• Title/Summary/Keyword: sewing speed

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Dynamics of lockstitch sewing process

  • Midha, Vinay Kumar;Mukhopadhyay, A.;Chattopadhyay, R.;Kothari, V.K.
    • The Research Journal of the Costume Culture
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    • v.21 no.6
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    • pp.967-973
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    • 2013
  • During high speed sewing, the needle thread is exposed to dynamic loading, short strike loading, inertia forces, friction, rubbing, force of check spring, bending, pressure, friction, impact, shock and thermal influence. The dynamic thread loading/tension alters throughout the stitch formation cycle and along its passage through the machine. The greatest tensile force occurs at the moment of stitch stretching, when the take up lever pulls for required thread length through the tension regulator. These stresses act on the thread repeatedly and the thread passes 50-80 times through the fabric, the needle eye and the bobbin case mechanism, before getting incorporated into the seam, which result in upto 40% loss in tensile strength of the sewing thread. This damage in the sewing thread adversely affects its processing and functional performance. In this paper, the contribution of dynamic loading, passage through needle and fabric, and bobbin thread interaction in the loss in tensile properties has been studied. It is observed that the loss in tensile properties occurs mainly due to the bobbin thread interaction. Dynamic loading due to the action of take up lever also causes substantial loss in tenacity and breaking elongation of cotton threads.

Neural Network-Based System Identification and Controller Synthesis for an Industrial Sewing Machine

  • Kim, Il-Hwan;Stanley Fok;Kingsley Fregene;Lee, Dong-Hoon;Oh, Tae-Seok;David W. L. Wang
    • International Journal of Control, Automation, and Systems
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    • v.2 no.1
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    • pp.83-91
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    • 2004
  • The purpose of this paper is to obtain an accurate nonlinear system model to test various control schemes for a motion control system that requires high speed, robustness and accuracy. An industrial sewing machine equipped with a Brushless DC motor is considered. It is modeled by a neural network that is configured as an output-error dynamical system. The identified model is essentially a one step ahead prediction structure in which past inputs and outputs are used to calculate the current output. Using the model, a 2 degree-of-freedom PID controller to compensate the effects of disturbance without degrading tracking performance has been de-signed. In this experiment, it is not preferable for safety reasons to tune the controller online on the actual machinery. Experimental results confirm that the model is a good approximation of sewing machine dynamics and that the proposed control methodology is effective.

Performance Improvement of BLDC Motor Speed Control Using Hybrid PWM Method (하이브리드 PWM 방식을 이용한 브러시리스 직류 전동기의 속도 제어 성능 향상)

  • 이동훈;오태석;전성구;김일환;남부희
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.7
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    • pp.491-500
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    • 2004
  • This paper considers a hybrid PWM(pulse width modulation) method which can be used in the brushless DC motor controller. Due to many disadvantages of bipolar PWM method, unipolar PWM method is mostly used in industrial field. In constant speed control application, the unipolar PWM method shows the good performance of speed control. But in the wide range of speed control application, it shows poor performance especially when deceleration is needed. So we propose the hybrid PWM method that utilizes both of bipolar and unipolar PWM methods according to the sign of the speed controller output. Simulation and experimental result show that the proposed method improves speed control performance of the brushless DC motor which is applied to the industrial sewing machines.

Performance Improvement of BLDC Motor Speed Control Using Hybrid PWM Method (하이브리드 PWM 방식을 이용한 브러시리스 직류 전동기의 속도 제어 성능 향상)

  • Lee, Dong-Hoon;Kim, Il-Hwan;Nam, Bu-Hee
    • Proceedings of the KIEE Conference
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    • 2004.05a
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    • pp.19-21
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    • 2004
  • This paper considers pulse width modulation (PWM) methods which are used in 3-phase brushless DC motor controller. Due to many disadvantages of bipolar PWM method, unipolar PWM method is mostly used in industrial field. In constant speed control application, the unipolar PWM method shows a good performance of speed control. But in the wide range of speed control application, it shows a poor performance especially when deceleration is needed. So we propose hybrid PWM method that utilizes two PWM methods according to the sign of speed controller output. The simulation and experimental result shows that the proposed method improves a speed control performance of the brushless DC motor which is applied to industrial sewing machines.

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Enhanced Cooling Performance of Polymer Actuators Using Carbon Nanotube Composites (탄소나노튜브 복합재를 이용한 고분자 액추에이터의 냉각 개선)

  • Piao, Chengxu;Suk, Ji Won
    • Composites Research
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    • v.30 no.2
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    • pp.165-168
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    • 2017
  • Coiled polymer actuators fabricated by twisting polymer fishing lines or sewing threads respond to heating and cooling with their contraction and relaxation. However, their actuation speed is highly dependent on the heating and cooling rates. In order to improve the actuation speed, the coiled polymer actuator was coated with polydimethylsiloxane composites. The introduction of multi-walled carbon nanotubes into the polydimethylsiloxane improved the actuation speed by about 13%.

