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FPC-feature

Flexible Printed Circuit(FPC) Surface Finishing Technology

Flex Printed Circuit(FPC) Plating

It may have adhesive or ink pollution on exposed copper conductor surface after FPC coating process when FPC plating pre-processing. There will be oxidation,discoloration due to high temperature process.we must remove the contamination and oxide layer of conductor surface in order to obtain a good adhesion of close coating,so that the conductor surface clean.But some of these pollution and copper conductor is very strong combination,it can not be completely removed with a weak cleaning agent,so we need use a certain strength of alkaline abrasive and throw brush to dispose.Covering adhesives are mostly epoxy resin and alkali resistance is poor,this will result in a decrease in bond strength.Although not obvious,the plating solution may penetrate from the edge of the cover,severe peeling of the cover.the solder drill into the coating below phenomenon.It can be said that the pre-treatment cleaning process will have a significant impact on the basic characteristics of the flexible printed circuit board FPC.Must pay full attention to the processing conditions.

When FPC thickness plating,the deposition rate of electroplated metal is directly related to the strength of electric field,the strength of the electric field follows the shape of the line pattern,electrode positional to change, In general the wire width is more thinner,the terminal of the terminals is more sharper,the closer distance to the electrode is,the electric field strength is more strong,the plating thickness is bigger.In use of flexible printed boards,there are different widths of the wires in the same FPC lead to the coating thickness is non-homogeneity. In order to prevent it happening,can attach a shunt cathode pattern around the line,absorbs uneven current distributed on the plating pattern. Great guarantee the plating homogeneity of whole areas. So it must work hard in the structure of the electrode. Here is a compromise, strict control for the high requirement of plating, and relax control for the standard requirement.

FPC Plating stains, dirt just plated with a good plating state,Especially the appearance is no problem, But soon some surface stains, dirt,discoloration and other phenomena.Especially did not find any defect when factory inspection,found the appearance problem when user received and make inspection.This is due to insufficient rafting,there is residual plating on the surface of the coating,after a period of time slowly caused by chemical reactions.Especially the flexible printed circuit board, due to the soft and not very flat, it easy have a variety of solutions accumulate in concave areas. And then occur reaction and discoloration in that areas. It need fully drift in order to prevent this situation happening,but also to be fully dried.It can use high temperature thermal aging test to confirm whether it’s drifting sufficient.

Flex Printed Circuit(FPC) Electroless

When the line conductor need be electroplated is isolated and can not be used as an electrode,it can only be electroless plating.General chemical plating used in the bath have a strong chemical effect,chemical gold plating process is a typical example.Electroless gold plating is a very high alkaline aqueous solution.use this plating process, it’s easy occur plating solution flow into under coating layer,especially if the quality of the coating process didn’t be controlled well,bonding strength is low,it’s more prone to happen this problem.

The electroless plating of the replacement reaction is due to the characteristics of plating solution.It’s easier to drill into under coating layer. Electroplating with this process is difficult to get the ideal plating conditions

Flex printed circuit(FPC) Hot Air Leveling

Hot air leveling was originally developed for rigid printed circuit board PCB coating and developed technology,it also applied in flexible printed circuit board FPC surface finishing as this technology is simple.Hot air leveling is direct immerse whole panel into the molten lead tin bath and blow the excess soldering.This condition is very harsh for flexible PCB.If the flexible printed circuit board does not take any protection can not immerse in the soldering.Prior cleaning and coating flux flexible printed circuit board,fold the flexible printed circuit board into titanium steel wire mesh and then immerse in molten soldering.Due to the hot air leveling process have same risk that solder drill under coating layer.Especially when the adhesive strength is low between cover layer and copper foil, it’s easier to happen this phenomenon frequently.As the polyimide film is easy absorb moisture.the moisture absorption water will evaporate as rapid heat lead to cover layer bubble and peeling.So it must be dry and moisture-proof management before FPC hot air leveling.

