Internal grinding machines are mainly used to grind the inner hole surface and end surface of cylindrical, conical or other shapes.
The internal grinding wheel in the grinding machine is generally installed at one end of the grinding wheel connecting shaft, and the other end of the connecting shaft is connected to the grinding head spindle. Some grinding machines also have internal grinding wheels directly installed on the spindle of the internal grinding tool. There are two ways to fasten the grinding wheel: thread fastening and adhesive fastening.
Screw fastening, this is the most common way to install the internal grinding wheel.
The following points should be noted when installing the internal grinding wheel:
1. The clearance between the inner hole of the grinding wheel and the extension shaft should be appropriate and should not exceed 0.2mm. If the clearance is too large, paper can be inserted between the inner hole of the grinding wheel and the extension shaft to prevent the grinding wheel from being installed eccentrically and causing vibration.
2. The two end faces of the grinding wheel must be padded with soft pads such as yellow paper, and the thickness of the pad should be 0.2-0.3mm.
3. The end face of the extension shaft of the pressure-bearing grinding wheel should be flat, and the contact surface should not be too small, otherwise the reliability of the grinding wheel tightening cannot be guaranteed.
4. The pressure-bearing end face of the fastening screw should be perpendicular to the screw to ensure that the grinding wheel is evenly stressed.
5. The spiral direction of the fastening screw should be opposite to the rotation direction of the grinding wheel. Under the action of the grinding force, it can ensure that the grinding wheel will not loosen.
6. Adhesive fastening is often used for fastening small grinding wheels below ￠15mm.
The commonly used adhesive is a paste-like mixture made of phosphoric acid solution (H3PQ4) and copper oxide (CUO) powder. When bonding, there should be a gap of 0.2-0.3mm between the extension shaft and the inner hole of the grinding wheel. In order to improve the bonding strength of the grinding wheel, the outer circle of the extension shaft can be rolled into a mesh shape. The adhesive should fill the gap between the grinding wheel and the outer circle of the extension shaft, wait for natural drying or drying, and cool for about 5 minutes.
When using adhesive to fasten the internal grinding wheel, pay attention to the following points.
When mixing, the copper oxide powder must be placed in a porcelain container, and the phosphoric acid aqueous solution must be gradually injected, while stirring continuously. The mixing must be uniform and the concentration must be appropriate.
The adhesive must fill the gap between the grinding wheel hole and the extension shaft.
After solidification, it is dried in an electric furnace, but the time should not be too long, otherwise the copper phosphate will expand rapidly during the rapid solidification process of heating in the electric furnace, causing the grinding wheel to crack. Observe the color of the adhesive with the naked eye. When the adhesive appears dark green, stop heating.
There are many formulas for adhesives. For example, some factories use sulfur as an adhesive. The method is:
First, turn the sulfur into liquid, then apply the liquid between the extension shaft and the inner hole of the grinding wheel, and cool it for about 5 minutes before use.
When the grinding wheel is connected to the extension shaft, when disassembling the extension shaft from the main shaft, it is necessary to figure out the rotation direction of the extension shaft. When the internal grinding wheel rotates counterclockwise, the extension shaft thread should be right-handed.
When installing the internal grinding wheel of the CNC grinder, pay attention to the handling in different situations, and install the grinding wheel carefully, so as to ensure that there will be no errors during grinding, and try to avoid it!
