• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1144-1149
• /
• 2003

It is very important to measure circular motion accuracy of NC lathes it affects accuracy, performance, interchange ability and quality of machine parts machined by the NC lathes in industries. So, in this study, measuring units system to measure circular motion accuracy two axes circular motion accuracy of NC lathes was composed of two optical linear scales installed on the z and x-axes of work coordinate system on NC lathe and a computer inserted with PC counter card enables to obtain measuring data. Here, ATC(Automatic Tool Changer) and moving part of linear scales are fixed with magnet bases in order to measure circular motion accuracy of the ATC of NC lathe. And next, computer software was developed in order to measure the circular motion accuracy of NC lathe under resolution of 0.1 $\mu\textrm{m}$ using two linear scales, and also computer softwares were developed so that measuring data could be modeled on plots and be analyzed numerically,

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.51-54
• /
• 2002

This paper deals with an implementation of NUBS interpolator and presents the process of its integration into PC-NC. For more accurate feed, NURBS algorithm is improved. Also, Evaluation of real time NURBS interpolator is provided to verify fred accuracy and geometrical accuracy of NURBS curve. NURBS machining of fee surface is simulated on the real time NC simulator so that machining time is compared to that of linear path machining.

• Journal of Mechanical Science and Technology
• /
• v.17 no.3
• /
• pp.336-342
• /
• 2003

Increasing demand on precision machining using computerized numerical control (CNC) machines have necessitated that the tool move not only with the smallest possible position error but also with smoothly varying feedrates in 3-dimensional (3D) space. This paper presents the simultaneous 3D machining process investigated using a retrofitted PC-NC milling machine. To achieve the simultaneous 3-axis motions, a new precision interpolation algorithm for 3D Non Uniform Rational B-Spline (NURBS) curve is proposed. With this accurate and efficient algorithm for the generation of complex 3D shapes, a real-time NURBS interpolator was developed using a PC and the simultaneous 3D machining was accomplished satisfactorily.

• Korean Journal of Poultry Science
• /
• v.42 no.2
• /
• pp.133-137
• /
• 2015

We investigated the effects of supplementing low energy diets with lysolecithin and sodium stearoyl-2-lactylate on growth performance and nutrient digestibility in broilers. A total of 768 1-d-old Ross 308, mixed gender broiler chicks with an average initial body weight of 44.3 g, were used in a 35-d feeding trial. Broiler chicks were sorted into pens with 16 birds per pen and every treatment consisted of 12 pens (192 chickens per treatment). Treatments were: 1) PC: basal diet, 2) NC: PC-100 kcal, 3) T1: NC+ 0.08% lysolecithin, and, 4) T2: NC + 0.04% sodium stearoyl-2-lactylate. Body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) were measured on a weekly basis. Chromium oxide was added to the diets at 0.2% on the last week of the experiment, as a marker for digestibility. Dietary treatments had no effect on growth performance for days 1 to 21. Low energy diet supplemented with lysolecithin and sodium stearoyl-2-lactylate in phase 2 (d 21 to 35) improved body weight gain (P<0.05). Addition of lysolecithin and sodium stearoyl-2-lactylate to the diets improved the digestibility of energy and nitrogen (P<0.05), but digestibility of dry matter was not affected. Overall, addition of an emulsifier to the diet of broiler chickens in the late growth phase enhanced growth performance and digestibility of energy and nitrogen.

• Animal Bioscience
• /
• v.35 no.11
• /
• pp.1752-1759
• /
• 2022

Objective: Effects of direct-fed Enterococcus faecium plus bacteriophages (EF-BP) were investigated as potential substitutes for pharmacological ZnO for weanling pigs. Methods: Dietary treatments were supplementations to a basal diet with none (NC), 3,000-ppm ZnO (PC), 1×10¹⁰ colony-forming units of E. faecium plus 1×10⁸ plaque-forming units (PFU) of anti-Salmonella typhimurium bacteriophages (ST) or 1×10⁶ PFU of each of anti-enterotoxigenic Escherichia coli K88 (F4)-, K99 (F5)-, and F18-type bacteriophages (EC) per kg diet. In Exp 1, twenty-eight 21-day-old crossbred weanling pigs were individually fed one of the experimental diets for 14 days and euthanized for histological examination on intestinal mucosal morphology. In Exp 2, 128 crossbred weanling pigs aged 24 days were group-fed the same experimental diets in 16 pens of 8 piglets on a farm with a high incidence of post-weaning diarrhea. Results: None of the diarrheal score or fecal consistency score (FCS), average daily gain (ADG), gain: feed ratio, structural variables of the intestinal villus, and goblet cell density, differed between the EF-BP (ST+EC) and NC groups, between EF-BP and PC, or between ST and EC, with the exception of greater gain: feed for EF-BP than for PC (p<0.05) during days 7 to 14 (Exp 1). In Exp 2, ADG was less for EF-BP vs PC during days 0 to 7 and greater for EF-BP vs NC during days 7 to 14. FCS peaked on day 7 and declined by day 14. Moreover, FCS was less for EF-BP vs NC, did not differ between EF-BP and PC, and tended to be greater for ST vs EC (p = 0.099). Collectively, EF-BP was comparable to or slightly less effective than PC in alleviating diarrhea and growth check of the weanling pigs, with ST almost as effective as PC, when they were group-fed. Conclusion: The E. faecium-bacteriophage recipe, especially E. faecium-anti-S. typhimurium, is promising as a potential substitute for pharmacological ZnO.

