He re-posted. Ran the cut on a scrap piece.
Cutting complex nests without allowing the sheet to cool down causes ambient heat to rise. When the torch returns to a hot zone, the cumulative thermal stress triggers cracking. How to Eliminate Hot Cracks Using SheetCam
In the context of SheetCam, "hot crack" issues usually arise from or heat management settings that cause localized overheating. Primary Causes of Hot Cracking
The evaluation version of SheetCam is limited to approximately 180 lines of G-code . Many cracks fail to bypass this reliably or cause the software to revert to evaluation mode mid-job, ruining expensive material. sheetcam hot crack
In plasma cutting, moisture or oil in the air lines alters the chemistry of the plasma arc, introducing hydrogen or oxygen that severely worsens cracking. Ensure your air filtration and drying systems are pristine.
Mark leaned his forehead against the cold metal of the control box. The machine wasn't just cutting steel. It was cutting him now. Every cracked part was another hour lost, another pound of scrap, another notch in the argument with his wife about why he couldn't make it home for dinner.
Always cross-reference your plasma or laser manufacturer’s cut charts. He re-posted
This article explores why hot cracks occur and how to use SheetCam’s advanced features to minimize them. What is a Hot Crack?
Worn nozzles or swirled rings distort the plasma arc, causing an asymmetrical heat distribution. Replace consumables regularly.
Corners are hot-crack hotspots because CNC machines naturally slow down to change direction, causing heat buildup. In SheetCam, apply Path Rules to automatically drop the plasma amperage or alter the feed rate when approaching tight corners. 4. Utilize "Leapfrog" or Strategic Cutting Orders When the torch returns to a hot zone,
Create a custom in SheetCam to handle the end of the cut. For example, you can create a rule that triggers "Output Air/Gas Only" or reduces current right before the end of the toolpath. Alternatively, use a rule that accelerates the torch slightly as it approaches the lead-out to thin out the heat input. Material-Specific Considerations
: For small holes or tight corners where the machine must slow down, disabling the THC is critical. If the torch slows while THC is active, the arc voltage can drop, causing the torch to dive into the material.
Materials with a wide freezing range (like 6000-series aluminum or certain stainless steels) are highly susceptible. Low-melting-point impurities segregate to the grain boundaries, leaving weak liquid films that tear easily under stress.
Never pierce directly on the cut line. Always utilize the tab in your SheetCam operation settings.
Eliminating hot cracks requires a combination of proper geometry management and optimized cutting parameters. Implement the following adjustments within SheetCam to solve the issue. Use Tangential or Arc Lead-Ins
