Component Placement Machines Research Articles

Data-driven system prognostics and diagnostics for SMT component placement machines

Prognostic-based maintenance analyses past events and predicts the future state of a machine based on the understanding of the degradation function of the machine’s components. Diagnostics-based maintenance tests equipment according to a fixed routine for a machine’s proper functioning and reliability. Current Surface-mount Technology (SMT) machines are not equipped with self-prognostic and diagnostic functions. In this paper, a system prognostic and diagnostic method is proposed, implemented in software, for estimating a machine’s health condition and faulty components of a SMT component placement machine outfitted with machine logs that consist of take-up count, miss count and time information. At each execution period the method processes features extracted from the machine logs to obtain a set of parity parameters, which are further used to analyse the machine. The prognostic algorithm computes the health status indicator of the component placement machine. The computed final status indicator is compared to a threshold value to check the system’s health condition. The diagnostic algorithm predicts and identifies the faulty pick-up nozzles and faulty input trays. The proposed algorithms minimise the effects of faulty components on production lines and assist to produce optimal maintenance decisions and reliability functions for equipment.

A Novel Coarse–Fine Method for Ball Grid Array Component Positioning and Defect Inspection

With high production efficiency and robustness, automatic component pick-and-place technology is widely used in modern electronic industries. As one of the core components of this technology, the visual measurement system requires a suitable positioning and fault detection algorithm with high speed, accuracy, robustness, and generalization abilities, especially for positioning and inspecting ball grid array (BGA) components. This paper examines the online positioning and defect inspection problem of BGA components for component placement machines. Incorporating coarse and fine positioning, an accurate, efficient, and robust universal positioning algorithm is proposed. Two types of key points are introduced to characterize the alignment of solder balls in BGA components. A distance transform-based circle detection method is first applied, and then a distance-based edge filter and a circle fitting method are employed to obtain the coarse and fine locations of solder balls, respectively. The approximate location of the component is estimated using a geometrical method and the fine location is calculated by solving a least-squares problem. A pair of overlapping ratios is introduced to conduct fault detection and inspect the alignment accuracy. The effectiveness of the proposed method is verified by applying it to several real component positioning and defect inspection experiments.

An adaptive clustering-based genetic algorithm for the dual-gantry pick-and-place machine optimization

This research proposes an adaptive clustering-based genetic algorithm (ACGA) to optimize the pick-and-place operation of a dual-gantry component placement machine, which has two independent gantries that alternately place components onto a printed circuit board (PCB). The proposed optimization problem consists of several highly interrelated sub-problems, such as component allocation, nozzle and feeder setups, pick-and-place sequences, etc. In the proposed ACGA, the nozzle and component allocation decisions are made before the evolutionary search of a genetic algorithm to improve the algorithm efficiency. First, the nozzle allocation problem is modeled as a nonlinear integer programming problem and solved by a search-based heuristic that minimizes the total number of the dual-gantry cycles. Then, an adaptive clustering approach is developed to allocate components to each gantry cycle by evaluating the gantry traveling distances over the PCB and the component feeders. Numerical experiments compare the proposed ACGA to another clustering-based genetic algorithm LCO and a heuristic algorithm mPhase in the literature using 30 industrial PCB samples. The experiment results show that the proposed ACGA algorithm reduces the total gantry moving distance by 5.71% and 4.07% on average compared to the LCO and mPhase algorithms, respectively.

Heavy-Weight Component First Placement Algorithm for Minimizing Assembly Time of Printed Circuit Board Component Placement Machine

This paper deals with the PCB assembly time minimization problem that the PAP (pick-andplacement) machine pickup the -weighted group of -components, loading, and place into the PCB placement location. This problem considers the rotational turret velocity according to component weight group and moving velocity of distance in two component placement locations in PCB. This paper suggest heavy-weight component group first pick-and-place strategy that the feeder sequence fit to the placement location Hamiltonean cycle sequence. This algorithm applies the quadratic assignment problem (QAP) that considers feeder sequence and location sequence, and the linear assignment problem (LAP) that considers only feeder sequence. The proposed algorithm shorten the assembly time than iATMA for QAP, and same result as iATMA that shorten the assembly time than ATMA. ▸

Combining and solving sequence dependent traveling salesman and quadratic assignment problems in PCB assembly

In this study we undertake the optimization of chip shooter component placement machines which became popular in assembling printed circuit boards (PCB) in recent years. A PCB is usually a rectangular plastic board on which the electrical circuit to be used in a particular electronic equipment is printed. The overall optimization of the chip shooter placement machines leads to a very complicated optimization problem which we formulate here for the first time (without any simplifying assumptions). However, it is possible to decompose the problem into placement sequencing problem and feeder configuration problem which turn out to be sequence dependent traveling salesman problem (SDTSP) and Quadratic Assignment Problem (QAP), respectively. We use simulated annealing metaheuristic approach and the heuristics developed for the SDTSP in an earlier study to solve these two problems in an iterative manner. We also attempt to solve the combined overall optimization problem by simulated annealing and artificial bee colony metaheuristics and compare their performances with the iterative approach. The results are in favor of iterative approach.

