A kind of high viscosity mortar cutting technique for silicon chip cuttingTechnical field
Invention relates to silicon chip of solar cell cutting technique field.
Background technology
Silicon chip cutting is the operation manufacturing solar-energy photo-voltaic cell substrate, and main employing mortar multi-line cutting process, carries mortar by steel wire gauze, monocrystalline or polycrystalline silicon rod are cut into many thin slices at present.The main purpose of mortar abrasive sand is brought in cutting seam to participate in cutting.
Mortar is made up of cutting fluid and wear-resisting sand grains, and cutting fluid generally adopts wellability good, and it is strong and have polyethylene glycol (PEG) base of excellent dispersing characteristic to carborundum class abrasive material or oil base is the compound that Main Ingredients and Appearance generates that row cuts ability.In photovoltaic slice, the general PEG molecular weight that adopts is between 300-500, and viscosity is 30-55mPa.s, because of the difference of concrete cutting technique, selects viscosity different.Wear-resisting sand grains is green silicon carbide, and generally adding rear viscosity can increase several times.
At present, mortar multi-line cutting process is: the mortar prepared, put into lathe mortar jar, precipitation is prevented by agitating device, be delivered in the jet pipe of gauze top, monocrystalline both sides through mortar pump through filtering tank and cooling tower, the online online face of equal uniform flow, carries mortar by steel wire and enters in monocrystalline cutting area, realize cutting by sand grains.After cutting, mortar is back to mortar jar after coarse filtration, and recycle, a mortar changed by every cutter.Along with the development of photovoltaic industry section industry, the domestic section ceiling for accumulation level of cutting is steel wire 100 μm, diamond dust 2000#, double direction wire arrangement, cutting fluid viscosity is 36-40mPa.s, and corresponding mortar viscosity is between 160-180mPa.s, and 8 inch monocrystalline cutting times were at 8.5-9.5 hour/cutter.
Viscosity characterizes mobility, and lower, mobility is better, and viscosity more high fluidity is poorer, suspends, to carry sand grains ability better.But can show sticky glutinous with viscosity increase, namely cut the chip brought and reunite, between sheet, (edge of a knife) blocks sand grains, forms the sheet phenomenon that rises.Therefore mortar viscosity can not promote again, and working (machining) efficiency can not get promoting, and often produces the quality problems such as stria sheet because of cutting power.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of high viscosity mortar cutting technique for silicon chip cutting, and it can use high viscosity mortar in silicon chip cutting, thus promotes silicon chip cutting power, raising finished product rate and operating efficiency.
For solving the problems of the technologies described above, the technical solution used in the present invention is:
For a high viscosity mortar cutting technique for silicon chip cutting, comprise the steps:
It is 1.48 ± 0.02g/cm that the cutting fluid of a, employing viscosity 60-65mPa.s and the green silicon carbide grains of sand are mixed with density3, viscosity is the mortar of 150 ± 10mPa.s and constantly stirs to prevent precipitation;
B, above-mentioned mortar is isolated dense slurry and low-density mortar through centrifugal screw-type seperator, and stir to prevent precipitation; Wherein, dense slurry is density is 1.68g/cm3, viscosity is 280 ± 10mPa.s, and low-density mortar is density is 1.35g/cm3, viscosity is 100 ± 10mPa.s;
C, dense slurry isolated in step b is delivered to mortar spray pipe, then be sprayed onto the steel wire gauze for cutting by mortar spray pipe, cut for silicon rod;
D, position corresponding to silicon rod below steel wire gauze are provided with soaking compartment, and the silicon rod of cutting part is positioned at the cell body of soaking compartment, and described soaking compartment comprises the square cell body that upper end is openend, is provided with inflow pipe in the bottom of square cell body; Low-density mortar isolated in step b is exported to be provided with bottom square cell body inflow pipe by mortar pump; Low-density mortar, from the spilling suitable for reading of soaking compartment, remains for soaking and rinsing carborundum between silicon chip, chip and mortar;
D, dense slurry used in step c is recovered to low-density mortar together with, again send into centrifugal separator and reuse.
Wherein, before mortar is delivered to centrifuge, first mortar is filtered.
Wherein, when adopting seperator to be separated in step b, pass through centrifugal force, mortar is by the edge got rid of to main centrifugal basket (8), the speed discrepancy that screw wing (5) and main centrifugal basket (8) control is 5-10 rev/min, the mortar of higher density is discharged from dense slurry outlet (2), discharge from low-density mortar outlet (11) overflow by paracentral comparatively low-density mortar, the centrifugal force controlled of seperator is at 600G-800G, and input flow rate is at 250-300L/h; Under stable flow, mortar forms stable density and viscosity, and dense slurry and low-density mortar outlet flow-rate ratio are: 1:1.5, and can isolate dense slurry is: density 1.68g/cm3, viscosity is 280 ± 10mPa.s; Isolating low-density mortar is: density 1.35g/cm3, viscosity 100 ± 10mPa.s.
