Optimizing the Cycle Time of a Multi-Spindle Pick-and-Place Machine

2007 ◽  
Author(s):  
Ashok Thiagarajan ◽  
Purushothaman Damodaran ◽  
Krishnaswami Srihari
Keyword(s):  
Cycle Time ◽  
Assembly Line ◽  
Vision System ◽  
Circuit Board ◽  
Cost Ratio ◽  
Solder Paste ◽  
Component Placement ◽  
Pick And Place ◽  
Feeder Assignment ◽  
Placement Machine

A typical Printed Circuit Board (PCB) assembly line comprises of three major process steps, namely solder paste printing, component placement, and soldering. A stencil printer is typically used to deposit adequate amount of solder paste at appropriate locations on the PCB. One or more component placement (pick-and-place type) machines are then used to populate the PCB. Finally, the entire assembly is passed through an oven for establishing the solder joint. It has been widely accepted that the component placement step is usually the bottleneck. Consequently, the cycle time of the placement machine has to be reduced in order to improve the throughput of the assembly line. Placement machines are expensive and hence their benefit-cost ratio can be improved by improving their cycle time. The objective of this research was to reduce the cycle time of a pick-and-place component placement machine with multiple spindles. The pick-and-place machine chosen for this study was the bottleneck in an assembly line at an electronics manufacturing facility. The primary functions of a placement machine are (1) to pick components from feeder slots, (2) check for any defects using the vision system, and (3) to place the components at appropriate locations. Two important decisions which affect the cycle time are (1) feeder assignment (component location along the feeder rack) and (2) the component placement sequence. A heuristic was proposed to determine the feeder assignments and the component placement sequence was determined by solving a multiple Traveling Salesman Problem (mTSP). The objective of the feeder assignment problem was to minimize the distance traveled by the head along the feeder rack (during the pick cycle). The objective of the component placement sequencing problem was to minimize the distance traveled by the head over the PCB (during the placement cycle). The individual placement tours are later sequenced such that the number of nozzle changes required is minimized. The time taken to populate a board (time to pick + place + nozzle changeover) using the proposed approach was compared to the software which was supplied by the vendor of the machine. Several ‘production boards’ were chosen for this experimental study. The proposed solution approaches outperformed the solutions suggested by the machine’s software for all the ‘production boards’ experimented with. The resulting improvements in cycle times demonstrate the effectiveness of the proposed approach.

Optimization of Multiple Head SMT Placement Machine: Model and Approaches

2002 ◽  
Author(s):  
Youjiao Zeng ◽  
Junqi Yan ◽  
Ye Jin ◽  
Tao Jiang
Keyword(s):  
Printed Circuit Board ◽  
Travelling Salesman Problem ◽  
Minimum Weight ◽  
Optimal Solution ◽  
Circuit Board ◽  
Matching Problem ◽  
Machine Model ◽  
Head Surface ◽  
Pick And Place ◽  
Placement Machine

In order to maximize the throughput rate of single multiple head surface mounted technology placement machine, the time taken for pick-and-place of components for each printed circuit board has to be minimized. This gives rise to two related essential problems, namely feeder assignment problem and pick-and-place sequence determination problem. In this paper, we introduce a model that simplifies problems. We regard all components during a pick-and-place cycle as a unit and give it a matching weight. In this way, we change multiple head machine problems into single head machine problems. The optimisation problem becomes two sub-problems: minimum weight matching problem and travelling salesman problem of these units. We presented algorithms to obtain near optimal solution and implement them as a computer program. We performed experiment on a real four head placement machine. The experimental results are presented to analyse their performance.

Optimization of Component Placement Scheduling for SMT Assemblies

2006 ◽  
Vol 505-507 ◽  
pp. 1123-1128
Author(s):  
Chung Hsien Kuo ◽  
M.D. Jeng ◽  
J.J. Wing ◽  
Tai Hong Wang
Keyword(s):  
Cycle Time ◽  
Heuristic Search ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Component Placement ◽  
Printed Circuit ◽  
Search Approach ◽  
Optical Positioning ◽  
Surface Mounting ◽  
Assembly Models

The surface mounting of electronic component is the major manufacturing technology for the electronic products in the last decade. The surface mounting technology (SMT) is an assembly process that assembles the surface mountable component (SMC) and the printed circuit board (PCB) together. The SMT mounter is an automatic assembly machine that processes the SMT assemblies in terms of the optical positioning and robotic handling. The SMT assembly consists of calibrating printed circuit board (PCB); vacuuming components form feeder stations; compensating the orientation of the vacuumed surface mountable component (SMC); and finally placing SMC chips on the PCB. In order to increase the throughput, the synchronous batch vacuuming of SMC components is designed. In addition, different types of component feeding and mixing in each batch increase the difficulties of finding the best component mounting sequence. In this paper, the optimal component placement scheduler is desired to perform higher assembly performance and to reduce the cycle time. The proposed optimal component placement scheduler is developed based on the rule based heuristic search approach. In addition, to evaluate the cycle time of each heuristic search, the route oriented Petri nets (ROPN) based SMT assembly models are constructed. The optimal component placement scheduler can be further determined in terms of evaluating the ROPN SMT assembly models. Finally, the practical test PCB board data is discussed in this paper.

scholarly journals Egocentric Gesture Recognition Using 3D Convolutional Neural Networks for the Spatiotemporal Adaptation of Collaborative Robots

