Heat press machines have two plates, or plates, as they are more often called. The top platen heats up and is called the heat platen. Once the machine is turned on the heat platen will heat up to the set temperature.
Most, if not all, heat press machines have a digital display on which you can set the time and temperature. Some more expensive machines will also allow you to set the pressure digitally.
The time range for most t-shirt presses is 0 – 999 seconds. Though no one is ever going to do a press for 999 seconds (16 minutes)! Most heat transfers only need 10 – 20 seconds to complete.
Most machines have a temperature range of 0 – 500° F. This is more than enough to perfectly apply for all heat transfers onto t-shirts (and other garments). A temperature higher than 500° F would likely burn or melt your transfers and t-shirts!
The pressure is set on most machines by turning a knob. This knob will be situated either on top of the control box at the back (unless it is sent digitally).
The pressure is described in terms of lightness to hardness. For example, Siser EasyWeed is pressed at medium pressure, while EasyWeed Extra is pressed at a light-medium pressure.