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OSP PCB surface

What Is OSP PCB Surface Finishing

PCB surface finishing OSP is abbreviation of Organic Solderability Preservatives. It grows a layer of organic film on clean bare copper surface through chemical method.This layer film has features like anti-oxidation,heat shock,moisture resistance, it can protect the circuit board copper don’t be oxidized or vulcanized,etc.But the protective film must be cleared instantly in the subsequent high temperature welding,so that the exposed clean copper immediately combines into to a solid solder joints with melting solder in a very short time.

The process of OSP:

Degreasing—>Washing—>Micro-Etching—>Washing—>Pickling—>Pure water washing—>OSP—>Pure water washing—> Drying

OSP Principle:

An organic film is formed on the surface of printed circuit board,firmly protects the fresh copper surface,and also be anti-oxidation and pollution at high temperatures.OSP film thickness is generally controlled at 0.2-0.5 microns.

Features of OSP:

  1. Good flat,no IMC between printed circuit board and OSP film.
  2. Good wetting,allow welding of solder and circuit board copper direct welding.
  3. Low cost,low temperature processing technology, it can reduce the use of energy when processing.
  4. Extensive using, it can be used in low-tech circuit board,also be used in high-density chip package substrate.

The types of OSP

  • Rosin
  • Active Resin
  • Azole

Disadvantages

  • Appearance inspection is difficult,it doesn’t suit for multiple reflow(generally no more than three times)
  • OSP film is easy to scratch
  • Strict environment requirement for storage
  • Storage time is shorter

Storage method and time

Vacuum packaging for 6 months(temperature 15-35℃,humidity RH≤60%)

SMT site requirements

  • OSP Printed circuit boards should be stored in low temperature and low humidity(temperature 15-35℃,humidity RH≤60%),and avoid exposure to acid-rich environments.OSP packs are assembled within 48 hours after unpacking.
  • Suggest to use it in 48 hours and save it in a low temperature cabinet without vacuum packaging.
  • Suggest finish DIP within 24hours after two sides SMT(surface mount technology) completed

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FPC-feature

Flexible Printed Circuit Board(FPC) Defect Detection Methods

Flexible printed circuit boards are more classification methods.According to FPC layer can be divided into: single-sided,double-sided,multilayer and Rigid-Flex PCB. Flexible printed circuit boards(FPCs) market share continues to rise as electronic products tend to miniaturization and lightness. But Flexible printed circuit boards(FPCs) frequently occur breaking, short circuit,line width incorrect defects in processing, feeding, placement and other production processes.This article mainly analyzes the flexible printed circuit boards defect detection method.

Flexible circuit boards(FPCs) have many advantages: good reliability,strong heat dissipation,easy installation and low comprehensive cost, it’s convenient for the high integration and high performance of electronic products.Different production process make it have many unique features.

  • ) High density assembly,reducing the connection between different parts.
  • ) Light weight,thin thickness can effectively reduce the weight of product,easy to carry.
  • ) Can be folded and any bending.

The status of defect detection technology for Flexible printed circuit boards(FPCs)

The existing Flexible printed circuit boards(FPCs) defect detection algorithm is mostly derived from the Printed circuit boards(PCBs),but it limits by its own unique feature,Flexible printed circuit board(FPC) defect precision is higher,the test sample dimension is larger,the test sample is easy to deform,making printed circuit boards（PCB) defect detection algorithm can not directly apply in n flexible printed circuit board defect detection,need develop appropriate detection algorithm according the actual characteristics of flexible circuit boards(FPCs).

In order to solve the problem that traditional template matching algorithm is slow and accuracy is low, the flexible printed circuit board(FPCs) line defect be divided into two types: global defect and local defect,use eight-connected domain area method and the histogram matching method to capture the global defects of the image,on basis of this,use projector matching and correlation coefficient method to recognize the local defects.This method is faster and more accurate than the traditional detection algorithm,but relevant defect classification is not enough.

