Predrill and Entry Positions

[tom2KXAJ]

New to this, sorry if a basic question. I have a series of holes and plan on using a drill to rough them out versus plunging an end mill. Having trouble figuring out how to tell the 2D Contour step that the hole has already been roughed out. I was thinking that using pre drill positions would tell the step that the hole had been cleared. Any help on how to tell the contour process the hole is already clean would be appreciated. Thanks.

[LibertyMachine]

Do you mind sharing the file so we could better understand what you are trying to do?

File > Export > Save to local folder. Return to thread and attach the .f3d file in your reply.

If that is not acceptable, at least some screenshots will give us more info

[euclidmandd]

Hey, I'm not sure that there is necessarily a way to tell the contour that the hole has already been drilled. What I typically do is select the circumference of the hole as the contour, then under the 'linking' tab with the 'predrill positions' option selected click on the hole, and finally select 'keep tool down'. This tells the contour to plunge in the center of the hole (where you had previously drilled) and then move to the contour, depending on the size of the drill and finished hole you may have to play around with the 'lead in/out' settings and how many step overs you want the cutter to take. I don't know why 'keep tool down' needs to be selected but if it isn't you get a warning.

You can do multiple holes in one 2d contour operation, just gotta select each hole as a contour and predrill location.

[LibertyMachine · Accepted solution]

If you use the Boring or Circular operations, you won't need to do any guessing or such.

Set the Top Height (not the Feed, Retract or Clearance) and Bottom Height to "Bottom of Hole" and it will plunge into the hole, down to depth and cut the diameter you select:

Ignore the "Collision Warning" I didn't spend any time making sure tools were proper, just wanted to get you a visual.

[tom2KXAJ]

Very nice! Thanks so much for taking the time to demo this. I tried it and it is exactly what I want to do, pre-drill the holes close, then finish off with endmill.

One question, Once you suggested this, I also tried drilling then using a 2D Contour. That seems to have the same effect with less manipulation. I am worried about the mill banging into the drill pocket, because it is not as deep as the hole bottom. It looks like using your approach I can easily figure that out and have the boring function handle that last little bit for me. I want to end up with a flat bottom hole so need to use a flat end mill for the last step.

Does that sound about right?

Again, thanks for the tip, real easy way to get what I want accomplished.

[LibertyMachine]

If Flat Bottom is what you are after, I would do exactly as you suspect:

Drill

Bore with a spiral. You can enter a positive offset into the Top Height value so you aren't starting from the top:

And then finishing it up with either a Bore of Circular operation. On the finish Bore operation, I'd have the Top Height with a value of .002" perhaps, so it's not going full rapid to finish depth, also allowing it to take an extra pass on the diameter

Yes, 2D Contour works just fine. However, if you are dealing with close proximity tooling, there is often a fair amount of manipulation to ensure that the tool doesn't collide with the wall on it's lead-in/out moves. The Bore/Circular functions do a great job of reducing that risk, with the "Lead to Center" options