customer print formed dims minimal, advice?

[chad38]

I'm working on what is actually a pretty simple part, however the customer prints only have a VERY minimal dimensions in the formed view, though they have provided a flat dxf as well. I'm struggling trying to infer what the formed view dims should be on this, and it's a little bit of hell. The customer dxf has an unknown bend equation, and on top of that, it has different distances to bend lines for flanges that (i assume) are supposed to be the same size.

What methods have you found to determine what the dimensions and original design intent might be?

EDITED TO INCLUDE PDF AND DXF FLAT

[blair]

You could do the work backwards for calculating the k-Factor. I am currently having problems attaching files to the new forum from work. Send me an e-mail to: blair dot stunder at arcticmfg dot com and I will send you a couple of spread sheets to calculate the k-factor. You have the flat length of the part and I assume the bend leg lengths. It should be straight forward.

[chad38]

No, I don't have the bend leg lengths, although I have inferred what they are supposed to be. I'm having problems figuring out the best way to place the holes that aren't dimmed, and also the eliptical cutouts. I swear, are they buying the formed part or just the flat pattern. Customers.

[swalton]

One trick is to print the formed drawing as large as you can.  Then get out your scale and measure a dimensioned feature on each view.  Use that to create a scale factor for each view and then measure to the un-dimensioned components.  I usually try to measure several dimensioned features on each view to get an average scale factor.

I do this when I can't get a complete print of purchased components.

[mcgyvr]

The ONLY proper advice is to contact the customer and ask them for a formed dxf file or step file.

That drafter just doesn't know what they are doing. 

[chad38]

Agreed. Problem is, asking this customer for a dwg or dxf with the formed views or a step file isn't an option. Believe me, I would like to. It's not an option in this instance.

Also agreed on the drafter doesn't know what he was doing. Believe it or not, there's still plenty of businesses out there who actually think that industry standard is for dims in the flat pattern to rule. Crazy. If I had my way, we'd make the parts off their flat. Perhaps then they would see why they want to fully define the part in a formed view. Flat Patterns are for reference only........unless you're fabricating the part yourself, you might want to describe what the finished part is supposed to be.

[mcgyvr]

---

@chad38 wrote:

Agreed. Problem is, asking this customer for a dwg or dxf with the formed views or a step file isn't an option. Believe me, I would like to. It's not an option in this instance.

---

WHY? and what happens when you "guess" and the parts are made wrong and the blame drops right on your lap..

It IS an option and its the ONLY proper solution. 

As a sheet metal vendor it is YOUR job to inform the customer that you don't have enough dimensions to properly fabricate that part..OR no quote it and move on.. 

There is NO reason you can't contact the customer. They sure as hell will contact you when its wrong. 

[chad38]

Because I'm being told by my cust service rep that it isn't an option with this customer. I guess they're pretty "just make it like we said in the flat" and they are pretty abrasive when additional info is requested. Cust serv. rep doesn't want to rock the boat, so to speak.

As a fabricator, we make what we're told to. If I had it my way I'd know more about this parts function so I could ensure it would work as intended. Absent design intent, I can only use the dims that are present as a guideline. And since there are very few dims present, if those dims are met, then we did what they asked. If the part doesn't fit because of some dimension that wasn't specified, technically the part conforms to the requested specs, and it isn't my fault that the customers designed part doesn't work. Believe me, I hear what you're saying, I've been a drafter in sheet metal fabrication industry since 2005. I want parts to fit and to work. But when a customer refuses to tell you what the part is supposed to look like, I have to just do what I can do without spending too much time worrying about one customers tiny part when I have so many other, probably more critical, parts to do. If I can avoid getting into a whole thing by doing what the customer says, sweet. The final part will conform to the dimensions on the print. If the part doesn't work for the customer, hopefully it will spark some dialogue between the two of us so we can figure out what they need on the print to ensure fabrication.

[Anonymous]

I've attached a part (IV 2014) that I modeled based on the DXF and the few dimensions on the PDF you provided. It's not exact (truncated after 0.00mm) but it should work. Whether or not the K-factor or Bend Radius needs to change is up to your fabrication end, but as drawn, the part and flat pattern look pretty close to what you posted. I also didn't constrain the (I'm assuming) ellipses at the end of either flanges as they're drawn as polylines in the DXF and I didn't feel like trying to recreate those.

I basically just copied the DXF into a sketch and placed the bends as shown on the PDF along the centerlines on the DXF and then just adjusted the Bend Radius to make the outer dimensions as close as possible to what was shown on the PDF. I then checked the flat pattern that Inventor produced and the dimension do the centerlines from the edges were really close to what was shown in the PDF.

[chad38]

Wow dude. I really appreciate that you went as far as you did. I also hate dealing with those ellipsed cutouts. I went about replacing them with a cfew radiuses, but dang they keep interfering with my bends on my formed modeled part.....and don't know if you noticed but those cutouts are very slightly off center and also askew. Oh well.

Thanks again for taking it as far as you did. Hope you had fun!

[Anonymous]

I didn't notice they were askew. I basically said to myself, "forget constraining these SOB's" and went on with the rest.

You're welcome. I like to learn and try to figure things out, so it was all fun over here.