The simple answer is that too much heat causes scorching. To eliminate scorching problems, you need a reliable dryer or flash cure with good temperature controls. Inks cure at relativity the same temperature, but the temperature can vary depending on the color and thickness of the shirt. Also, a white shirt cures at a slightly different temperature then a black shirt due to the thickness of the ink deposit applied.
In general, when curing ink it’s better to err on the hotter side instead of the cooler side, but a white shirt won’t always tolerate temperatures as high as a black shirt will take. When curing you have to take into consideration the amount of ink deposit, and how hot you can go without overdoing it.
In the case of a white T-shirt, 300 to 310 degrees Fahrenheit is all that you are going to need if you are printing properly, and that means you are not printing everything with 110 mesh. On a white T-shirt, if you are printing with 160, 180, or 200 monofilament mesh, you are going to have a fairly thin ink deposit, and it is going to cure beautifully at 290 degrees. So there’s not much of a chance you are going to scorch the shirt there.
If you are printing an athletic print with a heavy ink deposit on a black shirt and using a 110, 86, 60, 30 monofilament mesh, the temperature will need to be in the 340 to 350 degree Fahrenheit range because the ink is thicker and will take a higher temperature to get to the bottom of the ink deposit.
Curing is a cumulative process. If you are printing on a very temperature-sensitive fabric like Spandex, you may need to lower the dryer temperature and run the garments through twice.
Make sure the ink is reaching the right temperature to cure.This isn’t possible by just simply looking for smoke coming off the shirt. You should use a probe to accurately test the ink temperature. In general, if you are running the dryer at 290 degrees, you will not scorch the garment.