PCB Manufacturers do manufacture all kinds of PCBs. Some of the PCBs are meant to be smaller in size and some of them have to be in bigger size. Smaller size PCBs are used in cell phones and tablets and bigger size PCBs are used in computer, laptop and different electronic equipment circuit boards. Mainly they are made up of copper and electronic equipments are inserted into it. Some of the PCB Manufacturers get the authorization in their specified areas only. For instance some of the manufacturers are only authorized to manufacture cell phone, if they put them in manufacturing of computer and laptops, they are not allowed. Likewise some of the PCB Manufacturers are only allowed to produce computers and laptops if they put them in manufacturing of cell phone or tablets, they wouldn’t do that. You need to get the authorization from the national and international legislative firms before entering into manufacturing process.
You may find a lot of manufacturers who are producing high quality PCBs, some of the manufacturers are producing low quality PCBs. Every other manufacturer has its own area of production, some of them do produce for those customers who have high purchasing power and some of them do produce for those customers who have very low purchasing power. Depending upon their requirement PCBs are produced.
The PCB which is made up of solid stuff and has good connection is considered to be good one. You may get better performance from this PCB. For such PCBs which have loose connections and are not made up of good stuff don’t have a very good performance. There is a restriction imposed on a number of substances in the production of PCBs. The manufacturers cannot produce PCB using hazardous substances.