Mechanism of high speed cutting and experiment (in)

The heat in metal cutting of cutting of 3 high speed and cutting temperature are in cutting process, the origin of heat in metal cutting is before the meritorious service that cuts area area material to be out of shape place is done is mixed, hind the friction work that knife face place does, if pursue,10 are shown. Graph one part heat in metal cutting passes the origin of 10 heat in metal cutting in cutting bits to be cut bits is taken away; One part heat is passed in workpiece; In still one part heat passes cutting tool (graph 10) . According to research, after cutting rate rises, pass into cut bits and be cut the portion of quantity of heat that bits takes away is added much, and the portion of quantity of heat that passes into workpiece and cutting tool is reduced, reason workpiece, cutting tool warms up and not quite. Japanese establishs milling cutter with P10, cutting 45 steel and A15025 aluminium alloy, ap=2mm, f=0.

12mm/r. Graph the 11 allocation that are heat in metal cutting rate. Graph 11 heat in metal cutting allocate the manage austral rate China to be versed in the university did similar heat in metal cutting to allocate rate curve (graph 12) . Workpiece material is 45 steel (hot-rolling) , lathe tool uses YT15 bit, ap=0.

8mm, f=0.

12mm/r, v =400 ～ 800m/min. If the graph is shown 12 times, when V=400m/min, rc=49.

4% , rw=46.

7% , RT=3.

9% . When V=800m/min, rc=69.

4% , rw=28.

7% , RT=2.

3% . Reason all is reduced significantly in the RW when high speed and RT. Graph 12 heat in metal cutting allocate rate Rc, Rw and RT to be able to explain heat in metal cutting assigns rate only, the most important still is before the cutting temperature that knife face ― cuts interface of workpiece of ― of face of the knife after bits is mixed to go up or the temperature that are close to place to it. The measurement of cutting temperature is very difficult, have natural thermocouple, artificial thermocouple and infrared ray commonly usedly shoot a way. Some college did tone to pledge the turning temperature of steel and hard steel of temper by dipping in water experiments. Move qualitative steel: Ap=0.

2 ～ 0.

5mm, f=0.

2 ～ 0.

5mm/r, v=700 ～ 1000m/min. Hard steel of temper by dipping in water: Ap=0.

15 ～ 0.

3mm, f=0.

1 ～ 0.

25mm/r, v =100 ～ 400m/min. With infra-red measure Wen Yi to measure temperature, its are shown 2 times like the watch as a result. Express formula of experience of temperature of cutting of turning of 2 high speed to look, express 2 medium data to still be worth deliberate. In the past, the turning when 200m/min is less than in cutting speed when 45 steel, 3 elements formula is cutting temperature θ =C Vvalue="0.

41" HasSpace="False" Negative="False" NumberType="1" TCSC="0">0.

41f 0.

14ap0.

04 Shenyang manage is versed in university choose and employ persons is versed in thermocouple law measures the milling temperature below high speed, if its result pursues 13, the graph shows 14 times: Graph 13 milling temperature (45 steel) graph 14 milling temperature (aluminium alloy 5A02) German Sa Luomeng (Carl J.

Salomon) the doctor used big diameter circular saw 1931 at 1924 ～ piece undertook to nonferrous metal mill curiums cutting experiments. Discovery, increase when cutting speed, cutting temperature rises, to fixed cutting rate, cutting temperature is highest; Raise cutting rate again, cutting temperature drops instead (graph 15) . Later, spread this phenomenon other work material again. The test data at that time is lost entirely later, the staff member has not been had put, measure Wen Ye to not be clear about with what method. A lot of people think the curve in the graph is suspect. Most person thinks, cutting temperature is nonexistent a highest value (the peak is nodded) , cutting speed is mentioned very tall when, cutting temperature still answer slow rise. The manage of Shenyang of curve of temperature of high speed cutting of graph 15 Salomon is versed in the university developed sawing machine of a high speed, curium with high-speed steel piece (diametical φ 200mm, thick 3mm, 60 tooth) , top rotate speed is 24000r/min, in order to curiums cut mild steel to be in charge of (φ 20mm, thick 1.

