Hit a bad batch of aluminum stock yesterday and it cost me 4 hours

I was running a batch of 50 brackets on my Haas Mini Mill, nothing tricky just some 6061 plate I've cut a thousand times. About halfway through the run I noticed the finish was looking wavy and the tool was making this weird scraping sound that I've learned to hate. Turns out the supplier sent me some recycled stock that was loaded with inclusions, I found three hard spots in one piece that totally chipped my end mill. Had to stop the whole job, swap out the tool, and re-run every part that had already been cut. By the time I was done the shop smelled like burning coolant and my back hurt from leaning over the machine all afternoon. Has anyone else dealt with a bad batch of material from a supplier you usually trust, and how do you catch it before you start cutting?

2 comments

2 Comments

graym498d ago

Read an article a while back about some shops using a cheap hardness tester or even just a spark test on aluminum scrap before cutting, catches that recycled garbage pretty quick when the color or sparks look wrong.

morgan_butler8d ago

Why do you need to test every piece of stock before you start cutting? That sounds like a huge time suck for something that happens maybe once every couple years. I've been running a shop for over a decade and I've only seen a bad batch of aluminum twice, and both times the supplier made it right with free material and a credit. If you're chasing out every questionable piece of metal before it hits your machine, you're wasting more time and money than you'd ever lose from a chipped end mill. A bad hour or two every few years is cheaper than checking every plate that comes through the door.