1.B.2.Machine tools, as follows, and any combination thereof, for removing or cutting metals, ceramics, or composites, which, according to the manufacturer’s technical specifications, can be equipped with electronic devices for simultaneous “contouring control” in two or more axes:

N.B.: For “numerical control” units controlled by their associated “software”, see Item 1.D.3.
a. Machine tools for turning, that have “positioning accuracies” with all compensations available better (less) than 6 µm according to ISO 230/2 (1988) along any linear axis
(overall positioning) for machines capable of machining diameters greater than 35 mm;
Note: Item 1.B.2.a. does not control bar machines (Swissturn), limited to machining only bar feed thru, if maximum bar diameter is equal to or less than 42 mm and there is no capability of mounting chucks. Machines may have drilling and/or milling capabilities for machining parts with diameters less than 42 mm.
b. Machine tools for milling, having any of the following characteristics:
1. “Positioning accuracies” with all compensations available better (less) than 6 µm according to ISO 230/2 (1988) along any linear axis (overall positioning);
2. Two or more contouring rotary axes; or
3. Five or more axes which can be coordinated simultaneously for “contouring control”.
Note: Item 1.B.2.b. does not control milling machines having both of the following characteristics:
1. X-axis travel greater than 2 m; and
2. Overall “positioning accuracy” on the x-axis worse (more) than 30 µm according to ISO 230/2 (1988).
c. Machine tools for grinding, having any of the following characteristics:
1. “Positioning accuracies” with all compensations available better (less) than 4 µm according to ISO 230/2 (1988) along any linear axis (overall positioning);
2. Two or more contouring rotary axes; or
3 Five or more axes which can be coordinated simultaneously for “contouring control”.
Note: Item 1.B.2.c. does not control grinding machines as follows:
1. Cylindrical external, internal, and external-internal grinding machines having all the following characteristics:
a. Limited to a maximum workpiece capacity of 150 mm outside diameter or length; and
b. Axes limited to x, z and c.
2. Jig grinders that do not have a z-axis or a w-axis with an overall “positioning accuracy” less (better) than 4 μm according to ISO 230/2 (1988).
d. Non-wire type Electrical Discharge Machines (EDM) that have two or more contouring
rotary axes and that can be coordinated simultaneously for “contouring control”.
Notes: 1. Stated “positioning accuracy” levels derived under the following procedures from measurements made according to ISO 230/2 (1988) or national equivalents may be used for each machine tool model if provided to, and accepted by, national authorities instead of individual machine tests.
Stated “positioning accuracy” levels are to be derived as follows:
a. Select five machines of a model to be evaluated;
b. Measure the linear axis accuracies according to ISO 230/2 (1988);
c. Determine the accuracy values (A) for each axis of each machine. The method of calculating the accuracy value is described in the ISO 230/2 (1988) standard;
d. Determine the average accuracy value of each axis. This average value becomes the stated “positioning accuracy” of each axis for the model (Â_(x), Â_(y)...);
e. Since Item 1.B.2. refers to each linear axis, there will be as many stated “positioning accuracy” values as there are linear axes;
f. If any axis of a machine tool not controlled by Items 1.B.2.a., 1.B.2.b., or 1.B.2.c. has a stated “positioning accuracy” of 6 µm or better (less) for grinding machines, and 8 µm or better (less) for milling and turning machines, both according to ISO 230/2 (1988), then the builder should be required to reaffirm the accuracy level once every eighteen months.
2. Item 1.B.2. does not control special purpose machine tools limited to the manufacture of any of the following parts:
a. Gears;
b. Crankshafts or cam shafts;
c. Tools or cutters;
d. Extruder worms.
| Technical Notes: | 1. | Axis nomenclature shall be in accordance with ISO 841(2001), |
| | | |
| | | “Numerical Control Machines - Axis and Motion Nomenclature”. |
| | 2. | Not counted in the total number of contouring axes are secondary parallel contouring axes (e.g., the w-axis on horizontal boring mills or a secondary rotary axis the centreline of which is parallel to the primary rotary axis). |
| | 3. | Rotary axes do not necessarily have to rotate over 360 º. A rotary axis can be driven by a linear device, e.g., a screw or a rack- and-pinion. |
| | 4. | For the purposes of 1.B.2. the number of axes which can be coordinated simultaneously for “contouring control” is the number of axes along or around which, during processing of the workpiece, simultaneous and interrelated motions are performed between the workpiece and a tool. This does not include any additional axes along or around which other relative motions within the machine are performed, such as: |
| | | a. Wheel-dressing systems in grinding machines; |
| | | b Parallel rotary axes designed for mounting of separate workpieces; |
| | | c. Co-linear rotary axes designed for manipulating the same workpiece |
| | | by holding it in a chuck from different ends. |
| | 5. | A machine tool having at least 2 of the 3 turning, milling or grinding capabilities (e.g., a turning machine with milling capability) must be |
evaluated against each applicable entry, 1.B.2.a., 1.B.2.b. and 1.B.2.c.
6. Items 1.B.2.b.3. and 1.B.2.c.3. include machines based on a parallel linear kinematic design (e.g., hexapods) that have 5 or more axes none of which is a rotary axis.