Lean manufacturing has been a huge push in the past few years; one resulting product of this is cellular manufacturing. With so many companies incorporating “Cell” manufacturing into their shop floors, it can, and has changed how we apply tooling.

We all know that a cell is no more productive than the slowest process in it, and if that process has been optimized to the limit, most of us do not look much farther. Often, this is because we don’t believe any changes we can make will have significant impact on the overall cell productivity… or do they?

Stepping back and looking at the processes in these pieces of equipment, we can see there are often many process improvements which, on the surface, may seem to have little effect on productivity. Any effects they may have are typically difficult, if not impossible, to measure. Regardless, they can have a huge effect on the bottom line.

Let’s look at a hypothetical situation: on a secondary CNC machine, an operator is doing some drilling and light machining of a turned part with the cycle time being half that of the first process. The tooling costs per hole are $ .04 with the existing process, and nearly the same (per hole) using a high performance tool which lasts eight times longer. On the surface it appears that there is not any cost advantage to the high performance tool – the traditional thinking is that the cost per hole is the same, so why make the switch? Sometimes you shouldn’t switch, but on the other hand, have you looked at all the consequences of not switching?

Every time a tool is changed, there is the risk of someone putting in the wrong tool – it could be the wrong size, or tool material. Assuming all went well and we have the correct tool, the operator then takes it to the presetter, measures it, and accidentally transposes the number when entering it in the machine. Will it be ok, scrap, rework, or even worse a machine crash?

How important is part to part consistency to your customer? Generally speaking, a high performance tool will produce a very consistent surface finish and size throughout the life of the product. Dull tools cause burrs, which could require more operator time to remove. Will that take longer than what the cycle time is on the primary machine, or consume the time needed for part inspection?

The point is, sometimes it really doesn’t make sense to change a process in a secondary machine. On the other hand, it’s quite disheartening to see the above hypothetical situation play out in the real world. It really is part AND process dependant.