Note that web-based summaries of standard operating
procedures are not exhaustive.
Not all of the relevant safety information is included in this document. Further training is required for safe operation and will be provided in person. |
Weigh in correct amounts of BaCO3 and toner into glass vials; BaCO3 first, then add toner and shake to mix thoroughly.
|
BaCO3 |
7.30 ± 0.01 g |
|
Toner |
0.20 ± 0.01 g |
Refill hand pump with hydraulic fluid.
Place a large sheet of wrapping paper on the bench to make cleanup easy. Clean all parts necessary for pressing sleeves (die, small ring, center rod, and hollow push rod) before starting. This is best done with ethanol, large Kim-wipes and a small pipe brush. You will also need the dry-graphite lubricant and molykote. Note that the molykote product used for BaCO3 is not the same as that used for CaF2.
Spray thin film of dry-graphite lube into die, make sure that coat is even (roll die on counter if necessary), then spray very thin film on center rod and hollow push rod. All parts need to be dry before further use.
Put thin layer of molykote on small bottom ring and place ring with coated side up on bottom disk, then insert center rod (orientation does not matter). Place die right side up on bottom plate (up is marked with a 'V' scratched into the die), small bottom ring should slide in easily.
Pour BaCO3/toner mix evenly into the die. It should fill to within a few mm of the top.
Put thin layer of Moly on flat side of hollow push-rod (this side should have no scratches or just a few, compared to the other end or the push-rod), then insert push-rod with Moly side first into die as far as possible.
Place big aluminum centering-disk on Enerpac press frame, then put assembled die with bottom disk into the centering-disk (do not drop, or you have to start over...). Screw the big push-rod piece into the piston of Enerpac pump and center die assembly below. Close Enerpac valve (lever towards you) and run piston down until it almost touches the push rod of the assembly.
Increase pressure slowly to 6500 psi and maintain it between 6000-6500 psi for 5 minutes (use timer). Pressure may bleed initially but should become more stable after the first sleeve; you will probably end up adjusting pressure continuously for the first sleeve.
Release pressure after 5 minutes (Enerpac valve lever to the right), and let piston retract quite a bit. Remove bottom steel disk from assembly die to press out the sleeve, but make sure that you have the Styrofoam piece under the Enerpac frame to catch assembly without damaging it.
Replace big push-rod piece with small 1/2" push-rod insert (also used to press run assemblies out of the pressure vessel). Run out piston so that the tips of the push rods barely meet, then align very carefully and exactly (might take several attempts).
When push rods aligned satisfactorily, press out assembly with one fast and
constant motion. Retract piston and recover assembly. Handle assembly with extreme
care - inspect sleeve for obvious fractures, then remove small ring (should
come off easily).
Carefully twist the sleeve on the center rod to loosen it without pushing or
pulling to avoid breaking it. Remove sleeve from center rod without tilting
it, otherwise it is prone to breaking.
Inspect for fractures again and measure length. Length normally should be 31.5-32.0 mm, reject if shorter than 31.0 mm
If parts are consistently too long or too short it may be necessary to vary the amount of BaCO3/toner mix; pressure should stay between 6000-6500 psi. The sleeve length is also very sensitive to firing procedure, which normally shouldn't be changed.
[Store sleeve in safe location, clean all parts and press a few more sleeves]
Pre-heat the muffle furnace under the source-capture exhaust tube to 700 C and place sleeves upright into furnace. Bake the sleeves for 20 minutes, then take them out of the furnace and allow them to cool in air. Measure length again (should be 32.0-32.5 mm now) and put them into the drying oven for storage.
Do not fire at higher T (or for longer duration) beacause sleeves may shorten and warp.
Remember, if it's too hot to pick up with your hands, it's too hot to put down on a wooden bench. Doh!
NOTE: All the above is largely based on the manual from Rockland Research that came with the piston-cylinder.
MP 1999; Revised ACW 2010
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