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.1
• /
• pp.97-101
• /
• 2006

Certain amino acids are essential precursors of a variety of important biomolecules in addition to their major function as protein building blocks. ${\delta}$-Aminolevulinic acid (ALA) is synthesized from the condensed form of succinyl-CoA with glycine after decarboxylation catalyzed by ALA synthase. The objective of the study was to determine the effects of ALA supplementation on growth performance, behavioral characteristics and hematological/immune status in nursery pigs. A total of 144 pigs weaned at 21 d of age were allotted to three dietary treatments representing (-) control (w/o antibiotics; NC), (+) control (w/carbadox at 50 mg/kg; PC), and the treatment group with ALA supplementation (0.05%; TA). Each treatment had 6 pens (replicates) with 8 pigs per pen. Pigs were fed phase 1 (21.9% CP, 1.40% Lys) and 2 (20.6% CP, 1.15% Lys) experimental diets for 3 and 2 wks, respectively. Feed intake and weight gain were measured weekly during phase 1 and at the end of phase 2. At the end of phase 2, blood samples were taken and analyzed using an automated hematology analyzer. Skin color and activity of pigs (48 h) from all pens in each treatment were measured at the second week of phase 2. Growth performance was not affected (p>0.05) by the dietary supplementation of ALA during the 5 wk nursery period. Pigs in the TA (6.46) and PC (6.68) had a higher (p<0.05) number of red blood cells ($10^6cell/{\mu}L$) than pigs in the NC (6.15). Pigs in PC (12.16) had a higher (p<0.05) hemoglobin level (g/dL) than pigs in the NC group (11.29) and the TA group (11.47). Pigs in the TA and PC had darker (p<0.05) and less (p<0.05) yellow skin color than pigs in the NC. Pigs in the PC tended (p = 0.081) to be less active than pigs in the other groups. There were no differences in behavioral characteristics between the NC and the TA. The data suggest that ALA supplementation has no adverse effects on growth performance of nursery pigs. Moreover, ALA supplementation increased red blood cell counts which may be beneficial to pigs.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.12 no.3
• /
• pp.75-81
• /
• 2003

Pocket machining is metal removal operation commonly used for creating depressions in machined parts. Numerically controlled milling is the primary means for machining complex die surface. These complex surfaces are generated by a milling cutter which removes material as it traces out pre-specified tool paths. To machine, a component on a CNC machine, part programs which define the cutting tool path are needed. This tool path is usually planned from CAD, and converted to a CAM machine input format. In this paper I proposed a new method for generating NC tool paths. This method generates automatically NC tool paths with dynamic elimination of machining errors in 2$\frac{1}{2}$ arbitrary shaped pockets. This paper generates a spiral-like tool path by dynamic computing optimal pocket of the pocket boundary contour based on the type and size of the milling cutter, the geometry of the pocket contour and surface finish tolerance requirements. This part programming system is PC based and simultaneously generates a G-code file.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.8
• /
• pp.136-142
• /
• 2004

This paper deals with the design and implementation of an open architecture CNC system for Wire-EDM, with a consideration of the difference between Wire-EDM and NC cutting machines. Recent open architecture controller(OAC) related research results could be applied to directly access Wire-EDM systems at the CNC level. However, previous research about OAC is mostly aimed at NC cutting machines such as milling or lathes, and hence these results are inadequate to apply to Wire-EDM. To close the gap between previous general research on OAC and Wire-EDM specific needs, an open architecture NC model for Wire-EDM composed of a synchronization kernel and a NC functional module is proposed. Based on the control information flow and Wire-EDM specific machining process, the conceptual CNC model and the detailed implementation model for Wire-EDM is suggested.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.1039-1042
• /
• 1995

In real time application such as motion control, it is hard to find the application of non-causal filtering due to its need for future position data, even though it shows wide usage in off-line digital signal processing. Recently, some of motion control areas such as learning and repetitive control use non-causal filtering technique in their application. these kinds of zero-lag non-causal filter application are very usful not only to reduce the machine vibration, but also to increase control accuracy with comparatively less work. In this paper, genuine method to implement zero-lag non-causal filter in a CNC is introduced. Also the variation of this implementation for the learning operation is suggested to give the NC better control performance for a specific job. By adopting the new NC architecture call Soft-NC, all these implementions are made possible here, and especially large memory requirement which hinders their usage for many years is no longer barrier in their real world application.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.692-697
• /
• 1997

This paper presents a method of grinding and polishing automation of precision die after CNC machining. The method employs a robot system equipped with a pneumatic spindle and a special abrasive film pad. The robote program is automatically generated off-line from a PC and downloaded to robot controller. Position and orientation data for the program is supplied from cutter contact (CC) data of NC machining process. This eliminates separate robot teaching process. This paper aims at practical automation of die finishing process which is very time consuming and suffering from shortage of workpeople. Time loss for changeover from one product to next is eliminated by off-line programming exploiting appropriate NC machining data. Dextrous 6-axis robot with rigid wrist and simple tooling enables the process applicable to larger, rather complex 3 dimensional free surfaces