Organizing the nozzle magazine of a gantry-type PCB assembly machine

The present work studies the operation control of so-called collect-and-place component placement machines. These kinds of machines are suited for the flexible manufacturing of various printed circuit board products. These machines operate in cycles where a set of components is first collected from the component feeders to the vacuum nozzles of the component placement head. The head then moves on the circuit board and places the components to their appropriate locations. Different component types require the use of different nozzle types, but the placement head has only a limited capacity for nozzles. Hence, the ability to change nozzles every now and then allows the manipulation of a great variety of component types with the same machine. This is accomplished by storing a larger selection of nozzles in a separate nozzle magazine from where the nozzle collection of the placement head can be updated. The cost of changing the nozzle setup is, however, relatively large compared to the time costs of other operations in the placement cycle. What complicates things more is that the nozzle change cost is affected by the organization of nozzles in the magazine, too. The aim of this work is to determine the contents of the nozzle magazine in such a way that the change operation times are as small as possible. We develop two heuristics (a genetic algorithm and a swarm optimization algorithm) for this purpose and evaluate their performance on sample problems. Both heuristic approaches are capable of processing realistic production problems, in particular the genetic algorithm finds near-optimal results for small problem instances and outperforms clearly our other approaches for larger problems.

Estimating the operation time of flexible surface mount placement machines

Gantry type component placement machines are widely used in electronics industry due to their accuracy, speed and flexibility. In order to make optimal plans of their usage one has to know the manufacturing time of a given component placement work before the actual processing. This presupposes the use of a reliable machine simulator. In the present article, discrete-event simulation is applied to predict component placement times of gantry type machines. The generic simulator model is based on a circumstantial analysis of the time factors by the means of observing and measuring the times of operations performed by the machine. As a result of this, very high accuracy is achieved; the operation times predicted by the simulator are for a particular machine type (Universal Instruments GC-60D) in range ±1 % from the observed operation times.

APPLICATIONS OF SOLDER PREFORMS TO IMPROVE RELIABILITY

As early as the 1990s people were predicting the end of through-hole components, but they are alive and well with the numbers of dual in-line packages (DIPs) and connectors still measured in the 10s of billions per year. Many of these components are assembled by wave soldering, however in mixed technology (SMT and through-hole on the same board) where the through-hole count is low, it is often advantageous to consider selective soldering or the pin-in-paste process (PIP). PIP is a process in which solder paste is printed over or near the PWB through-holes. The through-hole components are then placed and the solder joint is formed during the reflow process. PIP has the advantage of eliminating the wave soldering process step. In many cases it is difficult to print enough solder paste to make an acceptable through-hole solder joint. Solder preforms were developed to meet this need. These solder preforms are typically shaped in the form of 0402, 0603, or 0805 passive components. The preforms are placed on the appropriate printed solder paste deposit by a component placement machine. Preforms come in tape & reel packaging. Today solder preforms are also used in other “solder starved” applications such as radio frequency (RF) shields, connectors, and under QFN thermal pads. In all cases, the extra solder delivered by the preform is vital to the reliability of the assembled product. In this paper, process, design, and assembly methods for solder fortification using preforms will be discussed. Four successful solder fortification examples will be presented along with the associated defect reductions.

Efficient operation methods for a component placement machine using the patterns on printed circuit boards

Operation of a PCB assembler is complicated to optimise since it requires simultaneous consideration of a component's rack assignment and component mounting sequencing. However, most previous researches considered the constraints separately on the optimisation process. Two different methods using special features on printed circuit boards are developed and presented in this research. Based on results from field surveys, it is found that identical components are positioned closely with each other or identical single boards are repeatedly printed on one big board to enlarge up to a proper size to be assembled in the machine. These patterns are adapted on the design of assembly methods to increase productivity. Simulation models are constructed using Visual C++ for performance evaluation purposes of the developed heuristics.

