[KSky]

I have a number of 3D parts that need a chamfer around circular bosses. I watched a number of Al's video's and am still a bit confused. Seems like the thing to do is extract a wire frame and then use the engraving option as shown in Al's video "3D Chamfer V25". I am using 3 Axis Pro V27.

Is this still the best way?

It seems like I would want an imaginary line where the top and sides intersect. But instead I pick the top of part and cut around it, doesn't seem that exact. Does it matter it I choose the top of the cylinder?

I have attached a screen shot of what I am talking about.

[The Engine Guy]

Yes, you can do this easily in V27, I have done it in V26 3 Axis Pro for you as I only have the V27 Demo and you wouldn`t be able to open the file, hopefully this file should give you some idea of how to go about it

The large odd shaped block has a varying Z height and the cylinder has a flat top as per your image, both are easy to do and don`t involve any wireframe at all, just simply select the edges of the the solids where you want the chamfers, you can do all or any combination of edges, if you want to chamfer for example the Z variable arc only then just select that edge and compute

Have a play around with the attached file, enjoy

Regards
Rob
:rainfro: :rainfro: :rainfro:

[KSky]

Thank's for sending that. I guess I wasn't clear on my issue. My solids already have the chamfer, when I want to cut them using a chamfer tool, do I select the top of the chamfer, the bottom, or is there way to get the actual corner of the part?

[The Engine Guy]

Ah, OK, wasn`t quite with it earlier

Tested this little issue and it would seem that selecting the bottom of the chamfer (Assuming you have used the "Chamfer Depth" option) works fine, what you have in your program for the stock will depend on whether you will actually see the simulation cut the chamfer, to see that you would need a stock that was full height without the chamfer.

Attachment 281630

Attachment 281628

File and image attached

Regards
Rob
:rainfro: :rainfro: :rainfro:

[KSky]

I agree with you there, the bottom seems to work well, but need to select the top one as the top of part.

Another Chamfer question. When I choose the Chamfer strategy, I have to choose a tool from the Chamfer tools. But I am using a 90 degree spot drill and BobCad will not let me select that. Or I don't know how. I tried adding one but Chamfers have to have a "Small Diameter", it cannot be zero like my pointed spot drill.

[The Engine Guy]

I agree with you there, the bottom seems to work well, but need to select the top one as the top of part.

Another Chamfer question. When I choose the Chamfer strategy, I have to choose a tool from the Chamfer tools. But I am using a 90 degree spot drill and BobCad will not let me select that. Or I don't know how. I tried adding one but Chamfers have to have a "Small Diameter", it cannot be zero like my pointed spot drill.

Why do you feel you need to select the top edge for the top of part ? It isn`t needed at all, you don`t have to actually select anything to set the top of the part, just set the top to 0.000 in the beginning of the Feature where it says "Top of Feature", job done If you feel the need to select something then just pick the flat top of the cylinder

Now there is a bit more confusion here, don`t look to use a "Chamfer Tool", use a "Chamfer Mill", a 90 degree spot drill is the same as a 90 degree Chamfer Mill, and yes, you can set the chamfer small diameter to a point, you are actually given a choice between a flat bottom tool or a sharp point tool.
Now, you are correct in that you can`t set the small diameter to a 0.000 point, however you can set the tool in the tool library to a small diameter of 0.001, that will allow you to select the "Sharp Point" option, once you do that selection then you will see the "greyed out" small diameter box change from 0.001 to 0.000, again job done

See image :-



The software doesn`t know that the actual tool you have put in the machine is a spot drill, all it cares about are the numbers specifying it`s size and shape, as long as the numbers are correct then all will work as expected

Regards
Rob
:rainfro: :rainfro: :rainfro:

[KSky]

I meant select the top part of the cylinder, my part has multiple cylinders of various heights. We are on the same page there.

What I was trying to get at, was when I choose the Chamfer Strategy, I can only pick from the Chamfer Mill's. If I want to use my spot drill, I have to add it manually from the select tool screen. I cannot pick from my spot drills. I don't see a "sharp point option" in the add Chamfer Mill.

One of these days I'm going to be the one answering questions...

[jrmach]

sharp point,sharp tool ?

BTW,it is impossible to have a zero point spot drill.....

[victorofga]

you can define a 0.001 flat tip, what is in reality ""sharppoint"" or using 0.01-0.02 what in reality the tip of a spotdrill.. tip..

you also can call your spotdrill to ""chamfer mill"" and define its geometry..

programs are have no clue about difference spotdrill or chamfermill, programs using the geometry you define..

from practical view even your tool really sharp, still worth to define a small tip, so you using the edges only..
ie: close to the tip the geometry never perfect..

[The Engine Guy]

I meant select the top part of the cylinder, my part has multiple cylinders of various heights. We are on the same page there.

What I was trying to get at, was when I choose the Chamfer Strategy, I can only pick from the Chamfer Mill's. If I want to use my spot drill, I have to add it manually from the select tool screen. I cannot pick from my spot drills. I don't see a "sharp point option" in the add Chamfer Mill.

One of these days I'm going to be the one answering questions...

Right, in the image you posted you have correctly set the small diameter, don`t worry about trying to go pick a spot drill, just make a Chamfer mill in the tool library as per your the dimensions of your spot drill and the tool path will be generated correctly, once you get to the screen that jrmach has posted if you choose the "Sharp Tool" option in that screen then it will definitely change to 0.000 in the "greyed out" box and all will be well

Regarding the cylinders with different heights, if you are chamfering them all within a single Chamfering Feature then don`t pick anything for the top of feature, just set it at 0.000 at the beginning of the Feature and then just pick the bottom edge for all your cylinder chamfers, of course if you have different cylinders with different size chamfers then you will I`m afraid have to do a Feature for each different size of chamfer.

You can make it easier if that`s the case by "saving feature" from the CAM tree and just reloading it each time and then it`s just a small alteration for the chamfer sizes

Hope that helps

Regards
Rob
:rainfro: :rainfro: :rainfro: