style="font-size:15px;">
▪Advertising material
▪Promotional brochures - overview
▪Promotional brochures - comprehensive
▪Sales oriented information
▪Service oriented information
▪Machine tool manuals
▪Control manuals
▪Parameters manuals
▪Training material with examples
▪Information specific to the CNC machine
How does all this information that may or may not be included in such diverse groups assist the CNC programmer during programming or the CNC operator during part setup and machining? The answer is ‘selectivity’.
Both CNC programmers and operators need only a very small portion of the overall information in the documentation provided by the control or machine manufacturers. This chapter tries to identify what data and other information are important to the CNC operator working at the machine, and to some extent, to the CNC programmer as well.
No specific machine specifications have been used. All information has been adapted from actual machine tools and is representative of the important features that directly affect CNC programming and CNC machining.
Every manufacturer of CNC machines provides the potential buyer with descriptions of their products, for three reasons - sales, information, and training. Sales definitely dominate. Machine specifications are a collection of data regarding a particular machine tool, without the control system. Control unit specifications, on the other hand, provide information about the control itself.
The following sections will concentrate on the three major groups of metal-cutting CNC machine tools:
| ▪ | Vertical Machining Centers | VMC |
| ▪ | Horizontal Machining Centers | HMC |
| ▪ | Lathes and Turning Centers |
Each group will cover specifications that are common to all machines, such as maximum and minimum axis motion or the range of spindle speeds. Each group will also cover specifications that are unique to that particular group of machines, such as indexing axis for horizontal machining centers.
In all examples, only those features that directly affect the work of CNC programmer and/or CNC machine operator will be described.
To make the specifications easier to read, the data will be collected in the form of tables.
This group of machining centers is often identified by the abbreviation VMC - Vertical Machining Center. VMC is the most widely used machine group in industry and many models, sizes and configurations are available to the end users.
Vertical machining centers are designed mainly for machining as the XY motions at a given depth. This is called 2-1/2 axis machining. Most of these machines also allow simultaneous XYZ motions. This feature is called 3-axis machining. Because of their design, cutting on sides is limited, unless special attachments are used.
For the CNC programmer, all features are equally important. For the CNC operator, some features are more important than others.
This group of machining centers is often identified by the abbreviation HMC - Horizontal Machining Center.
Only basic data for a 2-axes CNC lathe are included.
While the traditional and standard workhorse two-axis CNC lathe has been greatly improved by additional features, such as extra axes, sub-spindle, milling attachments, live tools, etc., the most important specifications still apply, regardless of the innovations.
The following tables contain typical control specifications of Fanuc CNC system and are based on the 0i, 21i and 18i models. Keep in mind that control specifications generally show the maximum capabilities which are not always present for a particular machine tool.
Most of the specifications listed are common to both milling and turning controls, although each control type has features specific to the particular machine tool.
Use the tables as general reference only and consult machine documentation for exact specifications.
| Programmable axes | 3 - X, Y, Z 4 - X, Y, Z, B 2 - X, Z (turning) |
| Simultaneously controlled axes | 3 or 4 |
| Least input increment | 0.001mm 0.0001 inch 0.001 degree |
| Max. command value | ±99999.999 mm ±9999.9999 in |
| Fine acceleration & deceleration control | Standard |
| Inch-Metric conversion | G20 (imperial) G21 (metric) |
| Interlock | All axes |
| Machine lock | All axes / Z-axis |
| Emergency Stop | Standard |
| Overt ravel | Standard |
| Stored stroke check 1 | Standard |
| Mirror
|
