will leave it alone for the present. No idea what type it is. From using the unit, I can appreciate more how the controller works but some day there will be a failure that needs a schematic of the controller. So I would really appreciate any information. ALSO, does anyone have information on the diff pump and if there is an easy way to change the oil without dismantling much of the unit ? I cannot see an easy way and am not intending to dismantle the unit while it is working so well just to find out ? Peter Smith.

Hi, I just got an 16" x 1" thick 1020 steel disc (SS was too expensive) for my new base plate. I turned it flat and to prevent rusting I would like to have it chromed. Is there any objections to chroming the base plate. Is chrome or niquel better? I now want to make a Stainless Steel chamber and have been wondering what is the minimum thickness I can use for an 14" bell shaped chamber. Regards and thanks for all the advices, Alfredo

On the collapsing pressure of cylinders subjected to external pressure. At one stage I was very interested in cylinders which would withstand being immersed to 1000 m depth in the ocean. So I tried to research the problem. And found it was NOT simple. Implosion of a cylinder, as opposed to bursting from excess internal pressure, is very complex. This is because internal pressure precludes buckling while external pressure feeds on any slight asymmetrical factor and causes buckling. Depending on the mode of buckling (2, 3, or more lobes can result) calculations change and with quite thin wall become almost meaningless. Then there is the end loading on a bell jar to complicate matters ! So I would be wary of a simple formular. It was probably derived to be used within bounds for a specific set of conditions which may not apply. On no account use a formular for internal pressure limits. This may, however, be a useful guide. From Machinery's Handbook (Ed 23) p 300. This is skewed towards Boiler Construction and is based on actual testing of Lap welded steel tubes. Where outside P difference < 580 psi, D is OD in inches, t is wall thickness in inches, and collapsing pressure is calculated in psi. Limiting pressure P = 50,210,000 * (t/D)^3 A basic safety factor of 5 is suggested but with fluctuating loads you may need up to 12. Since Atmospheric pressure on the exterior of a bell jar is 15 psi and minimum inside pressure is 0 then the P differential is 15 psi. The above formular, for a 14 inch diameter cylinder, suggests 3/16 may be OK (4.5 mm). Workmanship would be a significant factor. A rough asymmetrical tube would be far more prone to failure when collapsing from external pressure. I do NOT know how the compression from end forces will change this. Hope this helps someone. Peter Smith.

Caveat:- I havnt done this and dont know anyone who has, it was just a thought. Commercial food mixers such as these have a variety of stainless bowls that may suit. The top lip is rolled and they have reinforcing bands around some of them. http://www.hobartfood.com.au/products.asp?CID=60 (there are other manufacturers) They can be purchased second hand as well as new. As to price, I have no idea, as I said, it was just a thought.

Hi All, Could some one eligthen me on the difference of using HV DC and RF for plasma generation. What are the pro and cons of each method. Thanks, Alfredo

Hi All! well.....I m here in urgent need of RS232 commands reference documentation or manual to remotely access this gauge controller.Please provide me with links, literature or whatever may be...as I urgently need it......I 'll be grateful to u all....looking forward for your responses. Much Regards!

Hi all, I'm new to this group - looks like some of you have some fancy rigs I could only dream of. AnywayI've just dug out a very old Edwards single stage speedi-vac pump, model 1sc50, which has been on the shelf for many years. When I started it up, it did not produce hardly any vacuum ( only an absolute pressure of about 600 mbar, which is useless!!!). Before I start stripping it down, I was wondering if anyone had or could point me towards a manual? This pump is probably around 50 years old, but I remember it being refurbished by Edwards around 1975 and it hasn't been used since then. many thanks in anticipation, James

