Autodesk Inventor

[#1]

I suppose you should put it through the old drafting crucible of "does it communicate something useful"?

The flat pattern is, at least, useful for expressing the extents of the material reaquirement.... and... okay, it's flashy!

Please don't take away my flash.

[#2]

Thanks for giving me the opportunity to edit that, JD!

I probably shouldn't take over this post, but I was really trying to get at "manufacturing capability"... also an opportunity to build relationships and exchage knowledge through the refinement of the Bend Table and Tolerences.

I think you gave me a segue with your closing statements... I suppose the goal of a flat pattern should be to avoid the two "prototypes" that the customer didn't pay for!

[#3]

Sean,

The best answer I can give you is "it depends". All automated cutting equipment (laser, plasma or flame cutters) that I have run into use their own file format but are able to import DXF files. If you send a vendor a set of drawings of formed parts only the vendor will have to redraw your part into his system to be able to cut it. The DXF gives them a shortcut there. Depending on the system, most take into account the kurf of the cut and that is automaticly done. The concern deals largely with hohw the vendor bends the parts. depending on the bend allowances and how the material works. your flat pattern may give the vendor a flat sheet that is either to wide or to narrow. Often times a vendor will cut and form a part once or twice to ensure that they have the correct dimensions. If you have a close relationship with your vendor and know their equipment you may be able to enter the bend allowances to meet their system so the flat pattern is "right". But if you provide a flaat pattern that uses different allowances, you are in effect giving them two different sets of drawings that can create two different formed parts. If your trolerances for the formed parts are not too tight this may work for you. However if you need the formed parts "exact" you may be better served providing only the formed drawings and making sure they are very well documented. Which they should be anyway.

Hope this helps

[#4]

I agree with Jim We do both inhouse plasma cutting and folding, but for the thinner sheets (1.2 mm and less) we farm out. Our drawings include fully detailed and toleranced folded parts and a flat pattern view with the bend notes or direction, andgle and radius. But the note also includes "BEND DATA CORECT FOR BKS HACO PRESS #1".

When we farm out the work we supply this IDW and the DXF of the part. The outside firm then 'alters' our DXF file to suit their bending machines and what we get back is within tolerance.

So it really depends on what youare trying to achieve.

Best of luck.

[#5]

Well of course after I decide not to use a flat pattern, our fabricator is deciding to farm out sheet metal panels to be laser cut and asked me for a dxf drawing with flat pattern!!

Inventor does make this easy to do, but I have a few quetions now and what is required for a dxf drawing that is to be used for laser cutting.

1 -  Is the drawing to be detailed like a normal drawing? I have vaguely read somewhere on google, that laser cutting   

      acts on coloured layers of geomtry and no dimensional inputs? So the dxf will have to be scaled 1:1 when exported.

2 -  am I better to provide a fully detailed drawing with flat pattern?

3 -  does anyone have any examples of a drawing for laser cutting that they can share or link too

I have attached a .ipt file of something that will be laser cut. Does each hole, slot, and cutout need to be detailed?

Thanks

Sean

Version - Inventor Pro 2013

[#6]

The laser cutter only knows geometry, not dimensions. The shop will adjust the dxf if anything need changing like colors or layers.

I always give overall dim's. Aids the shop in giving quick cost estimates and eliminates any confusion about scale.

1:1 is best, but the shop can scale if necessary.

[#7]

So an ideal drawing would be one view of a flat pattern with some dimensions of size and shape for reference. Positioning of hole, slots, cut-out etc will be based of the geometry of the actual shape and size of the component?

I don't have direct contact with the laser cutter company and my fabricator isn't up to date on CAD, or requirements for this.

Thanks for any help!

Sean

[#8]

One normally works backward to calculate the bend-factor for each machine. The attached Excel file may help you in your calculations.

Get a pre-measured length the required material and do a ben to the desired angle, get your measurements and then calculate the proper k-factor for the machine and tooling for the materail and bend angle.

[#9]

I produce models, drawings, and flat patterns for internal and external use.  We have a burn table with oxy and plasma.  The software I use will take in DXF files (from Inventor) and spit out "g-code" cnc language.  I produce a drawing with the bent up part shown and dimensioned.  I also show a flat pattern with some dimensions for reference stating what others have said about the finished part being the objective.

Some external customers/vendors also want flat patterns for their machines.  I send them out with a disclaimer about the finished bent up model being the objective.

Hope this helps.

Rob