GENERATE FASTER PCB ASSEMBLY TURNAROUNDS

The Case of Night Shifts vs. Additional Production Lines for PCB Assembly Efficiency

For a small PCB prototyping business intent on serving some of the best-known and most respected tech brands on the planet, quick turnaround is more than a marketing gimmick – it’s a promise. PCB prototype assembly is by no means a simple activity, and small, time-consuming hang-ups can turn into lost orders and angry customers in an industry where 48-hour turnarounds are the norm.

In order to be able to reliably produce results on such short time frames, PCB assembly plants need to optimize nearly every aspect of their work ow for speed and consistency. At the heart of this need is an inherent conflict between maximizing the assets and resources you already own or adding additional assets and resources to your environment.

Essentially, what fast-turnaround PCB assemblers want to know is whether they should hire additional help and make more use of their machines, or buy newer, better machines that may let them make the most of their current staff.

Imperfectly Optimized PCB Planning Systems
Before jumping into the issue of whether manpower or machine power really generates fast turnarounds, we need to be sure that the PCB planning system itself is already performing optimally. As William Ho asserts, component placement is the bottleneck of any PCB assembly line.

Essentially, that bottleneck is made up of two parts – component sequencing and feeder arrangements. PCB manufacturers need to choose the optimal sequence of components and then assign them to the appropriate feeders
There are nearly infinite ways that PCB component sequencing and feeder arrangements can be approached. Finding the truly most efficient solution is simply not feasible in a business context – not, at least, with current computational technology, and certainly not within a two-day timeframe.

PCB assemblers on a tight deadline use genetic algorithms to determine near-optimal planning systems without getting lost on the way to the “perfect” solution. While this is not a problem that can be solved with today’s technology, it’s important to remember that no current PCB assembly process is perfectly efficient. This becomes an increasingly complicating factor for high-volume PCB prototype companies.

More Machines Means More Set Up Time

Knowing that any given PCB assembly process must be less than perfectly efficient, we can turn to time constraints on work ow processes.

SMT machines are not plug-and-play devices. Even efficient machines require changeovers of at least an hour – if you run eight to ten setups a week, that means that you’re losing an entire day in production time every week.

Changeover times can become a massive drag on production, especially when dealing with tight turnarounds. Time, once lost, cannot be recovered, and every second of time saved boosts revenue.

Since SMT machines can encounter nearly infinite production possibilities on a single run, and are often tasked with making multiple runs per day, any changeover time is downtime. As UIC shows in a simple set of graphs according to SMT machine revenue generating time, every second counts – an hour of downtime for a line that generates $10 million yearly costs $5000.

While there are always ways to improve the efficiency of a PCB assembly line, there is no way to account for $5000 in unnecessary losses. Considering that some SMT machines can take up to four hours to set up for a single run of a prototype PCB, making the most of each workday is by far the better option.

Moreover, installing additional production lines does not affect the productivity of each individual line. While it may appear to improve PCB assembly turnaround, adding more lines and workers may cost more than its worth if overall production volume doesn’t also increase. For this reason, keeping workers late or even hiring an extra shift is by far the better option.

Night Shifts Can Generate More Value
Maximizing the amount of time that each machine can run is the best way to ensure e ciency on short-turnaround PCB assembly projects. Finding workers willing to put in overtime – or hiring an entire night shift – is one of the best ways to ensure that you consistently meet assembly deadlines and minimize downtime.

