5. TPV - Technological section

TPV Technology section contains information about the basic types of materials and technological processes used by PRINTED Ltd. for PCB production.

5.1 Technological requirements for PCB design

PCB design should be based on certain technological conditions of production of printed circuit boards and if the designer is not bound by other necessities, it is advisable to keep. Deviation from these conditions from the recommended values ​​leads to an increase in technological intensity of production and the price increase DPS.

recommended width of joints and insulating gap is 0.3 mm. However, we can supply PCB wire / gap = 0.125 / 0.125 mm

final hole diameter = diameter of duct components + 0.2 mm

diameter solder eye pin diameter = 0.9 mm + components

Clasp solder mask = diameter of duct components + 1.1 mm

data are shown in the illustration . Specified parameters correspond to the resulting hole diameter tolerance DPS

5.2 Basic material for PCB

basic overview of the used materials is shown in the following tables . When you enter must bring their commercial designation, plate thickness and strength of plating copper foil.

5.2.1 Material category FR2

carrier material is celuozového several layers of paper attached with a phenolic resin, clad electrodeposited copper with a purity of 99.8%. It can be well machined grooves, cutting and pressing. Not suitable for higher temperatures, can not be applied HAL is unsuitable for planting holes contain toxic substances. Not in stock.

5.2.2 Material category FR3

carrier material is celuozového several layers of paper attached with epoxy resin and clad electrodeposited copper with a purity of 99.8%. It can be machined well, is suitable for use at temperatures of 90 ° C, it is inappropriate to prokovování holes. We recommend to use the one-sided PCB. Not in stock.

5.2.3 Material FR4 category

carrier material is several layers of fiberglass mat epoxy-clad United electrodeposited Cu with a purity of 99.8%. It is suitable for routing, mechanically resistant, has a high flexural strength, dimensional stability, heat resistance up to 130 ° C, can be applied HAL is for plating holes. It is suitable for the most demanding applications DPS.

5.2.4 Material category G30

basic design pad is similar to FR4 material. Used resin has a flow temperature of 260 C. We clad with electrodeposited copper with a purity of 99.8%. It is suitable for routing, mechanically resistant, has a high flexural strength, dimensional stability. Can be applied HAL or galvanic gold plating is designed for holes. It is suitable for the most demanding applications thermally stressed DPS.

5.2.5 Material category CEM1

carrier material is designed in combination celuozového paper attached with epoxy resin for the inner layer and laminated with a layer of reinforcing glass fiber mats for the outer layer which is clad with electrodeposited copper with a purity of 99.8%. The structure of the material is shown in Fig.16 . Has increased mechanical strength, duty, dimensional stability, resistance to thermal shock during soldering and higher resistance to climatic conditions. Against FR 4 shows the pressing less tool wear. Grooved PCB can be easily divided, can be applied HAL is not suitable for plating holes. Not in stock.

PRINTED Company Ltd. has access to a wide range of basic kinds of materials in different thicknesses substrate and cladding to be delivered 14 days. Offer the potential range is shown in Table 5

5.2.6 Material stencils

making stencils for solder paste screen printing use bronze composition CuSn6 foil with a thickness of 0.1 mm in size 320x480 mm. To create theme foil solder surfaces of Gerber data generated from a motive of PCB. Unless otherwise requested by the customer, these surfaces is reduced by 0.075 mm on each side (total of 0.15 mm). Areas for etching can also be entered by the customer in a separate layer, which is then no longer neupravuje.Po applying a photoresist film is a theme galvanically tin-plated and then etched. By default, the tin is stripped, but the customer can leave in tin foil design.

5.2.7 Material for resilient and flexible connections

production of flexible circuits used Pyralux material thickness of 0.1 mm. Cladding can be one-sided and double-sided media 35 or 18 mi. It can prokovit. Can withstand repeated bending through 180 degrees. The flexible PCB is used FR4 thickness of 0.1 mm. Flexible PCB have higher mechanical strength and can withstand repeated bending to 90 degrees. As we finish allover gold plating or tin plated. These connections can not be applied halls.

5.2.8 Material for the manufacture of the aluminum surface.

production of single-sided boards use imported materials GCCAF-04 Alu 5052 in the strength of 1.5 mm, 2.0 mm and 2.5 mm. On both sides we make plated materials in the course of production.

