Path Optimization For Computer Numerical Control-Printed Circuit Boards In Holes Drilling Process - Case Study

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1 Iteratioal Joural of Egieerig ad Techology Volume 6 No.10, October, 2016 Path Optimizatio For Computer Numerical Cotrol-Prited Circuit Boards I Holes Drillig Process - Case Study Motaz Daadoo Departmet of Computer Systems Egieerig, Palestie Techical Uiversity-Kadoorie (PTUK), Tulkarm, Palestie. P.O. Box 7 Tulkarm-Palestie ABSTRACT Electroic maufacturig sector uses Computer Numerical Cotrol (CNC) machies for drillig holes o Prited Circuit Board (PCB). Some machies do ot choose the optimal route whe completig their tasks. Hece, this paper proposes a approach, which is based o my Algorithm Shortest Path Search Algorithm (SPSA), for fidig the optimal route i PCB holes drillig process. I SPSA, whe the robotic arm at the iitial positio, the algorithm calculates the earest poit to the iitial positio from all poits that the wires starts or eds with. If the earest poit is a start-of-wire poit, it will use SPS algorithm 1. If the earest poit is a ed-of-wire poit, it will use SPS algorithm 2. This process is repeated util drillig all the lies. The, the robotic arm will drill all the holes accordig to the Simulated Aealig Algorithm (AS) which I used to determie optimal machiig parameters for millig operatios. Aealig is the process of slowly coolig a physical system i order to obtai states with globally miimum eergy. By simulatig such a process, ear globally miimum cost solutios ca be fouded for very large optimizatio problems. The results of the differet optimizatio algorithms Geetic Algorithm (GA) ad AS are compared ad coclusios are preseted. The modelig ad simulatio of route optimizatio i holes drillig process usig SPSA is explaied. The frame was desiged i a way that achieved the aims of this paper. The CNC machie cosists of compoets like driver, drill, three stepper motors, cables ad microcotroller PIC16f877A to cotrol the movemet of the machie. This paper also explais the detailed problem of iterest ad the mathematical formulatio of the problem is defied. Experimetal result idicates that the proposed SPSA-based approach is capable to efficietly fid the optimal route for PCB holes drillig process. With this methods, electroics maufacturig sector ca optimize the drillig process hece will icrease the productivity of the maufacturer. Keywords: CNC Machie Desig, Holes Drillig Process, Optimizatio, Routig Problem. 1. INTRODUCTION Computer Numerical Cotrol (CNC) drillig machie plays a importat role i today's maufacturig processes. The machies are applicable with procedure to drillig, spreadig, weaig ad threadig with a lot of precise holes. [Owubolu ad Clerc, 2004] developed a PC-based CNC drillig machie. Both the machie ad the drivig circuitry were built i house. They have used a PC as a separate froted iterface for the drillig machie. The system they had developed itegrated several features such as customized machie cotrol uit, ehaced parallel port commuicatio ad eural etwork based optimizer i order to fid the best distace optimized sequece of poits to be drilled. They have reported successful drillig of PCBs with their system. CNC machies have advaced the holes drillig process as this maufacturig process ow has bee completely automated. CNC drillig machie ca be classified as CNC Prited Circuit Board (PCB) drill, CNC vertical drill, CNC deep-hole drill, drillig ceter ad other large CNC drillig machie[wei et al., 2009]. This machie is used for drillig holes with umerical cotrol ad widely used i hole processig techology for the PCB. Optimal route plaig is ecessary for reducig the time for the CNC machie to complete its task. Curretly, route plaig i CNC machie is doe usig Nearest-Neighbor Algorithm (NNA). The algorithm might be simple to implemet. However, use NNA where the route plaig obtaied from this algorithm does ot guaratee optimal route. For that reaso, may researchers ad academicias attempt to solve the problem by proposig umerous algorithms [Ferdiado et al., 2005]. To achieve more effective results, optimizatio systems approach is required to be equipped i drillig machie. Euclidea Travelig Salesma Problem (TSP) is oe of optimizatio method that gives fast ear optimal solutio for the drillig machie movemet. The objective of this paper is to give best solutio i solvig the routig PCB holes drillig process. I this case, the lies to be drilled are the cities, ad the cost of travel is the time it takes to move the robotic arm from oe hole to the ext. The TSP problem is a combiatorial problem where the objective is to fid the sequece of cities to be visited for the salesma to complete his tour of cities provided the iter-city distace. Similar to TSP, the optimized route i holes drillig process ca be obtaied by fidig the holes sequeces that requires miimal distace travelled by the drill bit. By obtaiig the optimized route, the CNC machie is able to reduce its operatioal time per item, which leads to a icrease i its yield as more tasks ca be completed at a give time. Geetic algorithm (GA) ad simulated aealig algorithm (SA) are two optimizatio approaches that have bee developed idepedetly. Both of these algorithms are probabilistic search algorithms that are capable of fidig globally optimal results to complicated optimizatio problems. For applicatio i ISSN: IJET Publicatios UK. All rights reserved. 365

