Using different printed circuit board (PCB) materials will result in different circuit board specifications and prices with regard to PCB prototyping and production. Certain one- or two-layer boards need what is known as pre-preg core — which is a material made from fine layers of fiberglass that is pre-impregnated with a bonding agent or metal core — or several layer boards using two or more kinds of cores for construction. Board thickness varies from a few millimeters thick, for flexible boards, to as much as a quarter inch thick, for heavy burn-in boards. Core materials typically resemble thin double-sided boards with dielectric materials (e.g. fiberglass) as well as copper foil on each side, and they generally come in predetermined thicknesses.
FR4 is the most commonly used type of substrate for circuit boards and is made from a glass-fiber epoxy laminate. FR4 has higher temperature coefficients and lower dielectric constants — e.g. FR4 has a starting thermogravimetry (TG) of one hundred forty degrees Celsius, FR4-06 has a TG of one hundred seventy degrees, and the temperature increases as the family number increases.
Prototypes using metal core, which has impressive heat elimination, are quite popular for light emitting diode (LED) circuit boards. The metal core is an efficient heat sink and keeps the LEDs operating at safe temperatures. One section of a metal core printed circuit board prototype has a metal base, a non-conductive layer (usually aluminum), a copper circuit layer, integrated circuit (IC) components, and a solder mask.
Polyimide printed circuit board prototypes, which are tougher than FR4, can sustain significantly hotter temperatures, making them perfect for most electrical insulation applications. The polyimide is made up of a silicone adhesive and a polyimide film designed to withstand higher temperatures and will protect edge connectors, gold edge fingers (during wave soldering), and reflow soldering (during circuit board assembly). Polyimide can be distinguished from other boards by its distinctive brown color.
Polytetrafluoroethylene (PTFE) or woven glass base circuit board materials necessitate special drilling procedures because Teflon is much softer than, e.g., FR4. These types of materials are far more common than they once were. PTFE/woven glass base materials provide rapid growth of applications operations and easily meet high-frequency demands, and they consistently perform well.
You can also use Arlon materials for longer operating lives at high temperatures, or Isola range circuit board prototypes for broadband circuit designs requiring faster signal speed or better signal fidelity.
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