During our last AMEC-SE meeting January 27-28th a question was raised by me regarding the amount of time to operate the sieve tester (rotating and tapping time) There is a very slight difference between AMS2430 and AMS2431/1 and /2 as to where the difference in cycle time between where 5 and 10 minutes separate.
At the meeting a motion was made and seconded o change the tap time what is referenced in ASTM B214-07 The motion passed by unanimous vote with no objections. To my recollection we did not actually look at any ASTM specification during the meeting to confirm what it states! Now that I have had a month to get our meeting minutes in order Iíve had a chance to do some research. See below.
Reference AMS 2430 REV S section 220.127.116.11 The sample shall be run in the rotating and tapping machine for 5 minutes +/- 5 seconds where the smallest sieve used is 35 mesh or coarser and 10 minutes +/- 5 seconds where the smallest sieve used is finer than 35 mesh.
Reference AMS 2431/1 REV E section 3.9.1 Shaking and tapping shall be continued for 5 minutes +/- 5 seconds where the smallest sieve used is 30 mesh and coarser and 10 minutes +/- 5 seconds for sieves finer than 30 mesh.
As written, I believe this means that when testing new shot per AMS 2431/1 or /2, only S-110 and S-70 would require a tap time of 10 minutes S-170 and larger would be 5 minutes.
When testing in-process shot per AMS 2430 the requirements for testing time would be slightly different.
S-190 and larger would be 5 minutes and S-170, S-110 and S-70 would be 10 minutes.
The problem is ASTM B214-07 states that the rotating and tapping time shall be 15 minutes! I believe instead of fixing a slight problem (if there even was one) by needlessly increasing the cycle time. For me this would be a significant impact. Not to mention the additional wear and tear on the equipment.
At the next meeting I think we should be prepared to discuss an alternate fix.
Edited by Walter (03/03/14 10:42 AM)