5mm) with aluminium board (thick 10mm) , undertook measuring power, survey lukewarm test, highest cutting speed is amounted to minutely 10 thousand meters of above. Because curium be sure to cuts an area to be not secured, cutting time is very short, force, lukewarm measure measure not easily accurate, but the job that Shenyang manage is versed in university institute is done still is very commendable. Shandong university provides steel of strong tool of temper by dipping in water of Duan Xi T10A with SG-4 potter (HRC58 ～ 65) , v=110 ～ Value="177" HasSpace="False" Negative="False" NumberType="1" TCSC="0">177m/min, ap=0.

1 ～ Value="0.

5" HasSpace="False" Negative="False" NumberType="1" TCSC="0">0value="0.

5" HasSpace="False" Negative="False" NumberType="1" TCSC="0"> .

5mm, fz=0.

05 ～ Value="0.

127" HasSpace="False" Negative="False" NumberType="1" TCSC="0">0value="0.

127" HasSpace="False" Negative="False" NumberType="1" TCSC="0"> .

127mm/z, milling width B=40, 70, 100mm, do=160 of milling cutter diameter, 125, 80mm, =17 of cutting temperature θ .

5 V 1.

55 Ap0.

91 Fz1.

44B0.

46do-0.

31 (℃ ) . Shandong university still made turning of cutting tool of pottery and porcelain the cutting temperature of a few kinds of hard data experiments. 5.

4 cutting tool wear away with cutting tool of cutting tool life face of the knife after having wears away (VB) , before knife face wears away (crescent moon depression KT) , border wears away (VN) reach point of a knife to wear away (VC) , radial wears away (NB) etc. Face of the knife after people studies wears away VB is most. General, wear away for cutting tool with VB standard. Graph 16 lathe tool wear away place and reason of tatty of appearance cutting tool have: (1) grind bead to wear away, (2) felt (cold welding) wear away, (3) diffuse wear away, (4) oxidation wears away, (5) pyroelectricity wears away etc. Graph 17 wear away to cutting tool for cutting speed the influence of intensity. By the graph 17 visible, when cutting when rate is very high, give priority to with diffusing to wear away with oxidation. Graph 17 cutting speed wears away to cutting tool if the wear curve of model of influence cutting tool of intensity pursues show 18 times. Graph knife face wears away to be a standard to certain size after wear curve of 18 cutting tool, can establish the relation between T of cutting tool life and cutting speed V, namely T- V curve (namely peaceful straps Taylor equation) : V =A/Tm, or T=c/ V Z still can build distensible peaceful to strap equation: V =C V /(Tm, Apx, F Y) constant fast below, with turning of YT15 cutting tool 45 steel, general M=0.

2, x=0.

15, y=0.

Below cutting of 45 high speed, the trial work that people does in this respect is very insufficient, more ground observes cutting tool wears away form appearance, see wear curve and T- V curve rarely. Distensible peaceful straps equation criterion more lack. In high speed cutting, state of the function of material of the production quality of cutting tool material and cutting tool, workpiece, machine tool and craft condition cannot changeless, change randomly however, affect cutting tool service life thereby. General, wear away normally the change of next cutting tool life and distributinging obedience normal school (graph 19) . The change of life of the cutting tool below damaged circumstance and distributinging obedience lognormal distribution or Weibull (Weibull) distributing. In high speed cutting, answer to value the stability of cutting tool life very, still do not have serious research to the distributinging rule of cutting tool life however. Cutting tool wears away normally of life distributing to be subject to commonly damaged of cutting tool of normal school F (T) = wears away of life distributing to be subject to commonly distributinging F (T) = of lognormal distribution F (T) = or Weibull pursues 19 cutting tool wear away normally the life below distributings CNC Milling CNC Machining