Denton Vacuum Model DV-502 Vacuum Evaporator Usage Instructions

Denton Vacuum Model DV-502 Vacuum Evaporator - Usage Instructions

1. Turn on main power - white switch toward center-right on main control panel. (Switch should light when on, but bulb is burnt out...)

2. Turn on cooling water - on wall to the right of the evaporator. Make sure both the inlet and outlet valves are open. Check for cooling water flow at the drain in room 102A if uncertain.

3. Turn on roughing pump/mechanical vacuum pump - illuminated switch ('Mech. Pump') to far left of control panel.

4. Turn on thermocouple gauge - to right of control panel. Make sure selector switch is set to TC1/foreline position.

5. Once the thermocouple gauge reads below 100 mtorr (this should be very quick), open backing valve (left screw knob below main control panel) 4-6 revolutions. Do not open fully, as this will put extra wear on the valve.

6. Once thermocouple gauge reads again below 100 mtorr (again, very quick), turn on diffusion pump heating power - second switch from left on main control panel.

7. Wait for diffusion pump to warm up - 20 minutes minimum, but generally 30 minutes for full diffusion pump performance.

8. Load sample:

a. Make sure roughing valve is closed.

b. Open chamber vent valve - to left above main control panel. Watch thermocouple gauge to make sure there are no leaks (close immediately if there are!), and wait for bell jar to vent. Venting takes a minute or so.

c. After venting is finished (hissing stopped), remove bell jar. The best way is to twist until it unsticks, then carefully lift up and off. Do not bump seal against any internal hardware or touch to anything else. Place bell jar upside down where it will not roll, fall down, be damaged, or be in any way disturbed. Close vent valve.

d. Place sample in chamber in the geometry you wish to coat. Also, make sure the coating apparatus/apparati you intend to use are ready for use.
Hint: Sometimes including white paper, aluminum foil, or other white/shiny material in the chamber half-shadowed by your sample is helpful for estimating your coating thickness.

e. Inspect bell jar and bell jar seat - make sure they are clean (no fibers/dust!). If clean, replace bell jar. If not, clean, then replace. (This can often be done with a clean, dry fingertip for a single fiber. If more, than ethanol+Kimwipes followed by re-application of vacuum grease is required.)

f. Close backing valve.

g. While pressing down on the top of the bell jar with one hand, slowly open the roughing valve (right screw knob below main control panel). If there are no obvious leaks (hissing noises), fully open roughing valve after ~30 seconds. (Again, only open 4-6 revolutions rather than all the way to the stop, as this will put undue wear on the valve.)

h. Switch the thermocouple gauge to TC2/chamber. Wait for the pressure to drop to 50 mtorr. This may take several minutes or more, depending on how much your sample is outgassing.

i. Switch the thermocouple gauge back to TC1/foreline; close the roughing valve; open the backing valve; slowly open the main valve (lever to left side of main control panel) IN THAT ORDER. The thermocouple gauge/foreline pressure will spike.

j. After the thermocouple gauge/foreline pressure has dropped below 50 mtorr, turn on the high vacuum discharge gauge (to far right of main control panel) - turn range selector switch to 'zero' position. Wait ~30 seconds for the electronics to warm up.

k. After warmup, adjust the "zero" knob (below the discharge gauge selector switch) to zero the gauge meter.

l. Turn on the high vacuum discharge gauge: turn range selector switch to the 10^-4 range, then push 'vacuum read' pushbutton (to right of selector switch) for ~1/4 second. If the gauge turn itself off, wait ~1 minute before trying again. After start the range selector switch can then be used to select the sensitivity range of the meter.

m. Wait until pressure drops to at least < 5*10^-5 torr.

