Precautions On Model Selection - SMC Networks MWB 32-UT Series Operation Manual

1-3．Precautions on model selection
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C a u t i o n
① Choose the optimum lock unit size based on the operating condition in the application , such as load , travel
distance (stroke) , stroke time , mounting orientation , operating pressure, etc.
② Attention should be taken so that the operating speed does not exceed the maximum speed for the
cylinder.
③ Stroke time means the time taken for the load to move from the start
of the stroke to the end without an intermediate stop.
④ When the cylinder stroke and travel distance of the load are different
such as in double speed mechanism shown as anexample in Fig. 1
, select the model based on the travel distance of the load.
⑤ The example and method of selection below are based on the use of
an intermediate stop including emergency stops during operation.
The maximum load weight for the lock should only be used,
when kinetic energy is not generated during locking, i.e. for
preventing a static object from falling. Choose the actuator model
based on the operating pressure referring to the Graphs 5 to 7
so that the load mass does not exceed the load for the maximum
speed V = 100mm/s.
【Used with air cylinder】
・Load weight: m=50kg
・Travel distance: st=500mm
・Positioning time: t=2s
・Load: Vertically downwards
・Operating pressure: P=0.4MPa
Step 1
Calculate the maximum speed of the load: V
Calculate the maximum speed of the load, V (mm)
from travel time of the load, t (s) and stroke, st (mm).
Graph 1
Example
Movement
distance
of load
Step 1: Based on Graph 1
Calculate the maximum speed of the load.
∴Max speed V≒350mm/s
Step 2: Select Graph 6 based on the load conditions and
operating pressure. According to the max. speed,
V≒350mm/s calculated above and load weight m=50kG,
∴ø63, which means the bore size of MWB shall be
larger than ø63.
Step 2
Select the appropriate Graph based on the load conditions
and operating pressure. Find the intersection of the load
weight and max. speed from Step 1 . A suitable lock unit
size is indicated by the diagonal line above the intersection.
Load
Load applied perpendicularly to the rod
(Received by guide)
Load applied in extending direction of the rod
Load applied in retracting direction of the rod
- 6 -
Fig. 1 Double speed mechanism
Find the lock unit size
Operating pressure
0.3MPa~
0.4MPa~
0.5MPa~
0.3MPa~
0.4MPa~
0.5MPa~
Cylinder
stroke
Graph 2
Graph 3
Graph 4
Graph 5
Graph 6
Graph 7