Analysis of defect detection method for flexible printed circuit board(FPCs)

Aiming the problem of template matching in the global scope,flexible printed circuit board(FPCs) defect detection is implemented considering the local range template matching method.Considering the contour-based template matching method,the template should have significant contour characteristics.Although the conventional lines on the flexible printed circuit boards are regular,but these is no significant shape feature,moreover,the conventional lines are distributed in the whole image, and the template matching time is too slow,it’s unfavorable for line detection.

Shaped lines are irregular shape on the flexible printed circuit board(FPCs),generally including LED lights,S-shaped round.Due to the shape of the peripheral,the layout is generally related to the style of Flexible printed circuit boards. For this type of lines,consider the template matching method to implement test: First through template matching method of steer the various contour lines on the whole Flexible printed circuit boards position,access to contour lines,and then based on morphological theory for defect detection.

The detection process of the special shape line is below:

  1. Load the registration template related data information,including the registration template area,registration template contour information.
  2. Using the area information carried by registration template,locate the template search space,and search the template instance in the search image based on the normalized mutual correlation coefficient metric principle.
  3. Cut the contour area. The size of the profiled area is obtained by finding the smallest circumscribed rectangle of the shape template instance,since the shape template is a rectangular region,so the area obtained by the minimum circumscribed rectangle is the matching alien region. Any template matching can not make the two images perfectly aligned in space, there is a permissible range of matching. Flexible printed circuit boards(FPCs) local area of the deformation can be ignored,in the limited space on the shape of the template matching due to narrowing spatial range,shape template matching accuracy,the overall matching error of about 1/5 line width(3 pixels) range,is in allowable range.
  4. Considering the accuracy error of shape matching,before the standard template image and the profiled area image are directly measured, the small-size structural elements are used to etch the alien-shaped area to remove the boundary difference effect.when the image is defective,the corrosion operation at this size can not completely corrode the defective line, so it does not affect the final judgment result.
  5. The template image and the contour area of the regional difference set operation, access to the difference between the two areas.When there is no defect,the difference is 0.When there is a defect,the area difference set returns a binary image that is not zero.
  6. The difference image is connected to the domain label,split the different defect block.
  7. The area of each connected domain is calculated,and the center of the geometric dimension of the largest defective block is used as the center of the profiled area to output the defect inforation.

 

The FPC defect detection method is studied from the global and local scope,and the experimental results are drawn:

  • ) Due to FPC imaging deformation,based on the global scope of the template matching line dislocation,can not correctly locate the image on the defect information.   
  • ) Based on the local scope of the template matching,first cut out the FPC board relative to the conventional line with significant shape characteristics of the line area,as a template source. In the search image corresponding to the template area near the instance detection,compression search space,and then based on morphological theory to detect line defect information.

In short, the circuit board as the most basic part of the electronic circuit, a great impact on the quality of the entire electronic products. Therefore, how to achieve accurate detection of circuit board defects is an important part of product quality assurance, and most domestic enterprises generally rely on artificial visual inspection FPC defect detection, high cost, low efficiency, and because there is no relatively standardized quality standards, the staff Subjective awareness or visual fatigue and other reasons prone to missed and false detection; some enterprises to introduce foreign excellent testing equipment, by the equipment prices, technical support, after-sales service and other limitations, it is difficult to adapt to modern technology, low-cost, high-volume production needs. Therefore, the development of a fast and efficient FPC defect automatic detection system to meet the domestic market demand is imminent.

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PCB silkscree printing-feature

PCB Silkscreen Design Tips

Many PCB designers think the silkscreen legend is not as important as circuit,so they didn’t care about the legend dimension and place position.As a PCB expert, we should consider these particular details.There are some tips for those new PCB designers.

PCB silkscreen automatical machine

PCB silkscreen automatical machine

The standard design of PCB Silkscreen:

Oil printing: The minimum character width is 5mil, height is 28mil, the whole legend width is

16mil.

PCB silkscreen-1

Etching printing: The minimum character width is 8mil, height is 40mil,the whole legend width is 28mil.