2 machiig processes, besides [Shumugam et al., 2000] used GA to optimize the multi-pass face-millig ad obtaied optimal cuttig parameters. [Liuad Wag, 1999] improved the covergece speed of traditioal GA ad obtaied good results by defiig ad chagig the operatig domai of GA. This research presets the solutio of the optimal path optimizatio for holes drillig usig the SA techique. The results of the differet optimizatio algorithms GA ad AS are compared ad coclusios are preseted. The objective of this paper is to give best solutio i solvig the routig PCB holes drillig process ad verify the viability of usig SA to solve the holes drillig path optimizatio problem effectively, with miimum cost ad shortest time. We [Daadoo, M. ad Daraghmi, Y., 2015] desiged the frame of hardware i a way that achieved the aims of this paper. This paper aims at describig the desig of a CNC drillig machie. The said machie is desiged with a view to keep the cost of the machie at miimum, hece makig is suitable for use i small or medium scale idustries. Alog with the desig of the mechaical compoets, the electroics ad the software has also bee desiged. I this paper I used a C# laguage to create my software applicatio, which allows the easy itegratio of iput ad output fuctios with ay software that I develop i C#. The system cosists of three mai parts: a mechaical setup that ca move i X, Y ad Z directios, a drivig circuitry ad a software program that cotrols overall operatio of the whole system. I this iitial work, the system is developed such that it produces a trace lie o a PCB board ad drill holes o two pads at both ed of the trace lie. I show that my system successfully performs both of the above tasks. This paper also explais the detailed problem of iterest ad the modelig of route optimizatio i holes drillig process usig SPSA is explaied. Next, the mathematical formulatio of the problem is defied. Followed by the discussio of the implemetatio ad the experimetal results obtaied based o the proposed approach ad fidigs will be summarized. 2. LITERATURE REVIEW AND RELATED WORK The importace of improvig of the CNC process is sigificat; this ca be see by umerous studies published. Based o the reviewed literature, the earliest studies i holes drill routig was coducted by [Kolaha ad Liag, 1996], the researchers suggested the use of Tabu Search Algorithm (TSA) i solvig case study, which cosist of variable holes sizes. Few years later, the authors proposed a improved versio of the TSA i [Kolaha ad Liag, 2000] used a TSA approach to miimize the total processig cost for hole-makig operatios. They cosidered tool travel time, tool switchig time ad the cuttig time ad used the TSA to fid the solutio. I year 2004, [Owubolu ad Clerc, 2004] proposed the implemetatio of Particle Swarm Optimizatio (PSO) for holes drillig problem. [Ketli ad Alkaya, 2009] proposed a ovel hybrid algorithm, Record-To-Record Travel with Local Exchage Moves (RRTLEM) i fidig the optimized sequece. Focusig o CNC machie, the earliest work i holes drill routig problem was doe by [Sigl ad Mayer, 2005]. They itroduced the 2-Opt Heuristic Evolutioary Algorithm (HEA) i solvig drill routig for CNC machie. Usig CNC as the subject, [Abu Qudeiri et al., 2007] employed Geetic Algorithm GA i searchig the optimized route for holes cuttig process i CNC machie tool. While [Ghaiebi ad Solimapur, 2007] had itroduced a At Algorithm (AA) for holes drillig of multiple holes sizes. I year 2006, Zhu highlighted i [Zhu,2006] that PSO might covergeces prematurely. The author the proposed a improved algorithm of PSO which ivolved with Order Exchage List (OEL) ad Order Exchage Uit (OEU). The author proved that these compoets able to improve the result of covetioal PSO, especially i the area of premature covergece. The author use a case study of a PCB cosists of 14 holes of same size. The author the exteds his work to differet case studies i [Zhu ad Zhag, 2008]. Iterestigly, the case study i [Zhu, 2006] has bee take by other papers for bechmarkig purpose. [Adam et. al., 2010] proposed a differet PSO model to solve the case study. A year later, [Othma et al., 2011] applied Biary PSO (BPSO) o the same case study. Result idicates slight improvemet compared to [Zhu ad Zhag, 2008] but the authors also otice that BPSO covergece prematurely ad trapped i two local miima. I year 2012, [Saealal et al., 2012] suggested the use of At Coloy System (ACS) to solve the case study. At Coloy System performs really well for the case study due to the ature of route optimizatio problem which is fudametally based from TSP [Lawler et al., 1985]. Ismail et al. proposed the implemetatio of two latest