Right-Sized Machine

Production processes require assets to run them. You generally have choices. You can use a big machine that costs a lot of money but has tremendous functionality and flexibility. These machines, because of their cost, end up being used in several processes or for several products to defray the cost. This tends to disrupt flow.

The alternative is to buy or build a smaller machine that may have fewer functions. This machine is dedicated to a single process. It can then be located in a logical position to support one-piece flow without causing problems for other product families.

As mentioned earlier, the real reason to use smaller, right-sized machines is to support flow. If a machine is shared, it is not always available for a process. That means it must build inventory to support the processes for which it is not currently producing. There is also a need to transport completed items to and from the machine, as it will not be situated in the optimal spot for flow.

Creating right-sized machines solves these problems. It supports flow because there is nothing else that is competing for the machines’ time.

So, why then isn’t this done all the time? Generally, if something is easy, it is in common use. So what makes creating right-sized machines challenging? First, there is still the perception that bigger, faster machines are better. It is a hard sell to make people shift that perception. Right-size machines are often simple and don’t have the unit speed of massive CNC (computer numerical control) machines. The small machine might only be able to produce at a third of the rate of the large machine. While the benefits of simplicity and flow offset that disadvantage, it is not apparent on paper when someone simply compares the speeds of the machines.

Second, there is the problem that right-sized machines are not always available off the shelf. Some have to be designed and built. Many companies don’t have that expertise.

There are probably local companies that will build machines in your area. Despite the cost of customization, they can still be a better deal than multi-million dollar, multi-functional machines. Try to build your own, though. The tooling group, if you have one, is a good source of the expertise that you need. They may not be up to speed on the automation, but like anything else, it is something that can be learned.

Right-sized machines are best used when a product has a high volume and has a dedicated production cell (or there is intent to create a dedicated cell). This allows for the justification of the cost. If the cell is not dedicated, you will just be removing one of many piles of inventory but will still not be any closer to flow. The real gains come when several right-sized machines get co-located in series and eliminate the queues between them.