Technology information, important downloads, interesting special technologies, the right contacts and your advantages at Leiton.
FR4 Rigid printed circuit board | PCB | Tg 150 | Multilayer
FR4 printed circuit boards PCB (multilayer up to 48 layers)
Rigid Circuit Boards from India
"PCBs aren't just another item on your BOM."
Anyone in the electronics industry knows this well: while most components are available “off the shelf” in millions of identical pieces, printed circuit boards are always manufactured individually for each project. They serve as the foundation and connecting link between all other components – in short, the PCB is what makes electronics come alive.
At Leiton India, with our local manufacturing partners, we are deeply aware of the central importance of the PCB when it comes to reliability and quality. Every production run comes with its own challenges, which is why we place equal emphasis on careful consultation, precise planning, and dependable manufacturing. These three cornerstones ensure that even highly complex and specialized technologies are successfully realized.
Industrially Manufactured Quality Circuit Boards
Leiton offers you a wide range of high-quality printed circuit board technologies along with flexible options for order processing and logistics.
With manufacturing and support now also in India, in addition to our established locations in Germany and China, we can supply any required volume – from prototypes to mass production – and ensure a smooth transition from sample to series production. Our experienced teams in technology, quality, logistics, production, and sales work closely with you to implement your requirements and provide ongoing support.
Beyond traditional “make-to-order” processes, we specialize in customized logistics solutions that guarantee maximum delivery readiness – including call-off stock, consignment stock, sea-air split delivery for series production, and flexible framework agreements.
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Technology for rigid circuit boards
for rigid circuit boards
| Material properties | TG130, TG150, TG170, (TG250 - no FR4), halogen-free, black FR4 |
|---|---|
| Material manufacturers | Panasonic, Isola, Ventec, ShengYi, ITEQ, King Board, NanYa... |
| Material thicknesses | 0,1 mm to 4,8 mm |
| Maximum PCB size | Germany 508 x 572 mm2, China 1/2-layer 530 x 606 mm2, multilayer 516 x 592 mm2, oversized PCBs on enquiry |
| Copper thicknesses | 18µm / 35µm / 55µm / 70µm / 105µm / 140µm / 210µm / 300µm / 400µm |
| Layer count | 1 to 40 layers |
| Surface finishes | HAL-lead-free, HAL, ENIG, ENEPIG, immersin tin (iSn), immersion silver, OSP, connector-gold |
| Mechanical machining | routing, milling, scoring, jump scoring, chamfering, semi-flex, depth milling, countersinking, punching |
| Drill options | Micro-vias, blind-vias, laser-vias, stacked-vias (SBU), press-fit |
| Metallizations | Edge metallization, stamp-outlines, half-opens, oblong holes, metallized slots, metallized depth milling |
| Solder mask | Lacquer, flex lacquer, coverlay. Lacquer colors: green, black, red, blue, yellow, white, special colors (all RAL colors) and matt lacquers |
| Special prints | Peelable lacquer, carbon printing, UV reflection lacquer, silk screen printing |
| Special technologies | 2mil structures, coils, frame technology, prepreg or core pressed on one side, FR4-Flex, 3M on FR4, LP numbering, special layer structures, impedance measurement, plugging, filling & tenting, copper VIA filling |
| Quality Management & Certifications | ISO 9001, ISO 14001, UL, IPC2/IPC3, IATF 16949, EMPB, VDA2, PPAP, cross-sections (x-sections), measurements, declarations of conformity, data sheets, ESD packaging and more |
| Logistics | Framework orders, consignment stock, call-off stock, sea-air split orders, express delivery from 2 working days |
Downloads
Special Technologies
Rigid circuit boards (FR4, Rogers, High-TG)
Our Circuit Boards in Detail
Materials & Properties of FR4
FR4 material is rigid and has become the standard material for printed circuit boards, compared to older materials like Pertinax, FR1 or CEM1. “FR” stands for “flame-retardant” and has a UL classification of 94V0. In the case of rigid-flex circuit boards, it forms the stable part on which components can be assembled. A popular low-cost way to make FR4 boards partially bendable is the so-called "semi-flex", where areas are simply depth-milled to achieve a certain flexibility. Common manufacturers for FR4 base materials are ISOLA, Panasonic, Kingboard, Shengyi and Nanya.