Computatioal Itelligece Algorithms: Firefly Algorithm (FA) i [Ismail et al., 2012] ad Magetic Optimizatio Algorithm (MOA) i [MohdMuzafar et al., 2013]. Both fidig idicate slight improvemet from [Othma et al., 2011] but ot able to achieve result as [Saealal et al., 2012]. Usig the same case study i [Zhu, 2006], this paper attempt to aalysis the performace of SPSA compared to other metioed algorithms: [Zhu, 2006], [Adam et. al., 2010], [MohdMuzafar et al., 2013]. SA belogs to a class of local search algorithms kow as threshold algorithms. Local search is a improvemet type algorithm that starts with a complete solutio from which a series of better solutios is geerated. SA was first itroduced by [Kirkpatrick et al., 1983] to solve optimizatio problems. It has bee successfully applied to may combiatorial optimizatio problems i such diverse areas as computer-aided desig of itegrated circuits, image processig ad code desig, ad schedulig ad eural etworks. GA mimics the process of atural evolutio by icorporatig the survival of the fittest philosophy [Goldberg, 1989]. I GA, a poit i search space is represeted by biary or decimal umbers, kow as strig or chromosome. Each chromosome is assiged a fitess value that idicates how closely it satisfies the desired objective. A set of chromosomes is called populatio. A populatio is operated by three fudametal operatios, viz., reproductio (to replace the populatio with large umber of good strigs havig high fitess values), crossover (for producig ew chromosomes by combiig the various pairs of chromosomes i the populatio), ad mutatio (for slight radom modificatio of chromosomes). A sequece ISSN: IJET Publicatios UK. All rights reserved. 366

3 of these operatios costitute oe geeratio. The process repeats till the system coverges to the required accuracy after may geeratios. The GA has bee foud very powerful i fidig out the global miima. Further, these algorithms do ot require the derivatives of the objectives ad costraits fuctios. 3. PROBLEM FORMULATION The TSP is oe of the most widely studied combiatorial optimizatio problems, which has liks with may fields of pure ad applied mathematics, like graph theory ad iteger programmig [Lawler et al., 1985]. By the automatio of maufacturig, productio of good becomes a buch of steps ad sequeces like; bolt sequecig, cuttig, drillig ad weldig process steps. Most of these sequecig type egieerig problems ca be modeled as travelig TSP, which is widely kow i operatio research area. Eve though may kids of methods ad algorithms are developed for TSP, a few of them are applied to egieerig problems. The routig problem is a subset of TSP ad may literatures had covered TSP formulatio i great details [Adam et. al., 2010], [MohdMuzafar et al., 2013]. This cocer for calculatio of the miimum tool path legth betwee holes the drillig device has to visit all the lies ad holes oly oce, the machie sequece optimizatio of the lies is similar to TSP. So, the distace of the path ca fudametally be calculated usig TSP which formula writte as i equatio (1). M total = ( x i x j + y i y j ) P ij i=0 j=0 (1) Where is the umber of holes eeded. P ij is the decisio variable related to the assigmet of the drill bit from hole i to j. If movemet of the drill bit from hole i to j, thus, P ij = 1, otherwise, P ij = 0. Coordiates of hole i ad j is (x i, y i) ad (x j, y j).the case study used i this paper, as show i Figure 1, is similar to the previous work, which has bee carried out by [Zhu, 2006], where the objective is to fid the shortest distace for the drill bit to travel i completig its task. The case study is a PCB, which cosists of 14 holes. I the case study, all the holes are havig the same size. The iitial positio is located at the top left corer of the PCB image. The cost (or distace) from iitial positio to the first hole ad the last hole to the iitial positio are igored to stadardize the distace calculatio obtaied with [Adam et. al., 2010], [MohdMuzafar et al., 2013]. As stated i [Adam et. al., 2010], [MohdMuzafar et al., 2013], this case study produced 2 optimal solutios, it is either sequece: or iversed, The distace of the optimal solutio is 280mm. Figure 2, shows the route of the optimal route for the case study. 4. DESIGN Figure 1: PCB image of the 14 holes case study Figure 2: The optimal route for the case study We [Daadoo, M. ad Daraghmi, Y., 2015] desiged the frame of our hardware i a way that achieved the aims of this paper. This paper aims at describig the desig of a CNC drillig machie. It is desiged with a view to keep the cost of the machie at miimum, hece makig is suitable for use i small or medium scale idustries. Alog with the desig of the mechaical compoets, the electroics ad the software has also bee desiged. I this iitial work, the system is developed such that it produces a trace lie o a PCB board ad drill holes o two pads at both ed of the trace lie. We show that our system successfully performs both of the above tasks. Our PCB CNC drillig machie is equipped with three dimesioal movemets ad cosidered to produce good precisio accuracy for a competitive developmet cost comparig with aother machie products maufactured by other machies which is that are ot accurate, especially i drillig holes or trace lie ad with high cost material that is used i desig. Therefore, our desig of this machie ca be widely applied to various small ad medium scale maufacturig idustries, such as we ISSN: IJET Publicatios UK. All rights reserved. 367