The basic operation and process of SMT placement machin

The basic operation and process of SMT placement machine

As a high-tech products, safe and correct operation of the machine and the people are very important to safely operate the placement machine is the most basic operator should have the most accurate judgments, should follow the following basic safety rules and processes,


1, the machine operator should accept the correct method of operation training.
2, check the machine, replace the parts or repair and internal adjustment should be off the power (the maintenance of the machine must be pressed in the emergency button or power off the case.
3, make sure to "read the coordinates" and adjust the machine when YPU (programming part) is in your hands at any time to stop the action.
4, so that the "interlock" security equipment to keep effective at any time to stop the machine, the machine's safety testing can not skip, shorted, or prone to personal or machine safety incidents.
5, the production allows only one operator to operate a machine.
6, during operation, so that the body parts such as hand and first in the machine outside the scope of movement.
7, the machine must be properly grounded <true ground, not connected to the zero line.
8, do not use a gas or very dirty environment in the use of the machine.

note:
1) did not receive training is strictly prohibited on the machine operation.
2) the operation of equipment to be safe as the first, the machine operator should operate in strict accordance with the operating procedures of the machine, otherwise it may cause damage to the machine or harm personal safety.
3) the machine operator should be careful, careful.

SMT Mounter Workflow:
Function is mainly through the PCB board fixed -> components to absorb -> displacement -> positioning -> components placed and other operations.
1, to be mounted on the PCB board into the work area and fixed in the predetermined location,
2, the material is installed in the feeder, and according to the program set the location, installed to the patch head to learn the location.
3, the patch head will move to the position of the suction element, open the vacuum, the nozzle up to absorb the components, and then through the vacuum sensor to detect whether the device was sucked.
4, the component identification, read the components of the component characteristics and pick up the components compared to the evaluation of the evaluation does not meet, then the components will be thrown into the waste box.If the evaluation of the evaluation of the components after the center position and angle Calculation.
5, according to the program set, through the patch of the Z-axis to adjust the rotation angle of the component, through the patch head to move to the program set a good location, making the component center and PCB board placement point coincidence.
6, the placement machine nozzle will drop to the program set a good height, close the vacuum, the components fall, to complete a component placement operation.
7, all the components after the completion of the placement, the nozzle placed homing, the PCB board to the set position to complete the entire PCB board placement operation.
SMT soldering machine work flow summary: into the board and mark recognition -> automatic learning -> nozzle selection -> feeder selection -> component pick -> component testing to evaluate -> placement -> nozzle homing - > Out board

The similarities and differences of solder wire and silver-free solder wir

The similarities and differences of solder wire and silver-free solder wire 

(1) the melting point is different: due to the different metal alloy, so the melting point is also different. Silver-free lead-free solder wire melting point: 217 degrees, and lead-free solder wire melting point: 227 degrees difference of about 10 degrees.

(2) different metal composition: silver-free lead-free solder wire is made of tin silver copper alloy, and lead-free solder wire is a tin and copper alloy composition, excluding silver metal composition.


(3) Costs are different: silver-free lead-free solder wire is more expensive than lead-free solder wire because of the high price of silver metal. This is the biggest advantage of lead-free solder wire. The higher the cost, the more expensive the cost

(4) the overall performance of different: due to the role of silver metal, lead-free solder wire than lead-free solder wire firmness better, stronger, more solid solder joints.Second, the conductive properties in the solder joint is also very important , Silver is a very good conductive metal, so silver-free lead-free solder wire than lead-free solder wire conductivity, thermal conductivity and so on are better. These properties are lead-free solder wire can not go beyond.


(5) solder color gloss different: lead-free solder wire gloss is showing a certain degree of brightness, look better look. This is one of the advantages of lead-free solder wire, but the solder color does not mean the welding Point of its own welding performance, while the silver-free lead-free solder wire solder joints affect the appearance of the solder color brightness of the color.As the silver metal is matte metal, not bright metal, so silver-free solder wire solder Point gloss is matte color and brightless.

The key process of SMT reflow welding rework technology

The key process of SMT reflow welding rework technology 

Reflow before the appropriate preheating PCB board; re-flow after the rapid cooling of the solder joints. Two of the most critical processes for the successful repair of SMT are also the two most likely to overlook the problem:

Since these two basic processes are often overlooked by the repair technician, in fact, sometimes the repair is worse than the situation before the repair. Although some "rework"defects can sometimes be found by the post-process inspector, but in most cases always do not see, but in the future circuit test will soon be exposed.Preheat - Prerequisites for successful rework.