The beneficial effect adopting technique scheme to produce is:
Dense slurry, in multi-line cutting process, is delivered in cutting seam and is participated in cutting, cut for monocrystalline by " being separated and soaking flushing " thought that the present invention introduces and method; Low-density mortar is used for spray punching cut after the edge of a knife in chip, thus solve sticky glutinous phenomenon; Solve the sticky glutinous difficult problem that high viscosity mortar occurs, the high viscosity mortar that cutting power is outstanding is applied in production, and its beneficial effect is as follows:
(1) silicon chip cutting cutting efficiency is improved.For 8 inch monocrystalline, the chip time can shorten more than 0.8 hour;
(2) improve silicon chip cut quality, solve the defects such as side stria;
(3) enhance prop-carrying capacity, thinner steel wire can be adopted to cut, reduce the loss of silicon materials, cut down finished cost further.
(4) silicon chip cut is by cutting rubbing effect, general temperature is at about 80 DEG C, and after cutting feeding, the soaking compartment in step c is immersed in silicon chip decline, and in soaking compartment, mortar temperature is generally at about 26 DEG C, by silicon chip, cutting area is lowered the temperature, solve the problem of high viscosity mortar cutting cooling difficulty; Make the silicon chip gap uniformity after cutting by the low-density mortar suspension in soaking compartment, diluting effect, chip is easy to discharge.
(5) low-density mortar flows into from soaking compartment bottom, from soaking compartment spilling suitable for reading, under the diluting effect of low-density mortar, takes away the chip after dilution and heat.
Therefore, the present invention can use high viscosity mortar in silicon chip cutting, thus promotes silicon chip cutting power, raising finished product rate and operating efficiency.
Accompanying drawing illustrates:
Fig. 1 is soaking compartment and cutting silicon rod structural representation;
Fig. 2 is separator structure schematic diagram.
In figure: 1, support; 2, dense slurry outlet; 3, mortar import is supplied; 4, screw spindle; 5, screw wing; 6, screw spindle drive motors; 7, mortar outlet is supplied; 8, main centrifugal basket; 9, drum drive motor; 10, drum driven decelerator; 11, low-density mortar outlet; 21, home roll, 22, mortar spray pipe, 23, steel wire gauze, 24, silicon rod, 25, workbench, 26, soaking compartment, 27, inflow pipe, 28, filter screen.
Detailed description of the invention
Below in conjunction with Fig. 1, Fig. 2 and specific embodiment, the present invention is further elaborated.
For a high viscosity mortar cutting technique for silicon chip cutting, concrete steps are as follows:
It is 1.48 ± 0.02g/cm that the cutting fluid of a, employing viscosity 60-65mPa.s and the green silicon carbide grains of sand are mixed with density3, viscosity is the mortar of 150 ± 10mPa.s and constantly stirs to prevent precipitation;
B, above-mentioned mortar is isolated dense slurry and low-density mortar through centrifugal screw-type seperator, and stir to prevent precipitation; Wherein, dense slurry is density is 1.68g/cm3, viscosity is 280 ± 10mPa.s, and low-density mortar is density is 1.35g/cm3, viscosity is 100 ± 10mPa.s;
C, dense slurry isolated in step b is delivered to mortar spray pipe, then be sprayed onto the steel wire gauze for cutting by mortar spray pipe, cut for silicon rod;
D, position corresponding to silicon rod below steel wire gauze are provided with soaking compartment, and the silicon rod of cutting part is positioned at the cell body of soaking compartment, and described soaking compartment comprises the square cell body that upper end is openend, is provided with inflow pipe in the bottom of square cell body; Low-density mortar isolated in step b is exported to be provided with bottom square cell body inflow pipe by mortar pump; Low-density mortar, from the spilling suitable for reading of soaking compartment, remains for soaking and rinsing carborundum between silicon chip, chip and mortar;
D, dense slurry used in step c is recovered to low-density mortar together with, again send into centrifugal separator and reuse.
In specific embodiment, before mortar is delivered to centrifuge, first mortar is filtered.
As shown in Figure 1, soaking compartment comprises the square cell body 26 that upper end is openend, the bottom of square cell body 26 is provided with inflow pipe 27, filter screen 28 is provided with in the below of square cell body 26, soaking compartment 26 is positioned at the below of steel wire gauze 23, is the free end of silicon rod 24 directly over it, is entered by low-density mortar isolated in step b by inflow pipe 27, be filtered to cutting chamber cavity of resorption through filter screen 28 after being overflowed by the upper, open end of square cell body 26, converge recovery with by the dense slurry participating in step c cutting.
As shown in Figure 2, when adopting seperator to be separated in step b, pass through centrifugal force, mortar is by the edge got rid of to main centrifugal basket 8, the speed discrepancy that screw wing 5 and main centrifugal basket 8 control is 5-10 rev/min, is discharged by the mortar of higher density, discharge by paracentral comparatively low-density mortar from low-density mortar outlet 11 overflow from dense slurry outlet 2, the centrifugal force controlled of seperator is at 600G-800G, and input flow rate is at 250-300L/h; Under stable flow, mortar forms stable density and viscosity, and dense slurry and low-density mortar outlet flow-rate ratio are: 1:1.5, and can isolate dense slurry is: density 1.68g/cm3, and viscosity is 280 ± 10mPa.s; Isolating low-density mortar is: density 1.35g/cm3, viscosity 100 ± 10mPa.s.