Need Help!- simple 3d pocket/big problems

[chaz6966]

i have essentially a 4" x 2" x 1.250 pocket with 1degree draft and .250 radiuses all over. it is sunk into a 7x4 inch block.
when i try to z level finish or zlevel ruff or equadistant offset. and i pick the area to machine with cursor box, then unhighlite the p/l and the bottom underside of the block(bobcad picks this as a surface to machine for some reason) , the program cuts the inside of the pocketed area (some times) but it also cuts around the outside of the rectangular pocket- crashing through the solid steel. and i have innermost only and by level picked.
im using a .500 dia with a .030r. and ive tried a 3/8 ball.
why does it highlite the bottom of the block?
and why does it mill the inside and the outside of the rectangular pocket as if the shape was a thin surface(milling inside and outside) when it is a solid with the rectangular drafted surface extracted from it.
any help would be appiciated, thankyou...yes build 1137.v22

[mmc005]

Have you tried to only select the sections of the pocket that you want to machine? This was a problem in V22, maybe it crossed over into V23?.
The reason it picks the bottom of the solid is because you used a selection box, this will select anything that is in the box. If you pick your geometry by clicking on each surface, those will be the only ones used in your tool path generation.
Also, did you use any boundrys to limit your tool path? Can you post your file?

Dave

[chaz6966]

yes i can post the file. there is no boundary option in z level finish.
memory is a little fogy from trying 50 different things but i believe if i pick each side wall and radius individually them bobcad machines each surface randomly rapiding z up n down to get to each spot, instead of climb milling each surface as one continuous path. maybe i need to try by area instead of level.

[moldmker]

I do pockets quite a bit.

Select the whole model as the geometry to machine.

With Z-level paths select Innermost Only and By Area. This will contain tool path to pocket. If there is an interruption in the the parting line into the cavity (such as a runner or shut-off feature) you will need to create a temporary surface to seal up the cavity wall.

To protect the parting line, you can translate/copy the parting surface up .01".
This will allow you to grind or mill the parting surface later.

Boundaries work good with Equidistant. Be sure to pick whole model as geometry and use the boundary to limit toolpath.

Climb milling with 3d apparently isn't high on the list of enhancements. So you just can't be too aggressive with cut amounts in steel or aluminum.

moldmker

[chaz6966]

thanks for your response.

[Allen123]

Just to add to that:

You can use the stock geometry as a boundary for the Z level rough tool path. It's kinda tricking the software so sometimes it doesn't work right, but in many case it allows you to isolate an area for machining that is with in a solid.

The Z level finish has no boundary control as of now or none that I can find.

In most cases you want to select the whole solid and use boundarys to control where the tool path goes.

You can use "check" surfaces to stop the tool path from going places you don't want. It's not a real check surface it's just a surface you have dawn to block the tool path.

You select it as part of the solid and it will stop cutting when it gets to that surface.

Most cases you want all the surfaces stitched together, but you don't always have to.

I would rather not stitch my check surfaces, but sometime I have to in order to get good tool path.





Z level rough > inside only




Pocket to finish the bottom surface



Z level finish and the pocket finish tool




This is an example of using a "check" surface. I just sketched a surface and dropped in Z a little bit.

Selected it as part of the Z level rough> compute

If you can see the area below the green surface was not cut as part of the Z level rough. The tool path avoid this area.

[BurrMan]

Originally Posted by Allen123 You can use "check" surfaces to stop the tool path from going places you don't want. It's not a real check surface it's just a surface you have dawn to block the tool path.

Hello Allen,
What is "Check Surfaces" please.

Burr

[Allen123]

A check surface -

I use this term loosely. In other CAD CAM systems ( mastercam ) it is a real term.

In BobCAD I am just using the term because it describes what I am doing with it.

I restrict the tool path -usually in Z - with a surface. All I have to do is draw in a surface and select it as part of the tool path.

[BurrMan]

OIC, Thanks.