PSAS/ news/ 2005-04-16

Hybrid Meeting Minutes 04/16/05


In attendance: Brian O’Neel, Evan Waymire

Topics Discussed:

Not a big turn out so the only thing that really was discussed was the problem with our spin caster cracking the paraffin grains. We have deliberately not used the lathe because we did not what to run it for the extended paraffin cooling times since we anticipate we will be making a lot of grains in the future.

The big problem with the current spin caster is that it is not perfectly aligned so that an oscillating compressive force applied to the paraffin grain during cooling. This cyclic force is causing crack initiation and propagation. We came to the conclusion that maybe we could use the alignment of the lathe to mount the grain between centers but still use the Kollmorgen motor to accurately control and monitor the speed.

UPDATE (6/4/05):

The new method also seems to be flawed. The paraffin grains are better but the cracking is still occurring though it's not as sever.

The problem may not be due to alignment of the centers but there may just be a flaw in the design of using two aluminum end caps held by o-ring friction in either end of a cardboard tube. There is a certain amount of play in this method and the end plugs can tilt a slight bit causing their centers not to be on the same axis. A more rigid grain holder may be needed.

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