4 ca use our machie i aywhere places you eed especially i electroic idustries to processig ad productio PCBs. So, from our experimet we ca see the result of our work piece whe usig o traditioal tool of CNC drillig machie, is this machie did t have a heavy weight comparig with aother ad past CNC machie that is used a traditioal tool, so ay perso ca take it with o complex operatio to easy to use our CNC machie. The existig machie features are compared with the professioal CNC machie. After compariso ad makig the required improvemets, the machie is i a positio to mill complex cotours o PCB, soft wood ad soft metals with cosiderable accuracy ad speed. Achievig this primary goal is the result of the improvemets i both electrical ad mechaical desig. Explorig ew software with better capabilities also helped us i achievig this goal. The workspace ad job clampig system is also improved. Also our machie is super adjustable, ad is desiged to draw o all kids of thigs that are ormally "impossible" to prit o. 4.1 Desig Cosideratios guaratee the force, torque, precisio, ad robustess requiremets Frames Sub Assembly There are four cross sectio plates welded together to form each of the top ad bottom part of the frame. Also other plates are bolted vertically to these portios to form the frame structure. Two beams are placed horizotally alog X axis ad bolted to the vertical beams to form the guides for the X axis base. As show i Figure Work Piece Size As a basis for further developmet of the drillig machie, the maximum compoet size (maximum travel alog the axis) is selected as: X = 450 mm. Y = 300 mm. Z = 180 mm Cofiguratio Selectio The differet cofiguratios are cosidered from fabricatio poit of view, ad it is foud that the gatry cofiguratio is most suitable because of the followig qualities: Provides better rigidity. Better accuracy. Ease of operatio ad programmig Drillig Machie Compoets The drillig machie is divided ito three sub systems. These are The mechaical setup. The drivig circuitry. The software program. 4.2 Machie Desig The machies have desiged with three movemets coordiate, X, Y ad Z. Hole positio cosists of X, Y coordiates, ad Z coordiate is a parameter to move the drill machies up ad dow. The drill is moved horizotally to X, Y coordiates of a hole, moved dow i Z directio to make the hole, the withdraw ad traslated to aother place. Holes data file supplied ad calculated the route with Euclidea TSP by the software to cotrol the drillig machie movemet. The electro-mechaical system is resposible for the 3D motio to positio the drill, ad should be of real idustry stadard to Figure 3: Frame sub assembly X-Axis Sub Assembly Two bearigs are placed o either side of the X axis screw. These bearigs are the supported i the bearig seat provided i the side plates. Two guidig rods are fit betwee the two side plates. Each of the side plates has two M12 taps at the bottom to screw them to the frame. The motor is screwed to the motor support plate which is i tur attached to the guide rods. The shaft of the motor has a radial hole which is used to couple the motor to the screw. Figure 4: X-axis sub assembly Y-Axis Sub Assembly The Y axis is similar i costructio to the X axis sub assembly. The mid plate has two M12 taps for the attachmet of Z axis sub assembly. ISSN: IJET Publicatios UK. All rights reserved. 368

5 Figure 5: Y-axis sub assembly Z-Axis Sub Assembly The Z axis is also similar i costructio to the X axis sub assembly. The mid plate has a provisio for the attachmet of the drill motor. This feature gives our machie the possibility of chagig the Feather drillig ad used for multiple purposes. Figure 6: Z-axis sub assembly as well as to commuicate with the computer. The software program is developed to cotrol overall operatio of the machie. I this iitial work, we [Daadoo, M. ad Daraghmi, Y., 2015] have demostrated that the machie ca produce a trace lie o a sigle layer PCB board ad drill holes o two pads that are o both eds of the trace lie. I cotiue studyig to ehace differet aspects of workig of the system as they will be demostrated i the future works. The mechaical setup has a flat layer o which PCB is put o it to be processed. Above the flat layer, there is a drill that ca move alog X, Y axis. The drill ca also move up ad dow for a specified amout of distace. There is a bit coected to the bottom of the drill. Both trace lies ad holes are produced usig this bit. To produce a trace lie o a sigle layer PCB, we first adjust the drill such that it oly moves dow to 0.5 mm below of the surface of the board. We the sed start coordiate of a trace lie to the