1. Causes of Dross Formation at Metal Cutting Corners

1.1 Sudden Speed Changes at Corners Causing Heat Accumulation

During straight-line cutting, the cutting speed remains stable. However, when the path approaches a corner, the machine must decelerate—sometimes approaching near-zero speed at sharp angles—to maintain positional accuracy before accelerating again.

If the laser power remains constant during this speed drop, the corner area receives a longer exposure time, causing excessive heat buildup. Because the accumulated heat cannot dissipate in time, the metal becomes over-melted.

The excess molten metal surpasses what the kerf can accommodate and the assist gas can expel, and once it cools, dross is formed.

Even for rounded corners, a very small radius will still force the cutting speed to slow significantly, resulting in similar heat accumulation and dross formation.

1.2 Indirect Effects of Improper Parameter Matching and Equipment Conditions

Incorrect focus positioning can worsen corner dross:

If the focus is too far forward, the lower portion of the metal absorbs excessive heat, causing molten metal to flow downward and solidify as adhered dross.

If the focus lags behind, the metal may not fully melt, producing sharp residual edges,Additionally, nozzle wear or partial clogging disrupts the stability of the airflow,Insufficient assist gas pressure cannot provide enough force to expel molten metal effectively.

2. Adjustment Methods for Reducing Corner Dross

Adjusting the Duty Cycle Curve and Frequency Curve can effectively optimize cutting performance at corners and reduce molten-metal dross formation.

xTool MetalFab CNC Cutter Processing Curve Adjustment Tutorial

2.1 Relationship of Curve Nodes

The four nodes in the curve correspond to different sections of the cutting path. Adjusting each node allows you to modify cutting performance at specific regions of the path:

Node 1: Corresponds to the starting point of the cutting path.

Node 2: Corresponds to the first half of the cutting path.

Node 3: Corresponds to the second half of the cutting path.

Node 4: Corresponds to the end of the cutting path and fine-tuning of the final cutting result.

Each node directly affects energy delivery and cutting stability within its respective segment.

2.2 Methods for Adjusting Curve Nodes

When slight dross appears after cutting with the recommended parameters, you can adjust the Duty Cycle Curve and Frequency Curve to reduce or eliminate it. This can be achieved by increasing the speed and reducing either the duty cycle or the frequency at the corresponding curve nodes.

If dross forms at the starting point of the cutting path, you may apply the following adjustments:

Duty Cycle Curve: Increase the speed of the first node by 5% and reduce the duty cycle by 5%.

Frequency Curve: Increase the speed of the first node by 5% and reduce the frequency by 5%.

If dross appears at other positions along the cutting path, adjust the node that corresponds to that specific location. Each adjustment should be made with small, incremental changes, and values should not be altered too drastically at once.