9. Coat sample:

a. Turn filament selector switch to the electrode pair connected to your evaporation setup (left, rear, right) - selector switch at upper left of main control panel.

b. Turn filament/glow discharge switch to 'filament' (toggle switch near center-left of main control panel), make sure output voltage variac ('filament adjust') is at zero (large dial near upper center of main control panel), then turn on 'filament power' switch (third from left on main control panel). Any adjustment of the 'filament adjust' variac will now put that voltage across the selected electrodes.

c. Degas your evaporating filament - while watching the pressure gauge, slowly raise the voltage until your filament/carbon rod heats enough to glow (but not enough to evaporate!), then turn down again to zero. This will drive off most/all volatiles from the carbon rods/filament that will raise the background pressure in the bell jar. Wait until your background pressure drops below 5*10^-5 torr again. This step may need to be repeated several times with severely contaminated evaporator assemblies.

d. If evaporating from a filament or boat, raise heat sufficiently to melt the evaporant onto/into filament/boat, then cool. This can be done as part of step 9(c).

e. Evaporate: While monitoring pressure, turn the 'filament adjust' variac to evaporation voltage (will vary depending on the specifics of the evaporant and filament/carbon rod assembly) and hold for sufficient time to evaporate desired layer thickness. Do not hold at temperature for an extended period, as this can weld the electrode assemblies together. Also, stop evaporation if the bell jar pressure goes above ~2*10^-4 torr. (This is especially a problem if evaporating onto fragile/organic material.) Several short evaporation steps interspersed with cool-down, examination, and pump-out is frequently desirable.

10. Unload sample and shutdown:

a. Turn off HV discharge gauge (set range selector switch to 'off').

b. SLOWLY close main valve.

c. Open bell jar vent - to left above main control panel. Watch thermocouple gauge to make sure there are no leaks (close immediately if there are!), and wait for bell jar to vent. Venting takes a minute or so.

d. Remove bell jar and unload sample. Be sure to close the bell jar leak valve.
IF COATING MULTIPLE SAMPLES, go from here to step 8d.

e. Same as steps 8(e)-8(m): replace bell jar, close backing valve, crack roughing valve, rough pump chamber, close roughing valve, open backing valve, open main valve, pump bell jar down to 10^-5 torr range.

f. Turn off HV discharge gauge.

g. Close main valve.

h. Turn off diffusion pump heater.

i. Turn off thermocouple gauge.

j. Wait at least 20-30 minutes for diffusion pump to cool. If impatient, you can test D.P. temperature by touching the bottom of the diffusion pump with your bare hand. If warmer than body temperature, then the D.P. is not cool yet. (Warning: this can result in severe burns if you are careless!)

k. Close backing valve.

l. In quick succession, turn off the roughing pump, then open the 'M.P. vent' valve - to the right above the main control panel. Venting should only take a few seconds.

m. Close 'M.P. vent' valve.

n. Turn off main power switch on main control panel.

o. Turn off cooling water.

DONE

a.	Make sure roughing valve is closed.
b.	Open chamber vent valve - to left above main control panel. Watch thermocouple gauge to make sure there are no leaks (close immediately if there are!), and wait for bell jar to vent. Venting takes a minute or so.
c.	After venting is finished (hissing stopped), remove bell jar. The best way is to twist until it unsticks, then carefully lift up and off. Do not bump seal against any internal hardware or touch to anything else. Place bell jar upside down where it will not roll, fall down, be damaged, or be in any way disturbed. Close vent valve.
d.	Place sample in chamber in the geometry you wish to coat. Also, make sure the coating apparatus/apparati you intend to use are ready for use. Hint: Sometimes including white paper, aluminum foil, or other white/shiny material in the chamber half-shadowed by your sample is helpful for estimating your coating thickness.
e.	Inspect bell jar and bell jar seat - make sure they are clean (no fibers/dust!). If clean, replace bell jar. If not, clean, then replace. (This can often be done with a clean, dry fingertip for a single fiber. If more, than ethanol+Kimwipes followed by re-application of vacuum grease is required.)
f.	Close backing valve.
g.	While pressing down on the top of the bell jar with one hand, slowly open the roughing valve (right screw knob below main control panel). If there are no obvious leaks (hissing noises), fully open roughing valve after ~30 seconds. (Again, only open 4-6 revolutions rather than all the way to the stop, as this will put undue wear on the valve.)
h.	Switch the thermocouple gauge to TC2/chamber. Wait for the pressure to drop to 50 mtorr. This may take several minutes or more, depending on how much your sample is outgassing.
i.	Switch the thermocouple gauge back to TC1/foreline; close the roughing valve; open the backing valve; slowly open the main valve (lever to left side of main control panel) IN THAT ORDER. The thermocouple gauge/foreline pressure will spike.
j.	After the thermocouple gauge/foreline pressure has dropped below 50 mtorr, turn on the high vacuum discharge gauge (to far right of main control panel) - turn range selector switch to 'zero' position. Wait ~30 seconds for the electronics to warm up.
k.	After warmup, adjust the "zero" knob (below the discharge gauge selector switch) to zero the gauge meter.
l.	Turn on the high vacuum discharge gauge: turn range selector switch to the 10^-4 range, then push 'vacuum read' pushbutton (to right of selector switch) for ~1/4 second. If the gauge turn itself off, wait ~1 minute before trying again. After start the range selector switch can then be used to select the sensitivity range of the meter.
m.	Wait until pressure drops to at least < 5*10^-5 torr.