It is true that PCB processing at high temperatures (315-426 ° C) for a long time poses a lot of potential problems. Heat damage, such as pad and lead warping, substrate delamination, raw white spots or blistering, discoloration. Board Alice and Burning are usually caused by the inspector's attention. However, it is precisely because it will not "burn bad plate" does not mean that "plate is not damaged." High temperature on the PCB "invisible" damage even more serious than the above list of problems. For decades, numerous tests have repeatedly demonstrated that PCBs and their components can "pass" rework after the test and test, the decay rate higher than the normal PCB board. This kind of substrate warpage and its circuit element attenuation and other "stealth" problem comes from different materials of different expansion coefficient. Obviously, these problems will not be self-exposed, even in the beginning of the circuit test was not found, but still lurking in the PCB components.

Although the "repair" looks good, but as people often say a word: "surgery is successful, but the patient unfortunately died."Due to the large thermal stress, the PCB assembly at room temperature (21 ° C) has a temperature difference of about 349 ° C for the circuit board and its components when it is exposed to a hot iron with a heat source of about 370 ° C, a welding tool or a hot head. Variety,Produce "popcorn" phenomenon."Popcorn" phenomenon refers to the existence of an integrated circuit or SMD in the device inside the moisture in the repair process of rapid heat, so that moisture expansion,the phenomenon of micro-burst or rupture. 

Therefore, the semiconductor industry and circuit board manufacturing industry requires production staff in the reflow before, as far as possible to shorten the warm-up time,quickly rose to reflow temperature. In fact, the preheating stage of the PCB assembly reflow process has been included. Regardless of PCB assembly plant is the use of wave soldering, infrared vapor phase or convection reflow, each method are generally preheated or heat treatment, the temperature is generally 140-160 ℃. In the implementation of reflow before the use of a simple short-term preheating PCB can solve many problems when the repair. This has been in the reflow process has been a few years of successful history.the benefits of preheating the PCB assembly before reflowing are multifaceted.Since the preheating of the plate reduces the reflow temperature, both wave soldering, IR / vapor welding and convection reflow can be performed at about 260 ° C.The benefits of preheating are multifaceted and integrated. First, preheating or "heat-treating" components prior to commencing reflow helps to activate the flux, remove the oxides and surface films of the surface to be welded, and the volatiles of the flux itself. Accordingly, this cleaning of the flux prior to reflow will enhance the wetting effect. Preheating is to heat the entire assembly below the melting point of the solder and the temperature of the reflow. This can greatly reduce the risk of thermal shock to the substrate and its components. Otherwise rapid heating will increase the temperature gradient within the assembly and produce thermal shock. The large temperature gradient generated inside the assembly will form thermomechanical stresses that cause the material with low thermal expansion to be brittle, causing rupture and damage. SMT chip resistors and capacitors are particularly susceptible to thermal shock.

In addition, if the entire assembly is preheated, the reflow temperature and the reflow time can be reduced. If there is no preheating, the only way to only further increase the reflow temperature, or extend the reflow time, no matter which way is not appropriate, should be avoided.Reduced rework makes the board more reliable.As a benchmark for welding temperature, the use of different welding methods, welding temperature is not the same, for example: Most of the wave soldering temperature of about 240-260 ℃, steam welding temperature of about 215 ℃, reflow temperature of about 230 ℃. To be fair, the rework temperature is not higher than the reflow temperature. Although the temperature is close, it is never possible to achieve the same temperature. This is because all the rework processes require only one local component to be heated, and the reflow requires the entire PCB assembly to be heated, both for wave soldering and vapor phase reflow.

Another factor limiting the reduction in reflow temperatures in rework is the industry standard, which means that the temperature of the components around the repair point must never exceed 170 ° C. Therefore, the reflow temperature in the reflow should be with the PCB component itself and to reflow the size of the components to adapt to the size of the PCB board is essentially due to the local rework, so the repair process limits the PCB board maintenance temperature. The temperature range of the localized rework is higher than the temperature in the production process to counteract the endotherm of the entire board assembly.

