I am using the free openbuilds cam with a portable mill with 1/4" diamond encrusted finger bitts to carve 1/4" deep into concrete. I need the bit to stay in the cut and go round and round without lifting and plunging again each pass, also need to figure out how to setup a slow ramp. If this feature is unavailable what cost effective program would you recommend? This machine will kind of be a one trick pony and I just need to be able to tile and setup simple 2d pocket cuts. I do have the interface controller.
Try SketchUp and the SketchUcam Ruby script. Search this site for the SketchUp download and make sure to get the 2017 version and not a newer one. Search also for the SketchUcam here. These programs are free and work a charm. @David the swarfer is updating the SketchUcam and can help you with questions.
while SketchUcam is great, the slow ramp you want can be done in Fusion360 with the free private use license (-: staying down is as simple as removing the retracts from the Gcode, it is just a text file
I want to see this thing in action. It looks great. Estlcam is an easy to use program that will do a ramp at each pass of whatever angle you want. The process of generating the CAM is very similar to OpenBuilds CAM. I find it far easier to use for CAM generation than Fusion 360. You can try it for free as long as you want, or purchase a license for $59 if you want to pay for it. Here is a video of it being used to create a trichoidal milling toolpath in stone. I am not sure if this is what you are trying to do, but here you go.
I got fusion 360 free today and played with it for a bit, got it to ramp and for it to stay down but had to generate a custom bit profile. Still have some testing to do on feeds and speeds with the diamond encrusted .25" bits. I also need to find the right shape design and cutting profile to get the bit into the claw tips, it is not allowing that area to be cut so far.