Keyhole toolpath

[Anonymous]

I've been trying to figure out how to setup a toolpath to cut a keyhole in the back of a part, so that I can hang it on the wall like a picture frame, and am having very little luck.  Currently, I am using a 2D slot toolpath with a plunge ramp, and that gets me half way there, but I haven't found a way yet to get the toolpath to basically reverse and back out the way it went in.  Here's a picture to hopefully help illustrate:

Jim

[matthew.nichols]

that was an awesome TV show!

[Anonymous]

I am 2 episodes in and it has not told me why my tool is starting below the stock lol.....................am I doing it right?

[Steinwerks]

Yes you are, there's definitely a bug of some sort going on here. No height adjustments either in distance or geometry reference seem to make a difference.

@Anonymous can you take a look at @Anonymous 's file? Turning off Smoothing let the toolpath generate the initial clearance height but the tool still rapids into the stock.

[Anonymous]

So I finally tested the keyhole toolpath on my project and 10 ipm seems to work great for plunging and radial movement but I do have one issue that I am not sure how to correct.

When the tool path starts the tool in plunging down at rapid feed rate (my machine 800 ipm) and just knicks the surface of the stock I think 10 or 20 thousands and then lowers the feedrate to 10 ipm. This is a bit of a problem and I believe will break my tool if it happens to much 

When I simulate the tool path is shows a collision when you first start but as soon as it enters the stock the collision stops dose anyone know why this is happening? I have attached the .f3d file for you to look at. 

I think a work around might be to lower the rapid rate to 10 ipm but I really dont want to do that because it will add extra time to the cycle time 

I would very much like to get in touch with someone from Fusion 360 regarding this issue and hopefully resolve it 

[xander.luciano]

While this still seems like it might be a bug, if you go back and look at post 19, I described a way to create this toolpath that should suit for your needs.

Here you can see the toolpath will use a lead-in (green line) from the feedheight instead of a rapid movement (yellow line) into the stock.

I also attached the .f3d with the updated toolpath.

Hopefully this is what you are looking for! Let me know if this solves your issue 🙂

[Anonymous]

Hey thank you for that I see that you have put another sketch in of a straight line and just had the tool follow that 

How do you and why do you pin the sketch in the modeling tab?

[Steinwerks]

@xander.luciano

He shouldn't be experiencing a crash though. This should be able to be set with height settings and it isn't, therefor it sure looks like a bug to me since the toolpath is correct otherwise, and without using a workaround such as a sketch line.

[xander.luciano]

@Anonymous I think you're referring to the sketch visibility when you say pin, correct? If so The light bulb in the feature tree will toggle it's visibility. I made it visible so that I could select the sketch line in the CAM environment.

@Steinwerks Correct, it does look like a bug. He should still be able to set the height, but what makes the way I did this a "workaround"? It's still a completely valid way of creating toolpaths. 😉 Similar to how one might make a sketch profile to constrain a 3D toolpath.

[Steinwerks]

If the idea is to avoid a bug, it's a workaround. This isn't special geometry IMO.

[Anonymous]

Hello thanks for the reply 

I do think that it is a bug in the old tool path due the fact that the tool should never rapid below the level of the stock in any generated tool path

and plus it shows a collision in the cam simulation

However this will work for my current situation but it does add time to the overall design process of the part 

And no not the visibility of the sketch the pin(or ground) icon looks like it is turned on with the sketch that you provided  here is a screen shot

[fritter63]

Clamp a guide board on the back of the piece, put it in a plunge router, run the router along the guide board. plunge, push, pull, unplunge. Setup up start blocks on both ends for accuracy.

You'll be done in 10 minutes. 😉

[Anonymous]

In 2016 we build a fixture like this

And we are done in 16 seconds!! with every piece done being the same...........ehh a little quicker than 10 minutes me thinks?

[Anonymous]

or fixtures like this for multiple operations

[cj.abraham]

I'm a bit late to the game on this one. Xander's solution with the trace operation is the ideal case. I've attached a simplified version of your part to show you the best way to leverage sketches for both CAM and modeling. Hopefully this model will also generate correctly for you. The one caveat of the trace operation is that the selected contour is where the tool tip will be for cutting. This means that there is no "Top" or "Bottom" heights to be set, unlike a 2D contour with compensation turned "off" (which behaves the same as trace!). So long as the tool is below the feed plane, the tool will be using one of the four feedrates (plunge, lead-in/out, cutting). Anything above that can be a rapid move.

[Steinwerks]

@cj.abraham

This is much clearer in HSMWorks of course, and if there is going to be a "Feed Height" that is settable from any reference, it needs to obey that. I also realize there are exceptions such as Adaptive, but that uses a Safe Distance which Trace does not have.

Normally I would be sympathetic to a Trace operation rapids but not when it violates very explicit settings available in the UI.

Edit: Had to go back and look at my own example! Trace does have a Safe Distance and mine was set at .25, which puts the toolpath 1/16" above the entry position, violating the Feed and Retract heights respectively, but not crashing into the stock. Increasing the Safe Distance to .3125 puts it 1/8" over the stock before feeding into the part, using a Lead-in linking even though the Leads are turned off. I think some explanation of exactly how this is being calculated is warranted.

[cj.abraham]

@Steinwerks

My trace operation in the archive file I attached in my previous post respects the feed height regardless of safe distance. Not sure what you are referring to here.

[Steinwerks]

@cj.abraham

See post 7. Safe Distance is not intuitive although that file doesn't crash into the stock.

[jtromboukis]

I had some success selecting this path in the photo and doing a 2D contour operation. The bit exits where it's supposed to. I'm new to Fusion so I'm trying to figure out how to get the start point of the bit where its should be. Right now the center of the bit starts next to the WCS. If anybody can help me with that, thank you

[Anonymous]

Thanks for your input on the keyhole operation. I knew I wanted to do a trace operation to achieve the desired result. But I didn't have "repeat passes" and "both ways" checked under the Passes tab. Once I made that change, the operation worked perfectly.