Contactless power supply for moving sensors and actuators in high-precision mechatronic systems with long-stroke power transfer capability in x– y plane

In this paper, a new topology for contactless energy transfer is proposed and tested that can transfer energy to a moving load using inductive coupling. This contactless energy transfer topology is designed to supply power to the moving parts in high-precision mechatronic systems without cable slabs. The proposed topology provides long-stroke contactless energy transfer capability in the x– y plane and a short-stroke movement of a few millimeters perpendicular to the plane. In addition, it is tolerant to rotations. The electrical steady-state, electrical transient, combined electrical and mechanical transient and forces of the contactless energy transfer system are modeled. The experimental setup consists of a platform with one secondary coil, which is attached to a linear actuator. Underneath the platform is an array of primary coils, that are each connected to a half-bridge square wave power supply. The load on the secondary side is a rectifier with a 50 Ω resistor. The energy transfer to the load is measured while the secondary coil is moved over the array of primary coils by the linear actuator. The secondary coil moves with a stroke of 18 cm at speeds over 1 m/s, while up to 265 W of power is transferred continuously with 90% efficiency. The proposed system is very suitable for transferring energy without cable slab to planar actuators and to conventional linear (short- and long-stroke) actuators in high-precision motion systems, such as lithography, die-bonding and component placement machines.

Assembly time minimization for an electronic component placement machine

In this study, a new algorithm for a particular component placement machine is proposed. Also, a pairwise exchange procedure is designed and applied after the proposed algorithm. In the analyzed machine, previously proposed algorithms were mounting the components from lightest to heaviest where we propose to mount the components from heaviest to lightest. This method brings new opportunities in terms of performance gain on typical Printed Circuit Boards produced in the industry. The new algorithm is compared with former approaches on synthetically generated instances. It outperforms the former approaches by 1.54 percent on printed circuit boards with 100 components to be placed. It gives better results in 96 out of 100 instances. Applying the designed pairwise exchange procedure after the proposed algorithm further improves the total assembly time. Moreover, by taking advantage of inherent design of the analyzed PCBs, other promising improvement procedures are also suggested for minimizing total assembly time. By applying all the suggested techniques to the problem instances, performance improvement rate reaches up to 4.5 percent when compared with previous studies. Since the architecture and working principles of widely used new technology placement machines are very similar to the one analyzed here, the improvement techniques developed here can easily be generalized to them.

3505 多品種プリント基板実装ラインにおける段取計画技術(S50 生産システムの新展開(基礎理論/産業応用),21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

This paper considers the operation of an electronic component placement machine. We developed a new feeder setup planning algorithm for a turret-type placement machine to increase productivity of printed circuit board (PCB) assembly. It is based on offline setup strategy which exploits a feeder hot-swapping mechanism of the placement machine. The proposed algorithm is examined by real-life PCB data. The productivity by the offline setup strategy is compared to those of unique setup and group setup strategy. It is shown that our algorithm achieves significant improvement in productivity.

Investigating the self-alignment of chip components during reflow soldering

Since the application of lead-free soldering has become obligatory in the electronic industry by the 1st of July 2006, the in-depth analysis of the soldering process is more important than ever. The small chip components of the present days demand very accurate component placement machines to prevent common reflow failures such as skewing or tombstoning. The ability of components to be self-aligned during soldering works against these failures, therefore it matters to what extent the solder promotes this effect. Dynamic behaviour of SMT (Surface Mount Technology) chip components during lead-free reflow soldering will be demonstrated in the paper. A force model has been introduced with the five main forces which determine the movement of the chip component during reflow soldering, namely: the force originating from the surface tension, the forces originating from hydrostatic and capillary pressure, the force of gravity, and the force of dynamic friction. The self-alignment of 0603 size chip components has been investigated by real experiments. SM chip components are misplaced intentionally by semi-automatic pick & place machine, and before and after reflow soldering the exact location of components was measured. The results have shown that the self-alignment of components does occur even in the case of 400-500 \mu m lateral misplacements. The explanation of the equations of the applied theory and the results of the experiments are presented in the paper in details.

Modelling the operations of a component placement machine with rotational turret and stationary component magazine

Two major problems faced in the automated assembly of printed circuit boards are the determination of a component placement sequence and the internal arrangement of the component tapes in the feeder mechanism. The forms of these problems depend mainly on the physical design of the placement machine. The definition and solution of these optimization problems are attempted by many researchers and it is possible to find lots of relevant papers in the literature. However, most of these studies are concentrated on certain machine designs. In this study, the focus is on a particular machine type that has a rotational turret and a stationary component magazine. So far, this type of machine has received little attention among the researchers. The definition of the placement sequencing and feeder configuration problems are given and solution procedures are suggested. The performance of the suggested procedures are tested on real and randomly generated PCB assembly data.

