Hypertherm Powermax65 Service Manual Rev.1 - Manual (Page 125)

OperatiOn
powermax
65/85 Service Manual 4-23
To pierce a workpiece using the machine torch
As with the hand torch, you can start a cut with the machine torch at the edge of the workpiece or by piercing the
workpiece. Piercing will result in a shorter consumable life than with edge starts.
The cut charts include a column for the recommended torch height when starting a pierce. For the Powermax65 and
Powermax85, the pierce height is generally 2.5 times the cutting height. Refer to the cut charts for specifics.
The pierce delay must be sufficiently long that the arc can pierce the material before the torch moves, but not so long
that the arc “wanders” while trying to find the edge of a large hole. As consumables wear, this delay time may need
to be increased. Pierce delay times given in the cut charts are based on average delay times throughout the life of the
consumables.
When piercing materials close to the maximum thickness for a specific process, consider the following important
factors:
• Allow a lead-in distance approximately equal to the thickness of the material being pierced. For example, 20 mm
(3/4 in) material requires a 20 mm lead-in.
• To avoid damage to the shield from the buildup of molten material created by the pierce, do not allow the torch
to descend to cut height until it has cleared the puddle of molten material.
• Different material chemistries can have an adverse effect on the pierce capability of the system. In particular,
high-strength steel with a high manganese or silicon content can reduce the maximum pierce capability.
Hypertherm calculates mild steel parameters with certified A-36 plate.
• Using a “flying pierce” (that is, starting torch motion immediately after transfer and during the pierce process)
can extend the piercing capability of the system in some cases. Because this can be a complex process that
can damage the torch or other components, a stationary or edge start is recommended.