Does anyone have an idea on how to create an electronic edge finder for ER11 collets?
Ready made ones start at twice the diameter and are longer then my entire Z travel. So I have to make my own.
I really want to do Z, X and Y probing of the mounted blanks but my materials are always non-conductive.
I’ve made an electric contact detector. It is a mandrel that clamps in the mill collet, with a sprung tip. The tip is pushed down by a spring against three electrical contacts, in an enclosure attached to the mandrel. If it touches anything one (or more) of the three contacts will open, sending out a signal to the mill controller that it’s just touched. It works okay although it’s not as repeatable as I’d like.
Could you make your material conductive using aluminum foil?
aluminium foil is no option when you aim for 1/100mm.
Do your edges need to be that close? Plus most foil is thinner than the paper most use to space the bit when zeroing it…
But was just a thought. Cheap and no need to even remove it before you start cutting…
I’m mostly milling wax. Often cylinders.
This also means I’m melting my shavings into new blocks, so they need to be clean.
How do you suggest to attach the foil without damaging the blank or half-done part?
So you’re making “blanks” for molds? That’s very cool. You could just try using it as a spacer the way you would paper. All my thoughts are theoretical so… But I have thought of making a finder bit using a spring out of a pen (maybe a bit larger), with a metal rod through the center, the two being isolated from each other. This would result in a 360 degree contact switch. If you let the spring extend 1/10th or so past the end of the rod, and added a metal cap of some sort to the end, it should handle the Z axis as well. But as I said, just throwing thoughts out there, Hope it helps…
I’m making blanks for the CNC.
The CNC makes masters and mother-molds from them.
I use these to make molds for resin casting designs that I have prototyped on the 3D printers and want to produce in small volumes.
I tried that paper-spacer trick but found it to be less reliable. You can see it in the surface if the cutter was 1/100mm off. (and feel 1/1000 but that’s something a minute in the microwave cures.)
Still very cool. I’m interested in doing molds for some small foundry work…
@Mat_Helm – if you have access to a 3d printer, printing low-infill PLA makes for great lost-PLA green sand casting, much easier than classic wooden master forms because you can make incredibly complex shapes. Wax is really nice to work with as well because you can build up a complex shape from small pieces by welding them together with a hot wire. If you’re working with aluminum you can even use plaster of paris and melt out the PLA or wax in a kitchen oven, which means no more having to fight with mixing your own green sand or renewing burnt oil-based sand.