Omax JetMachining Center 2626 Operator'S Manual Download

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Maintenance

OMAX JetMachining® Center Operator’s Guide

400433D-EN

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Positioning Accuracy Overview

OMAX Jet Machining Centers specify a positioning accuracy of +/- 0.003" for ball bar circularity (over 12
inches) at maximum velocity and at any table location. In addition, the 2626|xp specifies a positioning
accuracy of 0.001" when environmental requirements are met.

These specified values use an industry standard method of measuring cutting tip positional accuracy. An
abrasive waterjet machine is a

soft

cut machine. This means cutting head accuracy is only one of several

parameters involved in the overall cutting accuracy of a part. A

hard

cut machine, such as a Bridgeport Mill,

has a hard tool that is always exactly in the same location relative to its spindle’s X- and Y-axis position. A

soft

machine may be positioned accurately, but the cutting process is also affected by a number of other

important considerations such as the mixing tube diameter, mixing tube out-of-round, jewel wear, mixing disc
wear, Z-axis being square to the table, cut taper, offset entered in Make, abrasive flow rate entered in Make,
etc., etc.

When positioning accuracy and tolerance become an issue with an OMAX JetMachining Center, carefully
investigate the following:

• Ensure that all lead screws and belts on all axes are adequately lubricated. The rotation for each

should be smooth as silk.

Caution:

The linkage arms on a Tilt-A-Jet do not require lubrication. NEVER lubricate them with WD40
(or equivalent). This lubricant will react with the joint epoxy, causing them to permanently
freeze up and require replacement.

• The jewel, mixing disc, and mixing tube should all be new.
• Install a new nozzle body and mixing chamber and last chance filter.
• Examine your settings for SETUP and PUMP AND NOZZLE SETTINGS. Is every value entered

accurately? When was the abrasive flow rate last measured? Was it repeated three times just to be
sure? Is the water pressure entered the actual pressure indicated on the pump when cutting? Is the
mixing tube rotated frequently? Are Barton’s abrasives being used; can the abrasive index be counted
on for accuracy? Is correct tool offset being used?

• Run the Z-axis up and down to ensure it’s square to the table. Has the Tilt-A-Jet been checked for

accuracy?

• Is there any end play in either X- or Y-axis? Oval holes may indicate this problem. If end play is

indicated, examine the axial bearing.

• Disassemble and lubricate all UHP swivels. Ensure that the two weldments on the 55100 rotate

smoothly on the swivel body. Install a new bushing if needed.

• The gantry style Y-axis may be out-of-alignment and requires re-squaring.
• Loosen one end of all UHP tubes on the cutting head or swivels. Retighten each ensuring that the tube

is not being twisted while tightening. A twist in the UHP tube induces friction into the swivel, affecting
positioning accuracy.

Water level too low.

On some machines, if the water level is raised too high, the air
bladder “burps” excess air back into the tank, causing water to
overflow over the sides. To prevent this, ensure there is enough
water in the tank to allow the water level to be raised sufficiently
before the air bladder fills.

Abrasive Piles Up on the Work Piece

Condition and Possible Causes

Corrective Action

The accumulation of abrasive silt at
the bottom of the tank is excessive.

Remove the slats and clean out the abrasive from the tank bottom.

The tank has an Unpleasant Odor

Condition and Possible Causes

Corrective Action

Excessive bacteria growth in the
tank.

Check the floating device to ensure it contains an adequate
amount of the bacteria-killing chemicals supplied with the OMAX.