IAI America CT4 - Manual (Page 67)

6. Life
61
6
. Life
The mechanical life of the High-Speed Orthogonal Robot CT4 is represented by the guide that
receives the moment load mostly.
One of the elements determining the operation life is “rated load”.
There are two types of “rated load”, one is the “static rated load” and the other is the “dynamic
rated load”.
x “Static rated load” : it is a load that makes a small dent mark on the interface when a load is
applied in a stopped condition
x “Dynamic rated load” : it is a load that the remaining rate of the guide not being broken and is
assumed constant after an operation for a certain distance is carried out
with a load being applied.
The guide supplier shows the dynamic rated load assuming the remaining rate of the guide not
being broken after 50km of operation is 90% for the life of the guide.
However, it is important to know the specific product life for the general-purposed industrial
machines also from the view of maintenance.
The life of the guide is sufficient for the radial load, and is mostly influenced by the moment load
caused by the offset from the center of the guide.
The operation life is set assuming 1.2 times of the load coefficient (safety margin) under the
allowable load moment.
X1, X2 and Y-axis are set as 20,000km. 5,000km set for Z-axis. [For the dynamic allowable load
moment, refer to 1.2. Specifications.]
 The formula of the dynamic allowable load moment when the operation life of X1, X2 and
Y-axis is 20,000km is as shown below:
The life with the applied moment can be calculated with the following formula.
 The formula of the dynamic allowable load moment when the operation life of the Z-axis is
5,000km is as shown below:
The life with the applied moment can be calculated with the following formula.
C
IA
= M 50
fw
50km
20000km
×
1
3
C
IA
: Allowable Dynamic Load Moment
fw : Load factor (=1.2)
M
50
: Dynamic rated moment when run for 50km and
remaining rate is 50%
L =
C
IA
P
3
× 20000km
C
IA
= M 50
fw
50km
5000km
×
1
3
L : Operating life (Remaining Probability 90%)
C
IA
: Dynamic allowable moment
P : Applied moment
C
IA
: Allowable Dynamic Load Moment
fw : Load factor (=1.2)
M
50
: Dynamic rated moment when run for 50km and
remaining rate is 50%
L =
C
IA
P
3
× 5000km
L : Operating life (Remaining Probability 90%)
C
IA
: Dynamic allowable moment
P : Applied moment