5.2.8 Material for aluminum front panels.

milled aluminum front panels are made of polished aluminum power 1.5 mm, 2.0 mm, 2.5 mm and 3.0 mm.

5.3 Mechanical processing DPS

This section provides information about the mechanical processing DPS, input method and resulting tolerances. By default, the DPS to size gouge, or milled. If it does not meet tolerances tolerated dimensions shown in Table 3, it is necessary to specify tolerances. Can be ordered contour milling, grinding his or slotting and milling. Cutouts, irregular holes, large holes of diameter 6 mm or deviations from the regular shape can be milled. These technologies should be consulted.

5.3.1 Drilling DPS

Drilling data consists of drilling file and drawing holes. Used to complete and unambiguous definition of the holes in the theme and their diameters. Data are always generated by the circuit. on the generated data, the components must be warned!

file data is entered in the format EXCELLON preferably in metric (Metric) with full construction (Leading) in the construction of 4.2 with no decimal commas and other punctuation. The data set is necessary to attach a file with averages used tools, which must be in text format, viewable without additional software. Using other formats drilling data do not exclude, but consultation is required.

Number of drilling tools is limited. With regard to the drilling time is appropriate to limit the number of used bits to the technological minimum.

smallest hole diameter is 0.3 mm, the largest drilled diameter is 6.4 mm.

narrow short groove odvrtávají sděřovým drill.

With regard to the mechanical stress of the material during drilling and formatting should be maintained distance "B" between the holes and the distance "A" from the edge of the PCB at least 0.30 mm as shown in Figure 5

holes can prokovovat diameter from 0.30 mm

drill diameter that are commonly available

at least 0.05 mm from 0.70 to 1.6 millimeters

in succession by 0.10 mm from 0.30 to 2.60 millimeters

in a row after 0.20 mm from 2.60 to 6.20 mm

Should a diameter that is not available corrects the average in cooperation with the customer or in the line-up.

Should a hundredth of a millimeter in diameter shall be rounded up to the industry average as follows:

at least 0.05 mm x, x1 and x, x6 mm

at least 0.10 mm from the x, x1 mm

U-sided PCB hole diameter is specified diameter. For double-sided PCB hole diameter is specified diameter of the resulting hole. Technological addition to the tool diameter prokovených DPS provides technical department. All holes drilled DPS prokovují simultaneously. The requirement to deliberate neprokovení some holes to be specified by entering a separate drill file or drawing neprokovených holes (drilled are additionally after plating DPS). Hole position is arithmetically rounded to tenths of a millimeter. Tolerance precision drilling is + / - 0.05 mm per 100 mm length.

Tolerance final hole to enter:

Neprokovené openings: - 0.1 / +0.05 mm

plated holes in the execution tin plated or gold electroplating: -0.05 / +0.5 mm in design technology hal: -0.1 / +0.05

Increased tolerance of the resulting hole plated PCB is given technological process of forging and hot-dip tinning hole. Cut a via hole is in Figure 17

5.3.2 Cutting DPS

Cutting the optical scissors is already non-standard method of making the final blank. Can be ordered peripheral grinding edges. Used for dimensions without specified tolerances. Tolerance sheared circuit is shown in Table 3 The cutting must be part of a theme nezamaskované corner marks according to Figure 3 For optical scissors is best drilled corner marker as shown in Figure 4 Due to the resulting tolerances and mechanical stress of the material in the division should follow the recommended minimum distance from the edge of the conductive theme DPS 0.50 mm.

