Fundamentals
Special types of milling machines allow performing both milling and grinding operations. A workpiece can thus be machined completely on one machine, even if complex milling and grinding operations are required.
Requirements
- Grinding (#156 / #4-04-1) software option
- Available kinematics description for jig grinding
The machine manufacturer creates the kinematics description.
Production processes
The term grinding encompasses many types of machining that differ in quite a few respects, e.g.:
- Jig grinding
Jig grinding is the grinding of a 2D contour. The tool movement in the plane is optionally superimposed by a reciprocation movement along the active tool axis.
- Cylindrical grinding
Cylindrical grinding refers to the grinding of workpieces that are rotationally symmetrical. During cylindrical grinding, the tool in the tool spindle rotates, as does the clamped workpiece on the rotary table.
- Surface grinding
Surface grinding refers to the grinding of flat surfaces.
Surface grinding is currently not available on the TNC7.
If grinding is enabled on your milling machine, (#156 / #4-04-1), the dressing function is also available. This means that you can shape or resharpen the grinding wheel in the machine.
Reciprocating stroke
For jig grinding, the movement of the tool in the plane can be superimposed by a stroke movement, the so-called reciprocating stroke. The superimposed stroke movement is applied in the active tool axis.
You define an upper and a lower stroke limit and can start and stop the reciprocating stroke and reset the corresponding values. The reciprocating stroke is active until you stop it. M2 or M30 will stop the reciprocating stroke automatically.
The control provides cycles for defining, starting, and stopping reciprocating strokes.
For cylindrical grinding, the control automatically determines the reciprocating stroke from the data in the definition and infeed cycles.
As long as the reciprocating stroke is active during program run. you can't switch to the Manual operating mode.
The control shows the reciprocating stroke in the Simulation workspace of the Program Run operating mode.
Tools for grinding
When managing grinding tools, other geometric descriptions than those for milling or drilling tools are required. The control provides a special tool table for grinding and dressing tools. In the Form workspace of the tool management, the control displays only the required parameters for the current tool type.
Grinding tool table toolgrind.grd (#156 / #4-04-1)
Dressing tool table tooldress.drs (#156 / #4-04-1)
You can use compensation tables to change the values of grinding tools during program run.
Grinding wheel edges and teeth of grinding tools
For dressing and cylindrical grinding you must select a grinding wheel edge.
For cylindrical grinding you choose which grinding wheel edge the control will use for positioning. For dressing you choose which grinding wheel edge the control will dress.
The grinding tool is viewed in the cutting plane with different grinding wheel edges. You select the grinding wheel edge with Cycle 1030 ACTIVATE WHEEL EDGE or in some of the cylindrical grinding cycles.
Cycle 1030 ACTIVATE WHEEL EDGE (#156 / #4-04-1)
Depending on the type of grinding tool and the machining mode, you can select the following grinding wheel edges:
Grinding tool type | Grinding | Dressing |
---|---|---|
| ||
| ||
Cup wheel |
When using inclined machining, you choose a tooth to be machined in addition to the grinding wheel edge. The straight line between two grinding wheel edges forms one tooth.
In the cylindrical grinding cycles the control displays the possible grinding wheel edges and teeth in a selection window.
Definition cycles for cylindrical grinding
The grinding wheel edges are either at the intersections of the adjoining teeth or at the intersection of the tooth with the tool axis. If the grinding wheel edge has a radius, the control still positions to the intersection of the adjoining teeth.
When changing the tool with a TOOL CALL, by default the control activates grinding wheel edge 9.