One last area of production we need to talk about is sheetmetal fabrication, whether you are programming a punchpress, a laser, a plasma torch, or maybe a combination machine. You might program a single part, or maybe fill up the sheet with a grid of that part. You can do manual nesting, and you probably want the capability to do automatic nesting, taking in your cut list and letting the system find an optimum nest. Once completed, you will need toolpath optimization, to make sure the program cuts out the parts the way you want, minimizing tool travel and tool changes, or maybe getting each part off as quickly as you can. Whatever you need, you'll want that sort of control in you manufacturing system.

One last time, back to our top level assembly, and let's drill back down to the cooling fan assembly. You'll notice on the back side, we have holding up one of the shafts a typical sheetmetal bracket. Let's take this bronze colored part and take a look at it. You want your manufacturing system to be able to take in 3-D parts and generate a flat pattern layout. You may need to modify the bend allowance, and you may even need to put in extra features such as clearance cuts or bend reliefs. Now I have my part flattened out, so let's go cut this in my manufacturing system.

I will start with a new sheet, so I'll define my blank and simply enter the dimensions to whatever size I need. Now I will bring in the design part we just looked at. No translation, I just say bring in that flat pattern, and I will use my mouse to manually nest it, rotate it around, and place it wherever I need to on the sheet. My one part is ready for cutting. I mentioned that you might want to fill the sheet, simply multiply with an X-Y spacing. This way I only have to program one part, and the system will cut out however many will fit on this size sheet. I can do a number of what if's, maybe move the part around to see how many I can fit. In this instance, I will only program a single part, since I will later be using it in an automated nesting routine.

The first thing I will do is to perform a tool shape, where the system looks at all of the tools in my punchpress turret and finds any matches to the geometry on this part. Maybe I have a punch/laser combination machine, so after I have punched out all the holes I can drive the laser around the outside of the part. I should never have to worry about lines touching or bend lines, I just select anywhere on the outside of the part to drive the tool along. So now my toolpath is ready to cut out this one particular part. Let's go ahead and save that, but let's make it part of something bigger.

If I open a new manufacturing model, and this time bring in a cut list. I'll start with the part we just programmed, and I'll say how many of those I need, essentially filling out my job order for today. It should be as simple as filling out a spreadsheet - the name of the parts, how many I want of each, maybe a priority. Then, based on the size of the sheet, the system will nest as many of the parts on the sheet as will fit. You can control grain constraint, or if you want to allow any rotation. You can then optimize the toolpath, minimizing tool travel and tool changes. And now I have a single program that cuts out, in this case, about 150 parts from one single nest. That is the sort of flexibility and control I want in the sheetmetal world from my manufacturing system.