laser cuts on sheet metal

[Anonymous]

Hey all!

I bet some of you faced this challenge before!

I have a back plate made out of 2mm Glavanized Steel.

And here is the drawing of this back plate flattened out:

You can see that the cut is 5mm between the back plate and bended out part. This part will be laser cut, instead of being pucnhed out.

Here comes the challenge- No matter what is the distance bethween bended out part and back plate laser will consider there to be two lines for it to cut *one line on the back plate and one line for bended part. And laer will go there two times even if I will make distance of 0,01mm. Is there any way to make this cut as one line, so laser will make one pass cut?

Will be waiting for some solutions on this.

Kind regards,

Vadim.

[Anonymous]

I would say that I need a Relief Gap option able to be 0, but I can't succeed in that. Any ideas?

[mcgyvr]

Are you making this "in-house" and you must program the laser? or are you outsourcing this part to a sheet metal vendor?

You dimensions 5mm.. What do you want it to be in the final part?

What about bend reliefs? Do you care about tearing at the corners when formed?

"seems" to me like you are overthinking this and trying to get involved in someone elses job (the laser programmer)

[terje.antonsen]

maybe try the split command in flat pattern edit mode

[terje.antonsen]

keep your part the way it is. in flat pattern make a sketch and project the lines you want cut. make another sketch and fill with an extrusion all holes around bends. 

export the flat pattern using the right click save copy as> Keep the light bulb on uncomsuded sketches. in IDW, you can find the sketch in the browser and choose to include it. for 3D views however, the best you are gonna get is a low gap (0,5mm?)

[Anonymous]

Nope, we are outsourcing the part.
There is no problem with this bend relief of 5mm. Only it makes this part more expensive to manufacture. Instead of making two passes to make these bended out parts- we could go with only one pass and bend them out.
My problem is when I tear the part- it still requires some bending relief gap.

This is what our supplier would like to have when part is unfolded (this is just an example and blue line is where the bend should be) but this "cut" is represented like a line and there is no gap in it just a vector line. In such a way laser will just follow this line once and make a nice and cheap cut. BUT in inventor it is impossible to bend out such a part, because it has no bending relief gap, creating pain in the neck to make another part with bending relief gap of something like 0.01mm. In such a way parts are not the same anymore. Although 0.01 will have no impact no a physical part. What I am just saying is it is my job to have a correct drawing- otherwise our vendor can just make whatever he wants (roughly), but still...

And if I go another way- create flange with tearing the corners- when I make unfolded part- it doesn't show any lines at all ...

[Anonymous]

Yeps, that is how I done it for now for a current project. But isn't there a way from the very beginning? This would also simplify my job as well in the future projects.

[mcgyvr]

If cost is the concern then WHY are you using a laser? 

What is the estimated monthly/yearly volume on that part?

[terje.antonsen]

Another idea, make it as a punch tool! If you dimension it well so it becomes adjustable, And the general shape is near the same for many bends, you could get away with only drawing a point and a line, I think.

---edit: because the punch tool doesn't ask for a relief gap.

[Anonymous]

I don't know why they have chosen to laser cut it. I believe it is easier to cut it with laser, because with a lot of radiuses around, maybe supplier does not have right tooling for a pucnhing machine. it is not up to me what manufacturing process to choose, it is our supplier who tells me what they would prefer to use from project to project. Maybe it has something to do with being occupied with another projects, I don't know...

I am not a sales person, so can't really say how many of these should be produced. But from what I heard maybe around 2000 pcs a year...

But I think we are getting little bit away from the challenge. I guess we just shall find a solution for a conrete issue, instead of thinking of ways of manufacturing...

[mrattray]

Are you supplying them a DXF of the flat? If it were me I would edit the DXF file output from Inventor in AutoCAD. I find myself "tweaking" DXF's for laser cutting pretty frequently.

[Anonymous]

I prepare both DXF and DWG files for them. But yeah, it looks like it is normal way of doing it instead of having proper function in Inventor for it ...

