Troubleshooting: Corners Are Too Dark, Too Light, Or Missing

If the Min Power setting is too high, the laser can leave scorch marks or wide kerfs at the slow areas of your jobs.

If your Min Power value is too low, you will see under-burned areas in slow spots.

If Min Power is so low that it falls below the firing threshold of your laser you will find completely unburned areas. If you are running a cut at very low speed, set your Min Power and Max Power to the same value to avoid this.

The firing threshold is usually around 10% of your laser's wattage. In other words, a laser with an 80W tube will usually fire around 8% power, but not below.

Start Speed in Machine Settings specifies the value where the controller begins ramping the power from Min to Max power. If the laser is moving at the 'Start Speed' or slower, the Min Power is used. The Start Speed is 10 mm/sec by default on most Ruida controllers, but some machines may have it set as high as 15 to 20 mm/sec, or may have it set lower.

If you are cutting at a low overall speed (for example, 10 to 20 mm/sec on a CO₂ machine) the laser might only ever use the 'Min Power' setting, so in that case it is best to use the same value for both. If you are doing 'surface marking' you ideally want Min Power to be just above the firing threshold of the laser, so corners still produce a burn, but without scorching.

With the exception of engraving Images in Grayscale mode, Min Power is not available on GRBL controllers. However, if the acceleration is set too low in the firmware, the laser may not speed up fast enough to fire at sufficient power when turning corners. Raising the X and Y Max Acceleration to 100-500 in Machine Settings may correct this.

You may also need to reduce your speed or adjust your S-Value Max setting. See more about GRBL Power Output problems.