- Select and install a suitable guide wheel
In multi-wire cutting, the design of the groove pitch of the guide wheel mainly depends on the target thickness of the silicon wafer, the diameter of the steel wire, the grain size of the abrasive and the performance of the equipment. In actual production, the diameter of the steel wire, the grain size of the abrasive and the equipment are relatively stable in a certain period of time. Therefore, various guide wheels with different groove pitches are usually prepared according to certain process conditions to meet the requirements of silicon wafer cutting of different thicknesses. Depending on the thickness of the cutting target and the current process conditions, select the appropriate guide wheel. After the guide wheel is selected, install the bearing flange seal, use the guide wheel carrier to move the guide wheel to the installation position, then install the movable bearing, locking screw, temperature sensor, bearing cover and cover ring, etc., and finally install the mortar rough. filter tank.
- Installation and replacement of reel
The wire wheel of the wire cutting machine is divided into a pay-off wheel and a take-up wheel. The pay-off wheel adopts different models according to the different crystals to be cut, and the model of the take-up wheel is fixed. There is a screw that is easy to move between the pay-off wheel and the take-up wheel, hang it on the fixing rod, put the brake sleeve on the fixing rod, fix it with a washer and a hexagonal nut, and install a protective cover. A used reel, even a new uncut thread, will not be able to continue to be used because it is not long enough. However, the empty reel can continue to be used, and the original unused steel wire can be removed and reused.
- Winding and adjustment
After the spool is installed, it needs to be wound. First, install the belt for the guide pulley so that the guide pulley can rotate uniformly, and then fix the steel thread end on the pay-off pulley on the belt through the tension system and the direction wheel. Start the motor in the winding state, pull the wire around the pulley with a belt and fix it in the corresponding slot. When the width of the wire is at least 10mm, fix the wound with adhesive tape. Lead from one slot to another. In this way, the steel wire can be wound independently by itself, until the wire is wound on each slot on the guide pulley, open the connector, pass the steel wire on the pay-off pulley through the tension system, and then pass the steel wire end on the guide pulley through the pulley on the take-up pulley Winding on the take-up wheel, in order to stabilize the steel wire, the steel wire should be wound several times on the take-up wheel, and finally input the length, diameter, spool and guide wheel diameter of the steel wire on the cutting machine, and cut out as needed. The silicon wafer adjusts the tension of the steel wire.
- Mortar preparation
Mortar is a mixture of abrasives and cutting fluids that play a role in the cutting motion of the steel wire and crystalline silicon. The main components of commonly used wire cutting mortars are silicon carbide and polyethylene glycol. Wire cutting requires the mortar used to have a certain viscosity, which is related to the strength of the wire cutting ability to cut silicon wafers. The viscosity of the mortar is related to the viscosity index of the polyethylene glycol itself as well as the proportion and stirring of the mortar. It usually needs to be continuously stirred for about 6 hours. Therefore, the mortar is prepared in advance and needs to be stirred continuously to prevent precipitation. When preparing the slurry, the polyethylene glycol is pumped into the mixing bucket, and a certain amount of silicon carbide abrasive is added for full stirring to make it uniform and reach the required viscosity. After the slurry preparation is completed, it is connected to the sand pump system of multi-wire cutting, and is pumped into the built-in sand tank for continuous stirring.
- System parameter setting
Before cutting, the system parameters should be set first, and the relevant data of crystalline silicon should be input, such as the number and diameter of the crystalline silicon, the diameter and groove spacing of the required guide wheel, the wire diameter of the wire wheel, the wire length and the operator, and then set the steel wire line speed and cutting feed rate. It is worth noting that the wire diameter, wire length and diameter of the guide pulley must be re-entered after each replacement of the guide pulley, pay-off pulley and take-up pulley.