Boolean subtract error

Josy_La

It seems this feature does not always work and I don't understand why. I applied a boolean subtract to one end of a part which worked perfectly. Then needed to do it to the other end but it return a failed message. Target part is one simple extrude nothing fancy and tool is a polygon sketch not complex at all. Tried a different approach using mirror feature also got an error so now i'm baffled.

Mesage edit: The only way I managed to make it work is by doing the same maneuvers a second time (derived sketch-extrude-transform-boolean). The first time I was attempting to reuse original but it did not work. This behavior does not seem normal and forces redundant work???

bradley_sauln

Sharing the document would be helpful to make sure I'm understanding this correctly.

From what I got from your description, by default the Boolean subtract tool will remove the part used to make the subtraction (the tool). If you check the box that says 'keep tools' you can then reuse the part: https://cad.onshape.com/help/#booleanparts.htm?Highlight=boolean

When you say the tool is a polygon sketch, remember that boolean works for bodies

Josy_La

Unfortunately I am bound to a non disclosure agreement thus cannot share documents so I tried to replicate issue with simpler shapes but wasn't successful. I managed to attach a snapshot with hidden areas, I hope it helps.

My initial part is extruded from a derived sketch did a second trial using a pasted sketch of the same shape and was able to boolean properly. Now I wonder why it does not work on the derived version?

mahir

@Josy_La, just to be clear, what you're trying to do is mirror a tool body and then subtract it from the main body? Typical workflow would be to first mirror the tool body, and then subtract both tools at the same time (vs having 2 boolean operations). Are you potentially creating any degenerate geometry (knife edges, etc)?

Josy_La

mahir: I need both end machining to be independent because I have multiple end conditions that can be applied on either side of part.