The stage amounts to transducer to measure the application in the experiment in cutting force

However, cutting Speed Is Effected By Workpiece Diameter.

For Obtaining A Legible And Perfect Hump Curve, a Delta Transducer Was Applied To Carry Out Stepless Speed Regulating Of The Main Electromotor Of Machine Tool.

Consequently, the Main Shaft Speed Was Decided By The Electromotor Working Frequency And Speed Selection Handles.

The Experiment Result Shows That The Legible And Perfect Hump Curve Can Be Achieved Under The Stepless Speed Regulating.

Keywords: A technology that principle of cutting of metal of 　 of foreword of Delta Transducer Machine Tool Stepless Speed Regulating Cutting Force Hump Curve 1 is law of treatment of research metal cutting is scientific. The cutting treatment of metallic stuff is to use the cutting tool of material of workpiece of hardness prep above to cut one part metal on workpiece, the appearance precision that gets satisfaction a requirement thereby, dimension precision and exterior quality [1, 2] . Law of treatment of research metal cutting tastes quality and manufacturing efficiency to raising high yield crucial, reason principle of this metal cutting is countrywide college the mandatory content of class of foundation of all enginery major. Metallic cutting process can understand for cut metal (the metallic layer that should be cut on workpiece) plasticity of the generation after the elbow that gets cutting tool is out of shape, from workpiece depart comes down to form the course that cuts bits. Of cut metal be out of shape is the result that cutting tool gives force effect, this force is cutting force, it is metallic cutting process in one of important phenomena [1-4] . The factor that affects cutting force has a lot of, cutting speed is having relatively special law to its influence. In conventional test, cutting speed suffers the effect of workpiece diameter, cause experimental effect not apparent, not ideal even. The article plans to use transducer to implement the stepless speed regulation of machine tool main shaft, it is cutting speed then also can stepless changes, make thereby every time the experiment can get relatively ideal test result. The influence of 2 cutting speed to cutting force when stuff of metal of brittleness of cutting of regular 　 　 (wait for) like brass of casting pig, lead, cut bits to submit collapse broken form, plasticity is out of shape small, knife - bits attrition is small, reason cutting rate is not old to the influence of cutting force. But when stuff of cutting plasticity metal (wait for) like 45 steel, nodular cast iron, the cutting speed influence to cutting force is shown 1 times like the graph. Popularly, cutting force cent is X, y, 3 component of force of Z direction, among them the component of force of Z direction gives priority to cutting force, express with Fc. By the graph 1 can see, what Fc follows cutting speed Vc is elevatory, appear " decrease - add - decrease " trend, this kind of relation of Fc-vc is called again " hump curve " , this basically is the influence be caused by that gets the lump that accumulate bits. In plasticity material cutting, in Vc not tall and can form when cutting bits continuously, near blade of cutting tool cutting often adhesion the nugget that a section plane shows a triangle, call the tumour that accumulate bits, its height Hb suffers Vc effect, hb is taller, make actual before part is larger, cause cutting strength smaller. When Vc<20m/min, those who follow Vc is elevatory, hb lifts gradually, make Fc is reduced gradually, around Vc=20m/min, hb rises to highest, make Fc occurrence minimum is worth; When 20m/min <vc<30m/min, those who follow Vc is elevatory, hb is decreased gradually low, make Fc increases gradually, around Vc=30m/min, hb is decreased gradually low to 0, accumulate bits tumour to disappear namely, make Fc appears great value; It is after that when Vc>30m/min, those who follow Vc is elevatory, appear without the tumour that accumulate bits again, fc is slow reduce. The Vc (m/min) of problem cutting speed in 3 experiments pursues the influence of 1 cutting speed to cutting force [2] 　 workpiece: 45 steel (normalizing, 187HBS) ; Cutting tool: YT15 solders lathe tool of the circle outside face of the knife before style is smooth, γ O=18o, α O=6o~8o, =4o~6o of α O ′ , κ R=75o, κ R ′ =10o~12o, λ S= 0o, r ε =0.

2mm; Cutting dosage: Ap=3mm, f=0.

25mm/r. Get a picture through turning experiment commonly 1 medium curve, but the Vc in turning by type (1) is calculated and get. (The D in 1) type -- workpiece diameter (Mm) ; N -- main shaft rotate speed (R/min) . Nextpage 　 by type (1) is knowable, the D in the experiment is smaller and smaller, make Vc is affected, workpiece diameter cannot pass small, can be not worth because of stiffness otherwise and produce vibration. N is a series of rotate speed that through rotate speed on the machine tool gear of handle adjustment drive realizes. For example CA6140 lathe main shaft has 10, 12.

5, 16, 20, 25, 32, 40, 50, 63, 80, 100, 125, 160, 200, 250, 320, 400, 450, 500, 560, 710, 900, 1120 reach 1400 R/min in all 24 class rotate speed. And below the circumstance that the extreme value dot in hump curve appears in Vc<40~50m/min only. Graph 2 gave out the workpiece diameter influence to cutting speed. See not hard, suffer workpiece diameter effect, when the timing having class that gear cooperates, when 20m/min <vc<50m/min, have 4~5 only several foothold, get not easily fitly " hump " medium extreme value dot. This needs reason to have stepless speed regulation to machine tool main shaft, make cutting speed changes continuously, get the extreme value in hump curve is nodded thereby. N (r/min) of main shaft rotate speed pursues the influence of 2 workpiece diameter to cutting speed the 4 stepless speed regulation that implement machine tool main shaft with transducer 4.

