Technology of ELID mirror grinding: Emery wheel is fast the research of nap technology

Summary: Unit of electric spark plastics is used to exceed hard abrasive emery wheel to have the technology of plastic nap to metallic bond in introducing ELID grinding. The emery wheel radial after nap beats the quantity is less than 1µm, emery wheel surface is slick, appearance precision is tall, it is good to grind the tall sex such as bead, comfortable use at accurate mirror grinding, have nap time short, cost the advantage with small loss of low, emery wheel. Metallic bond exceeds hardness of hard abrasive emery wheel tall, strength is great, maintain body ability strong, wearability is good, suit the application in the efficient and accurate grinding in difficult treatment material. Dan Jijian's hard metal bond brought great difficulty to nap of emery wheel figuration. The method of figuration nap has mechanical, electrochemistry, electric spark to wait normally. Nap of electric spark figuration is the new technology of nap of a kind of figuration that in last few years development rises, compare with photograph of before two kinds of methods, have figuration nap precision tall, efficiency tall, cost is low advantage, have wide applied perspective. The technical index such as the precision of quality of the productivity that the power source of pulse of development property index of the development pulse power source of unit of plastics of 1 electric spark machines to electric spark, surface, treatment, stability that machines a process and tool electrode loss has very big effect. To get very good treatment result, the specific requirement that machines pulse power source to electric spark is: The pulse that produces, did not lose half or lose half very small, effect of such polarity of ability make the best use of, improve productivity, reduce tool electrode loss: The main parameter of pulse is in OK adjustment inside very wide range: Small, job stabilizes bulk low, life grows reliable, cost, operation maintenance is convenient, consider even at the same time energy-saving. Graph circuit of graph of circuit of 1 pulse power source designs a basis afore-mentioned requirements, by the graph 1 shows circuit graph to design pulse power source. From the graph 1 in the key that can see parameter of craft of influence pulse power source depends on resistor R and capacitance C, other component simply considers according to power but. According to circuit requirement, voltage is successive between 0 ～ 220V adjustable, electric current is successive between 0 ～ 5A adjustable, such most high-power is 1000W, component of each electric equipment must satisfy power requirement. Referenced before study positive result, resistor of make choice of is 10, 20, 30, 40W: Capacitance is 8, 16, 24, 32µF: Filter wave capacitance needs to take high capacity electric capacity, take according to the condition for 220V, 320µF: Rectification component chooses rectification piece. The choice of electrode material and its design to assure the appearance precision of nap emery wheel, must choose material of electric corrode hidebound to regard a tool as electrode. Because this asks electrode material has high melting point, fusible heat and vaporization heat, consider cost cost even at the same time. We choose hard alloy to regard tool electrode as material. 1, 7.

Insulating envelope 2.

Axis 3.

Hard alloy 4.

Nut 5.

Cupreous tip 6.

Receive power source negative pole to pursue the tool electrode of plastics of electric spark of 2 emery wheel is in process of emery wheel nap, electrode is to rotating of the job below condition, emery wheel and electrode must be electrify, to satisfy electrify and gyral two-way requirement at the same time, the tool electrode that we design. The machine tool of experimental test system of plastics of electric spark of emery wheel of diamond of 2 metals bond: MG1420E high accuracy is all-purpose cylindrical grinder power source: Emery wheel of pulse power source: Emery wheel of iron radical diamond, granuality W7, electrode of primitive offset 57µm: When hard alloy experiment, 3 ungual chuck drive the head of a bed directly electrode rotates, rely on cupreous tip electrify, the stepless speed regulation that can adopt pair of 3 ungual chuck will change the rotate speed of electrode, the whirl of electrode and emery wheel have nothing to do with the clearance of electrode, can change the clearance between electrode and emery wheel arbitrarily so, in order to adjust treatment rate, improve exterior quality. Experimental result and the element that analyse speed of plastics of influence electric spark are very much: Resistor of power source voltage, capacitance, current limliting, frequency, pulse, occupy rotate speed of sky comparing, emery wheel and offset to wait. Resistor of effect of main research polarity, current limliting, capacitance and voltage are right in the experiment the influence of plastic speed. Condition of polarity effect experiment: Working voltage 220V, 20W of current limliting resistor, working capacitance 16µF. Experimental result sees a table 1, 2. The loss effect serial number when expressing 1 emery wheel to receive positive electrode loss of 1234 average emery wheel (Mm3/min)22.

5713.

6218.

6818.

0418.

23 electrode loss (Mm3/min)2.

121.

381.

491.

781.

06 opposite loss (%)9.

410.

18.

09.

875.

The 8 loss effect serial number when expressing 2 emery wheel to receive negative pole loss of 1234 average emery wheel (Mm3/min)11.

728.

249.

629.

059.

66 electrode loss (Mm3/min)2.

692.

242.

322.

602.

46 opposite loss (%)23.

027.

224.

128.

725.

5 from the watch 1, 2 can see, the opposite loss rate when electrode receives positive electrode is compared when receiving negative pole 1 times taller much. Because the pulse of generation of RC pulse generator is to belong to short pulse,this is, bombard action of the electron is more than ionic bombard action, the corrode that causes positive electrode eliminates rate tall negative pole is very much. Because this is when nap emery wheel,should receive emery wheel positive electrode. The loss block that expresses the emery wheel when 3 resistor are different and electrode is worth (loss of W)10203040 emery wheel (Mm3/min)34.

