Whip Mix Xcavator, User Manual

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Xcavator
Operating Instructions
6
Theory Of Operation
The Xcavator is designed to remove 95 percent of
investment material from a 100 gram or 200 gram
investment mold unattended. It will shorten the
overall press to pattern recovery time significantly.
Instead of removing a hot mold from your pressing furnace
and waiting up to 50 – 60 minutes for it to cool to a safe
bare hand handling temperature then spending another
Controlling the Depth of Cut
There are four factors which affect the depth of cut
in a given mold:
1. Air Pressure
2. Spindle Rotation Speed
(as set by the Depth of Cut Knob)
3. Density of Investment Material AND
Concentration of Special Liquid.
4. Bead Media Size and Hardness
As a rule of thumb, the air pressure should be set to the
lowest psi value that will yield satisfactory cuts throughout
the range of investment brands and concentrations by
adjusting ONLY the 16 position spindle speed selector
knob. Whip Mix has determined that
35 psig is the
pressure setting which will cover the entire spectrum
of currently available brands and concentrations
. The
hardest and highest density investment should be run on a
Depth of Cut setting towards the higher numbered positions
while less dense investments should be run on the lower
numbered settings.
An Important note
Regarding Air Pressure
Even though the incoming air pressure is perhaps
higher than you would normally select for manual
divestment, the direct comparison is not physically
valid for the following reason; when manually divesting
the nozzle is within less than a centimeter of the glass
pattern. The Xcavator jet nozzle nEVER comes within
2– 3 centimeters of the glass pattern and is in
COnSTAnT MOTIOn, making it impossible to dwell over
any given spot on the glass pattern for more than a few
seconds. The increased distance effectively drops the
pressure level of the air propelling the beads so that by
the time they reach the glass pattern the kinetic energy
the beads transfer to the glass is actually less than with
a manual divester.
You should use only one type and size of bead media. In
practice, the only one of these interactive factors remaining
variable should be the Depth of Cut Selector knob.
How Does it Work?
The Xcavator uses a robotic grade precision stepper motor
to digitally turn the investment mold in an ultra-precise rate
of rotation. This rotation is computer controlled to spin
slowly at the outside periphery of the mold and slowly
accelerate as the swing arm approaches the center of the
mold rotation. This precision is the key to controlling the
depth of cut and the uniformity of material removal
across the horizontal material removal plane. The nozzle swing arm is also controlled by a robotic
grade precision stepper motor to digitally position
the nozzle along each concentric cutting track with
minimal overlap and high repeatability.
5 –15 minutes to hand divest, you can remove the mold
from the press furnace, press the corresponding delay cycle
button and the Xcavator will announce when the mold is 95
percent divested with a beeping sound, and the green
Ready light will be lit. The divested mold will now be cool
enough to remove from the Xcavator by hand, and touchup
the remaining 5 percent by hand in as little as 30 seconds.