At milling work, mainly 3D, it is required that the machine operator possesses information about the length of the tool in the whole course of processing, however, mainly at the tool replacement. When inserting the first tool in the spindle there will be two measurements done: metering the zero position of the work-piece (surface) and also the tool length (tool overhang). At the replacement or with any other tool inserted only the measurement using the tool length sensor will be done and the controlling program will adjust the height of the Z-axis from the measurement as if it was an equally long tool. For comparison measurement use the sensor attached to the machine’s table; the position must be preserved during the whole processing cycle. There are many ready-made solutions and producers of such sensors; however, I can show you how to make such sensor easily at home. The result is not only accurate (±0.02mm), but it is also produced for much less than the ready-made industrial solution.
The objective was that all the parts needed for the tool setter production are available from the local hardware store (for the list of the items see the video). In fact, the only thing that may be difficult to obtain is the linear bearing. You can find it on ebay (Chinese, but cheap) or ask your local dealer or linear technician. I have bought mine in my favourite CNC e-shop. You can easily find any other things needed in trash or check your neighbour’s backyard :)
Here is the first part of the “Making of…” video simply explaining the work on mechanical parts. Don’t forget to use English subtitles.
And here is the second part. You can see how it works in manual and fully-automatic mode.
Below you can see a detailed electric diagram for the use in manual and automatic modes. Specified electrical connection is functional with GVE66 3-axis driver and with Armote control software for machine. It is also functional with 3-axis Chinese TB6560 based driver board and LinuxCNC. An adjustment of the electric diagram or a completely new connection may be required in a specific instance. Check your Operation Manual or ask someone competent.
Should you have any question, please, do not hesitate to leave a comment. Kindly bear in mind, that I will not be able to respond to issues regarding connection or operation of the tool setter on your own system without a more detailed information.