PCB silkscreen-2

The Silkscreen don’t overlap with vias:

If the silkscreen printed on vias, vias will break the silkscreen lead to legend can’ be recognition.

PCB silkscreen-3

Silkscreen direction:

Silkscreen characters should follow direction order from left to right,from bottom to top. Do not use four directions when placed, this will lead to operator is very tired for degugging,maintenance, welding.

PCB silkscreen-4

Don’t place silkscreen on high speed signal track:

Dielectric related the impedance value, if place the silkscreen on high speed signal track will lead to dielectric become non-homogeneity then effect the impedance control.

PCB silkscreen-5

 

Heavy copper board silkscreen:

For heavy copper PCB,we should’t place the silkscreen place to the gap between copper and base material, as big difference of height of heavy copper PCB.

heavy copper PCB

PCB silkscreen printing should be neat, clear, no staggered except above mention.

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Depth milling PCB

PCB Depth Control Routing Technology

PCB Depth control routing technology is the stepstair or groove shaped by partial routing in printed circuit boards(PCBs) manufaturing.It have great advantages in PCB assembly as the special shape of depth routing.

  • Use the step stair of PCB edge make card slot is favor for PCB fixed and installation.
  • It can avoid cold soldering as siphonic effect use NPTH stepstair slot.
  • Use the stepstair in middle of PCB apply in special module application,and degrade the height of PCB assembly,achieve refinement and miniaturization.
  • Use special size NPTH stepstair as resonant cavity of microwave signal,degrade signal loss and other special function.

PCB depth routing type

There are two main methods of manufacture stepstair .

Depth control routing:

PCB depth routing

Filling and embedding cushion material.

PCB depth routing

We main introduce the control depth of stepstair and manufacture capability for depth control routing. And learn the control of adhesive,the pattern of stepstair rim and the hole’s reliability,size capability of stepstair.

The study for Capability

Mechanical milling:

For the stepstair PCB of mechanical milling,the precision can be +/-4mil is very high as equipment factor.As the stepstair slot is always in the depth of 0.2-0.4mm at some layers, it’s impossible to keep milling to particular layer, there have depth tolerance as the control principle and mechanical precision. At present,main use two ways to control the depth of milling in stepstair milling process.

  1. Optical rule control Z axis height:through Optical rule induce and control Z axis height to finish depth control routing.

PCB Optical rule control Z axis depth

  1. Through milling tool and copper layer form a closed loop path to measure and control the height of principal axis down to finish depth control routing process.The copper layer can be surface layer or particular layer. The precision of this method can be achieve to +/-15um,so the copper thickness of stepstair minimum is 30um,it risk copper remain at bottom layer after depth milling process.

pcb depth routing

 

Filling and embedding cushion material.

Filling cushion material to make depth routing for that stepstair is in middle of PCB center, main control the resin flow at side wall,slot bottom and notch,ensure resin flow stability at bottom, resin flow homogeneity at side wall and no resin flow at notch.

PCB depth routing-2

For this kind of stepstair milling PCB, all use FR4 materials and CORE+CORE to lamination. The prepreg thickness 20mil, the chip thickness 20mil. There are different size of stepstair,minimum 20x20mm,maximum 200x200mm,the depth milling is 1.0mm.

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Multilayer PCB Lamination

What Is Multilayer PCB Lamination?

Multilayer PCB have played the leading role as double side PCB is a far cry from meeting demands as upgrading constantly of electronic products in nowaday. Most PCB users don’t know what is the multilayer PCB lamination, let us learn it today.

Multilayer circuit boards lamination is all inner layer bonding in to a whole. The whole process includes kissing pressing, full pressing,cold pressing.During the kissing pressing phase, resin infiltrates the adhesive surface and fills the gaps in the track,then enters full pressing to bond all voids.The cold pressing is make the circuit board cooling quick and maintain a stable size.

First,Laminating process need pay attention PCB manufacturing design must meet the pressing requirements of inner layer. Mainly the core and pre-preg thickness, PCB working panel size, registration tooling holes,etc.Requires inner layer is no open/short circuit,no oxidation,no residual film.

