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Bend up bend down notation


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Do you recommend using a b/u and b/d or fold up f/u & f/d text on flat patterns. I understand some companies do show bend lines and guidelines for the folders. Or is best practice for the flat to only have overall dimensions and not to show any bend lines or fold up/down guides. In this case do we need folders of a higher skill level.
I have seen b/u sometimes followed by angle (e.g. b/u 90deg). If you are working for a company that has it's own shop then they should be able to tell you what is or isn't helpful. If you are sending out the work to job shops then I'd recommend not providing a flat pattern since each shop will have it's own bend deductions based on experience and tooling.

This is with respect to precision sheetmetal; computer chassis and the like. If your industry is HVAC, heavy fabrication or something else then the norms may be very different.

> In this case do we need folders

> of a higher skill level.

It's been my experience that the shop knows more about how to bend the metal than the engineers designing it.

Bernie Hayden

I have found that showing the brake operators the overall dimensions of the flat and also show the brake axis lines with the break dimensions does the trick. Pro calculates the bend dims so let it do it's job and show the brake operators what dims o bend at. Also, we show the brake dim with an UP 90

or DOWN 90 brake note. That's just what we do, but it seem sto do the trick.

and yes, brake operators always seem to know more than the engineers.

I add an isometric to the drawing, a picture is worth a thousand notes or something like that.

The most parts in our production line are Sheet metal parts. From our experience I can tell you that it is better to make a note with information about bend line, bending angle and radii. There is never enough information on the drawings. We also make those parts for other companies and we need to put notes manually on paper documentation if they didn't make them. Our chief always says: People in production are here to work, you are here to think. So, if you want to help people to make your product faster and better, I think that you need to make a note.


Sorry on my bad English

Your English is great; sure wish I was fluent in at least one other language.

What you say about putting info on the drawings works because you are both an engineering firm and a shop. Trust me, it's better to supply only the required information than wrong information. Most shops have their own way of doing things and it's standard for production planners to add the pertinent info to the drawings or work orders. I bet if your parts went to an outside shop they'd end up marking up the drawings to suit their standards.

So, what I'm trying to say is that unless you work closely with a shop it's best to define the end product requirements rather than the process. Working from flat patterns that are developed using a different bend deduction and deciphering non-ANSI or ISO notations makes life hard.

Bernie Hayden


PS. I suppose I should apologize for my English and spelling :+)

I agree with you. For me, it would be easier not to put those notes but, as I said before, we must to make them only to reduce the time of our production.


PS. Your English is also great :))


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