Miller Electric DWF3 - Manual (Page 7)

SECTION 1 DESCRIPTION
OM-179 078 1-1
1.1 INTRODUCTION
Cold wire feed systems are designed for accurate application of filler wire into the weld or braze area. The
DWF–3 is designed to be used for GTAW and PAW processes. The Digital Wire Feeder System is made up of
a positive feeding wire drive with a zero backlash 3–axis wire manipulator. This combination of components
produces exceptionally good wire feeding characteristics. Systems will accommodate wire sizes from .020 in
diameter (.50 mm) to .094 in diameter (2.39 mm) and feed at an adjustable rate, continuously variable from 0
to 300 inches per minute. A standard DWF–3 system is shown in Figure 1.1.
1.2 CONTROL UNIT
The control unit uses solid state circuitry in its motor supply and control circuits and operates from a 115/230
VAC, 50/60 Hz line supply. Provisions have been made for forward or reverse jog to allow easy
pre–positioning of the filler wire. Start of wire feed and control of speed may be accomplished both manually
from the front panel or remotely through the interface connector located on the rear panel. The speed at which
the wire will feed is pre–set through use of the ”PUSH TO SET” function on the front panel and can be
controlled within 0.10 inch per minute increments. A digital readout of wire speed is provided. Start delay and
stop delay timers are also provided for cycle control. Timers can be pre–set within 0.10 second intervals from
0 to 9.9 seconds.
1.3 WIRE DRIVE UNIT
The wire drive unit uses urethane rollers to grip the wire and feed it in either direction depending on the signals
from the control unit. These rollers eliminate the need to change rollers when changing wire sizes from .020 in
(.50 mm) diameter through .062 in (1.57 mm) diameter wire. Special rollers are required for .094 in (2.39 mm)
diameter wire. All wire can be loaded into the drive while it is operating. There is no need to hand–feed the wire
through the mechanism before operating. Inlet and exit guides are provided with the wire drive. One inlet guide
covers the entire range of wire sizes from .020 in diameter (.50 mm) to .094 in (2.39 mm) diameter. Three exit
guides cover the range of wire diameters. Two of the exit guides are for the .020 in through .062 in range. The
third is for the .094 in wire. The guides are stored inside the drive housing. If a drive for .020 in – .062 in wire is
ordered, then two exit and one inlet guide will be supplied. If a drive for .094 in wire is ordered, then one exit and
one inlet guide will be supplied.
1.4 WIRE GUIDE ASSEMBLY
The wire guide assembly which is used with the DWF–3 wire drive unit consists of a guide mechanism,
conduit, liners, and tip. The guide mechanism is constructed to allow full position adjustment for vertical, cross
seam, feed angle and distance from the electrode. Tips and liners can be changed to suit the wire size being
used (see information listed in Table 1.1) Standard length of the conduit supplied with the system is 36 in
(914.4 mm). The length may be shortened by following steps 2.5A through 2.5D in the installation section.
TABLE 1.1 WIRE GUIDE DETAILS
WIRE SIZE ROLLER EXIT GUIDE LINER GUIDE TIP
.020 in (.50 mm) 179 170 179 173 179 184 –
.030 in (.76 mm) 179 170 179 173 179 184 –
.035 in (.89 mm) 179 170 179 173 179 184 –
.045 in (1.1 mm) 179 170 179 173 179 184 –
.062 in (1.5 mm) 179 170 – 179 185 –