Realize those who exceed way of high speed milling to discuss

When rough machining, machine the bulk token that efficiency gives with minutely treatment, treatment bulk and cutting speed, feed and cutting deepness become direct ratio; When semifinishing machining and finish machining, machine the area token that efficiency gives with minutely treatment, treatment area and cutting speed and feed become direct ratio. Reason raises cutting speed to be able to improve treatment efficiency into direct ratio ground. Come for years the technology that cutting treatment expert is researching to raise cutting rate all the time, although be in all sorts of research reports, ever introduced minutely achieve on the research result of the cutting speed of kilometre, but the achievement that is a lab, without put into production. One, the road that development exceeds high speed cutting 1.

From cutting theory knowable, the relation of cutting temperature Q and cutting speed V is: Q=cv0.

4. The rate that hard alloy cutting tool uses to machine steel to expect in be being produced at present is 100 ～ commonly 300m/min, use precision work of cutting tool of pottery and porcelain the cutting speed that steel expects is 200 ～ 500m/min, use nitrogen to change boracic essence cutting to machine steel makings to be 300 ～ 600m/min. Right now cutting temperature is 800 ～ about 1200 ℃ . By this cutting the rule can push cipher out, when be like cutting speed to be 5 000m/min, cutting temperature is 3300 ℃ about; If cutting speed is,4400 ℃ are when 10 000m/min. Accordingly, follow afore-mentioned fundamental patterns, the way that studies development exceeds high speed cutting basically is centered in the material with high temperature resistant development, the hear resistance of because high temperature is high hard data studies, do not have great progress in recent years, reason exceeds high speed cutting nearly 229 years to also do not have great progress. 2.

By cutting theory knowable, first-rate cutting condition is located in cutting tool and workpiece hardness to compare the largest area, if pursue 1. It is temperature when the abscissa, when ordinate is hardness, set a curve the 1 change that follows temperature for hardness of hard alloy cutting tool, curve the 2 change that follow temperature for workpiece hardness, it is 900 ～ when cutting temperature when 1100 ℃ , cutting tool hardness and workpiece hardness are compared the biggest, cutting tool is the right now most durable. The edificatory that it gives people is, if can try to distinguish cutting tool temperature and workpiece temperature, make cutting tool temperature keeps inferior, and make workpiece temperature rises taller, with respect to the likelihood open up gives development to exceed the new approach of high speed cutting. Graph the relation of 1 cutting tool and material hardness and temperature 2, the approach that promotes work area temperature 1.

pressure is out of shape those who cause temperature is elevatory, if graph 2a place is shown, set good heat treatment of temper by dipping in water of cutting tool classics, workpiece is did not quench steel, succumb when what P of pressure of cutting tool unit exceeds workpiece when intensity, workpiece material interior produces slippage, appear many inside attrition heat and temperature rise. And the compressive strength that right now stress is less than cutting tool, accordingly, the cutting tool with hard temper by dipping in water does not have in-house slippage and heat build-up. From intensity theory knowable, the stress of the biggest slippage is not on the interface of cutting tool and workpiece, and make an appointment with below in workpiece interface 0.

2mm is in (2b) seeing a picture. Accordingly, inside workpiece most place appears under preexistence tall interface crackle, form low intensity surface (2a) seeing a picture. Graph 2 cutting are out of shape with stress 2.

Super- high speed is tangential attrition causes temperature to lift again, be like graph 2a, if make cutting tool edge tangential again,V makes freeboard fast shift, what because cutting tool and workpiece surface are concave and convex,be in is occlusive with felt, of workpiece tangential tear off a face to be absent commonly interface, and majority already was forming micro-crack, parallel at interface below a plane. Additional, be taken away by cutting tool as a result of interface one part quantity of heat, temperature is inferior; And tear off face temperature opposite taller, intensity is inferior, cause cutting tool to take stuff of a workpiece thereby. If cutting tool is milling cutter, criterion a tooth is used pressure (feed) with attrition force (cutting speed) heat workpiece, the strength that creates work drops severalfold. Criterion hind the task of one tooth, be this one layer raze. Of course, hind a tooth (as above) it is again again hind a tooth heats workpiece. Reason its essence is heat one kind exceed high speed cutting. Graph field of temperature of 3 cutting area 3.

Use three-dimensional heat to conduct equation: Dq/dt=a(¶2q/¶x2+¶2q/¶y2+¶2q/¶z2) and finite yuan of law, can find lukewarm dominate equation, era enters concerned cutting parameter (specific parameter sees) of the 4th part, but field of temperature of area of cipher out cutting is shown 3 times like the graph, highest temperature is 922 ℃ . Right now, by the graph hardness of 1 workpiece material and temperature curve, the hardness that can get workpiece data will fall to be controlled to 8HRC by 40HRC. 3, the channel that carries low temperature of area of cutting tool blade raises cutting rate, reduce cutting tool and the time that workpiece engages. Set milling cutter diameter to be F1800mm, workpiece cutting length is 100mm, it is 1000m/min when cutting speed when, milling edge and workpiece contact time are 6ms; When milling rate is 10 000m/min, osculatory time is 0.

6ms, and quantity of heat is in the transmission speed in steel 0.

5mm/s. Accordingly, quantity of heat just was passed to 0.

When 3µm deepness, cutting tool is cut, namely quantity of heat still has not enough time to be passed in cutting tool. 2.

Strengthen the refrigeration of milling cutter. Diameter of if milling cutter is F1800mm, its circumference is Pd ≈ 5.

65m. Accordingly, tooth has 5.

The idle stroke of 65m, get a bit heat by cold to normal temperature. The graph shows the temperature curve that is area of cutting tool blade 4 times, temperature wanders to 300 ℃ limits in normal temperature from beginning to end. Graph curve of temperature of area of blade of 4 cutting tool tries to let edge form covering layer. The graph shows the metallographic grind segment that is tooth 5 times, see by the graph, after tooth aborning uses 24h, when cutting tool material is 65Mn, its metallographic organization still is martensite, of edge area microscopical hardness is 54HRC) of 564 ～ 570HV(53 ～ , return was before to quench hardness 50 ～ 55HRC. And in edge coping (outside round) the adsorption layer that has a white, its are microscopical hardness amounts to 70HRC) of ～ of 974 ～ 1094HV(68. Layer of this one tall hardness, replace edge undertaking cutting. Graph 5 tooth wear away metallographic photograph 4, the manufacturing practice that exceeds high speed cutting is in the billet cut of contemporary steelworks, the efficiency with very high demand, ability catchs up with the metre that connects rolling mill. It is used curium piece the diameter is F1800mm, rotate speed is 1500r/min, cutting speed is 8482m/min, feed is 100mm/s. Curium sheet makings is 65Mn, hardness is 50 ～ 55HRC. Service life amounts to 24h commonly, that is to say, already aborning came true to exceed high speed cutting. The author pursued afore-mentioned practice courses, undertook theoretical analysis to its. CNC Milling