Greetings, I have not posted here in quite awhile, but have been building my own metalization system. Last night, I was finally able to do my first ever aluminum coating test runs. The results went way beyond my expectations. I built this small system to coat laser mirrors and other small parts. The various posts by people here were very helpful to me in developing my system. My system consists of the following major components: 1) Edwards es200 roughing pump that was collecting dust for many years 2) MDC KMST-100-2 foreline trap(ebay) 3) 1 torr Barotron capacitance manometer rough vacuum sensor(ebay) 4) Leybold TMP150 turbomolecular pump (ebay) 5) 2 Edwards PV25PKA valves (ebay) for roughing pump isolation and Foreline 6) Veeco RG1002 Guage controller Bayard-Aplert Guage tube (ebay) 7) Leybold NT150 turbomoleculatr pump comtroller. 8) Custom 6 way 100ISO/NWF25 manifold - turned from aluminum on my lathe. 9) Eight inch Chamber - turned from aluminum on my lathe 10) Various NW25 and 100ISO fittings and adapters - turned from brass and aluminum on my lathe. 11) 2 STC 3 way Pneumatic valves to control the Edwards valves (ebay) 12) Eight inch Pyrex glass bowl for top of the chamber (Kmart) 13) various orings (online, Marco rubber) With extensive scrounging and careful shopping I was able to put this system together for around $500.00 (US) I used slow setting JB-weld epoxy to assemble flanges to manifolds, and feed-thru conductors to flanges. Various sources on the web indicate that this was a good cheap alternative to products like torr seal. It makes incredibly strong bonds to aluminum. I designed my epoxy joints to expose the minimum epoxy surface (annular ring) to the high vacuum. I was also careful to outgas the epoxy. To do this, I used a discarded pressure cooker as a chamber and my roughing pump to expand and remove any bubbles from the epoxy in the assembled joints. I needed to apply vacuum very slowly or the epoxy would explode out of the joints and make a mess. My chamber now pumps down in a few minutes to 5X10-6 torr with the turbo pump. Ultimate vacuum is in the high-mid 10-7 torr range. The ultimate vacuum is very sensitive to foreline pressure. I need to warm up my single stage roughing pump well, and gas ballast it for awhile in order to get the needed rough vacuum in the range of 10-20 millitorr. I started my depositions when I reached 5X10-6 torr with the turbo. My chamber being rather small, I used a single KJ Lesker basket emitter centered low in the chamber. This seems to be working well for now. I am using a rewound MOT and variac to hand-control the emitter power. I was very careful to baffle the throat of my turbo pump to prevent it from being in line of sight of the emitter. For my first test run, I coated a microscope slide. I fixtured it couple of inches above the emitter. I slowly ramped the emitter voltage up to 50% rated and this melted the aluminum and coated the tungsten basket. I used a half gram or so of electrical wire for my source charge. Once this was melted, I ramped power up to 100% rated (4.65 volts for my basket source), and after a couple of seconds *poof* and I had a coating. The microscope slide went silvery/opaque, and everything in line of sight of the emitter, such as areas of my chamber bowl, acquired a silvery coating. I then turned off power to the emitter. This was very encouraging. When I examined the results, I had a beautiful shiny coating exactly where I wanted it. There were some minor pits and streaks, but I was not especially careful with cleaning the slide, so I expected this. Next, I tried a prototype plastic part that a colleague from work wanted coated. This part was produced on a inkjet stereolythography printer, and it was a bit gunky from uncleaned process residue. I cleaned it up as best I could, and suspended it above the emitter and ran the cycle. The coating on the chamber top was a bit black this time, but the part, while not as shiny as I would like, turned out okay. I suspect the part was outgassing pretty bad. I will probably bake the next one a bit bef

Hey gang, I just cant seem to run my plasma cleaning system without it making soot on the optical surfaces. I am using the very expensive DOW 714 oil in both of my diffusion pumps, have water coolant on the oil traps above the pumps and only have 15kv on the transformer. Yet the plasma makes soot every time I turn it on. If I leave it off …….. no soot. Any ideas on how to eliminate the soot but still be able to use the plasma cleaning system ??? Drew in sunny Florida

Hello Group This is my first posting to the group. I am in the process of preliminary thoughts relating to a coating system. I was looking for information to look at designing and constructing a diffusion pump verses purchasing one, off coarse sizing is part of the process to. The size of the containment is or will be 36" in diameter @ 14 inches in depth, so approximately 8.25 sq.ft. internal volume minus internal components. I have at my disposal a reasonably complete machine shop so this aspect is complete. So that being said.... 1. Is there a rule of thumb for sizing the Roughing pump for reasonable pump and makeup due to degassing time? 2. Same Q relating to the diffusion pump? 3. More Q's guaranteed, relating to instrumentation etc. Thanks and look forward to your responses. Bill