Second, it need make black oxide treatment or brown oxide treatment of inner layer before pressing. Black oxide treatment is black oxide film formed inner copper layer, Brown oxide is organic film formed inner copper layer.

Finally, need pay attention the three main problems of temperature, pressure, time.Temperature,mainly is the resin melting temperature and curing temperature,hot plate set temperature,the actual temperature of material and changes of temperature.The pressure follow the principles of resin filled with voids of layers, discharge inter-layer gas and volatile. Time parameters, mainly the timing of pressure control,the timing of heating control,get time.etc.

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PCB defect

How To Quick Find PCB Defects?

PCB is printed circuit board,it mechanically supports and electrically connects electronic components using conductive tracks,pads and other features etched from copper sheets laminated onto a non-conductive substrate,achieve electronic components automated assembly,welding,inspection,guaranteed the quality of electronic devices,improved productivity and reduced the cost,it’s favorable for repair.

PCB from single layer to multilayer,flex,keep ourselves strong development.These years tend to high precision,high density,high reliably and small size to reduce cost and improve functions,PCB industry keep strong vitality in future electronic devices development.

Analysis of PCB board common defects

Various defects happened in usage follow PCB circuit complicate and components integrated.We summarized four common defects:

  • The PCB layout is inappropriate,electromagnetic interference from around components.
  • PCB circuit damage lead to system out of work.
  • Components unsteadiness lead to device unstable.
  • Incomplete welding lead to PCB board opening or short.

Works before PCB board inspection

  • Know about the environment of device working,main the electric parameter impact from external environment.
  • Inquiry the phenomenon led to PCB board failure and analysis the reasons caused.
  • C. Check up carefully components of PCB board,find out the important components.
  • D. Do the electrostatic prevention and electromagnet interference prevention measure.
  • PCB board inspection process and rules.

The PCB board inspection flow chart

defective PCB

The flow chart indicated common process,from graphic we know the first step is inspect PCB structure and appearance,then make test for the important discrete components and IC integrated circuit.Repair or replace failure components after found out defect parts,use instrument to re-test PCB.The discrete components,IC integrated circuit is the most important parts,we understand the flow chart into four items：from observe to measure,from outside to inside,from easy to complicated ,from static to dynamic.

From artificial observation to instrument measure

All components connected by surface circuit in PCB, So the fist thing we can observe appearance by magnifier or microscope when it happened errors.

  • Whether all components connected completely? If power and ground position can work.
  • Whether pins are correct welding of integrated chip,diode,BJT,resistance,capacitor,inductance etc.
  • Whether components have incomplete weld,miss welding and other operation problems.

Most damages can find through above initial observation and differentiate. But some defects can’t be discover by naked eyes,then need use multimeter to check.The normal impedance is 70~80 ohm between ground and power layer, if the value is too small meant some components perhaps be punctured,then we must find out the parts be punctured.In general we touch the burning hot parts and find out damages when power cord works. If the parts works then we need check and debug each components compared input and output parameter .

From outside to inside

The ratio failure components lead to PCB defects is large from above analysis,so how to find out the failure components is very important.As PCB structure feature,the components at outside of edge are easy damage,the ratio reach 86%.Components at outside major used in driver,inverter,isolation,protecting and communication for easy connection with inner circuit.They always be impacted from current surging,vibrating and external power lead to noise and dust,thus failure happened to this outside components.Components placed inside are major used in generate,amplify,transmit signal.Check the inside components after eliminated components at outside.

From easy to complicated

There related some test technology in PCB inspection,we follow rules:from easy to complicated in checking process.

a.The works before PCB test

Circuit Simulation is an effective way to reduce design period and cost.But simulation is in perfection condition ,it ignored all interferences at actually works,so shield all interferences before test is necessary.In general way shielding interferences is short of crystal oscillator and dismantle CUP avoid testing hamper.

b.From easy to complicated in special test way

We use rule “from easy to complicated “way to check components,because easy components can easy find out problems. We use exclusive method to check it one by one and record it.Retest that error caution PCBs to guarantee accuracy. We consider it important suspect for the PCBs failed test.

c. Complementary test method between different method

Sometimes we can’t find out the problem if only use one test way.we need use all kinds of test method to check from easy to complementary, now PCB test way from MVI,ICT to BST, and now more new test technology apply in PCB test.

