Home Forums General Discussion Shot Peening Process, Intensity, Coverage about coverage

Hello all,
Currently we met problem on the peening coverage.
we have two multi-satellite table machines. the old One with one 25Hp motor blast wheel, the other new one with one 20 HP blast wheel. They are the same wheel with differnt size motor.
The motor speed and current, cycle time are running at the same on both machines.The ARC height has not problem in the new machine. but the old one can achieve 100% coverage, the new one can only achieve 80%. Can any one tell me how to fix the problem? Urgent!!!!
Best regards,
David

Can you verify the wheel RPM and not just the motor?

Are you sure the shot size and hardness is the same?

The difference in coverage could be a factor of motor size since one is 20HP and the other is 25HP. Matching the motor currents may not be an accurate reflection of matched media flow rates. Can you increase the media flow rate on the 20HP wheel and run at a higher motor current level? This would increase the coverage rate.

thank you for the quick reply.

the shot size and hardness is the same.

The 20HP wheel is running at 28A which is full current and can not be higher. The 25HP one only runs at 26A.

Regards,

David

Hello Jack,

what I lean about the flow rate is that if the current is the same, the flow rate is the same, that is not right?
if you are right "Matching the motor currents may not be an accurate reflection of matched media flow rates", we may have to replace the motor. Any other way can I try? If I lower the satellite table speed, can I achieve the arc height and coverage during the same cycle time?

Thanks,

David

If you have two identical motors (same HP) then having the same current "implies" that you have the same flow rate. Since you have two different horsepower ratings you may not be getting the same flow rate. The motor efficiencies and other design characteristics can be making the difference. As you regulate the media flow rate the motor responds by drawing the current required to accelerate the media.
If you lower the satellite table speed you will still get the same amount of coverage since you are exposing the part for the same amount of time (cycle time). Your questiong about getting the arc height is troublesome. Intensity is revealed only by running four or more strips for various exposure times and constucting a saturation curve. The curve is then interpreted using the 10% rule to determine intensity.