Great links but on Ebay you could sometimes get a commercial/industrial vacuum gauge in great working condition for only around 35$ or even less sometimes. I have bought 4 under 1 year from Ebay and the last one only a week ago for a combined price of around 100$. It has been one with a linear output and the rest with analog outputs and some with setponts as well. I had some years ago planned to to build one like in the links but then i found that these types existed on Ebay and they worked right away so there wasnt any reason to that anymore, and they also had the required vacuum fitting needed. Just thought you might wanted to know. Regards Henry

a fend search for somebody able to make alluminysed at '''City called Okara, south of Lahore'', in india or need ther somebody in the group know a co able to do the job for a 6 inch only he try to look at silvered but allu is probaly better jack47'n 71'W

Some years ago I built several pirani gages using 110 V Christmas lights and 110 V panel light bulbs. I preferred the Christmas lights as they were chap on sale after Christmas. If details are of interest I may (!) be able to find some info in old files. From my memory the reasoning for design and construction was as follows: It had to be inexpensive. Most pirani gauges on the market sell for several 1000 $s, but the 'front-end' analog electronics remained the same by measuring the bridge voltage across a temperature controlled bridge circuit. This can be built with a minimal number of cheap parts. The new technology additions that came afterward are for convenience in calibration, interlocking, signal processing and safety shut down, data processing etc. Pirani made his discovery some 100 years ago with electronics of that time - if one is not determined to duplicate a commercial appearance then we should be able to do it with electronic parts found in dumpster today. The filament runs at 100 to 300 degC. From measurements, the cold resistance of the bulb was about 300 ohms. The resistance with dark red glow (observed in total darkness = about 550degC) was around 1 to 1.5 kOhm. From calculation (4W bulb @ 110 Volt) the full power hot resistance comes to 3.1 kOhm. Using the graph I chose 700 Ohms for the resistance of each leg in the Wheatstone bridge. Breaking the glass was tricky. An abrasive wheel on a Dremel tool after epoxy into the vacuum fitting did the trick eventually Parts were from salvaged stuff: A 741 op Amp as bridge controller, a Darlington transistor bridge driver, a variable reference voltage to offset zero fed to the inverting input of a 3 1/2 digit panel meter with 200 mV range. Electronics was driven from the power supply of the 3.5 digit LED panel meter. This approach is frowned upon by my el engineer friends but vacuum measurements are inherently inaccurate and the resulting CMR error should not be significant. (The calibration of hot wire filament gages are gas specific!) Calibration was against a borrowed TC vacuum gage operating simultaneously in the vacuum system. The low vac was around 10 mTorr. As a relative pressure instrument to verify that previous vacuum has been attained the precision was acceptable and it worked remarkably well for a no-cost/ three week-ends project. For absolute measurements the accuracy must be verified against a known standard. If you google you will find several home-built projects with schematics including: http://people.umass.edu/dac/projects/LightBulb_Pirani/Light_Bulb_Pirani_Gage_Project.html http://www.coultersmithing.com/OldStuff/piranigage.html http://www.vacuumlab.com/Articles/VacLab45.pdf www.physics.utah.edu/Phys5739/resources/Vacuum%20for%20SEM.ppt Hope this helps CUO

I read a post on and other group where the guy try to make a pirani detector and control for reading whit ordinary buld the kind of bulb we found on fancy cnadelabra whit flame form he cut the end and plug a kind of tube whit epoxy and afte degaxe it in the chamber he have not yet made the controler but waht do you thing about his chance to meke it realy is it realistic is it makable how can we help him jack 47'N 71'W group http://tech.groups.yahoo.com/group/edsworkshp/

I'm kind of new to this stuff. so far I have successfully coated with copper and silver but If I try nickle in a tungsten boat, the bottom just gets melted out of the boat. Everything I have read indicates that it should work but I must be doing something wrong. In case it matters, the vacuum I am using is somewhere between 1x10-5 and 7x10-6 torr. Roger