diy自动分中棒.pdf

Building a Digitizing Probe Martin Kennedy HMSC February 2012 Outline  Probes and edge finders  Design research  Making my own design  Probe fabrication  Software  Operation  Accuracy Types of probes / edge finders Edge finders  Simple operation  Accuracy  Manual 0.0002”  Electronic 0.0001”  Inexpensive Laser edge finders  Non contact  Beam can be focused to small point  Repeatability  0.0002”  Based on judgment  Cost $125 Video edge finder  Quick  Accuracy 0.005”  Interpretation required  Automation possible Digital probe  No interpretation  Accuracy 0.00002”  Can be automated  Can do 3D digitizing  Very fast  Higher cost  Precision machining required to fabricate 3D Digitizing  Create point cloud from object  Possible only with digital probe  Video Design research Typical operation Three normally closed switches in series Design research - Internet Commercial Probes  Renishaw  Low activation force  0.3 oz xy, 2.7 oz z  Accuracy  0.35 µm (0.000014 in)  Replaceable ruby tip module  Wireless available  CNC tool changer  Price over $1000 Low-price probe • CNC4PC.com • $135 Design research - Patents Design research - homebuilt From Mach3 Webpage Design research - magazine One more option – simplicity!  Probe with no moving parts  Rely on direct electrical contact at isolated probe tip  Can’t do non-conductive stock My design First design considered  Found on CNC discussion group  Had 2D DXF files posted  Began converting to 3D model  Body made entirely of plastic  Liked idea of using circuit board to electrically connect and hold ball bearings  Didn’t like tiny ball bearings used  D