High Mix Low Volume? Does it really matter?

High Mix Low Volume or Low Mix High Volume, you need to do it right!

It’s been months since my last blog post on the subject of “high mix low volume” the current catch phrase in the CNC machining world. I have been busy for the past six months getting ready for the arrival of our new 5 axis machining center the “Mother of All Machines” the MAM72-35V (details about the machine later). Why did we choose this machine?  To meet the growing demand for HMLV production. 

Customers want to order less, ship less, pay less, hold no inventory and want it yesterday, rightly so.  We understand the challenges, we want the same thing from our vendors. I thought the answer was in this machine. If you listen to the “sales pitch” the 72 in MAM72-35V is that the “machine is designed to run 72 hours unmanned”. Look at it, it has 32 pallets so you can load up tons of work (don’t forget about the fixturing). It also has 330 tools so you can load it up and keep the tooling you use in the machine, so you never have to “reload” tools as you are changing setups. Yes, that all makes sense. The goal is to be at the ready with enough tooling and fixturing in the machine to minimize the transition from job to job. New jobs come in, process, materials ordered or pulled from stock. Next, engineering CAD/CAM, verify the tool path BOOM! You’re making parts. First article inspection PASS and you’re in production within an hour or two. Sounds fast.  That should be how all the jobs go not just HMLV???

In theory, it works. It is also working on this machine, the answer is YES, and from what we have seen so far everything they say about this machine is TRUE!!!  98% uptime or “green light” time.  There is no fallout or scrap parts. From start to finish we are seeing consistent parts, not just in tolerance but EXACTLY the same part measuring results within tenths of an inch. On some of these parts we saw up to a 10% fall out and hours of setup involved in positioning and “dialing it in”. Now the cycle time is longer. We added operation just as deburring compete in the machine. Before we would machine the part and someone would “hand deburr” offline during the part cycle. You think that would be a winning combo until you see the inconsistency edge breaks. It’s not the guys fault, it’s just the human can’t match what the machine can do.

The quality is 100x better but it adds cycle time.  We are also probing / measuring the part in the machine, not every part or every feature but the ones we need to at the proper intervals adds cycle time but no bad parts. 100% right every time. The result are that the net part production per day is more and that has great value to us and the customer.  What does this mean for high mix low volume parts? For any quantity of parts for that matter???

I know that if we can process any mix of parts almost effortlessly and have complete scheduling flexibility (as far as this machine goes) then we are moving in the right direction. The machine is great and we are updating our processes to reflect how we are dealing with our product flow. The results are also carrying over into our other machining departments: lathe, vertical, and horizontal milling; as well as our sheet metal fab and welding surprisingly.

The answers lie within. The reason why HMLV is even a thing is that it is now possible to achieve.  We decided to implement the machine, update our ERP/MRP shop management system (future blog) and redo our ISO:9000 /AS9100 certification (future, future blog) .