A couple more simple questions for a CNC builder

[Danno]

What is the difference between "flood" and "mist" coolant? How is this achieved ? Different RPM on coolant pump?
The reason I'm asking is because the pump that came with my mill is only one speed, but yet there's a switch that toggles from flood to mist.

Also; Where is home position on a 3 axis mill ? I think the spindle should be at your left, as far away from you, and as high as the z axis can go (i.e. max X-, max Y+, max Z+ ) What is standard ?

Thanks, Dan

[mrcodewiz]

Flood cooling is achieved by using a pump to expel a stream of coolant at the cutter/work. The coolant is then recycled and re-pumped.

A mister combines a coolant feed with an air source to create a mist that is sprayed. Generally, misting systems do not recycle the coolant - at least not the ones I have used.

I work strictly on hobby stuff but a cooling system that could do both mist and flood seems interesting. For one thing, I thought you used different types of coolant depending on whether you were doing flood or mist.

[stevo1]

The origin positions on a machine can always be different. This is usually set by the MTB. Sometimes I will change my home positions depending on how I want the machine set up for production and programming purposes.

Now remember there is a difference between machine “Origin” and machine “Home”. Machine Origin is where you will “Reference” the machine at power up. Your “Home” position will be were the machine is set to go if you were to program X0,Y0,Z0.

On a 3 axis mill for machine “Orgin” there is usually about 3 different ways that I have seen. I always seen my Z and Y the same as below. The only change is the X-axis.
+Z axis is all the way up.
+Y axis is all the way back or furthest away.
+X axis tool all the way to the left(table right). I have also it to the center of the table or the right side of the table.

Now for machine home this will depend on the type of machine. Rotary table or not ect. On a VMC with no rotary table I usually leave X,Y the same as machine origin. However I have my Z0 set to the table face.

On a rotary axis table I have my machine home X0,Y0 as center of the table and the Z0 set to the table face.

Stevo

[Crevice Reamer]

If you use Mach3, you can set up your home whichever way you want. I have my SX3 homed to Z full up, X full right and Y full back. That would be Z+, X- and Y-.

CR.