PIC. Upo receivig this sigal, PIC moves the drill to the locatio of startig coordiate. Durig this movemet, the drill is at up positio. Whe the drill receives the specified locatio, PCB machie puts the drill at dow positio, starts drillig ad move cotiuously accordig to the coordiates set from computer. The coordiates have to belog to edges of a trace lie that is to be draw. Durig this process, the drill bit carves the copper layer o the surface of the PCB cotiuously as deep as 0.5 mm. Hece the trace lie is separated from the remaiig part of the copper o the PCB whe the process is completed. I order to drill a hole o the same PCB, we let the machie to fiish up the tracig, ad the readjust the drill so that it moves dow approximately 2 mm below of the surface of PCB. After that, we specify coordiates ad let the drill go to those positios ad perform drillig oe at a time. 4.4 Drivig Circuitry 4.3 Method Figure 7: Fial assembly This paper demostrates hardware ad software implemetatio of a PCB machie that is able to draw trace lies ad drill holes to desigated places o a board. The system cosists of a mechaical setup of that ca move i X, Y ad Z directios, a computer, a drivig circuit ad a software program. The drivig circuit is developed to cotrol the mechaical setup I this study the machie drills the wires first, ad the it drills the holes at the begiig ad the ed of wires. The previous study drills the holes first, ad the it drills the wires. A feasible solutio i PCB wires drillig is simply a complete sequece such that all wires must be visited ad each wire is visited oce oly. We desiged ad developed a drivig circuit give i the Figure 8 i order to operate the PCB machie. The drivig circuitry is developed usig a PIC16f877A microcotroller. It cotrols ad rus specific fuctios of the machie such as ruig step motors to move the machie i X, Y axis, ruig the drill ad eablig or disablig a actuator that moves the drill up or dow, it also commuicates with computer port. ISSN: IJET Publicatios UK. All rights reserved. 369

6 The computer is used to perform specific tasks such as sedig coordiates of trace lies ad pads to the drivig circuitry ad receivig ackowledge sigals from the PIC. A program is writte i C# to achieve overall cotrol of the machie ad to perform data commuicatio betwee computer ad drivig circuitry. Coordiates of trace lies ad pads are kept i a file i the computer. It is also a job of the C# program to ope this file, read coordiates ad sed them to the PIC i order to have the PCB machie to perform desired tasks. 5. MODELING ROUTE OPTIMIZATION IN HOLES DRILLING PROCESS May previous papers discussed the holes drillig path optimizatio, but the mai challeges i this paper was gettig the shortest distace path, the drillig the holes o the start ad the ed of wires i a optimizatio path, also the machie will cover the PCB to drill all the wires stored i arrays i program, startig from iitial poit (0, 0), ad it will retur back to iitial positio agai oce the task is completed. The iitial positio will set as the poit (0, 0) i this paper. 5.1 Mathematical Formulatio Whatever algorithm is used, whe the robotic arm arrives the other side of wire, it will agai calculate the earest poit to the curret positio, ad apply the appropriate algorithm, each Lie is drilled, it's two poits ( the start ad the ed poits) are removed from array which all the termiate poits are saved i. So, the distace betwee holes is as i equatio (2): M 1mi = ( x i earest x j earest + y i earest y j earest ) P ij i=0 j=0 The distace which the robotic arm drills wires is as i equatio (3): N 1 M 2mi = L K K=0 Where: N is the umber of lies. L k is the legth of the lie K. Figure 8: The schematic of the drivig circuitry (2) (3) So, the whole Distace which the robotic arm walk is as i equatio (4): i=0 M totalmi = ( x iearest x jearest + y iearest y jearest ) P ij + N L K (4) j=0 The case study show i Figure 1 cosists of 14 holes of same sizes PCB [MohdMuzafar et al., 2013]. This case study, distace betwee start positio to first hole ad last hole to start positio, was igored ad this leads to equatio writte stated i equatio (5): mi(m total ) = mi ( ( x i earest x j earest + y i earest y j earest ) P ij ) (5) i=1 j=1 Like ay other optimizatio techiques, SPSA cosists of two mai parts: iitializatio ad fitess evaluatio. The algorithm starts by iitializig PCB routig problem ad SPSA parameters. The, movig to the secod phase; fitess evaluatio. The fitess of the particles are calculated usig equatio (5). The geeratio ad optimizatio of the tools path is a importat role. Efficiet tool path optimizatio algorithm ca reduce the tool travelig distace ad ca improve productio efficiecy. I the process of geeratig umerical code, the poit is optimized by shorteig the chagig ad movig path to reduce idle travel time, the ca improve processig efficiecy. Therefore, it is worth studied to select the reasoable processig path. So it is very importat to reduce the tools chagig times to improve the processig speed. For the above reasos, I aimed to reach the best time to drill all wires, so, the least time is as i equatio (6): T Least = ( x i earest x j earest + y i earest y j earest ) P ij τ + N L K σ (6) i=0 j=0 Where: τ is the time which eeded to move from curret lie to aother lie. σ is the time which eeded to move from curret positio to ext positio at the same lie. The algorithm is repeated util maximum iteratio reached. Lastly, the algorithm will retur the best-foud sequece with the lowest distace as the recommeded sequece. N 1 K=0 N 1 K=0 ISSN: IJET Publicatios UK. All rights reserved. 370