5.3.3 Milling DPS

milling circuit is achieved by precise dimensions DPS. It should be used when formatting the PCB from the base material thickness of 2.00 mm or where theme PCB extends closer to the edge as 0.50 mm. The resulting dimension tolerance are shown in table number 3 Milling of internal cutouts allows obtaining internal holes of larger diameter to 6.30 mm and irregular hole or groove and locks. The standard tool used by the cutter diameter 2.00 mm. If it does not internal angles with the radius of curvature of 1.00 mm, it is necessary to negotiate when entering the size of the inner radius (sharpness internal angle). For this purpose can be used mill with a smaller diameter, or apex angle predrilled. The procedure will decide the technical department. Milling width of 0.80 mm - 1.50 mm (smaller instrument used) must be negotiated surcharge piece production. Milling program consists in manufacturing software CAM 350 v9.51, or directly on the mill. As the substrate is most independent film circuit and milled holes (eg EAGLE layer 20), or circuit generated in the film solder mask. It is inappropriate to generate these contours of the film motif in the creation of films must be removed. Details can be found in section 3.3 - Film artwork. Geometric shapes are defined by dimensioning a separate drawing. The circle center and radius, other shapes constrained vertex of the angle shape. DPS can be milled on a separate form or combined in the motherboard jumpers. The position and width of bridges can be entered in the drawing zakótováním or leave the decision on the location of the technical work. When creating the original film, the individual DPS together to pitch sizes 2.00 mm and milled with a single cut. The gap in the range of 2.00 mm is suitable for use in machine soldering.

5.3.4 Slotting DPS

splines are milled dividing line of mounted PCB bulk for later breaking to size. Preparation of documentation for gouging holes and location technology is reasonable to leave our technical department. DPS are grooved on pure size, but is to be expected burrs break about 0.20 mm (Table 3) and thus the relative magnification blank PCB. Groove geometry is shown in Figure 6 The groove is in the shape of a "V" and is performed simultaneously from both sides of the board. Root groove has a thickness of 0.3 mm. Therefore folding plates under the power of the basic material under 0.8 mm inappropriate. Under the thickness ratio of the force is the root of the groove to the base material has a comparable connection can not be reliably break without damaging PCBs. Especially dangerous is the installation of surface mount components. The machine is also adapted to folding boards with thickness of 2 mm.
Plates forces under 0.8 mm and 2.00 mm above it is necessary to divide milling.
The folding is a very suitable material CEM1, the core consists of paper insert that after slotting easily divided, see Figure 16

5.4 Plating Processes

5.4.1 Direct and galvanic prokovování holes

aim of this process is to achieve a continuous metal coating on the inner surface of the hole. This coating must adhere firmly to the support plate material and be easy soldering. For this process we use physical methods developed by SHADOW in continuous line company LAIF. Drilled holes are ultrasonically clean and the holes and the entire surface of the plate is coated with a solution of carbon coloid. Carbon is the surface of the laminate is fixed and rapidly dried by hot air. Excess carbon is made of a copper plate surface mikrozaleptáním removed when the plate surface etching 0.5 microns of copper. Tile line leaves the zvodivělými holes and the surface has been modified for applying photoresist. Throughput is 10 meters ^{2 . per hour. Following this basic zvodivění the PCB laminates resist and creates fotoprocesem conductive pattern. Conductive path and the inner surface of the holes are reinforced galvanic copper 20-25 um (Fig. 7). Ensures the plating thickness 20 microns. Size plating current and time Koven is determined by calculation. The etching is used selective etchant applied only to Cu. Parts that are to remain neodleptány must be covered galvanic coating of the resist. Our technology is used for this purpose Sn, Ni and Au. DPS is then etched. Cross section of a via hole is shown in Figure No 17 The thickness of the galvanic deposition of the metal is influenced by several factors, and therefore is given a higher tolerance of the resulting hole diameter.}

5.4.2 Hot tin HAL

Hot tin - halování the technological process of finishing DPS applying lead-free solder Cn100C company Balver Zinn SnPb on the surface of conductors and solder lugs. The etching PCB is removed in a chemical bath cover Sn resist to a clean galvanic copper. Parts not for soldering can be covered by solder mask. On the copper layer is in process equipment HAL immersion in a bath of molten Sn solder applied. Excess solder is removed by blowing with compressed air. Halování DPS is a high quality finish that allows long shelf life while maintaining good solderability DPS. Halované parts are covered hips joints without sharp edges and internal surfaces prokovených holes (Figure 17 and Figure 20). On the strength of the solder layer applied to multiple factors. The resulting thickness ranges from 10 to 50 micron, and therefore it is necessary to design PCB considering a tolerance of the resulting hole diameter. Uneven surfaces overlap solder Pmax = 50 um (Fig. 8) may cause problems in surface mount PCB assembly. This method eliminates the nationwide shortage of galvanic gilding DPS. For the best finish we consider technology OSP.

