Linear Encoders for Ultra-High Accuracy in Medical Machining

To monitor and prevent drift issues that can affect the high accuracy demands of micromachining, machining and measurement of surgical instruments, medical device components and more, LIF 400 series linear encoders from Heidenhain Corporation (Schaumburg, IL) have been redesigned with much improved contamination resistance and other enhancements. The new LIF 400 series has a position noise value of 0.6 Nm at one MHz and a low interpolation error down to ±12 Nm. A major update is the incorporation of the Heidenhain Signal Processor (HSP1.0) custom ASIC into the scanning unit to help lower the interpolation error and power through contaminations on the scale as it adjusts the LED intensity every signal period while moving at up to 4 mps. This compensation adjusts the amplitude and phase of the signals so that the control sees constant perfect signals even with contaminants such as large fingerprints, dust, and wafer pieces that may be on the glass scale.

Another addition is a status LED on the connector that indicates the status of the incremental signals and can also be used as a general mounting indication. It’s a simple red/green display for the signals and blue for a good reference mark signal. The new connector is also smaller versus the older version, which saves space and improves accessibility when plugged into tight spaces. This 15 pin male connector is 27 mm shorter than the previous version. The mechanics of the scanning head have not changed, and scanning units can be ordered with a one volt peak-to-peak interface with 4 micron signal period, or TTL versions with resolutions down to 10 Nm. The glass scale is also unchanged.

Heidenhain Corporation, 333 East State Parkway, Schaumburg, IL 60173, 847-843-2380, kkaufenberg@heidenhain.com, www.heidenhain.us.