7 5.2 Path Optimizatio i Track Drillig High-quality ad optimal solutios ca be obtaied by Modelig our Algorithm SPSA, for wires drillig process, It depeds o TSP algorithm, with more istructios to achieve the path optimizatio i movig betwee tracks. I apply SPSA o several cases, The result clearly proves that this algorithm are able to fid the optimal route for robotic drillig route problem at a faster rate tha other proposed models, makig it better tha other proposed models. I this study, I drill the wires first ad the drill the holes at the begiig ad the ed of wires. The previous study drills the holes first, ad the it drills the wires. A feasible solutio i PCB wires drillig is simply a complete sequece such that all wires must be visited ad each wire is visited oce oly. The algorithm calculates the earest poit to the iitial positio from all poits that the wires starts or eds with. With the cotributio i this issue, electroics maufacturig sector ca optimize the drillig process hece will icrease the productivity of the maufacturer The Nearest Poit is a Start-of-Wire Poit If the earest poit is a start-of-wire poit (all poits are o the right or dow of the first poit), it will use SPS algorithm 1, as show i table 1: Table 1: The SPS Algorithm 1 i pseudo-code Algorithm 1: SPS Algorithm for Routig i PCB Drillig Problem Whe The earest poit is a start-of-wire poit 01:Procedure Shortest Path Search Algorithm 1; 02:list track: has the (X, Y) coordiates for all holes; 03:begi 04:for every elemet i track 05:begi 06:if the Y coordiate of the curret elemet less tha the Y coordiate of the ext elemet the go a step dow; 07:if the Y coordiate of the curret elemet greater tha the Y coordiate of the ext elemet the go a step up; 08:if the X coordiate of the curret elemet less tha the X coordiate of the ext elemet the go a step right; 09:if the X coordiate of the curret elemet greater tha the X coordiate of the ext elemet the go a step left; 10:ed; 11:ed; The Nearest Poit is a Ed-of-Wire Poit If the earest poit is a ed-of-wire poit (all poits are o the left or up of the first poit), it will use SPS algorithm 2, as show i table 2: Table 2: The SPS Algorithm 2 i pseudo-code Algorithm 2: SPS Algorithm for Routig i PCB Drillig Problem Whe The earest poit is a ed-of-wire poit 01:Procedure Shortest Path Search Algorithm 2; 02:list track: has the (X, Y) coordiates for all holes; 03:begi 04:for each elemet i track 05:begi 06:if the (X coordiate of the curret elemet is equal to the X coordiate of the previous elemet) ad (the Y coordiate of the curret mius the Y coordiate of the previous elemet) greater tha 0 the go a step dow; 07:if the (X coordiate of the curret elemet is equal to the X coordiate of the previous elemet) ad (the Y coordiate of the curret elemet mius the Y coordiate of the previous elemet) less tha 0 the go a step Up; 08:if the (Y coordiate of the curret elemet is equal to the Y coordiate of the previous elemet) ad (the X coordiate of the curret mius the X coordiate of the previous elemet) greater tha 0 the go a step Right; 09:if the (Y coordiate of the curret elemet is equal to the Y coordiate of the previous elemet) ad (the X coordiate of the curret mius the X coordiate of the previous elemet) less tha 0 the go a step left; 10:ed; 11: ed; 5.3 Path Optimizatio i Holes Drillig May available algorithms ca achieve good solutios for holes drillig problem, so I have decided to implemet the best amog them. Sice its itroductio i 1983, SA has bee applied to a fairly large amout of differet problems i may differet areas, with high quality solutios to the problem i these areas. Holes Drillig problem is ot oe of these areas, o oe implemets it to fid the optimal path for drillig i PCB's. SA is a algorithm that starts with some solutio that is totally radom, ad chages it to aother solutio that is similar to the previous oe. It makes slight chages to the result util it reaches a result close to the optimal [Aarts et. al., 2005]. SA is a stochastic algorithm, meaig that it uses radom umbers i its executio. So every time you ru the program, you might come up with a differet result. It produces a sequece of solutios, each oe derived by slightly alterig the previous oe, or by rejectig a ew solutio ad fallig back to the previous oe without ay chage. Whe SA starts, it alters the previous solutio eve if it is worse tha the previous oe. However, the probability with which it will accept a worse solutio decreases with time, (coolig process) ad with the distace the ew (worse) solutio is from the old oe. It always accepts a ew solutio if it is better tha the previous oe [Nouraiet. al., 1998]. The probability used is derived from The Maxwell-Boltzma distributio which is the classical distributio fuctio for distributio of a amout of eergy betwee idetical but distiguishable particles. I this Study, I use this algorithm to get the best holes drillig optimizatio. The matrix desigates the total distace from oe ISSN: IJET Publicatios UK. All rights reserved. 371

