How to get ramp down for a pocket where you want it? Drill/Point not working?

[jgaertner]

Hello Forum,

I want to machine a round pocket in a part. I like to drill a large center hole prior to the pocket op. I would like to then ramp with my mill around the drilled hole so that the mill does not have to be 100% face engaged. I have set the Ramp to 1 degree Helix and said to start at the Pre drilled position with a ramp radius of .75". The mill just plunges, straight down at the center of my pocket, NO ramping what so ever. If I remove Pre Drill Position, it ramps off to one side of the center hole. Not where I want it to ramp down? Any positive suggestions will be appreciated.  Sample file attached.

[seth.madore · Accepted solution]

Indeed it would be nice if toolpaths behaved in somewhat the same way as we conceived in our minds. Alas, it is not so with Predrill and Ramp settings.

The easiest way to get what you are looking for is to place a Drill>Bore cycle before the 3D Pocket and change your Pocket to a Plunge move with Pre-Drill position selected.

Yeah, it's a clunky workflow and I wish there was a better method, but that's what I'm coming up with myself.

[jgaertner]

Hello Seth,

Thanks for your reply. As I was watching my parts being machine today.. I realize I can't do what you offered as good a solution as it was. I was pre drilling with a 1/2" drill, largest I can safely use on my CNC mill. And I was then using the pocket command with a 1/2 end mill. So drilling/boring would make a 1/2" hole and then the mill is 1/2" and my goal is to give the 1/2" end mill a break and ask it only to have to make the outer .120" WOC. I guess if I switched to a 5/16" end mill it would work but I don't have one or a hold for one... Wish the folks at AutoDesk would chance how this operation works in the set up. Thanks for your help. 

[DarthBane55]

Like this? (see pic below).

I used 3d adaptive with rest machining from previous operation, and did not select a pre-drill point, it starts in the center when it's a circle.  I removed a bunch of depth of cuts just for picture clarity.

[seth.madore]

That's interesting, for sure. I was focused on trying to get Pocket to behave proper, didn't consider what would happen with Adaptive. Turns out the toolpath is pretty darn close to the same for Pocket (outward spiral cutting at each depth)

[jgaertner]

I just set up and ran this 3D adaptive strategy with the center drill and it saved 30 minutes per part! Woo! Whooo!

[changedsoul]

Did the most recent update break helical entries? Sorry to rant but I need to get something done and I find fusion now selecting things that are not visible, not selecting things that are, and no matter what I do I absolutely cannot get it to helical into a hole. I am so frustrated right now with fusions inability to just do what it should.

I find I spend more time editing tool paths to try and get fusion to do hat it should just do on the first try. Fusion seriously needs to take a look at how these tool paths are being applied, or give the user an option to force things if need be. Rant over.

I need to helical into this bore and it will absolutly not do anything. It either will generate no path at all, or plunge down into the hole and take one pass. I have tried 2D adaptive, 2D Pocket, 2D contour, 3D Adaptive, 3D

Pocket...Nothing works. Its a half inch endmill going into a .9 diam hole.  Can someone lend a hand please?

[changedsoul]

I feel like a dope! After posting I realized my helical diam was larger than my hole "facepalm". Problem solved. Sorry for the rant.

[seth.madore]

Hey, it happens.. 🙂

[mmilleratticus]

It begs the question, why doesn't the Ramp type Helix get greyed out as an option when selecting Pre-Drill start location?  Or Alternatively, grey our Pre-Drill when Ramp is selected?  To me it's logical to want to select a Ramp to drive down into around a predrilled hole?  Or am I missing something?