5.4.3 Chemical gilding

technology used company SHIPLEY chemical gilding allows applying a thin layer of gold on a copper surface parts DPS. The PCB is etched in a chemical bath removed the cover resist Sn. On a clean galvanic copper is first applied about 8 micron nickel chemical and chemical 0.040 micron gold. This technology allows obtaining plane of soldering surface for mounting surface mount components vícevývodových. When soldering is to be used to increase the active flux and temperature brazing of 20%. After the introduction of nationwide galvanic gilding, this method is used only at the express request. This technology has not performed.

5.4.4 gold plating

5.4.4.1 gold plating plug blades

gold plating plug blades is done by deposition of about 8 micron galvanic nickel and about 1-2 micron galvanic gold. The thickness of the gold must be specified in the order. The basic version is 1 micron. After the introduction of technology nationwide galvanic gilding is no longer necessary galvanic connection gilded surfaces and is not determined by their position on the plate. Electrical connection is in agreement with the customer removed. The shape and location of the gilded surfaces on the plate can be arbitrary.

5.4.4.2 Nationwide gold plating theme

gold plating PCB theme replaces chemical gilding gold. Because it is a galvanic process, it is possible to accurately determine the calculation and make individual layer thicknesses and the result is a perfect PCB surface with flatness better than + / - 0.5 microns. The surface is perfectly soldered using conventional soldering flux and storability joints is not limited. Another advantage is the elimination of lead from the manufacturing process. Gilding is done only on the theme of PCB and galvanic connection form the Cu plating. Ozlacená layer creates galvanorezist resistant to the etchant used. This layer consists of 5 micron galvanic nickel and a thin layer of gold electroplating. Nickel provides good solderability and gold prevents oxidation of nickel. This way we make DPS designed for SMT assembly. Customers can also prescribe what power of gold to be applied to nickel, or locate in the area of ​​the board only gain some points motive PCB surfaces such as keyboards. For machine soldering is recommended to use solder paste Sn62 COBAR - 325-XM5, which adds PBT Ltd. Roznov http://www.pbt.cz/ . For manual placement is advisable to use a product supplied by ELCHEMCo Ltd., pasta Microprint 2004. For more information on http://www.elchemco.cz/SMT1.htm

5.4.5 Galvanic tin

Design PCB electroplating tin is one of the possible surface finishing DPS. PCB etching with the resist is coated pewter finished products for further manufacture of final finishes plating processes. Its advantage is the possibility of making cheap fast verification samples DPS intended for further testing or for use in lightweight structures and their own well-protected products. Layer thickness galv. Tin is 7-10 microns. PCA in this embodiment can not guarantee the long-term storage, since decreasing their initial solderability.

5.4.6 OSP - selective protective coating

Creating OSP coating is carried out in a horizontal line as the final production operations. The plate is sprayed with a solution OSP that only the exposed surfaces of the copper creates an organic coating that prevents further oxidation of the copper surface. The coating dissolves in contact with the solder and soldering takes place on a clean copper surface. The advantage of the vast flatness of solder surfaces. The disadvantage is the time constraints keeping for about six months.

5.5 Solder mask

Solder mask is used to protect against unwanted theme DPS shorting. It can be applied to all basic materials from both sides. The basic type is a UV curable photomask.

5.5.1 Photomask

basic type of solder mask design fotoprocesem. The PCB is etched ostripován Sn resist and after further Finishing DPS is on its surface aperture coating applied an even layer of solder masks. The mask is exposed to UV light through a film positive artwork. Unexposed areas are washed in the processing facility and the mask is thermally cured. This design allows precise solder mask border supply points with a small addition to the diameter of the solder eyelet 0.20 mm. This addition is necessary to halování side wires (Figures 9 and 17). The transition between the exposed places is sharp and abrupt. It is possible to mask locations distant to each other more than 0.20 mm in width mask 0.15 mm. For producing masks is a positive film with solder surfaces magnified by 0.20 mm. Covering wire solder mask both sides complete layer cover and other design parameters are shown in Figure 22nd For this production method is used to mask Electra in green semi-gloss paint. Green solder mask is applied to the machine casting equipment, other colors by screen printing.

