why do we leave Tags when we do CNC machinig

[LCform]

Hi All

watching this Video, I noticed the guy is leaving tags on the profile , and he explained this is to avoid the part to be cut off completely during machining , why do we do that ? why should we not cut the part off completely ?

 

[MikeHalloran]

Which video would that be?
Please provide a link.
Thanks.

Conjecturally, if the workpiece is not completely finished in one operation,
and for example needs to be set up in another machine for a subsequent operation,
it can make sense to leave some portion of the feature by which the part
was first located in a fixture, so that the subsequent operations'
fixtures use the same feature for location. When the part is
otherwise complete, said tags or whatever can be removed by
abrasive machining, or perhaps just snapped off, or even left
on the finished part if they don't interfere with any function.



Mike Halloran
Pembroke Pines, FL, USA

 

[LCform]

Thank you very much , I actually had put the video , if you clicked on the word "this " in the first words of the paragraph , where I wrote "this video", that was the link , but I got you , thank you

 

[berkshire]

You would also need the tags to hold the part straight during the machining operation . This looks like a routing operation where the part is being completely milled out. As the cutter gets to its final cut , the part will curl without restraint.
B.E.

You are judged not by what you know, but by what you can do.

 

[3DDave]

This was not always the practice. Instead the machining would have to stop to allow the machinist to move the hold-down clamps. After the majority of machining is done the tabs can be milled down to be very thin so they are easily removed, or hold-down clamps can be used to restrain the item to allow completely removed by machining as the final step.

Vacuum fixtures can also be used to avoid tabs.

 

[dicer]

Pretty simple stuff, if its cut off completely then when the second to the last one is cut, the part will just flap around when the last one is cut off, with the possibility of ruining the part and the cutter.
If there is a way to clamp it for tab removal then yes you can fully machine it then. Also low melting point alloys can be used to hold the part as well.