• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.3
• /
• pp.381-387
• /
• 2010

This paper presents a study of the influence of fixed pressure in turning. The effect of roundness error and diameter deformation were studied with respect to the fixed pressure applied inside the cylindrical work piece made by boring tool in CNC lathe. The boring tool used in this study is a tungsten carbide coated. The material of workpiece is SM45C and the machining method is dry cutting. Cutting conditions as cutting speed, feed rate and depth of cut are constant. Finally, the change of fixed pressure had influence on the roundness error and diameter deformation.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.5
• /
• pp.27-34
• /
• 2021

This study analyzes machining characteristics and presents optimal cutting conditions by measuring the surface roughness, dimensional accuracy, and dimension straightness based on the feed rate after processing the inner diameter hall of SCM415 steel using an automatic CNC(Computerized Numerical Control) lathe. The testing material was cut using an 11.8 mm-diameter Chamdrill after mounting the 32 mm-diameter round bar on an automatic CNC lathe. The cut depth was set at 3 mm, and the cutting speed was fixed at 1500 rpm. The surface roughness, dimensional accuracy, and dimension straightness of 15 testings were measured by changing the feed rate to 0.05, 0.1, and 0.15 mm/rev, respectively. It was difficult to process more than 15 tests during the maching due to noise or break. Additionally, the optimum cutting of SCM415 steel showed excellent surface roughness in the 10^th and 11^th of testing at cutting speed and feed speed of 1500 rpm and 0.05 mm/rev, respectively. The dimensional accuracy was measured in three dimensions after drilling, which showed good results with an average range of 0.0138-0.0208 mm. Moreover, the lower the feed speed, the higher the accuracy. Additionally, the measurement results of the dimensional straightness showed that the straightness is the straightness was the best at the 1^th and 2^th cutting regardless of the feed speed.

• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.1
• /
• pp.11-18
• /
• 2011

A worm screw is widely used in a geared motor unit for motion conversion from rotation to linear. For mass production of a high quality worm, the current rolling process is substituted with the milling process. Since the milling process enables the integration of all operations of worm manufacturing on a CNC(Computer Numerical Control) lathe, productivity can be remarkably improved. In this study, the tooling system for side milling on a CNC lathe to improve machinability is developed. However, the cutting tool-workpiece interference is important factors to be considered for producing high quality worms. For adaptability of various worms machining, the tool-workpiece interference simulation system based on a tool-tip trajectory model is developed. The developed simulation system is verified through several kinds of worms and experimental results.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.8 no.4
• /
• pp.76-82
• /
• 2009

A worm screw is widely used in a geared motor unit for motion conversion from rotation to linear motion. For mass production of a high quality worm, the current roll forming process is substituted with the milling cutter process. Since the milling cutter process enables the integration of all machining operations of worm manufacturing on a CNC(Computer Numerical Control) lathe, productivity can be remarkably improved. The tooling system for side milling cutter on the CNC lathe to improve machinability is developed. However, the runout of spindle and cutting tips are important factors to be considered for producing high quality worms because the tooling system has multiple tips. In this study, surface roughness variations accuracy according to runout was investigated in side milling cutter for worm screw. The result shows by simulation and experiment.

• Journal of the Korean Society for Precision Engineering
• /
• v.26 no.12
• /
• pp.47-54
• /
• 2009

A worm screw is widely used in a geared motor unit for motion conversion from rotation to linear. For mass production of a high quality worm, the current rolling process is substituted with the milling process. Since the milling process enables the integration of all operations of worm manufacturing on a CNC(Computer Numerical Control) lathe, productivity can be remarkably improved. In this study, the tooling system for planetary milling on a CNC lathe to improve machinability is developed. However, the cutting tool-workpiece interference is important factors to be considered for producing high quality worms. For adaptability of various worms machining, the tool-workpiece interference simulation system based on a tool-tip trajectory model is developed. The developed simulation system is verified through several kinds of worms and experimental results.

• Tribology and Lubricants
• /
• v.28 no.3
• /
• pp.130-135
• /
• 2012

This study presents a new methodology for realtime tool breakage detection by sensor fusion concept of two hall sensor and an acoustic emission (AE) sensor. Spindle induction motor torque of CNC Lathe during machining is estimated by two hall sensor. Estimated motor torque instead of a tool dynamometer was used to measure the cutting torque and tool breakage detection. A burst of AE signal was used as a triggering signal to inspect the cutting torque. A significant drop of cutting torque was utilized to detect tool breakage. The algorithm was implemented on a NI DAQ (Data Acquisition) board for in-process tool breakage detection. The result of experiment showed an excellent monitoring capability of the proposed tool breakage detection system. This system is available tool breakage monitoring through internet also provides this system's user with current cutting torque of induction motor.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.11
• /
• pp.1214-1221
• /
• 2009

A high-speed spindle can be very sensitive to rotating mass unbalance which has harmful effect on many machine tools. Therefore, the balancing procedure to reduce vibration in rotating system is certainly needed for all high-speed spindles. So, balancing procedure was performed with a spindle-bearing system for CNC automatic lathe by using numerical procedure. The spindle is supported by the angular contact ball bearings and the motor rotor is fixed at the middle of spindle. The spindle-bearing system has been investigated using combined methodologies of finite elements and transfer matrices. The balancing was performed through influence coefficient method and the comparison was made by whirl responses between before balancing and after balancing. As a result, balancing of simple spindle model reduced whirl orbit magnitude in case of a completely assembled spindle model.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.1
• /
• pp.45-50
• /
• 2012

This paper on analysis of roundness error after boring turning of Al-6061 materials with CNC lathe. Experiment applying turning parameters is based on experimental design method. A design and analysis of experiments is conducted to study the effects of these parameters on the roundness error using the S/N ratio and analysis of ANOVA. Multiple linear regression analysis is applied to compare experimental with predicted data in consideration of roundness error. To fixation pressure and the opening which are a turning parameter, the cutting depth and feed speed respected the objective attainment of dissertation and to be applied the result they investigated.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.391-394
• /
• 2002

This paper introduces that the lathe optimize for main and sub spindle's synchronous in Opening-CNC. In view of optimal design, the mathematical modelling and the frequency domain analysis of spindle's system are performed. For the compensation of synchronous error in compounded manufacture process, the optimization method of motor drive's control parameter and the related parameter is proposed. By the experiment in prototype machines using the server/client program, the validity of the proposed method is verified.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.16 no.5
• /
• pp.19-24
• /
• 2017

In this research, a practical stiffness calculation method is developed and applied for modifying the height of the headstock, turret, and tailstock of a CNC lathe to enlarge the turntable diameter. The casting structure is assumed to be a rigid body and the linear motion element to be an elastic spring to simplify the turret stiffness calculation model. The stiffness of the sliding guide and ball screw of the original lathe is measured with a push tester and LVDT sensor, and the turret stiffness of the modified lathe is predicted and compared with experimental results to verify the model. The measured stiffness of the original turret is $0.17kN/{\mu}m$ and that of the modified turret is $0.11kN/{\mu}m$, i.e., an 18% difference from the predicted result. The verified stiffness calculation model can be used to develop another modified lathe.