In this case, there is no good reason to say that the repair temperature of the entire board can not be higher than the reflow temperature in the production process, thus approaching the target temperature recommended by the semiconductor manufacturer.Three methods of preheating PCB components before repair or repair:Today, preheating PCB components are divided into three categories: oven, hot plate and hot air tank. It is effective to use an oven to preheat the substrate before reworking and reflow the components. Moreover, the use of baking is a favorable way to preheat the oven in baking out some of the internal circuits in the internal moisture and prevent the popcorn phenomenon. The so-called popcorn phenomenon refers to the repair of the SMD device in the humidity above the normal device humidity suddenly in the rapid warming will occur when the micro-crack. PCB in the preheating oven baking time is longer,Generally up to 8 hours or so.

One of the drawbacks of the preheating oven is that it is different from the hot plate and the hot air tank, and it is not possible to preheat by a technician and to rework it at the same time. Moreover, it is impossible to quickly cool the solder joint in the oven.Hot plate is the most ineffective way to preheat PCB board. Because the PCB components to repair is not all single-sided,Today is the world of hybrid technology, one side is all flat or flat PCB components is indeed rare. PCB on both sides of the substrate are generally installed components. It is not possible for these uneven surfaces to be preheated with hot plates.The second drawback of the hot plate is that once the solder reflows, the hot plate will continue to release heat to the PCB assembly. This is because, even after unplugging the power supply, there will still be stored residual heat in the hot plate to continue to conduct the PCB to prevent the solder joint cooling rate. This obstruction of solder joints can cause unnecessary lead precipitation to form a lead bath, reducing the solder joint strength and deteriorating.

The advantage of using a hot air tank to preheat is that the hot air tank does not take into account the shape (and bottom structure) of the PCB assembly, and the hot air can enter the corners of the PCB assembly directly and quickly. So that the entire PCB assembly heating evenly,And shorten the heating time.Secondary cooling of solder joint in PCB assembly

As mentioned earlier, the challenge of SMT to PCBA (PCB components) is that the repair process should mimic the production process. Facts have proved:
First, preheating the PCB assembly before reflow is necessary for the successful production of the PCBA; secondly, it is also important to quickly cool the components immediately after reflow. And these two simple craft has been ignored by people. However, in the through-hole technology and micro-welding of sensitive components, preheating and secondary cooling is even more important.

Common reflow equipment such as chain furnace, PCB components through the re-flow zone immediately after entering the cooling zone. With the PCB assembly into the cooling zone, in order to achieve rapid cooling,ventilation of PCB components is very important, the general repair and production equipment itself is integrated.The slow cooling of the PCB assembly after recirculation causes the unwanted lead-filled liquid pool in the liquid solder to reduce the solder joint strength. However, the use of rapid cooling can prevent the precipitation of lead, so that the grain structure is more tight, more solid solder joints.In addition, the faster cooling of the solder joint reduces the quality of the PCB assembly due to accidental movement or vibration during reflow. For production and rework, it is another advantage of the secondary cooling of the PCB assembly by reducing the possible misalignment and tombstone of small SMD.

Summary:
There are many benefits of secondary cooling PCB components when properly warmed up and reflowed, and these two simple procedures need to be included in the technician's rework. In fact, when preheating the PCB, the technician can do other preparatory work at the same time, such as solder paste and flux on the PCB.Of course, the need to solve the problem of new refurbished PCB component process, because it has not passed the circuit test, which is a real time to save. Obviously, there is no need to repair the PCB in the repair and save the cost.

SMT 0201 assembly from difficulty to conventional placement process

SMT 0201 assembly from difficulty to conventional placement process

AT one time the 0201 placement has been placed difficlity in the SMT industry, many OEM circuit board assemblers need to incorporate even smaller components and technologies into their products due to size, weight, and power consumption The contract manufacturer (CM-contract manufacturer) must also have new technology to keep the assembly process up to date and provide a complete range of services for the customer, and for the machine manufacturer, the challenge is to develop a more time in a dynamic technological change Resistant to outdated assembly equipment.