2021 ◽  
Vol 15 ◽  
Author(s):  
Dimitris Papanagiotou ◽  
Gavriela Senteri ◽  
Sotiris Manitsaris
Keyword(s):  
Gesture Recognition ◽  
Pose Estimation ◽  
Cycle Time ◽  
Assembly Line ◽  
Vision System ◽  
Human Robot Interaction ◽  
Human Operator ◽  
Physical Interaction ◽  
Collaborative Robots ◽  
Human Operators

Collaborative robots are currently deployed in professional environments, in collaboration with professional human operators, helping to strike the right balance between mechanization and manual intervention in manufacturing processes required by Industry 4.0. In this paper, the contribution of gesture recognition and pose estimation to the smooth introduction of cobots into an industrial assembly line is described, with a view to performing actions in parallel with the human operators and enabling interaction between them. The proposed active vision system uses two RGB-D cameras that record different points of view of gestures and poses of the operator, to build an external perception layer for the robot that facilitates spatiotemporal adaptation, in accordance with the human's behavior. The use-case of this work is concerned with LCD TV assembly of an appliance manufacturer, comprising of two parts. The first part of the above-mentioned operation is assigned to a robot, strengthening the assembly line. The second part is assigned to a human operator. Gesture recognition, pose estimation, physical interaction, and sonic notification, create a multimodal human-robot interaction system. Five experiments are performed, to test if gesture recognition and pose estimation can reduce the cycle time and range of motion of the operator, respectively. Physical interaction is achieved using the force sensor of the cobot. Pose estimation through a skeleton-tracking algorithm provides the cobot with human pose information and makes it spatially adjustable. Sonic notification is added for the case of unexpected incidents. A real-time gesture recognition module is implemented through a Deep Learning architecture consisting of Convolutional layers, trained in an egocentric view and reducing the cycle time of the routine by almost 20%. This constitutes an added value in this work, as it affords the potential of recognizing gestures independently of the anthropometric characteristics and the background. Common metrics derived from the literature are used for the evaluation of the proposed system. The percentage of spatial adaptation of the cobot is proposed as a new KPI for a collaborative system and the opinion of the human operator is measured through a questionnaire that concerns the various affective states of the operator during the collaboration.

Design of spline surface vacuum gripper for pick and place robotic arms

2020 ◽  
Vol 4 (2) ◽  
pp. 48-55
Author(s):  
A. S. Jamaludin ◽  
M. N. M. Razali ◽  
N. Jasman ◽  
A. N. A. Ghafar ◽  
M. A. Hadi
Keyword(s):  
Cycle Time ◽  
Industrial Robot ◽  
Annealing Process ◽  
Vacuum Suction ◽  
Robotic Arms ◽  
Custom Made ◽  
Pick And Place ◽  
Manufacturing Procedure ◽  
Production Flexibility ◽  
The Impact

The gripper is the most important part in an industrial robot. It is related with the environment around the robot. Today, the industrial robot grippers have to be tuned and custom made for each application by engineers, by searching to get the desired repeatability and behaviour. Vacuum suction is one of the grippers in Watch Case Press Production (WCPP) and a mechanism to improve the efficiency of the manufacturing procedure. Pick and place are the important process for the annealing process. Thus, by implementing vacuum suction gripper, the process of pick and place can be improved. The purpose of vacuum gripper other than design vacuum suction mechanism is to compare the effectiveness of vacuum suction gripper with the conventional pick and place gripper. Vacuum suction gripper is a mechanism to transport part and which later sequencing, eliminating and reducing the activities required to complete the process. Throughout this study, the process pick and place became more effective, the impact on the production of annealing process is faster. The vacuum suction gripper can pick all part at the production which will lower the loss of the productivity. In conclusion, vacuum suction gripper reduces the cycle time about 20%. Vacuum suction gripper can help lower the cycle time of a machine and allow more frequent process in order to increase the production flexibility.

scholarly journals Eco-Friendly Lead-Free Solder Paste Printing via Laser-Induced Forward Transfer for the Assembly of Ultra-Fine Pitch Electronic Components

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3353
Author(s):  
Marina Makrygianni ◽  
Filimon Zacharatos ◽  
Kostas Andritsos ◽  
Ioannis Theodorakos ◽  
Dimitris Reppas ◽  
...  
Keyword(s):  
High Resolution ◽  
Form Factors ◽  
Circuit Board ◽  
Lead Free ◽  
Process Conditions ◽  
Solder Paste ◽  
Electronic Components ◽  
Successful Operation ◽  
Fine Pitch ◽  
Forward Transfer

Current challenges in printed circuit board (PCB) assembly require high-resolution deposition of ultra-fine pitch components (<0.3 mm and <60 μm respectively), high throughput and compatibility with flexible substrates, which are poorly met by the conventional deposition techniques (e.g., stencil printing). Laser-Induced Forward Transfer (LIFT) constitutes an excellent alternative for assembly of electronic components: it is fully compatible with lead-free soldering materials and offers high-resolution printing of solder paste bumps (<60 μm) and throughput (up to 10,000 pads/s). In this work, the laser-process conditions which allow control over the transfer of solder paste bumps and arrays, with form factors in line with the features of fine pitch PCBs, are investigated. The study of solder paste as a function of donor/receiver gap confirmed that controllable printing of bumps containing many microparticles is feasible for a gap < 100 μm from a donor layer thickness set at 100 and 150 μm. The transfer of solder bumps with resolution < 100 μm and solder micropatterns on different substrates, including PCB and silver pads, have been achieved. Finally, the successful operation of a LED interconnected to a pin connector bonded to a laser-printed solder micro-pattern was demonstrated.

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