5.5.2 Screen printing masks

order to negotiate solder mask fabrication screen printing method. On the cleaned surface and ostripovaný DPS is applied to a two-component epoxy solder mask manufacturer PETERS using screen printing with the established pattern motif odmaskovaných seats and is thermally cured. The model is negative film with solder surfaces magnified by at least 0.40 mm. Print masks are carried out on semi-automatic screen printing and applying a mask is different according to the direction of pull squeegee. This procedure is suitable for application in NM-sided PCB. Among the solder points can be printed at a minimum spread NM 0.50 mm. The layer deposition NM and other design requirements for PCB are shown in Figure 23rd For at least 10 m2 DPS can be ordered fabrication NM in blue, red, white or golden yellow. Tampon do not do this already.

5.6 Imprints

making prints, to identify the individual components of mounted, removable coating resists and graphite paste is used screen printing technology. The basis of the film emulsion legibly.

5.6.1 Printing description

for printing the description used two-part epoxy heat-curable inks. Printing can be done on both sides in white, red, black, yellow. Film draft with a legible stored emulsions should have the weakest lines 0.20 mm. The design needed to ensure that the motif print interfere in pads. The piece orders 1-100 pcs printing is describe the implementation of UV curable white color (white photomask). The basis for this work is the negative of the original legibly emulsions. For printing described small number of plates used white, UV-curable solder mask. Printing must be clear, blur-free, clear the appropriate quality film footage, well cured and indelible organic solvents.
At present we are all UV-curable printing ink.

5.6.2 Printing removable nepájivým resist

This technology allows you to create masks to cover designated areas of the PCB to be machine soldered. Protective mask prevents watering holes Sn solder for subsequent soldering of components that have been fitted (wired connections). After successful soldering machine to disguise easily peeled off and covered holes can be individually soldered. Cover mask is applied to the finished PCB silkscreen, after all finishes. For the construction material used is of Coates and the substrate for the production of the film positive artwork.

5.6.3 Printing conductive pastes

Printing conductive, two-part, heat curable paste is screen printing method for coating graphite or silver contact points on the PCB. Used as a cheap substitute galvanic finishes in a PCB contacts with keyboards and other touch points DPS. The treated areas have permanent resistance and oxidize. Guaranteed number of cycles depends on the type of paste. Application is suitable for consumer electronics products. The basis is a positive film with a minimum width of bars and spaces of 0.5 mm. Is preferable to use methods galvanic gilding. This technology has not performed.

5.6.4 Protection against electromagnetic radiation - three-layer

theme PCB shielding against electromagnetic interference or prevention of radiation can either make a multi-layer printed circuit board connections or to apply screen-printed continuous layer of copper polymer. After curing, the surface is conductive and can be electroplated to coat the power specified by the customer. Typically, the surface is plated to 10 microns. Isolation between motive and shielding layer is formed in two layers deposited solder mask. This is due to the distance between the screen and flat shading flat only 40 microns. It can thus successfully to significantly increase the operating frequency of the circuit has been designed and DPS nezhotovovat four-layer board. Commercially they are called three-layer PCB. If the customer is not expressly required to perform three layers, so these boards are produced as a four-layer laminated with two same internal motives.

5.7 Packaging and shipping

boards are packaged by volume contract Individually or 25 pieces in a package samosmršťujícím bottled in polyethylene packaging. The order is shipped in cardboard boxes post. Free space in the packaging shall be displaced suitable material. The best person is taking the customer in our store. You can also arrange other means of transport. The delivery is a delivery note stating the type and quantity supplied DPS. If the shipment is sent, the package also attached invoice. If the agreed repayment documentation is sent separately to avoid damage during shipping. Normal postage is not charged. When sending express or EMS shipping company as shipping costs incurred.

5.8 Storage

manufacturer and the purchaser are required to store the PCB so as not to impair their quality. The boards must be stored in a horizontal position and in the original packaging dry, well-ventilated warehouse with temperature 0 ° C to 35 ° C, with no abrupt changes in temperature with max rel. humidity 75%. Stock must be free of chemical influences. Before processing DPS must be removed from packaging and stored for at least 24 hours at a room temperature of 18-25 ° C.