Originally Posted by
5artist5
I have another question, what is the difference between a jig and a fixture?
Way back in the Dark Ages when I did my apprenticeship the difference was drilled into me:
A fixture just holds the part.
A jig both holds the part and guides the tool; as in a drill jig where the drill is guided by a hardened steel bushing.
Which is why a "Jig Borer" would be used to make the jig; the holes for the hardened steel guide bushings had to be very precisely positioned.
Jigs are never used on CNC machines, fixtures are.
Regarding your fixturing for something 0.08" thick. It depends how many you are doing and how elaborate you want to get. Many times for thin sheet material I make an overlay piece out of thicker material which overlaps the thin stuff and is secured around the edges with a few bolts. All the machining is done through the overlay piece. Normally what I do is simply run the program for the part using a slightly larger tool and slow down the rapids. This machines away the overlay plate and then when the correct size tool is used it has plenty of clearance to work on the part.
For siginificant volume, i.e. many hundreds or into the thousands, I have made fixtures where the overlay plate is very thick and forms part of a bridge affair. Under the overlay bridge there is a plate with an air cylinder (a short one). The stock is slid in, the air turned on and the stock is clamped up against the underside of the overlay plate.
An open mind is a virtue...so long as all the common sense has not leaked out.