Cylindrical grinding machine
| Examples of various grinding processes: 3. Longitudinal cylindrical grinding 4. Transverse cylindrical grinding (plunge-cut grinding) 5. Centerless cylindrical grinding (without clamping) |
A cylindrical grinding machine is a machine tool for processing round, mostly metallic workpieces by grinding .
construction
The general structure of a cylindrical grinding machine is: main column (carrier of all components), workpiece spindle (rotates the workpiece), grinding spindle (tool: grinding wheel ) and, with external grinding machines, usually a tailstock.
Distinction
By type of control
Depending on the type of controls, a distinction is made between conventional and computer-controlled CNC cylindrical grinding machines. Conventional cylindrical grinding machines require the use of an operator and are inflexible. With modern CNC cylindrical grinding machines, on the other hand, complex, programmed machining processes can be processed automatically. The sharpening and calibration of the grinding tool is called " dressing ". This is usually done with a dressing diamond, dressing tiles or dressing rollers. When dressing the grinding wheel, the grinding wheel becomes smaller in diameter. Modern cylindrical grinding machines offset this difference in diameter. With dressing tools and profiles can be produced on grinding wheels.
According to the area to be processed
There are external and internal cylindrical grinding machines for machining external and internal contours of cylindrical workpieces or surfaces.
External cylindrical grinding machine
External cylindrical grinding machines are used to grind cylinders and surfaces on the outer diameter of cylindrical parts. In these machines, the workpiece headstock and tailstock are usually located on a movable slide (Z-axis), the grinding wheel moves on a support (X-axis), which is usually arranged at right angles to the Z-axis. Other structures are, for example, cross tables in which the grinding wheel is located on the X and Z axes.
Possible workpiece clamping systems are zero point clamping systems , magnetic clamping plates or " clamping between the tips ". Here, the workpiece lies with centering points in centering holes made on the face. Ground centers are required to minimize form and position errors between the centers and the shoulders to be ground. Center grinding machines are available for this.
Machine tools for centerless external cylindrical grinding are a special form . The workpiece is not clamped between the headstock and tailstock, but is guided between the grinding and regulating wheel and held from below by means of a rail. A distinction is made between plunge-cut grinding and through-feed grinding. With the latter method, very high throughputs can be achieved.
A special version are centerless shoe grinding machines in which the support rail and regulating wheel are replaced by steel shoes. This allows special geometries to be ground in one operation.
Internal cylindrical grinding machine
Internal cylindrical grinding machines are used to grind bores or surfaces on the inner diameter of cylindrical parts and often have different swivel-in grinding spindles.
Special variants
In the meantime there are also external and internal cylindrical grinding machines (orbital or pendulum stroke grinding machines) which can be used to grind "out of round". Here you can use interpolation to grind any shape that is still possible with the grinding tool (depending on the diameter of the grinding wheel) through the targeted interaction of the workpiece spindle and the X-axis (feed axis). That means, of course, you cannot grind an inner radius of 2 or 3 mm with a grinding pin with a diameter of 10 mm, but at least over 5 mm. This grinding is only possible with modern CNC grinding machines, since a great deal of computing effort is necessary. For example, a square shoulder on a shaft or a shaft with a polygon shape is possible.
Another variant of the non-circular grinding machine is mechanically "positively controlled" via a cam (e.g. camshaft grinding machines ). A high repeat accuracy is given here and much faster processing is possible. However, long set-up times and high costs for retrofitting (a special cam must be manufactured for every other shape) are a disadvantage. This problem does not occur with a CNC machine.
Furthermore, it is possible to grind a thread through the interaction of the workpiece spindle, a defined profile-trued grinding wheel and a corresponding computer control. This is mainly used for ball screws for machine tools or other high-precision threaded spindles and linear motors.
Areas of application
Cylindrical grinding machines are always used where machining of the workpiece with a lathe is impossible or difficult. Examples of this application are materials that are difficult to machine (such as hard metal ); high demands on the surface, accuracy, dimensional accuracy and freedom from twist; complex objects (such as camshafts - for example, these would require too many tool changes when turning).
literature
- K. Lindenau: Economic production with loops , Hanser Verlag, 2006 ISBN 3-446-40648-4
Individual evidence
- ↑ Henninger center grinding machines. In: Henninger. Retrieved January 3, 2016 (German).
- ↑ Crystec Technology Trading GmbH, centerless cylindrical grinding machines . Retrieved February 6, 2011.
- ↑ Crystec Technology Trading GmbH, centerless shoe grinding machines . Retrieved February 6, 2011.