0201 placement challenge
The placement of the 0201 component is more challenging than its previous component intervention, mainly due to the fact that the 0201 package is about one-third of the corresponding 0402 size.the original acceptable machine placement accuracy has immediately become a limiting factor in the introduction of the 0201. In addition, the traditional industrial taping specifications allow too much movement for reliable 0201 mounts, and process control levels must also be increased So that the 0201 placement becomes a production reality.Although these obstacles are very large, but they are far from being insurmountable.Of course, they need all the determination, because the 0201 placement of the necessary technology to obtain a lot of money and the highest management of the study Development (R & D) promise.

Reliable 0201 placement key
SMT equipment manufacturers have been able to make all the circuit assembly machine to 100% speed compatible with the ability of 0201, the minimum draw reliability of 99.90%, the target of the reliability of 99.95%, and the lowest placement reliability of 99.99%. At the outset, each aspect of the design has been evaluated for its ability to complete a complete 0201 program, as well as a single element of the closely related machine component parameters that proves to be critical to achieving success.

These parameters include:
Component Feeder Workbench.
The R & D program concludes that the ability to precisely locate the carriage table
And making minimal adjustments to compensate for the inaccuracy of the tape - is a key factor in achieving the reliability of the component above 99.95%. To achieve this, the feeder table must be machined to ensure a single feed Repeatable positioning of the device and the use of a two-track linearly movable guide in conjunction with a high-resolution semi-closed loop servo system which allows for a small adjustment - based on the accuracy of the absorption accuracy determined by the visual system. Close to the center.

Component feeder.
The feeder must be made to achieve extremely tight tolerances to ensure that the suction position is maintained repeatable, regardless of element height and a large number of possible changes in the position of the component. The mechanism used to position and position the feeder in position must be durable and precise In order to maintain user friendliness, the materials used to make the feeder must be of high strength and light weight to allow for ergonomic operation while ensuring the precise and repeatable delivery of the carrier tape.

The drive sprocket drives the sprocket to play a key role in the capacity of the machine positioning element. The shape, taper and length of the drive sprocket wheel significantly affect the ability of the feeder to orient the tape. Other factors are also investigated Such as the diameter of the drive sprocket and the number of contacts with the sprocket, etc. The change in the basic sprocket design improves the positioning accuracy, the earlier design increases by 20% in the X direction, 50% in the Y direction, The

Absorb the head.
After the feeder element is properly fed, the next step is to draw the element on the vacuum nozzle and take it onto the circuit board. The vacuum nozzle needs to be adapted to absorb the impact during the draw and mount element, The slight change in the height of the solder paste and the risk of rupture of the element. For these reasons, the nozzle must be able to move within its fixture. Material selection, material hardness, machining tolerances and thermal characteristics must be understood to construct a reliable The nozzle must be free to move within its holder without sacrificing accuracy.

Suction nozzle assembly.
The nozzleshaft is also a key design element - by overriding the entire nozzle and shaft assembly, eliminating the overdrive phenomenon due to the inertia of the top and bottom of the mounting head If the nozzle and the shaft are not in a straight line, they produce a little jitter (whip) - or overpressure. Overvoltage causes a change in positioning accuracy, which depends on the speed of movement, the weight of the nozzle and the weight of the component. By eliminating overpressure, To reduce the number of negative factors associated with component picking and placement.

Nozzle design.
The change in nozzle design is a very important factor in allowing the inclusion of the 0201 element. In order to draw 0.6x0.3 mm of the element, the nozzle must have an outer diameter of no more than 0.40mm. This forms a long and thin nozzle , Bending is fragile but also must be kept in order to maintain the high reliability of the drawing. The change from the linear axis to the tapered design increases the nozzle strength and allows the nozzle to resist bending.

