PCB_MF

9.3 BLANKING:When parts are designedrectangular and the volumethe expense of Building a dipunched from sheets by usi A Blanking operation is wmaterial. Odd shapes that cannot bshearing or sawing are eithe

to have shapes other thane is great enough to justify ie, the parts are frequently ing Blanking diewell adapted to paper-base be feasibly produced by er Blanked or Routed.

9.4 Shearing:When copper clad laminashear should be set with onclearance between the squa

ate are to be sheared, thenly 0.025 to 0.05mmare ground blades.

9.5 Sawing:Sawing the copper clad laaccomplished with a circula gives a smoother cut andnature of laminated materiadiamond-steel-bonded sa

aminates is bestar sawd because of the abrasivealsaws can be used.









9.6 ROUTING:Routing offers the fabricator tedge finishes and closer toleranshearing or sawing.It can eliminate the expense olead times associated with hard

the advantages of superiornces than can be obtained fromof blanking dies and the longd tooling.





9.7 DRILLING:To produce an opening thpermit a subsequent procesconnection between Top, BIntermediate conductor patTo permit through the boawith structural integrity and

hrough the board, this will ss to form an electricalBottom and sometimes in th ways. ard component mountingd precision of location.





9.8 CNC / LASER DHoles or via’s through a Pwith tiny drill bits made of sThe drilling is performed bmachines with placement ccalled numerically controlleFiles”. The drill file describe thedrilled hole.

DRILLINGPCB are typically drilled solid tungsten carbide. by automated drilling controlled by drill file ed drill (NC) files or ‘Exelone location and size of each





9.9 LASER & SYSTEMLASER : Light amplifstimulated EmissionThe most commonly used iare.1) NDYAG laser (Neody Aluminium garnet)2) Co2- carbon dioxide gaseous lasing mediu

M CONCEPT:fication vian of radiation. industrial machining lasersymium drifted yittrium laser, which has a um.





UNITMULTI LAY

T 10YER PCB









10.1 Description :What is MultilayerMultilayer boards consiststhin PCB’s stacked togetherwith insulting Prepregs to foElectrical connection betwconductive layers is done w

r Board? s of a certain number ofr and adhesively joined orm one rigid board. ween the differentwith plated through holes.

10.2 The need for m1.When weight and volumeare the parameters importaairborne, missile and spaceintegrated circuits are utilize2.When the complexity of insystems will require very cowiring or harnessing.

multilayere saving in interconnection ance as in militarye applications or when ed. nterconnection in subomplicated and costly

3.When coupling or shieldininterconnections is requireddistributed between the difdecoupling of power supplyspeed circuits.

ng of a large percent ofd. The high capacitancefferent layers gives a goody and this permits high

4. When frequency requiremcontrol and uniformity of coimpedances with minimumpropagation) characteristicshigh importance.5.When the spacing of terma sufficient density of interccircuit boards.

ment call for careful onductor (wavem distortion in signal s from board to board isminal points does not allow connection on two sided

6.The layout design is greatlthe absence of the VCC & grplanes.

ly simplified on account ofround lines on signal





Multilayer Board t•Finer Lines•Increased Density•Smaller holes•Closely spaced holes•Larger boards•Higher speeds•Surface mount•Higher power dissipatio

trendson.

MLB advantages :•Low-loss and low-dielectricspeeds become faster.•Dimensional stability as feaboard bigger.•Improved thermal propertiadhesion.•Surface mounted componecommon.•Lower x-axis expansion as b

c constant materials asatures become smaller andies as power becomesents become moreboard thickness increases.

Multilayer Board•Conventional plat•Buried via•Blind via

d Types:ted through hole.