Paragraph 2 2B001

Changes not yet applied. Later legislation changes this provision in ways not yet written into the text below:

Sch.1, Pt III, Contents amended by Export of Goods (Control) 1993 art.2(b)
Sch.1, Pt III, Group 1 am. and rev in pt by Export of Goods (Control) 1993 art.2(c)
Sch.1, Pt III, Group 3 am. and rev in pt by Export of Goods (Control) 1993 art.2(d)
Sch.1, Pt III, Group 3 am. and rev in pt by Export of Goods (Control) 1993 art.2(c)
Sch.1, Pt III, Group 2 amended by Export of Goods (Control) Order 1992 1992 art.2(b)
Sch.1, Pt III, Group 3 amended by Export of Goods (Control) Order 1992 1992 art.2(c)
Sch.1, Pt I amended by Export of Goods (Control) 1993 art.3
Sch.1, Pt III, Group 3 am. and rev in pt by Export of Goods (Control) 1993 art.2
Sch.1, Pt III, Group 3 amended by Export of Goods (Control) (Amendment No 7) 1994 art.2

Axis nomenclature shall be in accordance with International Standard ISO 841, “Numerical Control Machines—Axis and Motion Nomenclature”.

Numerical control units for machine tools, as follows, and specially designed components therefor:

Note:Head a. of this entry does not specify numerical control units:

Modified for and incorporated in machines not specified in this entry; or

Specially designed for machines not specified in this entry.

Having more than four interpolating axes which can be coordinated simultaneously for contouring control;

Having two, three or four interpolating axes which can be coordinated simultaneously for contouring control and:

Capable of real time processing of data to modify, during the machining operation, tool path, feed rate and spindle data by either:

Automatic calculation and modification of part programme data for machining in two or more axes by means of measuring cycles and access to source data; or

Adaptive control with more than one physical variable measured and processing by means of a computing model (strategy) to change one or more machining instructions to optimize the process;

Capable of receiving directly (on—line) and processing computer aided design (CAD) data for internal preparation of machine instructions; or

Capable, without modification, according to the manufacturer’s technical specifications, of accepting additional boards which would permit an increase above the levels specified in this entry, in the number of interpolating axes which can be coordinated simultaneously for contouring control, even if they do not contain these additional boards;

Motion control boards specially designed for machine tools and having any of the following characteristics:

Interpolation in more than four axes;

Capable of real time processing as described in sub—head a.2.a. of this entry; or

Capable of receiving and processing CAD data as described in sub—head a.2.b. of this entry;

Machine tools, as follows, 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:

Machine tools for turning, grinding, milling or any combination thereof which:

Have two or more axes which can be coordinated simultaneously for contouring control; and

Have any of the following characteristics:

Two or more contouring rotary axes;

Technical Note: The c axis on jig grinders used to maintain grinding wheels normal to the work surface is not considered a contouring rotary axis.

One or more contouring tilting spindles;

Note: Sub—head c.1.b.2. of this entry applies to machine tools for grinding or milling only.

Camming (axial displacement) in one revolution of the spindle less (better) than 0·0006mm total indicator reading (TIR);

Note: Sub—head c.1.b.3. of this entry applies to machine tools for turning only.

Run out (out—of—true running) in one revolution of the spindle less (better) than 0·0006mm TIR;

The positioning accuracies, with all compensations available, are less (better) than:

0·001° on any rotary axis; or

0·004mm along any linear axis (overall positioning) for grinding machines;

0·006mm along any linear axis (overall positioning) for turning or milling machines; or

Note: Sub—head c.1.b.5. of this entry does not specify milling or turning machine tools with a positioning accuracy along one axis, with all compensations available, equal to or more (worse) than 0·005mm.

Technical Note: The positioning accuracy of numerically controlled machine tools is to be determined and presented in accordance with ISO 230/2 paragraph 2.13, in conjunction with the requirements below:

Test conditions (paragraph 3):

For 12 hours before and during measurements, the machine tool and accuracy measuring equipment will be kept at the same ambient temperature. During the premeasurement time the slides of the machine will be continuously cycled in the same manner that the accuracy measurements will be taken;

The machine shall be equipped with any mechanical, electronic, or software compensation to be exported with the machine;

Accuracy of measuring equipment for the measurements shall be at least four times more accurate than the expected machine tool accuracy;

Power supply for slide drives shall be as follows:

Line voltage variation shall not exceed ±10% of nominal rated voltage;

Frequency variation shall not exceed ±2Hz of normal frequency;

Lineouts or interrupted service are not permitted.

Test programme (paragraph 4):

Feed rate (velocity of slides) during measurement shall be the rapid traverse rate;

N.B.: In the case of machine tools which generate optical quality surfaces, the feed rate shall be equal to or less than 50mm per minute;

Measurements shall be made in an incremental manner from one limit of the axis travel to the other without returning to the starting position for each move to the target position;

Axes not being measured shall be retained at mid travel during test of an axis;

Presentation of test results (paragraph 2):

The results of the measurements must include:

Positioning accuracy (A); and

The mean reversal error (B).

A positioning accuracy less (better) than 0·007mm; and

A slide motion from rest for all slides within 20% of a motion command input for inputs of less than 0·5 micrometre;

Technical Note: Minimum increment of motion test (slide motion from rest):

The test is conducted only if the machine tool is equipped with a control unit the minimum increment of which is less (better) than 0·5 micrometre. Prepare the machine for testing in accordance with ISO 230/2 paragraphs 3.1, 3.2, 3.3.

Conduct the test on each axis (slide) of the machine tool as follows:

Move the axis over at least 50% of the maximum travel in plus and minus directions twice at maximum feed rate, rapid traverse rate or jog control;

Wait at least 10 seconds;

With manual data input, input the minimum programmable increment of the control unit;

Measure the axis movement;

Clear the control unit with the servo null, reset or whatever clears any signal (voltage) in the servo loop;

Repeat steps b. to e. above five times, twice in the same direction of the axis travel and three times in the opposite direction of travel for a total of six test points;

If the axis movement is between 80% and 120% of the minimum programmable input for four of the six test points, the machine is controlled.

For rotary axes, the measurement is taken 200mm from the centre of rotation.

Notes: