Heat and agitation could be utilized to the bathtub to hurry the etching price. In bubble etching, air is handed via the etchant bath to agitate the answer and speed up etching. Splash etching makes use of a motor-pushed paddle to splash boards with etchant; the method has become commercially out of date since it is not as fast as spray etching. In spray etching, the etchant answer is distributed over the boards by nozzles, and recirculated by pumps.

Varying cloth weaves (threads per inch or cm), material thickness, and resin proportion are used to achieve the specified final thickness and dielectric characteristics. Available standard laminate thickness are listed in ANSI/IPC-D-275.

A PCB could also be 'silkscreen' printed with a legend figuring out the parts, check factors, or figuring out text. Originally, an precise silkscreen printing process was used for this function, however right now different, finer high quality printing strategies are usually used instead.

Adjustment of the nozzle sample, flow price, temperature, and etchant composition gives predictable control of etching charges and high production rates. Chemical etching is often accomplished with ammonium persulfate or ferric chloride. For PTH (plated-by way of holes), additional steps of electroless deposition are done after the holes are drilled, then copper is electroplated to construct up the thickness, the boards are screened, and plated with tin/lead. The tin/lead becomes the resist leaving the naked copper to be etched away. There are quite a number of totally different dielectrics that can be chosen to offer totally different insulating values relying on the requirements of the circuit.

Some of those dielectrics are polytetrafluoroethylene (Teflon), FR-4, FR-1, CEM-1 or CEM-3. Thermal expansion is a crucial consideration particularly with ball grid array (BGA) and naked die applied sciences, and glass fiber presents the best dimensional stability. Laminates are manufactured by curing underneath strain and temperature layers of fabric or paper with thermoset resin to type an integral last piece of uniform thickness. The size may be up to four by eight ft (1.2 by 2.four m) in width and size.