Printed circuit boards are manufactured using a variety of methods such as toner transfer, dry film development, and the like. The toner transfer method is the cheapest PCB manufacturing method, used by most PCB hobbyists. Typically, PCB traces are printed onto a special toner transfer sheet using a conventional laser printer and then transferred to the copper clad with heat. This is why it is called ‘toner transfer’.
The main problem with toner transfer is that the toner is not completely transferred to clad board due to poor contact area and improper heat application. Even use an oven to heat the transfer device, the lack of uniform pressure still will affect the transfer efficiency. To solve this problem, a PCB laminator is used to evenly and adequately transfer the image. This method ensures high-quality and clear PCB traces.
PCB laminators typically have two to four hot rollers that are held together with the help of tension springs. The tension can be adjusted as per requirements and board thickness. The temperature is set to the specification of each board. Temperature exposure is a critical parameter for efficient toner transfer, which is the reason why almost all PCB laminators have accurate temperature control settings. It is also possible to control the temperature exposure by adjusting the rotational speed of rollers.
In order to ensure that the complete transmission process is usually repeated several times. Some industrial processes use different thermal and tension settings for each iteration. This variable setting method helps to linearly increase the temperature to avoid damage to the circuit board. For double-sided PCBs, the PCB laminator is set to high temperature and fixed with maximum tension.