Materials of FR4 printed circuit boards
FR4 base material consists of the materials epoxy and a woven glass fiber fabric. Modern circuit board material has various fillers, which are usually required for higher temperature resistance. However, this makes the circuit board material a bit more brittle and high-TG-FR4 >150°C is therefore only of limited use for Semi-Flex. Copper is rolled-annealed onto the substrate as a conductive material.
Temperature resistance of FR4
The usual temperature resistance of FR4 is 130°C (TG130). For multilayer boards, a TG150 material is usually used as the standard, as such material expands less in the Z direction when heated and therefore allows more stable vias (PTH). High TG170 or TG180 material is used for very warm environments. TG210 materials are very rare and even higher TGs are currently not achievable with FR4, but you have to switch to polyimide or other materials. TG means “glass transition temperature”, i.e. the temperature at which the material becomes soft. The operation temperature should therefore not exceed TG minus 25°C.
| Material | Designation | Operating temperature | Material type |
|---|---|---|---|
| TG130 | Low-TG | ca. 110°C | FR4 (Epoxy-fibre-glass) |
| TG150 | Mid-TG | ca. 125°C | FR4 (filled epoxy-fibre-glass) |
| TG170 | High-TG | ca. 145°C | FR4 (filled epoxy-fibre-glass) |
| TG250 | Ultra-High-TG | ca. 220°C | Polyimide or ceramics |
Layer structure & standard thicknesses
The standard thickness of FR4 circuit boards is 1.6mm and 1.5mm respectively. Thin rigid base materials go down to 0.1mm or 0.2mm. A thickness of 2mm is a common choice for sturdier, larger boards. Copper thicknesses are based on an American system of "Oz/ft2", i.e. "ounce per square foot". One ounce (1 oz) of copper per square foot corresponds to approximately 35µm of copper thickness. We often speak of 1 oz, 2 oz (70µm), 3 oz (105µm) when the copper thickness is meant. Starting copper before electroplating is usually around 18µm (1/2 oz). The origin in the American system explains the crooked standard values in the metric system.
The layer structures for multilayers differ significantly depending on the manufacturer and material manufacturer.
An overview of the respective standard layer structures of various thicknesses and numbers of layers can be found here as a PDF download.
Electric strength
For high voltages it is important that the layers of a printed circuit board insulate sufficiently from each other. A parameter for this is the dielectric strength, which is specified in every data sheet under "Electrical Strength" in kV/mm (kilo-volts per millimeter). The IPC-TM-650 Chapter 2.5.6.2 requires at least 30kV/mm here. Common FR4 materials usually achieve 40-50kV/mm or even more.
You can find an overview of filter functions for various properties in our base material database.
FR4 printed circuit boards (PCB)
PCB is the English abbreviation for "printed circuit board". Circuit board prototypes are already very cheap today, which is why the breadboards used in the past are not common anymore. Also, such hole grids are only suitable to a very limited extent for the assembly of SMD components, which are increasingly dominating electronics.
The production of our printed circuit boards
The production of our printed circuit boards
The manufacturing process of printed circuit boards is largely identical in all common productions. It can be roughly divided into mechanical, chemical and photo-sensitive processes, with industrially manufactured circuit boards moving back and forth between these process fields several times during production. A detailed circuit board production process is available for download here. The individual process steps for production are briefly explained here.
Buy budget-friendly PCB prototypes online directly from manufacturer
At Leiton we offer inexpensive PCB prototypes in the online calculation or on request. A large selection of material is already available online, as well as various options regarding the number of layers, copper and total thickness, solder mask colors, special prints and finishes. Our prototypes are particularly inexpensive thanks to the “shared production” concept, with different layouts being placed on the same production blank. This saves initial costs and setup and leads to particularly low prices with the best quality.
FAQ
- What is FR4 material?
FR4 (or FR-4) is a base material for printed circuit boards (PCB) and consists of composite materials, primarily epoxy resin and glass fiber fabric. FR4 stands for "flame retardant, class 4". Fillers can give FR4 a higher temperature resistance (TG = glass transition temperature). Maximum operating temperatures (MOT) of FR4 material are mostly between 110°C and 150°C.
