six points of get in touch with find any type of displacement.
LinuxCNC contributor as well as machining enthusiast [Andy Pugh] is definitely not afraid to try making specialised tools to see exactly how well they work out, as well as this time around he’s been hectic making a touch probe (video, embedded below) for inspecting the accuracy of machining operations as well as general measuring applications.
These things are not cheap, since they are essentially ‘just’ a switch with a long probe, But, just like anything specialised as well as machined with tight tolerances, you can comprehend why they expense what they do.
After inspecting as well as costs a long time reverse-engineering such a unit, [Andy] then proceeded to grab some PEEK bar he had lying around as well as chuck it into the lathe (get it?). He notes Delrin would be more expense efficient for those wanting to reproduce this, however as long as you have the capability to machine it as well as it’s non-conductive, there are many other choices you might try.
Using no special tools other than a collet block (like this one) all the angled holes as well as slots were made with ease, with the assist of a specially 3D-printed install for the vise. A nice, simple approach, we think!
[Andy] tested the repeatability of the probe, mounted over his CNC-converted Holbrook lathe, reporting a value of 1 um, which seems rather good. Centering of the probe tip within the probe body was off a bit, as you’d expect for something made virtually by hand, however that is less of a issue as it would seem, as it results in a fixed balance out that can be compensated for in software. perhaps the next version will have some adjustability to dial that out manually?
The whole assembly is developed from two plastic parts, a handful of ground-finished hardened steel pins, as well as a huge spring. The only part remotely special is an off-the-shelf probe tip. during the electrical hookup, you may notice the utilize of a self-fluxing verowire pen, which was something this scribe didn’t understand existed as well as has already put an order for!
The recommendation 3D design for the style is shared from [Andy]’s Autodesk Drive for your viewing pleasure.
Of course, this isn’t the very first diy touch probe we’ve seen, here’s one for example, as well as over on Hackaday.IO, here’s an attempt to make one utilizing a piezoelectric transducer.