A genetic-based algorithm for the operational sequence of a high speed chip placement machine

Surface mount component placement machines are widely used in electronic manufacturing industry for automated placement of components on printed circuit boards. In this paper, we propose a new approach to the component placement problem using high speed turret style chip shooter machine and investigate the case of one single machine and one board type case with the objective of minimizing the assembly (cycle) time per board. The proposed method first groups the component types that can be processed at the same machine speed. Then the minimum spanning tree technique is employed to perform feeder duplications, reducing the distance effect between components of each type. Finally, a genetic-based algorithm with 2-opt local search using feeder arrangement list as solution representation is applied to determine the component placement sequence. Our experimental results indicate that the algorithm produces satisfactory solutions when a lower bound on cycle time per board is used as the evaluation criterion. It is also shown that the overuse of feeder duplication will produce a negative effect on the cycle time. Finally, the algorithm can help management to make a production plan that takes both component inventory cost and cycle time into consideration.

Allocation of Component Types to Machines in the Automated Assembly of Printed Circuit Boards

Although the use of electronic component placement machines has brought reliability and speed to the printed circuit board (PCB) assembly process, to get higher utilization, one needs to solve the resulting complex operations research problems efficiently. In this study, the problem of distributing the assembly workload to two machines deployed on an assembly line with two identical component placement machines to minimize the line idle time is considered. This problem is NP-Complete even in its simplest form. A mathematical model and several heuristics have been proposed to solve this problem efficiently.

Optimizing the operation sequence of a chip placement machine using TSP model

Surface mount component placement machines are being widely used in electronic manufacturing industry for automated placement of components on printed wire boards (PWBs). Their performance is determined by their board assembly time. Factors that determine this include the machine's architecture and placement sequence algorithm, and component locations on the board. For a given machine and a board, the assembly time can be improved by optimizing the placement sequence algorithm. This paper presents a formulation and solution of the assembly time optimization problem for the FUJI FCP-IV component placement machine. The formulation gives a mathematical description of the assembly time that can be optimized as an integer programming problem. A near-optimal solution that can be obtained in a computationally efficient manner has been obtained by relaxing the problem to an instance of the traveling salesman problem (TSP). Simulation has been conducted on some actual boards and the results have been compared with those obtained by the actual runs at Lexmark, Inc., Lexington, KY. This shows that significant reduction in component placement time can be achieved by the proposed optimization algorithm.

Optimal Robotic Component Placement

An increasingly common feature of manufacturing companies is the use of robotic component placement machines in the assembly of electrical goods. These machines place electronic components at predefined positions on printed circuit boards. A robotic arm, which carries one component at a time, collects components from feeders and places them, under computer control, onto the printed circuit board.Using examples provided by a major New Zealand manufacturer, we investigated the problem of assigning component reels to feeder positions and then constructing efficient placement sequences for such a robotic placement machine. An integer programming formulation is developed for this problem that, unlike previous solution techniques in the literature, can produce solutions which provably minimize total placement time for all company supplied sample problems. This solution method generates solutions approximately 10% better than those generated manually by the manufacturer's engineers.

Optimal Robotic Component Placement

An increasingly common feature of manufacturing companies is the use of robotic component placement machines in the assembly of electrical goods. These machines place electronic components at predefined positions on printed circuit boards. A robotic arm, which carries one component at a time, collects components from feeders and places them, under computer control, onto the printed circuit board. Using examples provided by a major New Zealand manufacturer, we investigated the problem of assigning component reels to feeder positions and then constructing efficient placement sequences for such a robotic placement machine. An integer programming formulation is developed for this problem that, unlike previous solution techniques in the literature, can produce solutions which provably minimize total placement time for all company supplied sample problems. This solution method generates solutions approximately 10% better than those generated manually by the manufacturer's engineers.

PPA-A precise, data driven component tool

This paper outlines the development of a data-driven, fine pitch component placement machine, PPA-A, which is an integrated robotic workcell developed for attaching fine pitch integrated circuit components to printed circuit boards. In particular, the objectives for the machine are reviewed, and an overview of the solution is given. Problems encountered during the development are discussed, and details of the algorithms developed to solve these problems are given. These problems relate to achieving very precise placement of components, and are solved by novel calibration and execution schemes. >