What You're Seeing

Print lines are appearing wavy, misaligned, or non-overlapping. The issue may not be present at the start of a print session but can develop progressively over time. Both print heads may be affected equally.

Why This Happens

Wavy and non-overlapping lines are typically caused by one or more of the following:

• The tracker was bumped or disturbed during printing, shifting its position or tilt without the operator noticing
• Control points are placed too close together, causing small Z-direction (elevation) errors to appear larger than they are — a deviation of even a fraction of an inch over a short distance can be enough to affect print quality
• The slab surface is uneven, which can contribute to Z-errors if control points are not placed on level ground
• The tracker tilt changed after being disturbed, causing the FieldPrinter to misinterpret its orientation

How to Fix It

1. Verify the tracker has not been disturbed. The reflector should be placed on top of a known control point to confirm alignment. If lines are not lining up as expected, the tracker may have been bumped, or a tripod leg may have shifted.

2. Check control point placement and spacing. Control points should be spread out as much as possible across the work area. Points placed too close together amplify small elevation differences, which can lead to wavy lines, particularly with the AT930 tracker. Z-errors visible in the stationing info screen are a strong indicator of this issue.

3. Re-station the FieldPrinter. After the tracker position and control points have been verified, a fresh stationing should be performed. Lines should then be reprinted in the affected area to confirm the issue is resolved.

4. Inspect the tracker level. The tracker leveling screen on the iPad should be checked to confirm the tracker is properly leveled. Even a tracker that appears stable can develop tilt issues if a leg has shifted slightly.

5. Confirm the caster and wind guards are secure. The caster should be checked to ensure it is not loose, and wind guards should remain in place during operation.

What to Avoid

• Placing control points too close together, especially on uneven slab surfaces
• Continuing to print without re-stationing after a tracker disturbance is suspected
• Assuming wavy lines are caused by print head issues — both heads being equally affected typically points to a positioning or stationing issue, not a hardware defect