Hey,
I recently finished building a CNC router I am spending too much time aligning and touching off my workpiece. I would like a 3D touch probe but I haven't found what I am looking for.
From my research, the really good probes are expensive and have accuracy which is much higher than needed for CNC routers (0.0001" range). There are also a lot of cheap Chinese or DIY probes but they suffer from dirty contacts and inconsistent readings.
I have decided to design and build my own probe purpose built for use on CNC routers but I would like some feedback before I get too far into this.
Here are the specs I have come up with:
- Accuracy of 0.001"
- Most CNC routers are not that accurate, so better sensing accuracy isn't necessary
- Robust, Low Maintenance
- Should not need to take apart to clean contacts
- Only maintenance should be adjusting runout
- Simple runout adjustment
- I'm thinking about eccentric ring. Rotate rings relative to each other to adjust amount of offset. Rotate together to select direction of offset.
- Operate on 5V to 12V input voltage
- Used to power internal circuit, LEDs, switches
- Isolated from touch input/output wires
- Touch triggers a switch
- Probe signals a touch by completing a circuit between probe input and probe output signals.
- Normally open circuit closes when probe signals touch.
- Works the same way as a conductivity touch probe.
Undecided Specs:
- Ruby Probe or Stainless Steel Probe?
- I don't think a ruby probe tip is necessary since the desired accuracy is only 0.001"
- CNC routers cut softer materials like wood, plastic, aluminum so wear shouldn't be a concern
- Stainless steel would be cheaper, easily customized.
- Cost
- How much should a good CNC router 3D touch probe cost?
I am a mechanical engineer and I have been discussing this with an electrical engineer. We think we have a solution for a simple touch probe. We have identified the issues with popular switch based probes and believe we have a solution.
It will require a custom electronics board to make it work so I would like to know if you guys think we are heading down the right path.
What do you guys think?