Ok, I have the HF mini mill. I got it all set up for CNC and have tested it a bunch of times. Very pleased with my setup!! Anyway, I have cut a piece of aluminum on my band saw and surface cut it to size with the mill manually. Now its ready for the g code that I made. I have tested this code on pieces of aluminum and it is perfect. My only question is how do I set up the mill so it starts to cut in the exact right spot? I need to position the mill to start in the lower left corner since that is 0,0 . Please help me get this right the first time!! I dont want to mess up after all the work I have already done!!!

What are you using to run your mill? Most nc software allows you to set 0,0, you will need to set you metal in the correct orientation that you programed in relation to 0,0.

I am using master5. I used delta cad to draw the part and I imported dxf into master5 and it sets the 0,0 in the lower left corner. I am not sure exactly where to set up the aluminum so it will start to cut exactly where I want it.

If you have located it on 0,0 than you're metal will be where the 0,0 is set on the machine. Run another test and see where it will cut.

xknacx,
To add to this,
I would try and get in the habit (where practical) of drawing your part in the -X and -Y quadrants and z = 0, that way you always know that any cuts will be in the - consequently less confusion. This would be the lower left quadrant.

As you know your controller's work offset (G54) needs to know where X=0 and Y = 0 (like in your drawing) You would then set your work offset to match the drawing, in this example you could use an edge finder to locate the back side of the block (Y-0) and the right side (X=0).

I am wondering if there is a misunderstanding here.
I believe xk is asking how to set up the machine.

Lets say you want to hold your part in a vise.
First you bolt the vise to the table and when in the process of tightening the bolts you need to tram (with a test indicator) the face of the fixed jaw true to the table ways.
When complete clamp in your workpiece & (depending on accuracy required) you would normally edge find the X0, Y0 part edges and set those coordinates as your fixture offset.

Hope this helps; if I misunderstood the question please disregard.

My only question is how do I set up the mill so it starts to cut in the exact right spot?

I understood that he wants to know how to locate the part on the machine for that it cuts the part out based on the material being cut to size?

xknacx, if you are wondering how to set your X and Y, there are a couple ways to go about it. First, is probably the most common - an edge finder. These can be purchased at about any place that sells CNC tools and supplies.

The second quick and dirty method, is to use either a drill or spot drill (anything that is straight and comes to a point). Put it in the spindle and turn on the spindle. Bring the tip of whatever you are using down just above the material. Position the point over the X0 side of the part, and give the software a G92X0 command. Then do the same thing for Y. With a little practice, and the right tool, you can get amazingly close with this method. A guy at work saw me doing it this way, and he said that I probably wasn't even withing .020". We checked with an edge finder and I was within .002 on each axis.