Base structure.
All the machines are vibrating during operation. The base frame design is the first step in reducing the speed and motion effects of vibration and harmonic resonance. By using cast iron base frames and art-level structure techniques, vibration and harmonic resonance can be achieved in the machine To a manageable level, so that negative effects can be met.

Up to standard
Through all six key factors, reliable 0201 placement barriers have been eliminated.Therefore, R & D's focus has shifted to newer, smaller components, and 0201 is no longer considered a leading edge component packaging technology.
For 0201 component placement, the current process window is about 0.075mm X and 0.075mm Y at 3 Sigma. In order to achieve 6 Sigma mount reliability, the tolerance of X and Y must be reduced to 0.050mm. High-speed placement equipment has a rating of 0.066mm, the actual standard deviation of about 0.035 ~ 0.045mm. With 0201 components become more widely used and manufacturing process tight, can achieve improved accuracy.

3D SPI principle and detection metho

3D SPI principle and detection method

SPI (SolderPaste Inspection) refers to the solder paste detection system, the main function is to detect the quality of solder paste printing, including volume, area, height, XY offset, shape, bridge, etc. How quickly and accurately detect extremely small solder paste , The general use of PMP (Chinese translation for the phase modulation profile measurement technology) and Laser (Chinese translation for the laser triangulation technology) detection principle.

Laser triangulation technique

The detection light source is laser, the laser beam in different height plane distortion, the detection head in a certain direction of continuous movement, the camera according to set the time interval to take pictures, so as to obtain a set of laser distortion data, and then calculate the test results (As shown below)
Advantages: faster detection
Disadvantages: 1) laser resolution is low, generally only 10 - 20um level.
2) Single sampling, low repeatability accuracy.
3) Sampling in the movement, the external shock and transmission vibration on the detection of a greater impact.
4) laser monochromatic light on the PCB board color is weak.
Market conditions: laser technology has gradually withdrawn from the SPI industry. At present, South Korea Parmi is still using laser technology (dual laser technology)

PMP phase modulation contour measurement technology
1) Using a white light source, the solder paste is measured by the phase change of the structural grating
2) Using the grayscale change of the structural grating, a high accuracy is obtained
3) the use of phase changes, each solder paste for 8 times to ensure that the detection of high repeatability accuracy
4) PMP technology is divided into FOV walk-off and Scan scanning two detection methods

4.1 FOV stop
When the test is carried out, the motion is not sampled and does not move during sampling, and the effect of vibration on the detection is minimized.
Advantages: 1) PMP principle detection resolution is high, 0.37um.2) stable multi-sampling, detection repeatability is extremely high .3) on the PCB color is not critical.
Disadvantages: the speed is relatively slow.
Market: to stabilize the detection results identified by the industry as the best SPI solution to South Korea KohYoung as the representative of foreign brands.

4.2Scan Scanning
The phase change of the structural grating is formed by the continuous motion of the detecting head, while sampling is carried out while moving.
Advantages: 1) PMP principle detection resolution is high, 0.37um.2) on the PCB color is not critical .3) multiple sampling, detection repeatability than laser-type equipment .4) detection speed faster than FOV stop.
Disadvantages: the impact of external shocks, detection repeatability is low.
Market: China Taiwan TRI as the representative of the Chinese Taiwan brand, represented by the foreign brand of Cyber.

SMT land structure technology & analysis

SMT land structure technology & analysis

The basic constituent elements of the surface mount assembly used to form the land pattern of the circuit board, that is, the combination of pads for the particular component type design. There is no worse than the design of the pad structure It is difficult and sometimes impossible to achieve the desired weld point when a pad structure is not designed correctly. The pad has two words: Land and Pad, which can often be used interchangeably; , In function, Land is a two-dimensional surface feature for surface mount components, and Pad is a three-dimensional feature for pluggable components. As a general rule, Land does not include plated through holes (PTH, plated through (via) is a plated through hole (PTH) that connects different circuit layers. The blind via connects the outermost layer with one or more inner layers and the buried bypass holes Only connect the inner layer.

