Sheet Metal - K Factor User Modification

[DDMFGCOINC]

Coming from a manufacturing environment, one thing that I see often is that a .44 K-factor does not hold up to reality.

If a customer brings a design to my shop for fabrication, I often see that the developed pattern is incorrect and must make adjustments in house to produce the results they desire. Most designers include a note that the final size is more important than the developed flat pattern and thus I have to work as if they have not given me a developed pattern in the first place. I have always sent samples to the shop to verify a part that requires a tight tolerance, however, I do not see a reasonable way to take this back to the computer and document it for future use. It appears that what Fusion produces as a flat pattern is the only solution that can be documented, short of drawing the part flat from scratch.

An example; this morning I drew a part that is a very common material and punch for my shop; .06 Carbon Steel, R.06 Punch. I made the part 2.00" long with a 2.00" long flange at 90° (Height Datum: Outer Faces, Bend Position: Inside). This, typically, works out to a .118 Bend Allowance (developed length of 3.882) with our press brakes, which equates to roughly a .30 K-factor, while Fusion's developed length is 3.896 when the part is unfolded. While the .014 difference between these two is not significant, the accumulated variation in a part with multiple bends, and the variation in a part with large radii is what hurts in the end.

The only work around that I can think of at the moment is to play with the radius until I get a flat length that is correct to my machinery.

[Thousand_Mile_Designs]

@DDMFGCOINC

Fully agree that k factor needs to be able to edit.  It is listed under each material but is not capable of being changes and for that matter you can not change the miter/rip/seam gap either.  Hopefully that is something that is editable in the released version.  I know that when we roll material we need a different k-factor as well to end with the correct diameter.

[DDMFGCOINC]

@Thousand_Mile_Designs

Rolling requires a different set of rules to press forming, I agree. Coining will also take a separate set of rules.

I do quite a bit of rolling, but normally it's relatively straight forward. I don't do any coining, so that's not a problem for me. I think it would be good for those shops that do make complex parts through rolling or coining to have the ability to use the power of Fusion to their advantage.

[TravisJoe]

I totally agree as well. This is really just a detail in the sheetmetal rules and how easy/hard they are to manage and edit. The K-Factor just being one of the biggest details outside of material thickness. My suggestion was to have rules be somewhat similar to appearances. You can have your common library as well as local (inside of the part file) custom parameters. In this way you could get your customers files, edit them as needed and save the custom K-Factor with the file.

One really nice benefit of the versioning, especially with the new branch merge features is you can make a branch just for this customization while maintaining the original customer part settings for references in the same place.

These would be relevant post regarding the higher level use of the sheetmetal rules.

http://forums.autodesk.com/t5/preview-functionality/unable-to-change-sheet-metal-rule/td-p/6826132

http://forums.autodesk.com/t5/preview-functionality/sheetmetal-rules-managed-like-appearances/td-p/6...

[DDMFGCOINC]

I like the idea of more control over the features. Though, from a design standpoint, I don't see it as being as much of a deal breaker. From a manufacturing standpoint, it will drive me crazy! That brings me to drawings, which really requires it's own post, and possible me spending more time playing around with Fusion.

Thinking about what you've posted between those two posts, I wonder if the Parameters UI would not work better.

I would have to mull that one over a bit. Since we're dealing with constant material thickness, my biggest concern would be bend radius. This would obviously create a need for multiple rules per component, which I believe AD is working on. I'd like to see how that's implemented prior to making a judgement on which interface would be more beneficial.

[TravisJoe]

I also thought about referencing the parameters UI, which would work well also. The main reason that I compared it ti the appearance UI is that it clearly has a "standard library", you custom items, and also shows what is unique to the document. It also shows that it is cloud synced.

I think all CAD packages have trouble with multiple rules per component/body and just rely on manual overrides on these cases.

Realistically a hybrid of what exist, as well as the parameters UI and appearances UI and workflow seems ideal to me.

[DDMFGCOINC]

Manual overrides is an acceptable solution, provided the variables are still present (K-factor, corner notching, etc.). It might be the most legitimate solution.

I agree that a hybrid approach would probably be best, however, setting up a UI in a cohesive fashion, while still getting all of the information displayable may be an issue. It's possible that a "highlights" view with a pop-up (or drop down view) of full details is the ultimate solution.

[gavbath]

Just adding my vote that k Factor absolutely needs to be able to be adjusted. I'm sure that is the plan anyway?

[LMD001]

@DDMFGCOINC

Hello,

My vote also.

K-factor depends, amongst others, on material, bending mode, bending speed, bending tools.

When working with different materials and tools, absolutely yes, K-factor needs to be adjustable.

Best regards,

Ludo

[brownst]

+1 and include Miter/Seam gap to be editable as well per Rule.

[promm · Accepted solution]

@DDMFGCOINC,

Unfold / Fold is our solution for cutting across bends and does not take into consideration the calculation of K-Factor.  This is the major reason why sheet metal is in preview.  The team is working on our flatten functionality, which will be a part of our initial release.  We are doing a preview to get feedback on sheet metal creation, giving us an opportunity to react to feedback while the team is developing flatten.  I also want to ensure you that K-Factor will absolutely be an editable parameter when we have flatten.

Cheers,

Mike Prom

[DWhiteley]

I agree here, the K-factor must be editable.

Dave Whiteley

Envisage UK Ltd

[DDMFGCOINC]

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@promm wrote:

@DDMFGCOINC,

Unfold / Fold is our solution for cutting across bends and does not take into consideration the calculation of K-Factor.  This is the major reason why sheet metal is in preview.  The team is working on our flatten functionality, which will be a part of our initial release.  We are doing a preview to get feedback on sheet metal creation, giving us an opportunity to react to feedback while the team is developing flatten.  I also want to ensure you that K-Factor will absolutely be an editable parameter when we have flatten.

Cheers,

Mike Prom

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@promm

Mike, the K Factor is calculated and used in the unfold/fold command. It's just static at .44 of the material thickness. This was just an attempt to put out there that it should be editable.

Thanks for the head's up, though I've been tied up the last few days, I've tried to play around in my spare moments... Thus far, I think there is a solid base.

I'm curious, however, I thought by your e-mail that exporting the flat to .dxf was a part of the preview. Looking back at the e-mail, it seems that it's in progress and not part of the preview. Is that the case? If not, and it is part of the preview, I'm missing the export function and could you please tell me where I'm missing it at?

[promm]

@DDMFGCOINC,

Dxf export for sheet metal is not a part of the workflow at this time, we need an accurate flat pattern to make a manufacturable dxf.  My goal of having it in the what we are working on part of my email is to let those of you who are using sheet metal know that it is something we are working on.  Right now in Fusion 360 you can create a dxf from a sketch and as a path inside the CAM environment.

Cheers,

Mike Prom

[DDMFGCOINC]

Good deal, that's what I thought, just wanted to make sure.

Thanks!