flatten (?) something like an auger segment 1

[Ralph2]

There must be a way to do this.. can someone point to a tutorial or other information.

At work (a fabrication shop) we are occasionally asked to manufacture augers of various diameters and pitches.. Cutting from flat plate and then forming the "auger" part entails a lot of trial and error..

We have a seat of Solidworks(2007)that I am trying to get familiar with. I can model the auger easy enough but there must be some command or process to allow me to unwrap one pitch (or portion) and print out the flat equivalent shape. Ideally with the bevel cause by the thickness of the plate shown as well

I have watched a number of sheet metal tutorials but nothing seems to quite match what I want to do.

Thank you for your time.
Ralph

 

[ctopher]

Maybe something here can help?

http://www.sheetmetaldesign.com/Cad-SolidWorks/index.htm

Can you show a pic of your auger? I know what one is, but may help to see yours to have a better understanding of how to model in sheetmetal.
The sheetmetal will consist of several pieces.

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated 10-07-07)

 

[Ralph2]

Not sure if I can attach a quick and dirty sample. What I quickly did in SW was to sweep a helix. Add a sketch of the shape of my auger flighting (sp) and sweep it
Thanks for any help

 

[CmAnD]

Hi Ralph2,

I do not believe that there is a way to do it in SW because the form of the auger is actually deformed flat plate. I think that SW is not capable to unwrap that kind of form.

 

[Ralph2]

Thank you CmAnd..

This is not an uncommon task in the fabrication world and the fact that SW is not capable of unwrapping / flattening such a shape surprises me.

If SW is not the software to do this... anyone with an idea of software that might?

Ralph

 

[smcadman]

At a previous company we made chutes that are similar in design to augers. Chute sample (That particular design has a "v-shape" section)

We made them by cutting several blanks, welded them together, and then forming. Here is a blank sample: Chute Blank You will notice that it is very similar to a flat pattern for a cone.

I do not know the process you are using to form your auger, so I cannot give you the proper formula to make these. That said, I would use excel for your formulas, and then draw the flat pattern in SW.

Flores

 

[CorBlimeyLimey]

Some of the SW partner products can do that.

http://solidworks.com/pages/partners/partnerproducts.html

Most of the mainstream mid-range CAD systems cannot.

 

[Ralph2]

Thanks CorBlimeyLimey... but of the 24 odd selections available from your link.. which one?.. Or, what is the technical term of the process that I am trying to find a solution to.

 

[smcadman]

Did you click on any of the links? The first one, Blankworks has a free 7 day trial. The other ones MIGHT have demos available also.

As for the technical term of the process, if one of these products can do complex sheet metal, then the auger would be simple.



Flores

 

[TheTick]

This is not an uncommon task in the fabrication world and the fact that SW is not capable of unwrapping / flattening such a shape surprises me.

If you knew that it wasn't mathematically possible you would be a lot less surprised.

Your auger shape is a non-Gaussian surface, which means it can not be unfolded without deformation or tearing. This means that the unfolding is a bit more complex than unfolding a regular 90° bend in sheet metal.

All is not lost. If you model a section as a lofted bend, SW will make its best honest attempt at flattening. It will not be 100% accurate, but probably close enough. Other CAD programs enjoy the same limitations.

If you need more flattening horsepower you need something like BlankWorks. <

http://forming.com/blankworks.htm>

Honesty may be the best policy, but insanity is a better defense.

http://www.EsoxRepublic.com

-SolidWorks API VB programming help

 

[Ralph2]

Thanks.. did try a few... but not the obvious "sheet metal software " selection.

 

[smcadman]

Speaking of mathemetically possible. If you knew the formula, it would be a piece of cake to do these. Not sure why the chute link wasn't working, so here is a different image of it: Chute sample again

You will notice that not only is the bottom in a v-shape, but it has a flange on the side. Solidworks can't make these automatically, but if you had excel and the will, these could be made rather easily.

I say this because the above chutes were made with Excel and plain vanilla AutoCAD over 8 years ago. We simply entered a few numbers into Excel, and then basically used a point cloud in ACAD and played connect the dots.

Square-to-rounds, frustum cones, the chute above, etc. can all be done mathematically without having to use a scribe and triangulation to lay it out on a sheet.



Flores

 

[Ralph2]

Excel / AutoCad might be worth looking into.. Need to dig out some old layout books.. Thanks

 

[gatz]

Maybe not exactly what you asked as far as having SW flatten a model, but if only the dimensions for a single pitch of an auger are needed, it can be done mathematically in Excel and then drawn as a new SW part in a flat pattern.

The helix is a right triangle wrapped around a cylinder, where the horizontal leg is the circumference of the basic OD of the auger. The pitch becomes the vertical leg. The hypotenuse, then, is the circumference of the large circle which defines the flat part.
Likewise, the smaller ID circle can be arrived at the same way.

This gives you a flat that when cut from metal and when a slit is made from the centerline outward, it can be stretched into a single auger pitch or flight.

Obviously this only works for thin material and there can be a problem with material of substantial thickness.
The ID may have to be slightly enlarged and the OD slightly reduced to make sure they match with the actual tube(s) being used and make up a complete 360deg pitch.

For instance, a 12" OD x 2" ID auger with a pitch of 4" would result in a "new" flat circular pattern of 12.07 OD x 2.371 ID.

In this sample SW part, the actual values for the helixes divided by PI give those dimensions .

 

[Ralph2]

Thank you gatz for your time working on this issue