Hypertherm PAC500 Water Injection Plasma Cutting System - Manual (Page 35)

4-4 PAC500 Instruction Manual
4
OPERATION
incorporates a Delrin liner ® which extends the life of the cap. This cap should not be used for piercing plate over
1 inch thick, or for cutting plate over 3 inches thick, as the liner can be melted by the metal ejected during piercing,
or by the reflected heat of High Current Cutting.
The tapered brass retaining cap is suitable for cutting or piercing thicker materials within the limits of Table I on
page 4-3. It must always be used for cutting in the conventional mode (High Current Mode).
The cutting conditions listed in the Cut Charts will generally produce excellent cuts without any modifications. Some
materials, particularly mild steels tend to vary somewhat in composition and may require slight deviations from the
conditions provided in the Cut Charts. The variables which will have the most significant effect on cut quality are in
decreasing order of effect: Travel Speed, Torch-to Work Distance (arc voltage), and Current. The water and gas
flows are optimized and should not be considered variables. Changing these flows from the recommended settings
will adversely affect consumable life and likely will reduce cut quality.
Thickness Range: 3 in. to 6 in.
The PAC500 is operated in the conventional mode in this thickness range. The water spray from the .250 nozzle is
used for cooling purposes only and does not constrict the arc. A mixture of 65% Argon-35% Hydrogen is used
instead of nitrogen because it produces a deeper penetrating arc. This mixture is available in commercial high
pressure cylinders. Some gas distributors may not routinely stock this mixture but since it is readily available they will
usually stock it if requested to do so. It is possible to mix the gases on site with a gas proportioning device but this is
not recommended due to the capital investment required and the maintenance needed to assure the proper mix.
Converting the PAC500 to the conventional mode requires the following steps:
1. Install .250 Nozzle–Part No. 020047 and .062 Swirl ring–Part No. 020048 in torch.
2. Install Tapered, Brass Retaining Cap Part No. 020034 on torch.
3. Remove Water-Muffler from torch.
4. Lower water level in Water-Table to four inches below workpiece. Shut off nitrogen flowmeter on operator
panel. Disconnect Torch gas hose at console and reconnect to Argon-Hydrogen Manifold. Adjust cutting
conditions as listed in Cut Chart – Operating Data for High Current Cutting, and in this section.
5. Shut off nitrogen flowmeter on operator panel.
6. Disconnect Torch gas hose at console and reconnect to Argon-Hydrogen Manifold.
7. Adjust cutting conditions as listed in Cut Chart – Operating Data for High Current Cutting, and in this
section.
Operation in the conventional mode is identical to operation in the Water-Injection mode except that the gas flow is
adjusted on the Argon-Hydrogen Manifold.
WARNING
Do not attempt to use Argon/Hydrogen mixtures through the console as it is not vented for
flammable gases and could result in an explosion if a leak were to develop within the console.