• Title/Summary/Keyword: Setup Time

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Tool-Setup Monitoring of High Speed Precision Machining Tool

  • Park, Kyoung-Taik;Shin, Young-Jae;Kang, Byung-Soo
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.956-959
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    • 2004
  • Recently the monitoring system of tool setting in high speed precision machining center is required for manufacturing products that have highly complex and small shape, high precision and high function. It is very important to reduce time to setup tool in order to improve the machining precision and the productivity and to protect the breakage of cutting tool as the shape of product is smaller and more complex. Generally, the combination of errors that geometrical clamping error of fixing tool at the spindle of machining tool and the asynchronized error of driving mechanism causes that the run-out of tool reaches to 3$^{\sim}$20 times of the thickness of cutting chip. And also the run-out is occurred by the misalignment between axis of tool shank and axis of spindle and spindle bearing in high speed rotation. Generally, high speed machining is considered when the rotating speed is more than 8,000 rpm. At that time, the life time of tool is reduced to about 50% and the roughness of machining surface is worse as the run-out is increased to 10 micron. The life time of tool could be increased by making monitoring of tool-setup easy, quick and precise in high speed machining tool. This means the consumption of tool is much more reduced. And also it reduces the manufacturing cost and increases the productivity by reducing the tool-setup time of operator. In this study, in order to establish the concept of tool-setup monitoring the measuring method of the geometrical error of tool system is studied when the spindle is stopped. And also the measuring method of run-out, dynamic error of tool system, is studied when the spindle is rotated in 8,000${\sim}$60,000 rpm. The dynamic phenomena of tool-setup are analyzed by implementing the monitoring system of rotating tool system and the non-contact measuring system of micro displacement in high speed.

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An M/G/1 Queue under the $P_\lambda\;^M$ with a Setup Time

  • Lee Jiyeon;Kim Jongwoo
    • Proceedings of the Korean Statistical Society Conference
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    • 2004.11a
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    • pp.301-306
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    • 2004
  • We consider the $P_\lambda\;^M$ service policy for an M/G/1 queue in which the service rate is increased from 1 to M at the exponential setup time after the level of workload exceeds $\lambda$. The stationary distribution of the workload is explicitly obtained through the level crossing argument.

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The study of stochastic inventory model with setup cost and backorder rate (Setup cost와 Backorder rate를 고려한 확률적 재고모형에 관한 연구)

  • 유승우;서창현;김경섭
    • Proceedings of the Korea Society for Simulation Conference
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    • 2003.06a
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    • pp.129-134
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    • 2003
  • In this paper, we determine optimal reduction in the lead time and setup cost for some stochastic inventory models. And we propose more general model that allow the backorder rate as a control variable. We first assume that the lead time demand follows a normal distribution. And we assume that the backorder rate is dependent on the length of lead time through the amount of shortages. The stochastic models analyzed in this paper are the classical continuous and periodic review policy models with a mixture of backorders and lost sales. For each of these models, we provide a sufficient conditions for the uniqueness of the optimal operating policy. We also develop algorithms for solving these models and provide illustrative numerical examples.

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Parallel Machine Scheduling Considering the Moving Time of Multiple Servers

  • Chong, Kyun-Rak
    • Journal of the Korea Society of Computer and Information
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    • v.22 no.10
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    • pp.101-107
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    • 2017
  • In this paper, we study the problem of parallel machine scheduling considering the moving time of multiple servers. The parallel machine scheduling is to assign jobs to parallel machines so that the total completion time(makespan) is minimized. Each job has a setup phase, a processing phase and a removal phase. A processing phase is performed by a parallel machine alone while a setup phase and a removal phase are performed by both a server and a parallel machine simultaneously. A server is needed to move to a parallel machine for a setup phase and a removal phase. But previous researches have been done under the assumption that the server moving time is zero. In this study we have proposed an efficient algorithm for the problem of parallel machine scheduling considering multiple server moving time. We also have investigated experimentally how the number of servers and the server moving time affect the total completion time.

Post-Silicon Tuning Based on Flexible Flip-Flop Timing

  • Seo, Hyungjung;Heo, Jeongwoo;Kim, Taewhan
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.16 no.1
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    • pp.11-22
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    • 2016
  • Clock skew scheduling is one of the essential steps to be carefully performed during the design process. This work addresses the clock skew optimization problem integrated with the consideration of the inter-dependent relation between the setup and hold times, and clock to-Q delay of flip-flops, so that the time margin is more accurately and reliably set aside over that of the previous methods, which have never taken the integrated problem into account. Precisely, based on an accurate flexible model of setup time, hold time, and clock-to-Q delay, we propose a stepwise clock skew scheduling technique in which at each iteration, the worst slack of setup and hold times is systematically and incrementally relaxed to maximally extend the time margin. The effectiveness of the proposed method is shown through experiments with benchmark circuits, demonstrating that our method relaxes the worst slack of circuits, so that the clock period ($T_{clk}$) is shortened by 4.2% on average, namely the clock speed is improved from 369 MHz~2.23 GHz to 385 MHz~2.33 GHz with no time violation. In addition, it reduces the total numbers of setup and hold time violations by 27.7%, 9.5%, and 6.7% when the clock periods are set to 95%, 90%, and 85% of the value of Tclk, respectively.

