MK Products Copperhead Weldhead - Manual (Page 15)

CopperHead ® Owner’s Manual - Page 7
Weldhead Coolant
Use Cobra Coolant (Aluminum Protection), P/N 931-0060. Cobra Coolant
does not contain reactive sulphur or chlorine and does not react with copper,
brass or aluminum.
DO NOT USE AUTOMOTIVE ANTI-FREEZE
This may contain additives that are not compatible with this equipment
and will void the warranty.
Section B Operations
Weldhead Calibration
The software program in the orbital welding power-supply provides for
weldhead rotor speed and motor controller calibration. This calibration
program consists of driving the rotor at predetermined speeds for a set
number of revolutions, depending on the welding power supply used. The
start and end of each rotation are detected by the passage of the reed switch
or “home” sensor in the weldhead. The rotation is clocked by the computer
and, by process of adjusting and recalculating, provides very accurate and
consistent speeds.
WARNING
Always perform a motor calibration when changing weldheads or
powering up the power source. Leaving the same calibration coef-
ficient corrections with a different weldhead may give erroneous
speed results.
Weldhead Calibration Sequence – ACL ®
Due to small variations among weldheads and because the ACL ® uses a
tachometer feedback control system, there are small but significant varia-
tions in speed among the weldheads for the same command from a particu-
lar ACL
® . There are also slight drift effects within the same weldhead when
used over a long time frame mainly caused by temperature build up in the
weldhead motor case.
To account for these variations, the ACL ® provides two functions to measure
the variation and then to factor out the variation so that the weldhead can
maintain absolute and repeatable results: 1) the first function is a Full Motor
Calibration sequence performed from the Main Menu, 2) the second function
is a quick update that is performed before each weld if the pre-weld homing
function is programmed into the weld procedure. For programming infor-
mation for the Motor Calibration Update, please refer to the ACL
® Owner’s
Manual.
The first function is performed to take out gross variations between
weldheads. The second function is a shortened update of the full calibration
procedure performed to take into account any drift that may occur over a
long time frame with the same weldhead.
Full Motor Calibration Sequence
Upon initiation of the calibration sequence, if the rotor is at home position,
it starts rotating in its normal welding direction for at least two complete
revolutions from home switch closure to home switch closure at a default low
speed setting of 2 rpm. Once complete, the weldhead rotor changes speeds
and continues in its normal welding direction for at least two complete revolu-
tions from home switch closure to home switch closure at a default high
speed setting of 6 rpm.
The ACL ® uses the home switch closure as an absolute indicator of rotor
position and times the duration between switch closures as one complete
revolution. Dividing this time into 60 seconds gives the rotor speed in rpm.
The ACL ®
uses two samples of data (hence two complete revolutions) at