Datasheet
Adsorption Response Time
5
When a vacuum pad is used for the adsorption transfer of a workpiece, the approximate adsorption response time can be
obtained (the length of time it takes for the pad’s internal vacuum pressure to reach the pressure that is required for adsorption
after the supply valve {vacuum switching valve} has been operated). An approximate adsorption response time can be obtained
through formulas and selection graphs.
Relationship between Vacuum Pressure and Response Time after Supply Valve
(Switching Valve) is Operated
The relationship between vacuum pressure and response time after the supply valve (switching valve) is operated as shown below.
Vacuum System Circuit
Vacuum Pressure and Response Time after Supply
Valve (Switching Valve) is Operated
Supply valve
Pad
Switching valve
Work
Pad
Work
Pv: Final vacuum pressure
T1 : Arrival time to 63% of final vacuum pressure Pv
T2 : Arrival time to 95% of final vacuum pressure Pv
Arrival time (sec)
Vacuum pressure (P)
Supply valve
(Switching valve)
operation
Calculating Adsorption Response Time with the Formula
Adsorption response times T
1
and T
2
can be obtained through the formulas given below.
For the conductance, the equivalent conductance can be found in “8. Data: Conductance by Tube I.D. (Selection Graph (3)).”
T
1
: Arrival time to 63% of final vacuum pressure Pv (sec)
T
2
: Arrival time to 95% of final vacuum pressure Pv (sec)
Q
1
: Average suction flow rate L/min (ANR)
Calculation of average suction flow rate
• Ejector
Q
1
= (1/2 to 1/3) x Ejector max. suction flow rate L/min (ANR)
• Vacuum pump
Q
1
= (1/2 to 1/3) x 11.1 x Conductance of vacuum pump [dm
3
/(s·bar)]
D : Piping diameter (mm)
L : Length from ejector and switch valve to pad (m)
V : Piping capacity from ejector and switching valve to pad (L)
Q
2
: Max. flow from ejector and switching valve to pad by piping system
Q
2
= S x 11.1 L/min (ANR)
Q : Smaller one between the Q
1
and Q
2
L/min (ANR)
C : Conductance of piping [dm
3
/(s·bar)]
Adsorption response time T
1
=
———
Adsorption response time T
2
= 3 x T
1
Piping capacity
V =
——
D
2
x L x
––––
(L)
V x 60
Q
3.14
4
1
1000
Model Selection
Suction flow rate
Vacuum p
ressure
Air consum
pt
ion
Front matter 18