From static to dynamic

All the methods above mentioned multimeter and other methods are static inspection.But sometimes the reason is very complicated and we can’t diagnose in static status.We use multimeter to check when power is on if static inspection can’t work.Integrated IC always use this method to check.

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PCB robot

Robots Apply In PCB Industry.

PCB industry is technology-intensive,capital-intensive,labor-intensive industry.A middle scale factory have thousands workers, most of automatic machines need worker pile line operation.This years Chinese government impel corporation upgrade the structure of industry and the new labor contract law implement,lead to PCB factory face labor cost raise sharply and shortage,then impact production plan,products quality and profit capability.Follow the Robot skill improvement and price down,Robot+Automatic machines will replace Labor+Automatic operation.

The type and feature of industry Robots

Industry robots is automated equipment and system through programmable and automatic control to finish one or more operations.it can connect manufacture host or production line organized to one or more automated machine system to achieve transport,welding,sorting,assembly and plating operation etc.The first uses of modern robots were in factories as industrial robots:simple fixed machines capable of manufacturing tasks which allowed production without the need for human assistance, digitally controlled industrial robots and robots making use of artificial intelligence have been built since the 1960s.

There are three main types of industrial robots: Scara,Delta robot,6-axes robot,

Three advantages of Industry robots:

  • Programmable

Industry robots are programmable follow the change of tasks and environment,so it adapts in prototype and small volume manufacture, it’s an important part of Flex PCB manufacture system.

  • Artificial Intelligence

Industry robots can walking,bow,have arm,wrist and claw like human.also it have more sensors like human’s Biology Sensor:Touch Sensor,Pressure Sensor,Vision Sensor,Sound Sensor,Language skill,etc. Robots sensor function improved its adapt capability of around environment.

  • Commonality

In general,all industry robots have good commonality can adapt in different tasks operation.Just need change the end effector of robots can execute different tasks.

Industry Robots application in PCB Industry

Industry robots main applied in automobile manufactory in early years,it finished welding,assembly,transport,spraying,these process don’t need high precision and speed.In PCB industry, robots need connect PCB equipment to pick up and down material,turnaround board,sorting and inspection,it make high demands for Robots in fore-end,precise position,work rhythm as PCBs diversification.Now,robots main applied in PCB AOI,exposure process,OPE,Ag plugged,Legend Spraying,Brown Oxide,Pre-Laminate,Package,OSP,Cleaning,etc.

We introduce three typical robots:

6-axes robots apply in AOI inspection

The traditional AOI process is need worker to put,rolling over,collect PCB panel.one worker manage two machines can finished about five hundreds panel each day,Robot can finish seven hundreds PCB panels each day, means it can pick up a panel one minute included AOI test time.It great increased productivity.

Scara robots apply in PCB hole inspection

Robot can inspect all holes one time instead of worker one by one to check out.it avoid missing inspection by worker’s mistake.

Delta robots apply in FPC package

FPC have typical small size,light weight,flex feature.more FPC need in reel loading after be finished,worker use tweezers to put one by one in traditional factory,the productivity is very low. Delta800 robots vision system can recognize FPC side ,position and angle from convey belt, then inform robot fore-end suction pad to grab and adjust angle put into reel, the speed is 60 pcs/min,completely instead of labor.

The advantage of Robots replace labor

Robots replace labor in PCB industry will bring more favorable to factory.

  • Cut down labors,extend working time,improve productivity,reduce manage cost.
  • Improve operation precision,improve produce quality.
  • Avoid working environment threaten worker’s health and safety.
  • Avoid workers are low emotion as repeat and boring working.
  • Optimize work flow,decrease working space.
  • Robots can keep working in 24 hours.

