Hot Crack: Sheetcam

Sometimes a "crack" is actually just the torch piercing too close to the cut line or the kerf being set incorrectly. If the kerf width is too wide, the torch may sit on the edge of the material too long during the lead-in, creating a hot spot before the cut even begins.

The Fix:

Go to Corner Loops and select "Sharp Loop" or "Dwell" .

When we talk about a hot crack in SheetCam, we are usually referring to corner overheating. This happens when the cutting torch has to slow down to navigate a sharp corner. As the machine decelerates, the torch dumps more energy into a smaller area for a longer period. sheetcam hot crack

The result?

Essentially, your toolpath is "cracking" the integrity of the part because the physics of the cut weren't accounted for in the CAM software.

To solve the sheetcam hot crack problem, you must respect the three states of metal: Expansion, Fusion, Contraction. Sometimes a "crack" is actually just the torch

Imagine cutting a long, thin rectangular slot inside a 1/2" steel plate. As the plasma travels down the long side, the steel on both sides of the kerf tries to expand. But it is trapped by the cold, solid surrounding material. The result? Elastic strain. When the torch finally closes the loop (the "cutout"), the trapped energy releases violently. The plate flexes, and a hot crack shoots across the narrowest point.

In thick plate (1" or more), this is catastrophic. The crack is often followed by a loud "ping" and a visible gap of 1/16" or more.

One of the most common causes of a hot crack is cutting internal holes. If you cut a hole in a single continuous motion, the heat concentrates in the center of the part, often causing the surrounding metal to warp. Essentially, your toolpath is "cracking" the integrity of

The Fix: Instead of cutting a hole in one go, use a Cool Down pass.

Let’s get into the practical fix. If you are currently suffering from a sheetcam hot crack, open your operation settings and adjust these five parameters immediately.

When you see a crack, ask these three questions: