What is a Surface Grinder?

Surface grinder is a kind of grinder. The grinding wheel is mainly used to grind the workpiece to achieve the required flatness. According to the shape of the table, it can be divided into two types: rectangular table and circular table. The main parameters of the rectangular table surface grinder are the table width and length. The main parameter of the shape table is the table diameter. According to the type of shaft, it can be divided into horizontal shaft and vertical shaft grinder. Such as M7432 vertical axis round table surface grinder, 4080 horizontal axis rectangular table surface grinder.

Surface grinder is

1) The spindle of the grinding head is overheated and locked

The main cause of this phenomenon is the impurities in the hydraulic oil. For example, dust, iron powder, etc. The impurities in the hydraulic oil will block the small oil holes in the bearing pads, causing some hydraulic chambers to be free of hydraulic oil, making the main shaft unable to form a symmetrical pressure oil chamber. When the main shaft rotates, it is not in a pure liquid state, and friction with the bearing shell generates heat. After disassembling the main shaft of the surface grinder and inspecting each part, it was found that the roundness of the main shaft was not excessive, but the surface finish was poor. The roundness of the inner hole of the bearing shell is not too bad, the surface of the inner hole is scratched, and the section of the bearing shell is scratched. Capillary oil holes in the bearing pads are blocked. After polishing the surface of the main shaft and the end face of the inner bore of the bearing shell with metallographic sandpaper, the service standards can be reached.

The difficulty in repair is how to remove the impurities in the 0.5 mm capillary oil holes in the bearing pad. Only by opening the various oil holes in the capillary can the static pressure balance be established in the bearing shell. The bearing bush is assembled in a cast iron bushing. A special pull hammer is required to separate the bearing bushing from the bushing. After the bearing pads are separated, the bearing pads can be cleaned and each oil hole can be opened. Finally clean the fuel tank and replace with new hydraulic oil. After all repairs are completed, the test drive can be reloaded.

2) Poor finish of grinding work

The radial runout of the main shaft is too poor, which causes the grinding wheel to generate greater vibration during the grinding process, thereby making the surface finish of the workpiece to be ground worse.

The main reasons for the radial runout of the surface grinding machine spindle are:

(1) The main shaft collides or is deformed by force.

(2) The circularity of the inner hole of the main bearing support was too poor.

The surface of the grinding head of the surface grinder adopts the support mode of the front and rear bearing pads. The static pressure technology is used therein. Two oil return grooves with a depth of 0.8mm and a width of 4mm are formed at the front end of the bearing pad. The processing and assembly accuracy of the bearing bush will have a serious impact on the quality of the M7140 static pressure grinding head. The clearance between the bearing pad and the main shaft in the diameter direction is 0.07mm. You can troubleshoot and repair the accuracy according to this data. After the main shaft was disassembled, it was found that the main cause of the shaft vibration was the poor circularity of the bore in the bearing shell, which caused the static pressure balance to be destroyed, causing the main shaft to generate large vibrations during rotation. The inner hole of the bearing shell can be repaired and the roundness of the inner hole of the bearing shell can be restored by grinding.

Firstly, three grinding rods of different sizes are made of cast iron. The three grinding rods of different sizes are used for rough grinding and fine grinding of the bearing bore. The length of the grinding rod is unified to 600 mm according to the size of the bearing. And the grinding rod needs to be made into a waist drum shape. Assemble the bearing pads and steel sleeves of the main shaft uniformly. Pay attention to protect the oil circuit on the bearing pads during assembly. Use a chuck of a lathe to clamp and position the bearing pad and the steel sleeve, and pay attention to the flatness of the bearing pad surface to ensure the verticality of the clamping. When using a grinding rod for grinding, a crane hoisting the grinding rod is required to perform up-and-down reciprocating motion, and the grinding rod is manually rotated around the axis of the bearing pad. Grinding is carried out according to the steps of roughing and finishing, and during grinding, dry grinding is performed with a grinding rod having an outer diameter smaller than the inner diameter of the bearing bush by 0.015-0.025 mm. The number of grinding times should be controlled during dry grinding. After grinding, the surface finish of the inner hole of the bearing shell can reach

Reload test run when it is above 0.8.

The large number of static pressure spindle components used in machine tools has brought the design and manufacture of machine tools to a new level, and has also brought new problems to the maintenance of machine tools. The repair process of the static pressure spindle is more complicated and delicate, the repair period is long, and it is easy to affect production. Therefore, the usual maintenance work is vital. ^[3]