How China PCB manufacturer control the dielectric thickness and tolerances for laminates?

    As we all know, multi-layer PCBs need to be laminated except for 1L PCB and 2L PCB. It will involve the dielectric thickness between each layer of the printed circuit board and how should the thickness tolerance be controlled when laminating, so do you know how China PCB manufacturer control the dielectric thickness and tolerances of the laminates ?

    Shenzhen Vip Circuit Co.,Ltd. will control the thickness and tolerances for laminates according to the IPC 4101 Class B/L column which in the following picture if the customer does not specify the requirements for us. Among them, the requirements of Class A/K are the lowest, and the requirements of Class D are the most stringent. Please see the following picture for detial :