The TNC 320 CNC replaces the current TNC 310 and is aimed at less sophisticated machine tools, typically 3- or 4-axis machining centres, with an additional emphasis on the cost-effective upgrading of existing machines. It is the first Heidenhain CNC to feature the company’s new NC Kernel (internal operating system). This new system offers users far greater modularity, meaning it is far more flexible in how it can be used and applied. In its basic form the TNC 320 has four control loops (three closed-loop axes plus a servo-controlled spindle). Through use of various options, this can be expanded to four closed-loop axes plus a servo-controlled spindle with positional input or five closed-loop axes plus a spindle without servo control or positional input. Rebuilding is considered a major target. By retaining analogue control, the TNC 320 provides a cost-effective upgrade option. The TNC 320 will be applied where the top-of-the-range 530 would previously have been used. The result should be reduced costs, in some cases by as much as 66 per cent in the case of an analogue-to-analogue retrofit.