Although the lateral cutting force of a waterjet is low (typically under a few pounds), the high-velocity jet forces air into the catcher tank, creating a significant upward force that can lift thin sheets and lightweight materials off the support slats. Preventing movement requires a combination of passive locating, active clamping, and smart toolpath design.

Active Clamping Is Essential for Thin Materials

For sheets thinner than 6.4mm (1/4 inch), aluminum, or thin shim stock, the upward force from aerated water is often enough to displace the workpiece. Clamping directly to the slats is not recommended because slats can sway and do not reliably prevent lateral movement. Instead, clamp the material against the rigid tank frame or use a corner square (L-plate) bolted to the tank, with spreader clamps pushing the material firmly against this reference edge. For high-precision work with tolerances below 0.25mm, active holding (weights or clamps) is mandatory to counter vertical lift.

Tabbing for Small Parts

Small parts can easily fall through the slats or shift once separated from the parent sheet. The standard solution is tabbing—leaving small uncut bridges of material that connect the part to the surrounding skeleton. Tabs can be as thin as 0.8mm depending on the material. Place tabs on non-critical edges, avoiding precision mating surfaces, small-radius corners, and visible decorative edges. Long or asymmetrical parts may require multiple tabs to prevent rotation.

Cutting Sequence Optimization

The order of cuts directly affects part stability. A practical sequence is: cut internal holes and enclosed features first, before the outer profile; process less stable features while the surrounding material is still rigid; and complete the outer boundary last. This preserves the skeleton's stiffness for as long as possible and prevents the part from moving after most of its perimeter has been separated.

Support and Slat Maintenance

Worn or uneven slats can cause the material to rock during cutting. Ensure slats are level across the work surface and replace worn slats promptly. For very thin or delicate materials, a sacrificial layer such as a waterjet brick or thin plywood placed between the workpiece and slats can provide additional support and protect the underside from jet rebound.

Winwin offers a complete range of waterjet cutting equipment, high-pressure pumps, and genuine waterjet accessories, including material holding kits, corner squares, and slat systems. Every machine is fully customizable to your materials and production needs. Winwin provides comprehensive after-sales service for products shipped worldwide, including professional installation, calibration, operator training, spare parts supply, remote technical support, and full lifecycle service, ensuring your equipment performs reliably wherever you are.