The electric control 　 of 1 transducer timing changes to can make Vc successive, namely stepless of main shaft rotate speed changes, use a stage to amount to VDF075V43A transducer to be opposite CA6140 lathe advocate electric machinery has stepless speed regulation. Graph 3 gave out the electric control hookup of transducer timing. When needing stepless speed regulation, close by pushbutton SBB contactor KMH and KMB(KMY disconnect) ; When wanting stepless speed regulation, close by pushbutton SBY contactor KMY (KMH and KMB disconnect) , such one machine is amphibious. When applying actually, still must undertake to the parameter of transducer necessary adjust [5] . Of electric machinery start and stop to be controlled by pushbutton SB, locomotive frequency is given by slip rheostat R, set limits is 0~50Hz. Graph the electric control hookup of 3 transducer timing 4.

The cutting speed 　 after 2 frequency control advocate electric machinery implemented stepless speed regulation, main shaft rotate speed still can adopt change of rotate speed handle, reason after frequency control, main shaft rotate speed by advocate frequency of electric machinery job and rotate speed handle decide jointly, to CA6140 lathe, but derivation gives the relation between frequency and cutting speed: (γ of the N in 2) type -- rotate speed of the main shaft after frequency conversion (R/min) ; γ -- transducer frequency (Hz) , already set is 0~50Hz; N0 -- handle of rotate speed of box of lathe main shaft indicates rotate speed (R/min) . Be like D=100mm, n0 =400r/min, criterion according to type (2) is knowable, cutting speed can be in 0~125.

The stepless inside the limits of 6 M/ Min changes, can satisfy experimental requirement. Nextpage5 test system and effect are comparative 5.

　 of 1 test system pursues 4 gave out the experimental system that CA6140 lathe frequency control measures cutting power. For convenient observation and operation, on the Control Panel that the installation such as the digital position operator transducer, pushbutton and slip rheostat is matching to do. Collect a system to measure cutting power with amplifier of the Kistler9257A appearance that measure power, 5807A charge and computer data. Graph the experimental system that frequency control of 4 CA6140 lathe measures cutting power 5.

Laboratory of 　 of contrast of 2 tests result is 45 steel round bar to expect with workpiece material (normalizing, 180HBS) , d=82mm of the diameter when the experiment, choose N0 =900r/min, by type (2) knowable Vc can change in the stepless inside the limits of 0~232m/min. If use rotate speed rotate speed of handle adjustment main shaft, vc is attainable 2.

In 57~232m/min at 22 o'clock, but according to type (1) computation has only between knowable 20~50m/min at 5 o'clock. Laboratory cutting tool is YT15 but lathe tool of the circle outside dislocation, γ O=14o, =6o of ′ of O of α O= α , κ R=75o, =15o of κ R ′ , λ S= -6o, r ε =0.

4mm. Cutting dosage is Ap=1mm, f=0.

1mm/r. The experiment uses rotate speed first rotate speed of handle adjustment main shaft, measure 2.

When the 22 cutting speed in 57~232m/min advocate cutting force, get having the Fc-vc relation curve when degree timing via data processing. Adopt transducer stepless speed regulation after that, make Vc from 2.

57m/min lifts continuously to 232m/min, the Fc-vc relation curve when direct attainable stepless speed regulation. Graph 5 gave out circumstance of experimental result contrast. By graph 5 A) knowable, the dinky B is worth a dot in hump curve appears around Vc=30min/min, more apparent, but the great C that be worth a dot is not apparent, should be between Vc=50-75min/min. See not hard by graph 5 B) , the dinky B that be worth a dot also is near Vc=30min/min, and when the great C that be worth a dot appears in timing having class between 2 o'clock, showed stepless speed regulation to be able to get the hump curve of cutting force and cutting speed thoroughly thereby. The B) of Fc-vc relation curve when Vc (m/min)a) of speed of cutting of cutting speed Vc (m/min) has degree timing the Fc-vc relation graph when stepless speed regulation circumstance of contrast of 5 tests result besides, return by graph 5 B) knowable, electric machinery and gear are when low speed movement, somewhat oscillatory, together with, accumulate bits tumour to arise and fall off periodicly, comprehensive account brings about A-B paragraph wave motion of cutting force signal is bigger; B-C paragraph, electric machinery and gear movement rate rise, vibration is reduced, the tumour that accumulate bits disappears gradually, make wave motion of cutting force signal is reduced. 　 of 6 conclusion 　 (the hump curve of force of the cutting when 1) changes continuously to get cutting rate, use a stage to amount to transducer to the machine tool advocate electric machinery has stepless speed regulation, designed add control circuit, easily of transducer enter and exit, after use transducer, main shaft rotate speed makes frequency and timing handle decide jointly by electric mechanic; (2) the influence that stepless speed regulation can make cutting speed does not suffer workpiece diameter to change, classics experiment is comparative, the hump curve of cutting force and cutting speed can get thoroughly when stepless speed regulation; (3) uses transducer to the machine tool advocate electric machinery has stepless speed regulation, still can wear away in cutting tool experimental middleman and guarantor maintains cutting rate constant, expanded to use range. CNC Milling CNC Machining