What are the types of printed circuit boards?Printed circuit boards differ significantly in the number of layers (1-layer, 2-layer (through-plated) and multilayer ?4 layers). Furthermore, the type is differentiated: rigid (PCB), flexible (FPC), rigid-flex (RFPCB = rigid and flexible areas on a printed circuit board). Materials are another feature of different types: FR4 (standard), ceramic (for RF applications), polyimide (flexible circuit boards) and aluminum IMS "insulated metal substrate" are just a small selection.
What is Tg for printed circuit boards?The Tg is an important characteristic of printed circuit boards (PCB) because it indicates the temperature resistance. Tg stands for "temperature of glass-transition", is given in °C and describes the temperature point at which the material becomes mechanically unstable. Usual FR4 material has a of Tg130°C (low-Tg) as standard, for multilayers mostly Tg150°C (mid-Tg) or Tg170°C/Tg180°C (high-Tg) is used. Higher Tg of up to ≈260°C mostly require polyimide or other materials than FR4. The maximum operating temperature (MOT) is approx. 20C° below the specified Tg.
How are printed circuit boards manufactured?Conventional printed circuit boards require 3 types of processes:
- mechanical (M)
- chemical (C)
- photosensitive (P)
In short, the process of a 2-layer circuit board is as follows:
drilling (M) → through-hole plating (PTH/THP) (C) → laminating & exposing (P) → etching (C) → solder mask & exposing (P) → surface coating (C) → milling (M).
There are also various intermediate thermal processes, tests and cleaning steps.
How much do printed circuit boards weigh?The specific weight of printed circuit boards (PCB) largely depends on the copper content (copper thickness, number of layers and occupied copper area), since copper has a specific gravity of 8.9 kg/dm³ and FR4 base material only approx. 2.3 kg/dm³. The fact that a printed circuit board usually consists of far more FR4 than copper can be assumed for a standard printed circuit board (2-layer, 1.6mm thick with 35µm copper, 75% covered) of approx. 4 kg/m² printed circuit board area. A circuit board with the above parameters of size 100 x 100 mm² weighs approx. 40g.
How much does a printed circuit board cost?The cost of a printed circuit board (PCB) depends on various parameters. In addition to the technical specifications and the urgency (express surcharges), the quantity has an immense influence on the costs. The factor between a prototype and a large series can be many times over here. If a prototype costs e.g. EUR 50, the price in a large series can quickly be far below EUR 1 per piece.
How can I order printed circuit boards?Printed circuit boards (PCB) can be ordered via our online calculation or via e-mail. The prices are identical. The production data must be transferred in a common layout format (Gerber, Eagle, Target, KiCAD, etc.). When ordering, the quantity, desired lead-time and technical specifications (thickness, copper plating, colour, surface finish, etc.) must always be specified.
How do I assemble PCBs?Printed circuit boards are assembled (PCBA) either by hand or with a machine. The choice of the right process depends on the number of pieces and the components used. For very small quantities, it is sometimes not worthwhile to set up a machine for automatic assembly at great expense. On the other hand, very complex/small components can require automatic assembly, since manual assembly would be too imprecise.
What is PCB material?PCB does not stand for a material, but is the English abbreviation of "Printed Circuit Board", i.e. a "printed circuit" or “circuit board”. Typically, a PCB is made of FR4 material. Various electronic components are attached to a PCB, which are connected to one another via conductor tracks made of copper in order to achieve a desired electrical function.
Why are PCBs green?The green color of printed circuit boards (PCB) comes from the so-called solder-stop mask. As the name suggests, solder-stop mask is intended to “stop the solder”. In other words, the green laquer is applied to prevent short circuits when the PCB is soldered. Even if all colors are possible today, most printed circuit boards are still green. There are several reasons for this: on the one hand, green contrasts well with the copper-colored surface. On the other hand, green used to be a dye that was very easy to produce. But why it is still dominant today is due to the good processability in terms of exposure time. Exposure time is optimal for green laquer. Lighter colors reflect the light in this process above average, while dark colors absorb the light very much. Both mean that the exposure times have to be longer and the structures that can be produced are not as fine as with green solder mask.