We have purchased computerized dual shot peening machine "Progressive". The medias to be used are cast/cut wire shot and ceramic beads. The machine is equipped with magnetic media separation and screens in SWECO units.

However some small media mixing can happen due to residues of media in the cabin and hoses. If there are some criteria for quantity of other media particles present in the sample for media check in the machine?

Alexander,

Mixing media of different types or hardness is generally not a good idea. Are you concerned about ferrous contamination on the parts that are peened with ceramic shot, or are you just concerned about cross contamination of media types? I can tell you that we have machines that are capable of running two sizes of media, but we would never have two different types, the only difference we allow is size, i.e. ASH-70 and ASH-170.
How close in size is the cast steel/CCW to the ceramic bead you are using?

The cast steel shot is ASR-110, the ceramic beads are AZB425. There is magnetic separation but we still see several particles of ceramic beads in the sample of steel shot. No evidence of steel shot in ceramic media.

When you say "particles" I assume you mean broken particles of ceramic correct?

On your machine you state to have a Sweco screener. What size screens are you using? Do both types use the same screener?
As you know the types of media you are using are close in size
AZB425 .425mm and ASR 110 .300mm. Your Sweco will basically only maintain the size of the media, broken partials need to be removed by using a spiral separator. Do you have one?

Certainly, we have separator and all the broken media is removed. may be the wording is not so good, when I said "particles" the meaning was ceramic beads. For the first sample I found about 3 beads for a window of 1/4x1/4". The neat 4 samples taken after several hours of working of the separator and Sweco had only 1 bead.

So the beads of ceramic are not broken, they are entact beads correct?


Do you know what size screens are in your Sweco? This appears to be the root of the problem.

One more thing. Where and how are you collecting your test sample?

The problem is that we separate the ceramic beads from steel shot
by magnet method, but it is impossible to separate non-magnetic ceramic media from the steel shot. The sizes are overlapping and all the time we have few ceramic beads in the sample of steel shot taken from the cabin.