8 city to aother (b: diagoal is 0 sice the distace of a city to itself is 0), the followig pseudo-code describes simulated aealig [Aarts et. al., 2005]. Table 3: The simulated aealig Algorithm i pseudo-code The AS Algorithm, Parameters 01: Procedure SIMULATED. ANNEALING; 02:begi 03:Iitialize (istart, c0, L0 ) ; 04: K :=0; 05:i:= istart; 06:repeat 07:for l:=1 to Lk do 08:begi 09:GENERATE (j from Si) ; 10:if f(j) f(i) the i:=j 11:else 12:if exp f(i) f(j) > radom[0,1) the i:=j C k 13:ed; 14: k= k+1; 15:CALCULATE _LENGTH(Lk); 16:CALCULATE _CONTROL(Ck); 17:util stop reiteratio 18:ed; So, whe implemeted this algorithm i this case study apply it to several cases, the previous results led to the followig geeral observatios: 1. High quality solutios ca be obtaied usig the implemetatio of this algorithm. 2. I may practical situatios, the simulated aealig is the best betwee the curret used algorithms. 3. It gives accurate results i a part of secods, it is the fastest. 4. Icreasig umber of holes does't affect the time ad the quality of the give solutio by simulated aealig algorithm. The results show that the SA is better tha GA i fidig the optimal path for the holes drillig. So, the computer scietists should have take this ito cosideratio. By plottig a chart diagram betwee the umber of holes ad the legth of the optimal path i SA, we will have these results: 6. IMPLEMENTATION AND EXPERIMENTAL RESULT It was ecessary to build a strog software which operates the hardware ad computer elemets. So, a software is built to help the user to draw his ow circuit accurately ad easily, ad the press o butto "start" to sed it to the hardware to have his ow PCB. The optimizatio procedures developed i this work are based o the various o-traditioal approaches that have bee implemeted usig C# laguage. So, the program is writte i C# ad the simulatio is performed 50 times o a laptop that is equipped with 2.20 GHz Itel(R) Core(TM) 2 Duo T6600 processor with 4 GB RAM. As stated, i order to test the approach, Zhu s 14 holes drillig problem [Zhu, 2006] has bee chose due to its popularity. Table 4 lists the iformatio related to the case study show i Figure 1. Table 5 cotais the compariso betwee the commo parameters used i several literatures with this study. Table 6 cotais the compariso betwee the results obtaied by other literatures ad this study. From Table 6, the proposed approach is able to fid the optimal solutio of the case study, which has a fitess of 280mm. I terms of average fitess, the proposed approach has a better fitess compared to GCPSO, PSO, BPSO ad FA. Table 7 shows the experimetal results by applyig the GA ad the SA for the same circuit every time accordig to the legth of the optimal path i each algorithm. There are may optios to select the best algorithm to achieve the optimal path i drillig holes. The SA algorithm ad the GA are the best algorithms accordig to previous studies, ad also accordig to the results o these algorithms. Figure 9: The relatioship betwee the legth of the optimal path i SA ad the umber of holes. As show i the above chart diagram the slope is small, so a icrease i umber of holes does't affect the legth of the path. Whe we apply the SA to the case study, we get the followig result: ISSN: IJET Publicatios UK. All rights reserved. 372

9 Figure 10: The simulated aealig algorithm o the case study So, the SA is a accurate fast algorithm, ad the best i fidig the optimal path i holes drillig. The followig figures of UML diagrams used i this case study are:- Figure 12: Cotext diagram Figure 11: Case diagram Figure 13: Activity diagram ISSN: IJET Publicatios UK. All rights reserved. 373

10 Figure 14: Sequece diagram The followig figures of the software applicatio iterfaces:- Figure 16: Mai iterface The followig figure shows how the drill moves alog the lies: Figure 15: Start dialog iterface Figure 17: Path optimizatio iterface ISSN: IJET Publicatios UK. All rights reserved. 374

11 Table 4: Iformatio of PCB used i the case study Number of holes, 14 Legth 100mm Wide 70mm Hole Number Coordiate (x, y) Hole Number Coordiate (x, y) Hole Number Coordiate (x, y) Hole Number Coordiate (x, y) 0 (0, 0) 1 (10, 60) 2 (10, 10) 3 (18, 16.5) 4 (18, 27.5) 5 (32.32, 57.34) 6 (37.7, 43.6) 7 (37.7, 26.4) 8 (62.3, 26.4) 9 (62.3, 43.6) 10 (90, 60) 11 (82, 53.5) 12 (82, 42.5) 13 (72.59, 14.25) 14 (90, 10) Table 5: Compariso of the commo parameters used i several literatures with this study [Zhu, 2006] [Adam et. al., 2010] [Othma et al., 2011] [MohdMuzafar et al., 2013] Commo Parameters Curret Study Number of iteratios, t Number of computatios Table 6: Compariso of the result obtaied i several literatures with this study [Zhu, 2006] [Adam et. al., 2010] [Othma et al., 2011] [MohdMuzafar et al., 2013] Curret Study GCPSO PSO BPOS FA SPSA Iertia weight, ω Not Applicable Not Applicable Legth of optimal solutio Average fitess after computig 50 computatios ISSN: IJET Publicatios UK. All rights reserved. 375

