Machines have inherent inaccuracies. Historically these were minimised by taking extreme care to manufacture critical machine components to a very high accuracy, and by using accurate jigs to assemble the machine.

Then the machine had to be tested, inaccuracies identified, their source located, and changes made. This process was repeated until the desired accuracy was attained. Making machines accurate was a time consuming, lengthy and very expensive process.

Some machine controllers can compensate automatically for a range of mechanical errors, these however have to be measured and logged. Error compensation dramatically improves the accuracy of machines, it is available on all NEE AMC controllers.

Measuring and logging errors can be automatically performed by NEE's ECM software. The benefits of this software include:

• System setup is accomplished by a 'wizard'
  
  
• Once setup the machine can be automatically or manually controlled, errors are automatically measured and logged
  
  
• The required accuracy can be preset
  
  
• Results can be presented numerically and graphically
  
  
• The process aids in identifying mechanical problems
  
  
• Accuracy tables and graphs can be printed
  
  
• Accuracy results can be saved for future reference
  
  
• Machine backlash can be tested and the results saved
  
  
• Comparisons of two sets of results can be shown graphically
  
  
• PC based comprehensive 'Help' is provided
  
  
• The effect of temperature changes on your machine can be measured and logged
  
  
• The system permits you to make changes to your machine and to measure their impact
  
  

The system uses the AMC controller, ECM software running on a PC, and a precise linear encoder temporarily fitted to the machine axis currently being tested

The setup procedure requires the operator to define a number of parameters including the mapping start and end positions, the distance between sample points, the maximum number of iterations permitted, the required final accuracy and the number of validation loops.

After each pass the error table generated so far is used and updated on the next pass. The measuring and recording process is then carried out automatically under control of the PC. Passes are repeated until the error table remains unchanged for a defined number of check passes.

The process is carried out for each machine axis.

When all axes have been mapped the resulting text file is permanently flashed into AMC memory for subsequent automatic use during machine operation.