BLDC(Brushless DC) Motor Control Algorithm to be easily Realized by a Micro Processor (마이크로 프로세서로 손쉽게 구현 가능한 BLDC(Burshless DC)-모터 제어 알고리즘)

  • 이영주
    • Proceedings of the IEEK Conference
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    • 2002.06e
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    • pp.59-62
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    • 2002
  • BLDC motor is widely used in automation areas for its good maintenance and controllability. In this paper it is designed for a speed control servo system of sinusoidal typo BLDC motor that can be easily adapted to automation systems with lower cost. Also, control parameters & periods are made adjustable according to the sensors of the motor, electric and mechanical time constant, and PI and PD control are used. The processor for the proposed system is a low cost 16bit One-Chip microprocessor. By experimental results from application to the industrial sewing machine, one of the application of BLDC motor, it can be verified that under the given reference, the system is enough as a speed and position servo without overshoots.

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A Study on the Conditions of Apparel Products of Stretch Material (II) (스트레치소재(素材) 의류제품(衣類製品)의 생산실태(生産實態) 연구(硏究)(II))

  • Park, Jin-Young;Sohn, Hee-Soon
    • Journal of Fashion Business
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    • v.2 no.2
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    • pp.77-84
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    • 1998
  • As a result of surveying the process for sewing, the problems involving the outlook of sewn apparels were error off the standard dimensions and uneven sizes, which verifies the need for urgent technological guidance and development. On the other hand, the majority of the businesses were operating their sewing machines at the speed of 2,000 rpm or higher. Such a conventional working method may not well reflect the properties of the stretch fabrics, causing poorer quality products. Moreover, most of the businesses were using the ball-point needles which should be replaced with appropriate ones for stretch fabric. The types of feed dog which were used most were Drop feed, Union feed, Confound feed, Differential feed in their oder. Anyway, the automatized dog should urgently replace these inefficient ones for stretch fabric. Meanwhile, the types of presser foot which were used most were Plain foot, Teflon foot, Roller foot, Ring foot in their order, which also necessitates their replacement which Teflon foot. 2. As a result of surveying the process for finishing and inspection, while the causes scores less than 3 points, those due to pressers scored more than 3 points. This results suggests that a technological guidance is needed for the pressing work. Lastly, the causes of defect due to poor outlook attributable to such notions as button or zipper and those due to the uneven sizes scored more than 3 points, which suggests that the entire of needle works should be reformed through scientific research and technological guidance.

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Continuous PTFE Coating Process on Basalt Sewing Thread (현무암 재봉사의 연속식 테프론 코팅 공정)

  • Lee, Soo
    • Journal of the Korean Applied Science and Technology
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    • v.31 no.2
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    • pp.183-189
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    • 2014
  • On the basis of our previous research results concerning a batch Teflon coating process on the surface of basalt fiber which has superior fire-resistance and chemical resistance, we have tried to set up suitable operating conditions for continuous polytetrafluoroethylene(PTFE) coating process. The basalt fiber was continuously pre-treated with 7.5 wt%(6.5% of DPU) of triethoxytrifluoropropylsilane(TMTFPS) and then coated with 20 wt% of PTFE dispersions containing 0.25 wt% of penetrating agent sodium bis(2-ethylhexyl)sulfo succinate (DOS-Na) to get the highest tensile and loop strengths. After dipping process, the PTFE coated basalt fiber was dried under 2 m drying chamber at $120^{\circ}C$ with 12 m/min of winding speed and consequently sintered under 2 m sintering chamber at $380^{\circ}C$ for 40 s. Conclusively, PTFE coated basalt fiber whose tensile and loop strengths were to $3.4g_f/D$ and $2.3g_f/D$, respectively, applicable to high temperature sewing thread could be continuously prepared with our pilot scale process under optimum conditions.

The Maximum Needle Piercing Force through Fabrics Dyed with Loess (황토염색직물의 최대침관통력)

  • 장정대
    • Journal of the Korean Society of Clothing and Textiles
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    • v.23 no.7
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    • pp.971-979
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    • 1999
  • The experiment was conducted on five different kinds of fabrics dyed with loess. The sewability of fabrics dyed with loess by measuring the maximum needle piercing forces(MPF) through fabrics has been studied, MPF measurement using tensile tester was done 60 times for each fabrics at fixed low speed of 300mm/min. The nature of the loess on the dyed fabrics was physically jammed betweenthe fibers or adhered to the surface of fibers in the form of the fine particles so that the MPF through fabrics increases extremely in proportion to the increase of loess uptake and the plying number of fabrics dyed with loess. This results indicate that the MPF through fabrics is affected by mean value of the coefficient of friction on the surface of fabric(MIU) and cloth cover factor(Kc) in this experiment. Fabric was finished with softner to decrease the MPF during sewing operation, The MPF through softner finished fabric was decreased remarkably.

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재봉(裁縫)바늘의 위편성물(緯編聖物) 관통(貫通)에 관한 연구(硏究)

  • Lee, Choon-Gye
    • Journal of the Korean Society of Costume
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    • v.11
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    • pp.51-60
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    • 1987
  • The penetration force of needle and penetration energy kave been investigated, in order to research into the sewing factors that influence the weft knitted fabric with high elastic property. The results of the studies are a follows: (1) As the results have showed a high correlativity between the needle penetration energy and force, it proves that the dynamic energy produced by the friction of the needle as it penetrates and withdraws from the knitted fabric contributes to the heat growth of the needle. (2) To reduce frictional force the use of thin needles, medium ball point needle and super needle are effective. (3) The reduction in number of plies of fabric or also in the case of a decrease in penetration speed have been effective in lowering the penetration energy and force.

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