Flexible PCB, HDI PCB, Aluminium PCB supplier

Flexible Circuit Card’s advantage of Increased system reliability

admin — Sun, 18 Nov 2012 04:59:03 +0000

Reliability engineers have always been quick to point out that, when an electronic package of any type fails, it most typically fails at some point of interconnection. Flexible circuit card are ideally designed with an eye to reducing the levels of interconnection. As such, when properly designed and applied to an electronic packaging problem, flexible circuits should prove an excellent means of increasing reliability by reducing the number of levels of interconnection required within an electronic package or assembly.

PCB Circuit Board Manufacture Process—4

admin — Wed, 07 Nov 2012 16:35:09 +0000

2.10 Hot air leveling of PCB Circuit Board

During this stage of the fabrication process, the panels are dipped in solder bath, so that all PTHs and solder points are covered with tin-lead plating. These panels are passed through a conveyor, while hot air is blown from one side of the panel, so that all the tin-lead covered holes are cleared.

2.11 PCB Circuit Board Trimming

During this stage of the process, the panels are cut to the required size of individual PCB. Printed circuit boards contain holes which are plated through and some which are not to have any plating in them at all. Since the electro-less copper process will deposit copper inside drilled holes, a second drilling step is needed. These holes are mainly used for mounting the components and ﬁxing the connectors etc.

2.12 PCB Circuit Board Legend printing

The legend or nomenclature, is screen-printed onto PCBs to identify the components, for assembling and testing purposes. This screen-printing operation is performed using legend print ﬁlm supplied by the customer. Since legend is permanent, once it is dried, legend-printed panels must also be checked for legibility and completeness of the printed image.

2.13 PCB Circuit Board Inspection

Inspection is done at various stages of the fabrication process. If the panel is accepted at that stage, it is passed on to the next stage. Otherwise it goes back to rework, to the same stage of operation. In some cases, when the panel is beyond rework, it is rejected.

PCB Card Manufacturing Process—3

admin — Mon, 05 Nov 2012 03:28:47 +0000

2.5 PCB Card Pattern imaging

After the holes have been plated, the circuit pattern is imaged on to each of the panels. The image deﬁnes the circuit for plating and etching purposes. Negative circuit ﬁlm is used for this purpose. Both sides of the panel are coated with a thin layer of dry ﬁlm photo resist. The circuit ﬁlm is laid on one side of the drilled panel and exposed to ultraviolet light. Except the circuit area, all the other area on the panel is polymerized and hence becomes hard. This is repeated for the other side. The unexposed photo resist is washed away during development, to leave the circuit pattern. This process is carried out for each panel.

2.6 PCB Card Pattern plating

In this stage of the fabrication process, the thickness of copper tracks on the panel is increased by 20 – 30 mm. Over the copper tracks, tin-lead plating is done, which protects the conductive copper from oxidation thereby preserving solderability, and acts as etch resist for the subsequent etching stage to follow.

2.7 PCB Card Etching and tin-stripping

Once the pattern plating is done, the dry ﬁlm photo resist is stripped by a solvent. This bares the unwanted copper foil which is etched away to leave the plated circuit. Copper foil is etched by spraying the etchant to both sides of the panel as it moves on a conveyor.

2.8 PCB Card Solder masking

Solder mask is an epoxy barrier applied to one or more sides of the panels. It prevents solder bridges from forming during the wave soldering operation performed by the board user. It also reduces the ability of molten solder to adhere to the board’s surface, and acts as a barrier which prevents damage to the circuitry due to scratches. The solder mask is typically applied by screen printing using solder mask ﬁlm which enables the entire board surface to be covered, except for the holes, pads and contact ﬁngers.

2.9 PCB Card Contact ﬁnger plating

Contact ﬁnger plating is the next operation (optional) in the fabrication of PCB cards. Contact ﬁngers are the rows of tabs along one or more edges of the boards. These tabs ﬁt into connectors in the electronic equipment in which the PCB card is used. They must be durable and resistant to tarnishing and oxidation. Over the bare copper tracks, plating is done ﬁrst with nickel, then with gold. Nickel serves as a wear-resistant barrier between the copper and gold and gold is used on the top because of its excellent conductivity and resistance to oxidation.

Flexible Electronic Co., Ltd is a leading provider of complex contract manufacturing & assemble services including flexible PCB, HDI PCB, Aluminium PCB as well as the circuit board layout. We provides manufacturing solutions for original equipment manufacturers in the military, aerospace/avionics, medical, communications, and industrial controls markets. For further information, please contact us.

PWB Manufacturing Process—2

admin — Sat, 03 Nov 2012 01:48:49 +0000

2.3 PWB Drilling holes

Once the panel is cut, the next stage is the drilling of holes. Either CNC drilling or manual drilling is used for this purpose. It is observed from past data that 98.92% of the jobs are drilled on CNC drilling machine and only 1.08% of the jobs are drilled on optical drilling (manual). Manual drilling is only used in one or more of the following situations: (1) very low order quantities, (2) non-availability of drill data, and (3) number of holes on the PWB is too low for using the CNC drilling machine. The panels are pinned together in stacks from one to four high, depending on panel thickness. These are loaded onto the drilling machine. NC part program is loaded into the CNC drilling machine and all required holes are drilled at proper locations, with correct drill size. Latest CNC drilling machines are equipped with automatic tool changer which will automatically change drill bits when the hole size changes. Some CNC drilling machines are also equipped with multiple spindle, so that simultaneously multiple stacks of panels can be drilled. Once all the holes are drilled, the panel is cleaned and deburred.