7119.

5016.

165.

70 electrode loss (Mm3/min)2.

291.

651.

520.

44 opposite loss are led (%)6.

68.

59.

47.

The 7 resistance effect to experimental result experimental condition: Emery wheel receives positive electrode, electrode receives negative pole, working voltage 220V, working resistor 10, 20, 30, 40W, working capacitance 16µF. Experimental result sees a table 3. From the watch 3 can see, speed of emery wheel purify follows the accretion of resistor and reduce, but not be inverse ratio relation. Because,this is, according to type Vw=LWfff is knowable, corrode divides F of speed Vw and Wf of odd pulse energy, frequency to become direct ratio, craft parameter L and F of pulse utilization rate change along with resistor lesser, can ignor. F=[RCln(1-k)-1]-1, f is reduced along with the addition of resistor R, w of odd pulse energy however as frequency rise and rise. The loss capacitance that expresses the emery wheel when 4 capacitance are different and electrode (loss of µF)8162432 emery wheel (Mm3/min)18.

5437.

1255.

5373.

97 electrode loss (Mm3/min)1.

863.

244.

306.

11 opposite loss (%)10.

08.

77.

78.

The 3 capacitance influence to experimental result experimental condition: Emery wheel receives positive electrode, electrode receives negative pole: Working voltage 220V, working resistor 20W: Working capacitance 8, 16, 24, 32µF. Experimental result sees a table 4. From the watch 4 in can see, speed of emery wheel purify and capacitance concern into direct ratio. Because,this is, corrode divides speed Vw and frequency F and Wf of odd pulse energy accumulate direct ratio. Occupy type F=[RCln(1-k)-1]-1 again knowable, frequency and capacitance concern into inverse ratio. Frequency is reduced bring about voltaic arteries and veins wide increase, make voltaic arteries and veins wide concern into direct ratio with capacitance. The addition of capacitance can bring about discharge electric current to increase again. Because arteries and veins is wide,increase as the accretion of capacitance with electric current, odd pulse energy and arteries and veins are wide with electric current accumulate direct ratio, make odd pulse energy increases along with the accretion of capacitance square, frequency increases as capacitance and reduce, of such frequency and odd pulse energy indigestion just form direct ratio concern with capacitance, make thereby speed of emery wheel purify and capacitance form direct ratio concern. The loss voltage that expresses the emery wheel when 5 voltage are different and electrode (loss of V)130160190220 emery wheel (Mm3/min)14.

2717.

5220.

8324.

20 electrode loss (Mm3/min)1.

784.

536.

7111.

14 opposite loss (%)12.

525.

932.

246.

The 0 voltage influence to experimental result experimental condition: Emery wheel receives positive electrode, electrode receives negative pole, working resistor 20W, working capacitance 16µF: Working voltage: 130, 160, 190, 220V. Experimental result sees a table 5. From the watch 5 can see, speed of emery wheel purify and voltage concern into direct ratio. Because,this is Vw=LWfff, as the accretion of voltage, l, F did not change almost, f and voltage have nothing to do, because this F, F is OK,regard as invariable. Electric current of pulse peak value and voltage concern into direct ratio, because frequency is changeless, arteries and veins is wide changeless also, make Wf of odd pulse energy and voltage concern into direct ratio, get emery wheel corrode becomes direct ratio concern except speed and voltage thereby. But voltage cannot exorbitant, will produce electric arc otherwise, surface of attaint emery wheel. Graph the emery wheel of cast-iron fund firm stone that the device of electric spark nap that radial of 3 emery wheel beats the relation of quantity and nap time uses afore-mentioned place to develop uses to the place on cylindrical grinder has plastic test, if pursue,as a result 3 are shown. By the graph 3 can see, in plastic process, the ratio of radial and jumpy change of emery wheel is changing in the begining bigger, later taper. Because,this is, when emery wheel is beginning plastic, circularity error is bigger, the surface is rough, plastic area is lesser, because this radial is jumpy metabolic rate is older. As nap undertake ceaselessly, error of emery wheel circularity is reduced gradually, plastic area increases gradually, the radial and jumpy decrescent of emery wheel. From above experiment the result can see, use electric spark to undertake to emery wheel of cast-iron fund firm stone plastic has efficiency surface roughness of tall, surface is worth small, use convenient wait for a characteristic, can better land is achieved expect an end. Bond of 3 conclusion metal exceeds the electric spark plastics of hard abrasive emery wheel, use RC pulse power source, its structure is simple and reliable, the effect is good, can satisfy plastic requirement. In process of emery wheel of bond of metal of electric spark nap, begin to use resistor of tall voltage, small current limliting, large electric capacity, in order to obtain electric current of high peak value, raise exterior purify rate. When electric spark discharge is even, should use resistor of low voltage, big current limliting, small electric capacity, in order to obtain electric current of low peak value, implementation makes treatment to the light of emery wheel surface. CNC Milling