I was wondering if any of you experienced fabricators out there could give me any advice on the best way to create a jig for a production run. Heres the story, its kinda long. I have a part, which will take about 4 or 5 different tool changes to create but I don't want to be forced to run through each stage one full part at a time (obviously because its slow, and will probably ware out my already much too old draw bar). Instead I would prefer to cut say... 10 parts, then change tools and recycle them though and repeat for the next tool and so on. Also, I'm working with aluminum plate about an inch thick to help visualize this.
What I have discovered so far is how difficult it is to remove a part half way though its creation and then put it back for the next stage say to within 2 or 3 thousandths of where it began in both the X and Y directions. I keep thinking that I should go with rails to keep everything aligned, but my parts require outer profiling, which means my outer dimensions change. Since this is the case, its pretty much is forcing me to bolt down through the part since I cant profile through clamps very well right. This is all fine and dandy but heres the real problem. Even with the exact same hole pattern drilled in my jig exactly matching the pattern of my part, drilled with the same drill bit dia, It still aligns sloppy. It looks real close to the naked eye but I'm not convinced its exact because I can wiggle the part while on the jig even when pinned together with the drill bit used to drill them both.
I know I'm not the first person to attempt this , so if anybody has any good tip to create a system like this, where one can take a part out at any stage of the run and throw it right back in at the exact same position (within reason of course) it would be greatly appreciated.