2.4 PWB Electro-less copper plating

Once the panel is deburred and inspected, then it goes to the next stage, that is, electro-less copper plating. The sole purpose of electro-less copper plating is to metallize the wall of drilled holes. This hole metallization (1) provides an electrical connection between the two sides of the board, and (2) serves as a metal substrate upon which subsequent copper may be deposited electrolytically. This connectivity is done by peridium coating on the inner side of holes by passing each panel through a series of electrolyte baths. After this is done the panel is cleaned and dried.

PCB Board Manufacturing Process—1

admin — Thu, 01 Nov 2012 01:14:34 +0000

PCB Board technology may be divided into three basic phases or stages: Engineering, photography and manufacturing. The circuit diagram in the form of a schematic diagram is photo-plotted on a ﬁlm which is one of the inputs for the fabrication process. The following paragraphs brieﬂy describe the stages involved in the PCB board manufacture process. From below content you will have a general idea about the various stages in the PCB board production process:

2.1 Photo ﬁlm inspection

The following documentations required for the fabrication process are collected from the customer, along with the sales order: schematic drawings, manufacturing speciﬁcations, circuit ﬁlms, drilling details, and CNC drill data etc. Once these documentations are reviewed for their correctness, then contact ﬁlms are developed from the circuit ﬁlms. These contact ﬁlms are used in fabrication process. If the documents are not suitable for manufacturing, it is returned back to the customer.

2.2 Panel cutting

Copper clads with thin layer of copper on both sides are used for manufacture of double sided PCB board. The standard thickness of copper layer is 18 and 35mm. This copper clad is cut into pieces. These pieces of copper clad are called as panels. Depending on the size of PCB boards to be manufactured, a panel accommodate one or more than one PCB board. Cutting these panels to the PCB boards of the required size is done at the trimming stage of the process. On all the four sides of the panel, extra space is left which is required to hold the panel during different stages of manufacture process, without affecting the PCB board area.

Printed Wiring Board Fabrication Process

admin — Wed, 31 Oct 2012 00:14:59 +0000

Printed Wiring Boards are found virtually in all electronic equipments. They are also the most custom-designed part of any electronic equipment. Printed Wiring Boards provide mechanical support apart from functional electrical interconnection between components. A Printed Wiring Board is a dielectric substrate with metallic circuitry photo-chemically formed upon that substrate.

Typically, there are two major types of board materials (dielectric substrates) that are used for the baseboard, ﬁberglass (glass-epoxy) and phenolic paper. The baseboard is also known as copper clad. There are three types of Printed Wiring Boards available today.

Flex PWB advantage of Assembly Error Reduction

admin — Mon, 29 Oct 2012 04:36:02 +0000

While the design may be in error, a flex pwb cannot induce errors of a human nature. Human error in hand-assembly is a constant risk. An area especially vulnerable is in the assembly of hand-built wire harnesses. With flex pwb, all design features are controlled by the design itself. As a result, with the exception of process-induced errors in manufacturing, it is not possible to route circuits to points other than those designated by the circuit design.

Circuit Engineering Co., Ltd is a leading provider of complex contract manufacturing & assemble services including flexible PCB, HDI PCB and Aluminium PCB. We provides manufacturing solutions for original equipment manufacturers in the military, aerospace/avionics, medical, communications, and industrial controls markets. For further information, please contact us.

HDI PWB Test Vehicle

admin — Sun, 28 Oct 2012 02:19:43 +0000

HDI PWB test vehicle is an ideal platform to test electrical performance and signal integrity structure stack-ups before they are used on a product. Microvias have nearly one-tenth the parasitics of THs. These structures can validate the lower inductance in microvias and, when combined with low-inductance decoupling capacitors and via-in-pads, show the merits of noise reduction in high-speed but reduced-voltage designs. Other simulations and test vehicles have already proven the advantage of HDI PWB at higher frequencies. the same simulation, using a 0.15 mm (0.006”) microvia, 0.100 mm deep (0.004”), where the microvia has fewer reﬂections and a much larger frequency tolerance than does the TH.

The lower inductance of a microvia (~30pH) is useful when coupling to power and ground, especially above 1.5 GHz, for decoupling capacitors. A typical TH will have an inductance of at least 2-3 nH, and this inductance will inhibit the performance of decoupling capacitors in the GHz range.

HDI Printed Circuit Board’s Performance Improvement

admin — Fri, 26 Oct 2012 01:49:28 +0000

When performance improvements are required for Printed Circuit Boards, HDI Printed Circuit Board is the leading contributor. In addition to making them smaller, lighter, and thinner, HDI printed circuit board will give them superior electrical performance. Some of the performance improvements are:

· Lower order of magnitude via electrical parasitic

· Minimal stubs

· Stable voltage rail

· Removal of decoupling capacitors

· Lower crosstalk and noise

· Much lower RFI/EMI

· Closer ground planes

· Closer distributed capacitance

· Surface ground planes with via-in-pads cut emissions.

Printed Circuit Board Assembling

admin — Thu, 25 Oct 2012 02:55:40 +0000

In assembling printed circuit boards (PCB), the use of numerically or computer controlled electronic component placement machines has become quite popular in the last decades. However, serious operations research problems arise through their use such as, allocation of component types to machines, board production schedule, feeder configuration and placement sequencing. In this study, the problem of allocation of component types to machines is taken up where two non-identical machines are deployed serially on a line to complete the assembling process of Printed Circuit Boards. For the solution of this problem three heuristic algorithms are suggested and their performances are investigated on experimental data.