User guide

Chapter 5. Custom Profiling 175
; Program second constant ratio
FOLRN3 ; At a 3 to 1 ratio
FOLMD1 ; Over a master distance of 1”
D3 ; Slave will travel 3”
GOBUF1 ; Build motion
; Program ramp to lower ratio
FOLRN1 ; Go to a 1 to 1 ratio
FOLMD0.5 ; Over a master distance of 0.5”
D1 ; Slave will travel 1”
GOBUF1 ; Build motion
PLN1 ; Close motion loop
; Define the exit motion
FOLRN0 ; Stop slave at zero ratio (and zero velocity)
FOLMD1 ; Over a master distance of 1”
D0.5 ; And a slave distance of 0.5”
GOBUF1 ; Build motion
END ; End definition of example program 3
PCOMP EXMPL3 ; Compile example program 3
; **********************************************************
; * To execute the program, enter the PRUN EXMPL3 command *
; **********************************************************
NOTE: The GOBUF command has been added to the “Define the exit motion”
portion of the program despite the fact that an infinite loop has been programmed earlier in the
program. This is to avoid an error message when the program is compiled.
Compiled Motion — Sample Application 4
A manufacturer of stamped molds needs to make a machine which will stamp molds into a
continuous flow of extruded plastic material. The stamp must be lowered 0.5 inches into the
plastic to leave the correct impression. Because the flow is continuous, the stamp must also
move in synchronization with plastic in the direction of flow as it is lowered and raised. The
initial design approach to the machine required two axes of motion. One was needed to lower
and raise the stamp, the other to allow the stamp to follow the plastic. With the availability of
complex Following cam profiles the job can done with a single axis.
In the drawing below, the stamp is attached to a rotating arm in such a way that the stamp
remains level as the arm rotates. The length of the arm at the stamp fixture, or radius of
rotation, is exactly one inch. The arm is mounted above the plastic so that at the bottom of its
rotation (270 degrees), the stamp will be 0.5 inches into the plastic. Using trigonometry, the
horizontal and vertical positions and speeds may be calculated at other arm angles. Because the
stamp must follow the flow of the plastic, we must adjust the ratio of rotational speed to
plastic speed so that the horizontal velocity component of the arm stays at 1:1 with the plastic
while the stamp is in the plastic.
V V
30°
V
30°
drawings are not to scale