Advanced Software Features
7 - 2
Modified: 9/17/08
MedWeld 4000 Operator’s Guide
M-032116 Programs #T03300, #T02300 and #T02400
Example of
Decreasing C-Factor
In an application of shunts in a fixture indexing gun, the guns will pull
on the cable. These forces cause strands of wire in the cable to break. As
fewer conducting strands remain, the current pathway will decrease,
increasing the resistance. This, in turn, will decrease the C-Factor.
This is illustrated by the following data:
•
The control is firing the following weld function:
WELD 10 CYC 10000 A.
•
The control required 53% initially to achieve the 10,000 A. Over
time, the control actually requires 60% to achieve the desired
10,000 A.
•
The initial C-Factor = 10,000 A. / 53% = 189
•
Final C-Factor = 10,000 A. / 60% = 167
Conversely, where C-Factor increases, the total capacity of the system is
increasing. This increase in C-Factor is associated with shorting/
shunting conditions in the welding environment.
When shorting or shunting arises, less resistance is seen because the full
current is not passing through the entire welding circuit.
This is a concern. If the full current is not passing through the weld
point, a weld below the desired current will occur. Depending on the
amount of shunting, the weld nugget may possibly fail to be formed.
Example of Increasing
C-Factor
In this example, a robot uses a kickless cable. The robot’s motions will
cause the cable to twist. As a result, individual wires within the cable
will rub against each other.
This action will eventually cause the cable insulation to break down.
When this breakdown occurs, the current will start to shunt between
wires within the kickless cable.
As this grows, the current at the weld will diminish, and the current
pathway will actually decrease. This, in turn, will increase the C-Factor.
This is illustrated by the following data:
•
The weld control is firing the following function:
WELD 10 CYC 65% I
•
The control initially sees 12,450 A.
•
After the shorting condition occurs, the control may see 14,300 A.
•
Initial C-Factor = 12,450 A. / 65% = 192.
•
Final C-Factor = 14,300 A. / 65% = 220.
