A Jig grinding machine is a specialized machine tool designed to remove heat treatment deformations from materials.
The jig grinding machine is capable of grinding holes with high precision and various contour shapes. It features a precision coordinate mechanism and its moving parts, such as the grinding wheel frame and table, are equipped with digital displays to show the amount of movement.
The structure of a jig grinding machine is similar to that of a jig boring machine, with the difference being that the boring spindle has been replaced by a high-speed grinding head. The workpiece is secured to a table that can be moved via coordinates and the grinding wheel rotates at high speed while also undergoing slow revolution through a planetary transmission mechanism and vertical feed motion. Radial feed can be achieved by adjusting the planetary motion radius of the grinding head.
The grinding head can either be a high-frequency electric grinding head or an air turbine grinding head. In addition to grinding cylindrical holes, the jig grinding machine can also grind inner and outer surfaces of arcs and conical holes and is mainly used for machining hardened workpieces, dies, and stampers.
By installing grinding attachments on the grinding head, the axis of the grinding wheel is positioned horizontally, allowing the grinding wheel to only perform reciprocating up and down motion, similar to an insertion type. This method can be used to machine inner ring gears, indexing plates, and cams.
With the integration of digital control technology, jig grinding machines have expanded their capabilities to grind various forming surfaces.
The technical specifications of the jig grinding machine are as follows:
Workbench length: 610 mm Workbench width: 280 mm Longitudinal stroke (X-axis): 450 mm Lateral travel (Y-axis): 280 mm Vertical stroke (Z-axis): 92 mm
For single column operation: Vertical slide stroke: 320 mm Spindle center to vertical slide distance: 250 mm Maximum grinding diameter: 127 mm With display panel: 304 mm Spindle end stroke: 340 mm Operating voltage: 50Hz, 3-phase, 380V Machine weight: 1900 Kg Dimensions: 2500 x 1800 x 2500 mm
Accessories include: Number of digital reading axes with a precision of 0.001 Grinding head speed options: 20000 RPM 40000 RPM
The following precautions should be taken when using a jig grinding machine for high-precision machining:
- The jig grinding machine must be installed in a temperature-controlled room with a temperature of 20°C ± 1°C and a relative humidity not exceeding 70.5%. The room should be protected from direct sunlight and local heat sources, and the temperature change should not exceed 0.5°C per 4 hours.
- The floor beneath the jig grinding machine should have a shock-absorbing groove.
- The compressed air used for the jig grinding machine should be dry and filtered, with a dew point temperature lower than 10°C.
- The processed parts should be left in the temperature-controlled room for 2 to 3 hours to reach thermal stability, and the same should be done for any measuring tools.
- The weight of the workpiece should not exceed the maximum load capacity of the workbench.
- The workpiece should not be in direct contact with the work surface to avoid damaging it.
- The spindle axis thermal stability device of the jig grinding machine is an electronic system that reduces the impact of thermal displacement caused by temperature changes during operation and ensures machining accuracy. It should not be altered and must be kept powered even when not in use. If the machine is turned off for a long period, it must be allowed to heat up for at least 4 hours before use.
- The axes should be zeroed after the machine is turned on each day and after it is restarted following a power interruption.