12 Table 7: A compariso betwee the GA ad the SA Number of holes 7. DISCUSSION AND FUTURE WORK The developmet of CNC PCB drillig machie have bee doe. I its developmet, the cost icurred is very competitive ad relatively cheap compared with the drillig machies available o the market. Several tests must be coducted to adjust the appropriate parameter such as time delay or motor rotatio speed for the optimal work. The comig work, cotiue to ehace differet aspect of the PCB machie i order to have it perform lie tracig ad hole drillig of a complete circuit schematic o a PCB. The system is developed for educatioal purpose ad is curretly i use at Microprocessor Cotrol Lab at A-Najah Natioal Uiversity. 8. CONCLUSION Legth of the optimal path i GA Legth of the optimal path i The proposed CNC PCB drillig machie is equipped with three dimesioal movemets ad cosidered to produce good precisio accuracy for a competitive developmet cost comparig with aother machie products maufactured by other machies which is that are ot accurate, especially i drillig holes or trace lie ad with high cost material that is used i desig. We have desiged ad developed a PCB machie that is able to draw trace lies ad drill holes o a sigle layer PCB board. We have tested our system ad showed that the PCB machie successfully draw a trace lie ad drilled holes o both ed of the lie. I this study, the proposed approach SPSA is implemeted to fid the optimized path for PCB holes drillig process. It is a simple method ad easy to implemet to fid the best route for holes drillig process. High-quality ad optimal solutios ca be obtaied by modelig the SPS algorithm for wires drillig process. This algorithm ca effectively solve the problem i the multi-poit processig. It ca ot oly shorte the processig time but also make up for the deficiecy of productio efficiecy of CNC machies. The result clearly proves that these algorithms are able to fid the optimal route for robotic drillig route problem at a faster rate tha other proposed models, makig it better tha other proposed models. SA I this paper, I verify the viability of usig SA to solve the holes drillig path optimizatio problem effectively, with miimum cost ad shortest time. May available algorithms ca achieve good solutios for holes drillig problem, so I have decided to implemet the best amog them. Optimizatios procedures have bee developed i this work based o the o-traditioal approaches, i.e., GA ad SA, ad are implemeted successfully for solvig the optimizatio problem. Software has bee writte i C# laguage ad results obtaied by the differet approaches are compared ad the performaces are aalyzed for the multiobjective fuctio of miimizig total pealty cost ad miimizig total machie idleess. Through this cotributio electroics maufacturig sector ca optimize the drillig process hece will icrease the productivity of the maufacturer. ACKNOWLEDGMENT The author would like to thak Palestie Techical Uiversity Kadoorie (PTUK) ad A-Najah Natioal Uiversity for supportig this research ad allowig him to coduct this work i the uiversity labs. My Sicere thaks go to Dr.Saed Tarapiah from A-Najah Natioal Uiversity for his cotiuous cooperatio. The system is developed for educatioal purpose ad is curretly i use at Microprocessor Cotrol Lab at A- Najah Natioal Uiversity. REFERENCES Aarts, E., Korst, J., & Michiels, W. (2005).Simulated Aealig. Search Methodologies, Abu Qudeiri, J., Yamamoto, H., & Ramli, R. (2007).Optimizatio of operatio sequece i CNC machie tools usig geetic algorithm. Joural of Advaced Mechaical Desig, Systems, ad Maufacturig, 1(2), Adam, A., Abidi, A. F. Z., Ibrahim, Z., Husai, A. R., Yusof, Z. M., & Ibrahim, I. (2010, May). A particle swarm optimizatio approach to Robotic Drill route optimizatio. I 2010 fourth Asia iteratioal coferece o mathematical/aalytical modelig ad computer simulatio (pp ).IEEE. Daadoo, M., & Daraghmi, Y. (2016, April). Desig ad Implemetatio of Low Cost Computer Numerical Cotrol- Prited Circuit Boards Drillig Machie. Joural Iteratioal Joural of Egieerig ad Iovative Techology, 5(10), Ferdiado, H., Sadjaja, I. N., & Sajaya, G. (2005, September).Automatic Drillig Machie for Prited Circuit Board. I Proceedigs of The 6th Symposium o Advaced Itelliget Systems, Surabaya Idoesia (pp ). Goldberg, D. E. (1989).Geetic Algorithms i Search, Optimizatio ad Machie Learig, Addiso-Wesley Publishig Compay, Ic., New York. Ghaiebi, H., & Solimapur, M. (2007).A at algorithm for optimizatio of hole-makig operatios. Computers & Idustrial Egieerig, 52(2), ISSN: IJET Publicatios UK. All rights reserved. 376

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