Electronics LP-24 - Manual (Page 15)

15
The advantage of using the Almen strip method lies in the ability to detect the many changes that
can occur in a blast machine cleaning operation. Many quality departments are demanding real
time process control to satisfy customer requirements for documentation. Instead of relying upon
the operator’s judgment of cleanliness, the Almen strip method provides a scientific basis for quali-
fying the machine. The following are the changes that can be detected by the Almen method:
a.
Wrong shot size added to machine (check the bag or drum for correct size)
b. Wrong shot size, dust collector not removing all small or broken shot
c. Wrong shot hardness (check the bag or drum for correct hardness)
d. Incomplete coverage, due to exposure time, shot flow rate adjustment, or improper targeting
e. Improper targeting caused by worn wheel blades or control cages out of adjustment