hi all - help on this would be appreciated - what point is dipicted by bends lines in a flat pattern? my flat pattern bend lines are not making sense to us. see below...
fyi solved: check how your shop floor calc bends and tool placement and then customise either a bend allowance or bend deduction table to suit your particular materials and processes.
Good morning Michael,
Welcome to the forum,
Your picture is hard to see, however I am assuming you have the tagent lines visable, right click on the drawing and select the Tangent Lines Removed,
hi john should be able to click on drawing image to enlarge..
as you can see its 100 to the inside face
but bend line shows at 100.4 - what is this 100.4 measureing to exactly?
can't be centre or outside bend radius centre as its inside the flange!
Here is what you need to check;
Yes I can click on the drawing and enlarge, however even after I do that it is very hard to read, did you check the tangent lines???
yes thanks john. i think the question i should be asking is, what does the flat pattern bend line represent? is it;
the tool radius
or the radius of the bend on the inside of the material
or the radius of the bend on the outside of the material
or the radius of the bend on the neytral axis of the material
Bend line represents the centerline or the sheet metal die tool radius location.
The lines on the outside; represent the outer edge of the bending moment.
Bend line represents the centerline OR the sheet metal die tool radius location.
Bend line represents the centerline OF the sheet metal die tool radius location.
Or, Oh, But, If,
I'll pick Of
still no joy sheet metal part is 100 long with an inside 50mm flange at one end.
when flatterned the bend line is at 99.18 & fab having difficulty understanding why the parculiar dimension - also don't know where to put tool when presented with this dimension? any ideas
I see you have already received a correct answer but allow me to give you my opinion. I can't see from the picture but I will assume that the material is 1.6mm or .063 thick. For that thickness of aluminum I would generally specify a bend deduction of 2.59mm or .102 as you appear to show a bend radius approximately equal to the material thickness.
For the moment I will ignore that you show a minus tolerance on the bend dimensions. Also please note that I prefer to work to outside dimensions.
To explain where that line is I would take the 100mm plus 1.6mm material thickness dimensions and subtract 1/2 of my bend deduction to arrive at 100.3mm which then tells me that your bend deduction actually is .105 to .107. That line locates the actual center of the bend or where the top die would be located to make the bend correctly.
Because it is very important for me to deliver accurate models I only use actual bend deductions.
Hope this helps!
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