Home Forums General Discussion Media, Shot, Beads, etc. 425 Ceramic Shot Testing

Is anyone else having this problem? I am changing from the AMS 13165 standard to AMS 2430 using 425 ceramic shot, the in-machine material test is going from a single sieve to a dual sieve inspection. AMS 2430 requires a 35 top and 50 bottom sieve inspection with no more then 0.5% retained on top sieve. My test is coming up with between 35 and 45% held on the top sieve. The material passes AMS 2431/7 receiving inspection. Since the machine wont make the material grow I decided to inspect new material using the machine test requirements and it also failed. Am I the only one struggling with this problem? Any suggestions?
Thanks in advance for the advice,
Scott Bonar

Your media sounds OK to me, just not used enough to fit into the "in machine" tolerance range.

Walter, Thank you for your response. To my knowledge ceramic media doesn't reduce significantly in size during usage. I believe it breaks down before changing in size. There is no conditioning requirement and I think the cycle time required to reduce the media size to the machine size requirement would be extremely long. Please let me know if I misinformed.

Scott,

How much usage has the ceramic media seen? Your correct that the media will not change size significantly but we're not talking about a significant amount. In my opinion the specifications should be revised to state that in machine media is actually the low end of the tolerance scale. Otherwise you would put brand new media in the machine then have to screen out a significant amount of media to meet the "in machine" requirement. This is not the intent of the AMS-2430. What screens are you using to check new media? If you'd like you can send me a sample and I screen it for you to verify your results.

-Walt

Walt,
I have done 2 seperate tests. The first test was media in the machine which had a minimum of 40 hours usage. This media was inspected using a 35 top sieve and 50 bottom per the AMS 2430 requirement (sieves are brand new from fisher scientific)and it held to high (40%) on top sieve indicating a large condition. I then inspected new material (which passed AMS 2431/7 receiving inspection) using the in machine requirement, it also failed holding 44% on top sieve. I agree with your statement referencing the intent of the "in machine" requirement. When comparing the receiving inspection requirements and the in machine requirements there appears to be a disconnect allowing to receive material larger then the expected in machine requirement. I think the the 2430 table is incorrect but I am the small fish here and no one else appears to be having this problem. Do you use ceramic media in your processes? I am experiencing a similar condition with my 210 size as well. I may take you up on your offer to verify my results. Thanks again for your input, Scott

Scott
The following may be the key to your problem. Only AMS 2431/7 and J1830 define the sizes and screen requirements for AZB425 (Z425 in J1830). Both define the size at .425mm to .600mm. The max .5% on screen is #25 and the max 10% pass screen is #40. The other specs do not reference AZB425, but only list a .425mm bead and require #35 and #50 screens. I believe the #35 and #50 screens are not valid for AZB425 because .425mm beads are smaller than and therefore not AZB425.
Pete Bailey

Pete,
Thank you for your reply. You are under the same opinion as myself, I to think AMS 2430 "in machine" sieves requirements are incorrect for the ceramic media. I need to know if there is anyone else out there having the same problem. If I get enough information maybe we can get this requirement changed on the upcoming revision. Thank again, Scott

AMS 2430L requires a top screen of 25 mesh and a bottom screen of 40 mesh AZB425. (You were looking at the wrong line in 2430L. There are only six ceramic bead sizes. You are using AZB425 which is the third size in AMS2431/7. You must come down to the third size in AMS 2430L also. It's confusing since it is labeled .024 (0.660) but it is the correct line to use for AZB425).
As soon as AMS 2430M is published you'll see where we put AZB425 on the same line as S-170 and AWC-20 etc. This should clear up the confusion.