Measurement of Setup and Hold Time in a CMOS DFF for a Synchronizer (동기회로 설계를 위한 CMOS DFF의 준비시간과 유지시간 측정)

  • Kim, Kang-Chul
    • The Journal of the Korea institute of electronic communication sciences
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    • v.10 no.8
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    • pp.883-890
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    • 2015
  • As the semiconductor processing technology has been developing, multiple cores or NoC(network on chip) can be contained in recent chips. GALS(globally asychronous locally synchronous) clocking scheme that has multi-clock domains with different frequencies or phase differences is widely used to solve power consumption and clock skew in a large chip with a single clock. A synchronizer is needed to avoid a synchronization problem between sender and receiver in GALS. In this paper, the setup and hold time of DFF required to design the synchronizer are measured using 180nm CMOS processing parameters depending on temperature, supply voltage, and the size of inverter in DFF. The simulation results based on the bisection method in HSPICE show that the setup and hold time are proportional to temperature, however they are inversely proportional to supply voltage, and negative values are measured for the hold time.

GLSP setup algorithm based on a GMPLS (GMPLS 기반의 GLSP 경로 설정 알고리즘)

  • Kim, Kyoung-Mok;Oh, Young-Hwan
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.43 no.11 s.353
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    • pp.192-199
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    • 2006
  • Establishment of bandwidth and effective traffic processing are required to treat various traffics according to a rapid increase in Internet traffic. A path setup algorithm was introduced to support backbone franc processing but the failure probability is increasing according to fixed operation in nodes. In other words, fixed maximum permitted time can be raised failure probability. So as to solve this problem, this paper introduces variable path setup time algorithm which support channel service of excessive traffic that is generated from not allowed channel. We proposed GLSP(Generalized Label Switch Path) setup algorithm that use variable path setup time parameters. This algorithm can improve path setup probabilities of backbone network that is composed of fixed way.

An analysis of the $M^{X}/G/1$ system with various vacations and set-up time (준비기간을 포함한 다양한 휴가형태에서의 $M^{X}/G/1$ 시스템 분석)

  • Hur, Sun;Yoon, Young-Ho;Ahn, Sun-Eung
    • Journal of the Korean Operations Research and Management Science Society
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    • v.27 no.2
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    • pp.111-121
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    • 2002
  • In this paper, we analyze an M$^{x}$ /G/1 with three types of vacation periods including setup time. Three types of vacations are : N-policy, single vacation, and multiple vacation. We consider compound poisson arrival process and general service time, where the server starts his service when a setup is completed. We find the PGF of the number of customers in system and LST of waiting time, with welch we obtain their means. A decomposition property for the system sloe and waiting time is described also.

Impact of Call Setup Time on UPT Performance Based on AIN Platform

  • Baik, In-Kywan;Jo, Jun-Mo;Kim, Sung-Un;Jung, Sin-Il
    • Journal of Korea Multimedia Society
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    • v.1 no.2
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    • pp.249-255
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    • 1998
  • This paper analyzes the impact of Call Setup Time on UPT performance based on the AIN platform. Call Setup Time is used as the performance parameter. In implementing UPT based on the AIN platform, the geographical location of VLR affects network performance. In order to find an optimum location of VLR among three different types of structures, i.e. VLR is located close to Service Switching Point and Cell Site Controller and located at Service Control Point, each Call Setup Time on proposed time delay model is calculated and compared. Network performance is analyzed by changing the number of STP in No.7 signaling network in UPT and the utilization ratio, $\rho$, for SSP, STP and SCP.

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Heuristics for Sequencing Printed Circuit Boards on a Surface Mount Device Placement Machine (SMD기계의 PCB 생산순서 결정을 위한 발견적 기법)

  • Song, Chang-Yong;Shinn, Seong-Whan
    • IE interfaces
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    • v.13 no.2
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    • pp.195-203
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    • 2000
  • This paper considers the problem of sequencing printed circuit boards(PCBs) on an automatic surface mount device(SMD) placement machine in order to minimize total setup time. Since the total set of component feeders needed by all boards cannot be loaded simultaneously on the magazine, the setup must be made between two successive boards in the sequence. It is assumed that the setup time depends on the number of component feeders to be replaced in the magazine. An important characteristic is that each feeder occupies a different number of slots in the magazine. This problem is equivalent to travelling salesman problem(TSP) except that the distances between two cities, that is, the setup times between two boards, are not known in advance. So, TSP-based heuristics with new distance functions are presented and their performances are compared through various test problems. Computational results indicate that our heuristics outperform existing methods.

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