The Design And Research Of Die-casting Machine's Punch With Bionic Unsmooth Surface

1 introduction Attrition is one of fundamental modes which the machinery equipment expires, because wear causes the spare part to discard, either the replacement spare part or the machine discard. It has the extremely tremendous influence to the industrial production efficiency and the cost, so the economic loss is extremely huge. As the key component, the die-casting machine drift's service life is very low because of wears. The domestic factory uses the alloy steel drift, its life has 6-7 work-times, but its price is expensive. The modular cast iron drift works only one work-time although the price is cheap. The material waste is serious.The die-casting machine is the continuous working way. It will inevitably affect the working efficiency when the engine frequently put off to replace drift. If the resistance to wear enhances one time, the enterprise will be able to reduce the massive costs. In order to solve the existing problem , it is necessary to take the suitable measure to enhance the drift the resistance to wear, and lengthens the drift service life. According to traditional ideas, object surface is smoother, the friction drag is smaller, wear is also fewer. Therefore, the working part or the product which needs to reduce the friction drag is all designed the smooth surface. However the nature demonstrates this question to the people: In the sky soaring biology, its body surface either the wing surface evolves by no means the smooth epidermis or the wing membrane, but has the low energy non-smooth surface which the feather composes. Biology roams through which in the water, moves the agile biology (for example the deep sea shark, the eruption start speed is astonishing quick in particular, may achieve 10-20m/s), its body surface is not the smooth surface, but is contracts the non-smooth surface by the lamella or the hypodermic knot which the organization constitutes, the water-dunnel experiment also confirmed the suitable design non-smooth surface must be smaller than the smooth skin resistance. Take the pangolin, the dung beetle and the mole cricket and so on as an example. It shuttles back and forth for a long time and comes in and goes out in the sand and crushed stone or the soil. But the body surface does not have the damage. The bionics research indicated, the non-smooth surface (for example has bulge, pit, grid and so on) the resistance to wear is better. We apply the bionics theory in the die-casting machine drift, and design processing biological modeling non-smooth haploid in its surface. It will be able to enhance the resistance to wear. The biological non-smooth surface uses the thin view non-smooth, so the traditional machine-finishing has not been able to meet the needs, therefore uses the laser processing 2 experimental plans The research is discovered, which the nature multitudinous biology have the fine wear-resisting function is concerning with the different form non-smooth shape. Imitation biology body surface shape, use laser technology test specimen surface treatment with drop, stripe and grid shape biological modeling non-smooth surface(Fig1-3). With test specimen , Author has studied the laserparameter's influence to the biological modeling haploid, and the influence of the biological modelling haploid shape and the distribution to the attrition. 3 lasers parameter's influence to the bionics non-smooth cell 3.1 Cell structure Chart 4 is the laser processing cell section schematic drawing. It may be seen that bionics non-smooth cell congeals is composed by the melt and the transition region. When high energy laser beam illumination, material which contacts with the laser beam is mostly vaporized and ejected but produces the pit. The area where materials melt and congeal is assumed the crescent shape. The laser processing parameter decides the cell structure size. The cell's width and depth by different laser energy processing are different. Chart 5 and chart 6 are the electric current and the scanning velocity influence result to the cell's depth and width. By the charts, the cell's depth and width also increase along with processing electric current increasing when the scanning velocity is invariable. Themaximum current 300A compares with the minimum current 150A , the cell's depth increases about 5% and the width increases about 5%. When the processing electric current is invariable, the cell's depth and width reduce along with scanning velocity increasing. Scanning velocity 0.5mm compares with scanning velocity 2.5mm, the cell's depth increases about 20%,and the width increases about 15%. 3.2 Cell organization Chart 7 is the microstructure picture of the area of laser processed melt congeal. In the picture, the area of melt congeals in the surface of the test sample after the laser processing is the extremely tiny Lai's organization, has the stripe shape distribution along the radiation direction. Picture 8 is the microstructure picture of laser processed transition region. May see by the chart, the transition region receives relatively smaller influence of the laser processing, therefore the carbide is not obviously fractionized , the organization is transformed to martensite completely. 3.3 Cell rigidity Chart 9 shows the influence of the laser parameter (electric current, scanning velocity) to the cell rigidity. May see by the chart, when the scanning velocity is certain, along with the increasing of the laser electric current , the degree of the cell rigidity increases. When the electric current is certain, the degree of the cell rigidity changes contrarily along with the the increasing of the scanning velocity 4.The wearable quality of non-smooth superficial 4.1 The influence of non-smooth surfaces cell shapes to the attritione biological modeling non-smooth surface. When the gap is 1.96mm, we can see from the chart: regardless of which kind of the attrition of non-smooth shape is better than the attrition of smooth surface, the wearable quality of the drop non-smooth surface is 1.75 times as much as the the wearable quality of smooth surface. The wearable quality of the streaky non-smooth surface is 1.85 times as much as than the smooth surface, the grid non-smooth surface is 2.5 times as much as the smooth surface.The wearable quality of the streaky non-smooth surface is 1.06 timers as much as the quality of the drop non-smooth surface the wearable quality of the grid non-smooth superficial is 1.43 times as much as the quality of the drop non-smooth surface . 