[mcgyvr · Accepted solution]

---

@Anonymous wrote:

I don't know why they have chosen to laser cut it. I believe it is easier to cut it with laser, because with a lot of radiuses around, maybe supplier does not have right tooling for a pucnhing machine. it is not up to me what manufacturing process to choose, it is our supplier who tells me what they would prefer to use from project to project. Maybe it has something to do with being occupied with another projects, I don't know...

I am not a sales person, so can't really say how many of these should be produced. But from what I heard maybe around 2000 pcs a year...

But I think we are getting little bit away from the challenge. I guess we just shall find a solution for a conrete issue, instead of thinking of ways of manufacturing...

---

The answer to your question is that the dxf output from Inventor must be modified in Autocad to produce what you want.. Now lets move on to the real problem...

I'm just trying to help you save money.. And producing this on a laser for those quantities is NOT COST EFFICIENT. 

What I'd expect (and it happens with many sheet metal vendors if you don't know any better) is that their laser isn't getting enough work to justify it like they thought it would and now they are pushing work that shouldn't be going to it to just make it look like a good purchase.  Its happens ALL the time. 

That part can easily be punched and WILL be cheaper. 

And its 100% YOUR companies responsibility to dictate how a part is made.. 

Not to mention I have NEVER had a sheet metal vendor push a part back on me telling me its MY job to provide the flat pattern to make it cheaper to laser..

I will NEVER give an outside vendor a flat pattern.. Thats their JOB and can cause problems as K factors are machine dependant.. 

Heck our sheet metal vendor adjusts press brake setups even for slight thickness differences in raw material.. (as any good vendor should) 

[mcgyvr]

Just adding some more info..

Its ALWAYS a good idea to get a tooling list from your vendor and "try" to design with those punches in mind.

Always start designing as if it is going to be punched part.. Laser IMO is ONLY used for intricate shapes (which your part is not or doesn't need to be) and for low volume production runs.. We will have a part lasered if we just need a couple (5 or 10 pcs) and can't guarantee a repeat order.. but over a few pieces its ALWAYS best to punch it when cost is a concern.

This is part of the reason I think this DFM (Design for Manufacturing) buzzword thats come up in the last few years is an absolute joke.. That should be and always has been part of an engineers (or designers) job from the start. 

There is no DFM in my eyes.. Its either an engineer who doesn't know what he is doing or one that does.. Plain and simple.

[mrattray]

Well said, mcgyvr.
To add some perspective, I'm one of those sheet metal venders and when I do receive a blank from a customer, I throw it out and develop my own every time.

[Anonymous]

FINALLY !!! JUSTIFICATION TO MY WORDS !!!

You know, problem is that I am only 25 and I started working in this company 3 years ago. I told them before that it is not my job to prepare working drawings for our vendors, especially without knowing what machinery is used, what are the capabilities and in case of sheet metal what are the K-Factors and all those machine setups... I mean we have absolutely no gain when I am preparing productin drawings for our vendor and that is really a loss of money.

Sometimes I do advise better/cheaper ways of manufacturing stuff, but because I am only 25 my words mean very little as now I am considered mostly for 3D drawings, though everything looks like I am the decision maker within the reality it is not so...

Thank you for jsutifying my thoughts! I will refer at some point to this topic and your words!

But it is a bit tricky with this vendor, as now if I will ask our purchaser to ask for the prices on the same part but punched out, they will probably quote higher price. Well, I am not sure about that, but as you said they want to justify that using laser is more cost efficient than pucning out... But I'll try to talk about this with our main egineer and I'll see what he says, because he is the decision maker ...

[mcgyvr]

I sent you a PM.. If you want,  email me the step file and 2d drawing along with the current price you were quoted and the quantites you want quoted and I'd be happy to pass it along to my sheet metal vendor to requote for you. 

Or if you prefer I can just send you the name and contact information so you can quote it yourself through them.. I'll give you my name and thecontact to talk to.