Have You Ever Thought Of TQM Systems

In electronics, printed circuit boards, or PCBs, are utilized to mechanically support electronic elements which have their connection leads soldered onto copper pads in surface mount applications or through rilled holes in the board and copper pads for soldering the part leads in thru-hole applications. A board design may have all thru-hole parts on the top or component side, a mix of thru-hole and surface area mount on the top just, a mix of thru-hole and surface area mount elements on the top and surface area install elements on the bottom or circuit side, or surface install parts on the top and bottom sides of the board.

The boards are likewise used to electrically link the required leads for each part using conductive copper traces. The element pads and connection traces are engraved from copper sheets laminated onto a non-conductive substrate. Printed circuit boards are designed as single agreed copper pads and traces on one side of the board just, double agreed copper pads and traces on the top and bottom sides of the board, or multilayer designs with copper pads and traces on top and bottom of board with a variable number of internal copper layers with traces and connections.

Single or double sided boards include a core dielectric material, such as FR-4 epoxy fiberglass, with copper plating on one or both sides. This copper plating is etched away to form the real copper pads and connection traces on the board surface areas as part of the board production procedure. A multilayer board includes a number of layers of dielectric product that has been fertilized with adhesives, and these layers are used to separate the layers of copper plating. All of these layers are lined up then bonded into a single board structure under heat and pressure. Multilayer boards with 48 or more layers can be produced with today's innovations.

In a normal four layer board style, the internal layers are often used to supply power and ground connections, such as a +5 V plane layer and a Ground airplane layer as the 2 internal layers, with all other circuit and element connections made on the top and bottom layers of the board. Really complicated board designs may have a large number of layers to make the numerous connections for various voltage levels, ground connections, or for connecting the numerous leads on ball grid selection gadgets and other big incorporated circuit package formats.

There are usually 2 kinds of material utilized to build a multilayer board. Pre-preg material is thin layers of fiberglass pre-impregnated with an adhesive, and remains in sheet form, generally about.002 inches thick. Core product resembles an extremely thin double sided board in that it has a dielectric material, such as epoxy fiberglass, with a copper layer transferred on each side, normally.030 thickness dielectric material with 1 ounce copper layer on each side. In a multilayer board style, there are two approaches used to build up the desired number of layers. The core stack-up technique, which is an older technology, uses a center layer of pre-preg material with a layer of core product above and another layer of core product listed below. This mix of one pre-preg layer and 2 core layers would make a 4 layer board.

The film stack-up method, a more recent innovation, would have core material as the center layer followed by layers of pre-preg and copper product developed above and below to form the final variety of layers required by the board design, sort of like Dagwood developing a sandwich. This approach permits the manufacturer flexibility in how the board layer densities are combined to satisfy the finished item density requirements by differing the number of sheets of pre-preg in each layer. As soon as the product layers are finished, the entire stack goes through heat and pressure that causes the adhesive in the pre-preg to bond the core and pre-preg layers together into a single entity.

The procedure of making printed circuit boards follows the steps listed below for many applications.

The procedure of identifying materials, processes, and requirements to fulfill the customer's specifications for the board design based on the Gerber file information offered with the order.

The procedure of transferring the Gerber file information for a layer onto an etch withstand film that is put on the conductive copper layer.

The standard process of exposing the copper and other areas unprotected by the etch resist movie to a chemical that gets rid of the vulnerable copper, leaving the safeguarded copper pads and traces in location; newer processes utilize plasma/laser etching rather of chemicals to remove the copper material, enabling finer line definitions.

The process of aligning the conductive copper and insulating dielectric layers and pushing them under heat to activate the adhesive in the dielectric layers to form a solid board product.

The process of drilling all of the holes for plated through applications; a 2nd drilling procedure is used for holes that are not to be plated through. Details on hole area and size is consisted of in the drill drawing file.

The procedure of using copper plating to the pads, traces, and drilled through holes that are to be plated through; boards are put in an electrically charged bath of copper.

This is needed when holes are to be drilled through a copper area but the hole is not to be plated through. Prevent this process if possible due to the fact that it adds cost to the ended up board.

The procedure of applying a protective masking product, a solder mask, over the bare copper traces or over the copper that has had a thin layer of solder applied; the solder mask protects versus ecological damage, offers insulation, safeguards against solder shorts, and protects traces that run between pads.

The process of finish the pad areas with a thin layer of solder to prepare the board for the ultimate wave soldering or reflow soldering process that will take place at a later date after the components have been positioned.

The procedure of using the markings for element designations and element lays out to the board. May be applied to just the top or to both sides if parts are installed on both leading and bottom sides.

The procedure of separating multiple boards from a panel of similar boards; this procedure also permits cutting notches or slots into the board if required.

A visual evaluation of the boards; likewise can be the process of examining wall quality for plated through holes in multi-layer boards by cross-sectioning or other techniques.

The procedure of checking for connection or shorted connections on the boards by means using a voltage between various points on the board and figuring ISO 9001 Accreditation out if a current circulation takes place. Depending upon the board intricacy, this process may require a specifically designed test component and test program to incorporate with the electrical test system used by the board maker.