4.2 The influence of the distributing of cell to the abrasion. From chart 11 to chart 13 are respectively the result of abrasion test when the punctuate, the streaky and the meshy biological modelling non-smooth cell distribution spacing are different. We can see from the chart, the density of distribution of the cell are different, the wearing capacity are different, increases along with the gap, the wearing capacity increases gradually.When the distribution gap of the meshy shape cell distribution gap is 0.98mm ,the wearing capacity is smallest. 4.3 The mechanism of abrasion The fig₁4 to fig₁6 is shown the abrasion of drop shape, stripe shape and grid shape respectively. We can see from the fig, the scull on body appearance is deep and dense, the scull on the cell body disposed by laser is few and gently, which shows the cell body can resist worn. Contract with the diffent shape of non-lubricity surface,the most abrasion is body surface, the less abrasion is the grid body surface, the striation is the least. The fig₁7 is the earlier bionics of non-smooth surface friction sketch map. There are lots of heaves on the non-lubricity surface, We can see from the fig, during the friction process, the friction subsidiary contact with the heaves of the cell body firstly. Friction subsidiary is supported by the heaves, so the heaves of the cell body is first scrubbed. The rigidity of the cell body is increase from HB174 to HV564^HV720, during the abrasion with the friction subsidiary, abrasion is reduced deeply. So the material wearable of bionics of non-lubricity surface is increased deeply. It is changed into the non-lubricity cell body and body contact with the friction subsidiary after the rigidity of the cell body is rubbed down. Chart 18 is the friction schematic drawing of the cell smoothed by grinding. After the attrition of the cell unevens protrudes partial, the material surface is ground to the plane having the pit, rubs vice contact with the substrate and the cell at the same time. They are wearing at the same time, because the cell and substrate degree of hardness is dissimilar, rubs vice carry on the attrition to them slectivly. Substrate degree of hardness is lower than the cell degree of hardness, then is more serious than the cell attrition. The cell is exposed, this time the process wearing turn to the situation of the initial period, the later attrition duplicates the above two processes unceasingly, until material is frayed disabled. On the friction biological modelling non-smooth surface, Compare the selects shape, the stripe shape and the grid shape three kind of shapes biological modelling non-smooth haploids, when Fig.17 Friction schematic drawing Fig.18 Friction schematic drawing of non-smooth surface in initial period after haploid being wornbetween the same gap, as the gap with is 1.96mm, the stripe haploid accounts for the substrate surface area 29.4%. the selects shape accounts for the substrate surface area 7.3%. So the rigidity of stripe non-smooth is higher than the selects non-smooth surface, resistance to wear to be also good; The grid shape haploid accounts for the substrate surface area 50.1,which is larger than the stripe haploid,which accounts for the substrate surface area 29.4%,so the rigidity is higher , resistance to wear is better. Compare the homogeneous shape but different gap haploid, like the grid shape, the spacing respectively is 0.98mm, 1.96mm, 3.92mm, the haploid occupies the material substrate the surface area proportion respectively is relatively 74%,50.1%,35.4% .That is to say,the gap is smaller, The area proportion is bigger, the surface rigidity of material is higher, its resistance to wear also increased. We can also see from the above sketch map, rubs vice-and the non-smooth surface constitute many cavities, this cavity can reserve the lubricant, the friction merit reduced and the material resistance to wear enhanced when friction. 5. Industrial experiment On the basis of the tests result, non-smooth shape of the better grid shape will use to the drift surface, processed by the laser technology . The test result indicated that, the bionic non-smooth surface enhanced the resistance to wear of the drift. The hardness of the superficial bionic non-smooth cell maintained about HV380 best, the service life might lengthen 3 times. 6. Conclusions 1.When the bionic non-smooth cell is processed by the laser, the scanning velocity is certain, along with laser processing electric current increasing, the width and the depth of the cell increases, Cell rigidity also increases; when the electric current is certain, along with laser scan speed increasing, the degree of hardness and the depth of the cell obtained reduces. 2. The resistance to wear of the bionic non-smooth surfaces surpasses the smooth surface, under the same condition, resistance to wear of the grid shape bionic non-smooth surface is best. Gap bigger, the resistance to wear is worse.3. The reason of the enhancement of the resistance to wear of the bionic non-smooth surfaces: a. The cell organization is the Lai's organization, degree of hardness enhanced thus the superficial resistance to wear strengthened. b. The cell and the substrate wore in turn, the substrate's resistance to wear enhanced. c. There are many cavities between the rubbed vice-constituted and the bionic non-smooth cell, the lubricant is stored between these cavities, when it rubs, the friction is reduced, the resistance to wear of the material is enhanced. 4. Making the die-compression casting machine drift like the grid shape non-smooth surface, the service life enhanced 3 times. It will have tangible wear-resisting effect.