PA Industries Precision AirFeed - Manual (Page 8)

6
PRESS FEED TIMING
The Reciprocating Linear Motion of the Feed Slide must
be timed to the press crankshaft rotation for optimum
performance. The Actuating Valve’s vertical motion
controls the sequencing of the Stock Clamp, Feed
Clamp, and the Feed Slide.
To understand how the rotary crankshaft and linear
Feed Slide motion work together in a Press Feed Cycle,
it might be helpful to visualize a Clock Face. The
position “Top Dead Center” of the Ram Stroke would be
12 o’clock, half way down would be 3 o’clock, “Bottom
Dead Center” is 6 o’clock, and moving half way up
would be 9 o’clock.
The optimum Feed cycle requires two thirds of the
crankshaft rotation (240 degrees) to feed the material
into position. During the remaining 120 degrees, the
Feed Slide returns to the Stop Screw for more Material.
As soon as the Stamped Part has been ejected and the
Punches are clear of the Die (approximately 8 to 8:30
on the clock), the Feed Clamp will grip the Stock and
then the Feed Slide will begin moving towards the Feed
Body.
CAUTION: To properly complete a Feed Stroke, the
Feed Slide must have enough time to contact the Feed
Body before 4 o’clock and then return to the Stop Screw
before 8 o’clock during the 360 degree crankshaft rotation
otherwise erratic short feed progressions will occur. Another method of controlling the Feed Timing is
to use the Remote Electric or Pneumatic Actuation
Systems to suit the Press and Part applications.
These methods require the same 240° feed and 120°
return timing cycle.