a.	Turn filament selector switch to the electrode pair connected to your evaporation setup (left, rear, right) - selector switch at upper left of main control panel.
b.	Turn filament/glow discharge switch to 'filament' (toggle switch near center-left of main control panel), make sure output voltage variac ('filament adjust') is at zero (large dial near upper center of main control panel), then turn on 'filament power' switch (third from left on main control panel). Any adjustment of the 'filament adjust' variac will now put that voltage across the selected electrodes.
c.	Degas your evaporating filament - while watching the pressure gauge, slowly raise the voltage until your filament/carbon rod heats enough to glow (but not enough to evaporate!), then turn down again to zero. This will drive off most/all volatiles from the carbon rods/filament that will raise the background pressure in the bell jar. Wait until your background pressure drops below 5*10^-5 torr again. This step may need to be repeated several times with severely contaminated evaporator assemblies.
d.	If evaporating from a filament or boat, raise heat sufficiently to melt the evaporant onto/into filament/boat, then cool. This can be done as part of step 9(c).
e.	Evaporate: While monitoring pressure, turn the 'filament adjust' variac to evaporation voltage (will vary depending on the specifics of the evaporant and filament/carbon rod assembly) and hold for sufficient time to evaporate desired layer thickness. Do not hold at temperature for an extended period, as this can weld the electrode assemblies together. Also, stop evaporation if the bell jar pressure goes above ~2*10^-4 torr. (This is especially a problem if evaporating onto fragile/organic material.) Several short evaporation steps interspersed with cool-down, examination, and pump-out is frequently desirable.

a.	Turn off HV discharge gauge (set range selector switch to 'off').
b.	SLOWLY close main valve.
c.	Open bell jar vent - to left above main control panel. Watch thermocouple gauge to make sure there are no leaks (close immediately if there are!), and wait for bell jar to vent. Venting takes a minute or so.
d.	Remove bell jar and unload sample. Be sure to close the bell jar leak valve. IF COATING MULTIPLE SAMPLES, go from here to step 8d.
e.	Same as steps 8(e)-8(m): replace bell jar, close backing valve, crack roughing valve, rough pump chamber, close roughing valve, open backing valve, open main valve, pump bell jar down to 10^-5 torr range.
f.	Turn off HV discharge gauge.
g.	Close main valve.
h.	Turn off diffusion pump heater.
i.	Turn off thermocouple gauge.
j.	Wait at least 20-30 minutes for diffusion pump to cool. If impatient, you can test D.P. temperature by touching the bottom of the diffusion pump with your bare hand. If warmer than body temperature, then the D.P. is not cool yet. (Warning: this can result in severe burns if you are careless!)
k.	Close backing valve.
l.	In quick succession, turn off the roughing pump, then open the 'M.P. vent' valve - to the right above the main control panel. Venting should only take a few seconds.
m.	Close 'M.P. vent' valve.
n.	Turn off main power switch on main control panel.
o.	Turn off cooling water.