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PCB welding defect

Why Occurs Rough Unshaped Welding in PCB Assembly

PCB design and manufacture is critical and don’t allowed any mistake.The article will analyses why occurs rough unshaped welding in PCB assembly.

There have many factors lead to rough unshaped welding,like PCB PTH weldability, welding temperature incorrect,solder components incorrect,etc. It’s unfavourable for PCB components running,so we must avoid rough unshaped welding.

PCB PTH weldability

If PCB PTH weldability is not good, it makes weld defect and impact parameter of components, components connects multilayer unstability,lead to whole PCB miss function.

Welding temperature

If the welding temperature is overhigh,then the welding material expedite spread and achieve high active lead to surface oxidized immediately between PCB and welding material.then appeared rough unshaped welding.

Welding components

Welding material is very important constituent part in welding chemistry process,common low smelting point metal Sn-Pb or Sn-Pb-Ag, need strict control impurity rate avoid impurity oxide be dissolved by soldering flux lead to rough unshaped welding.

PCB bow and twist

It’s easy make PCB bow and twist when make assembly, stress changed lead to rough unshaped welding. The main problem is PCB out-of flatness.For large PCB,itself weight drop down can lead to bow and twist.The space should be 0.5mm between component and PCB board edge.

PCB design

In PCB layout, if the dimension is too big. Although it’s usefull for welding ,but the trace is too long lead to impedance increase,resist noise capability decline,increase cost.If the board dimension is too small lead to heat dissipation drop.It’s unhelpful for welding.the adjoin trace will interfere each other.so need optimize design.The best PCB dimension long/width rate is 4:3. The trace width should be symmetry,avoid big area copper cover.

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PCB manufacture tips-feature

Who stole your money in PCB manufacture

As a PCB manufacture engineer, we saw many PCB designers didn’t considered the produce feasible lead to PCB fabrication cost be raised a lot and they didn’t realized. As most of PCB designers don’t have knowledge of PCB manufacture and don’t know how to optimize design can save money.

Seven tips you should know:

Copper Layer

pcb trace

  • The min. trace width/space should be more than 4/4mil although King Sun can make 3/3mil, but it need extra charge.the big the better for fabrication.
  • The space should be more than 20mil between copper to board edge.

Vias

pcb vias

  • The min vias should more than 0.3mm(12mil),the ring of pad should more than 4mil, 6mil is better.although King Sun can make min hole 0.15mm(6mil),there also need extra charge.
  • The space is more than 6mil between via rim to via rim. 8mil is better.
  • For inner layer of multilayer, the space is more than 8mil between via rim to trace.

PTH

PCB PTH HOLE

  • The PTH holes diameter should larger 0.2mm than pin at least.For example pin is 0.6mm,then you need design the holes diameter 0.8mm.
  • The ring of PTH pad should be more than 0.2mm(8mil).
  • The space of PTH hole rim should more than 0.3mm(12mil), the big the better.
  • The space should more than 20mil between PTH pad to board edge.

Solder mask

PCB solder mask

  • The solder mask opening of PTH pad and SMT pad should be more than 0.05mm(2mil).But take care solder mask opening is not the bigger the better.4-6mil is perfect.
  • The space of IC pad should more than 8mil to keep the solder mask bridge.

Silkscreen

pcb Silkscreen

The width of legend should more than 0.15mm(6mil),the height should more than 0.8mm(32mil),depth-width ratio should be 5. For example legend width 0.2mm, then height need be 1mm.

Slot

pcb slot

  • Min width of PTH slot should be more than 0.8mm.
  • Min width of NPTH slot should be more than 1.6mm.

Build Panel

pcb v-cut

  • If panel delivery the space of units should be more than 1.6mm. 2mm is popular.
  • If the space of units is 0, than we need use V-CUT to produce, the min. Board width of V-CUT should be more than 8cm,otherwise the board will drop into equipment.

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