Phone it in Lean Manufacturing for Metal Stamping
Have you ever been sick and wished the doctor could just phone-in a prescription so you didn’t need an expensive visit; not to mention take time out of your busy day?
Well, the following ideas and best practices are meant to be a quick prescription that costs you nothing and lets you be on your way in better “Lean Health.” Hopefully, it will be just what the doctor ordered and will save you an expensive visit from a Lean Consultant.
In the spirit of full disclosure… I am a Lean Consultant. Sure, I like getting paid too but a little free help is a good “lean way” of getting you hooked on Lean Manufacturing and helping America’s manufacturers compete despite the hurdles thrown in front of them.
Some of the biggest “bang-for-the-buck” improvements we have found on the shop floor related to stamping are:
1. Staging – Stage Everything! Make sure you have the new tools/dies and any supporting materials in “on-deck” locations so the second you scoot the “old dies/tools/materials” out of the way, you are ready to slide in the new tools/dies/materials etc. Optimize all movements. Just how close you can put everything to where it ultimately needs to be is often only a matter of a little creativity. Just like a pit crew; a changeover team should do as little work as possible while the press is down and take care of tasks like putting things away and cleaning up once the press is running at rate. Consider leaving “machine specific” tools at, or near, the machine. The only exceptions should be space, safety or maintenance considerations. Does it really make sense to haul tools around the building? It’s generally a “control” issue and nothing more. Stage everything you can at “POU” (Point of Use.)
2. 5S – Make it Visual! 5S is more than a buzzword! Hanging tools on shadow boards so they are handy and easily found has saved and earned untold billions for companies around the world! Do what makes sense in your work area without locking all the tools into cabinets and tool boxes. Keep all the “regular use” tools at arms length where possible and NEVER allow the sharing of tools between machines or departments. OK, never is a strong statement but you can generally justify the purchase of new tools (over sharing them,) in a day or two if you just count the downtime tool sharing costs in production losses. A rare exception might be an extremely expensive meter, analyzer or measuring device that may be centrally located and/or scheduled around. A clutter-free workplace that has “A Place for Everything and Everything in its’ Place” is a wise and worthy investment! Insist on it and implement 5S throughout your entire company.
3. Standardize – Standardize Everything You Can! As it turns out, Lean Manufacturing is best achieved through standardization. In stamping that means making dies/tools of similar heights and sizes. It can mean “automatically” locating center points on presses and tools and marking or modifying platens for easy and error-free alignment. Some of the best measurements and alignments are 100% automatic! You never need to break out your tape measure or ball peen hammer… or the “Bigger Hammer.” Use common plates and risers where possible and consider hydraulic clamping devices and systems. They’re not always appropriate but can often drastically cut downtime when compared to standard clamping.
4. Design – Design FOR Manufacturing! Sure, you may not have much (or any) control over what design specs your customers send along with the tooling but when you can, get involved from the inception of stamped parts. We often find manufacturers trying to exceed the limits of the equipment they intend to use in production. If the tool isn’t capable of .05 tolerances then don’t expect it to perform at that level. Yeah, it sounds like common sense but it IS a common practice to expect the unreasonable in stamping, punching and many other processes. To some extent you can even plan for “normal” wear and extend tool life by creative shimming and sectional replacements. Yeah, quality will begin to drift but it may or may not be of great concern… not all parts require pleasing aesthetics or dimensional perfection. There may be acceptable options. Of course you must hit all minimum quality standards all of the time! Non one is suggesting you compromise on quality… but no one is suggesting you over-spec everything in the name of quality either!
5. Plan Your Work – Work Your Plan! Schedule your work so “standard” tools/dies and/or materials can be left in presses when possible. In the Lean world of shorter runs and more changeovers this technique may save you a lot of downtime and tool movement. The best changeover is still “No Changeover.” Can your tools multi-task? Choreographing the tasks that must be completed for changeovers of all types and regular PM’s (Preventative Maintenance) schedules on every piece of equipment yields increased up-time and quality and should be a basic part of every plan. Also; try to stick to the schedule. Far too many companies setup for one part, run a few, and then switch to the “HOT” part the boss just screamed about before the full run of the current part has completed. Although Lean encourages frequent changeovers, doing them mid-stream is generally counterproductive. A simple decision, you might even say “shop floor protocol” to “finish the run and let the “HOT” part go next” can solve a lot of problems and eliminate a ton of waste! It will also generally reduce the chain-reaction of losses spawned from just one premature changeover.
6. Continuous Improvement – Try New Things! It wasn’t that long ago that one press held one tool. That was our father’s and grandfather’s reality. Someone; not sure who to give credit to, came up with the idea that multiple operations could happen at every stroke of the press. Often times that meant carefully setting up various tools in sequence. It was difficult to get it all “just right” so we began seeing tools that held multiple dies within them (progressive and transfer tools & dies.) Recognizing that not all parts of the larger tools wore at the same rate, we started to see customized tools with removable and replaceable components. The evolution of the industry is in the hands of die makers, engineers, operators and mad scientist all around us! What’s next is anyone’s guess!
Of course there is more to say and do when optimizing your stamping operation and making it a Lean system. If you’ll follow the basics outlined in this “phoned-in prescription,” you’ll be miles ahead of much of your competition and create a considerably more efficient and less wasteful and cumbersome operation.
Lean starts with a dream, a vision of what could possibly be; the extent to which you realize the dream is proportional to the actions taken.
It’s a great journey and worthy of your best efforts! Engage!