As noted above, the pad Land typically does not include electroplated through-holes (PTH). The PTH in a pad Land will take a significant amount of solder during soldering and, in many cases, solder pads that are insufficiently solderable. However, in some cases, component wiring density forcing to change to this rule, the most noteworthy is the chip size of the package (CSP, chip scale package). 1.0mm (0.0394 ") spacing below, it is difficult to a The wires are routed through the "maze" of the pads. The blind vias and micro-channels are produced in the pads, allowing direct wiring to the other layer, since these bypass holes are small and blind, so they do not Will suck too much solder, the results of the solder the amount of tin is very small or no effect.

There are many industrial literatures available from IPC (Association Connecting Electronics Industries), EIA (Electronic Industry Alliance) and JEDEC (Solid State Technology Association), which should be used when designing the pad structure.The main document is the IPC-SM-782 "Surface Mount Design and Padding Structure Standard", which provides information on the pad structure used for surface mount components.When the J-STD-001 "Requirements for Welding Electrical and Electronic Assemblies" and IPC-A-610 "Acceptability of Electronic Assemblies" are used as solder joint process standards, the pad structure should conform to IPC-SM-782.If the pad deviates significantly from the IPC-SM-782, it will be difficult to achieve solder joints that conform to J-STD-001 and IPC-A-610.Component knowledge (ie, component structure and mechanical dimensions) is a fundamental requirement for the design of the pad structure. The IPC-SM-782 uses two components widely: EIA-PDP-100 "Registration of electronic components with standard mechanical form" And JEDEC 95 publication "Registration of Solid and Related Products and Standard Outline." It is indisputable that the most important of these documents is the JEDEC 95 publication because it deals with the most complex components. It provides all registration of solid elements And the standard profile of the mechanical map.

JEDEC publication JESD30 (also available for free download from JEDEC website) Defines the abbreviation of the component based on the characteristics of the package, material, terminal location, package type, pin form and number of terminals. Features, material, position, form and quantity The identifier is optional.

Package Features: A single or multiple letter prefix that confirms features such as pitch and contour.

Packaging material: a single letter prefix, confirm the main packaging material.

Terminal position: A single letter prefix that confirms the terminal position relative to the package profile.
Package Type: A two-letter mark that specifies the outline type of the package.

Pin New: A single letter suffix to confirm the pin form.

Number of terminals: a one, two or three digit suffix, indicating the number of terminals.
Surface Mount A simple list of encapsulation feature identifiers includes:
 E to expand the pitch (> 1.27 mm)
F spacing (<0.5 mm); limited to QFP components
 S contraction pitch (<0.65 mm); all components except QFP.
· T thin (1.0 mm body thickness)
Surface Mount A simple list of terminal position identifiers includes:
• Dual pins on either side of a square or rectangular package.
• The Quad pin is on the four sides of a square or rectangular package.
Surface Mount A simple list of package type identifiers includes:
· CC chip carrier (chip carrier) package structure
· FP flat pack (flat pack) package structure

· GA grid array (grid array) package structure

Small outline package structure
Surface Mount A simple list of pin form identifiers includes:
B is a straight handle or a spherical pin structure; this is a non-compliant pin form
F is a straight pin structure; this is a non-compliant pin form
 G A wing-shaped pin structure; this is a conforming pin form
A "J" -shaped pin structure; this is a conforming pin form
N is a pinless structure; this is a non-compliant pin form

An "S" -shaped pin structure; this is a conforming pin form

For example, the abbreviation F-PQFP-G208 describes 0.5 mm (F) plastic (P) square (Q) plane package (FP), winged pin (G), number of terminals 208.
Detailed analysis of the component and plate surface characteristics (ie, pad structure, reference points, etc.) is necessary. The IPC-SM-782 explains how to perform this analysis. Many components (especially dense pitch components) are strictly metric units Do not design an inch pad structure for metric components. The cumulative structural error does not match and can not be used for dense spacing elements. Remember, 0.65mm is equal to 0.0256 "and 0.5mm is equal to 0.0197".