Hi,
Does anyone use half shears for precise locating two pieces of sheet metal to be joined.
How do you create them?
How do sheet metal shops recognize the feature in your files to indicate what punch to use to create the feature during punch.
Thanks,
-Mel-
Hi Mel,
I started using the half shear (round) in the late '70s when we bought our first Amada turret. At first we used them for shearing flat blanks when an angle other than 90 degrees was required. You would extrude the half shear up on the turret (so it could eject off the tool) and then flip it over in the shear. Pull the half shears to touch the edge of the bottom blade and 'chomp' perfect cut every time.
Later is when we discovered we could use them for assembly or spot welding thus reducing fixtures and improving accuracy. I think they are a invaluable tool for sheet metal fab.
If you are making drawings that will be used to be sent to a fabricator (not your in house shop) I would not put limitations on the size or locations. You could make a simple annotation in the file, or on the drawing. If you are making the part file for you own use, all you would need is the hole size for the female half of the half shear operation. Then make a half shear library tool and graphically show where on the flat pattern the location and orientation.
Hi Mel Lewis
Attached is the Half shear tool which we use.
We will provid sectional view at half shear location and provide the details for shop floor.
Regards
Chethan
I've usually done it by cutting out the shape of the punch, and then extruding the same sketch "offset" from the sketch plane (top of extrude menu) by the distance equal to the depth/height of the half shear.
Features like this are typically Datum features (or at least they should be) so they get dimensioned on our print, and the sheet metal shop would get the shape and location detail from the print.
Maybe not the "most correct" way, but no issues so far, at least none that have been communicated back to me.