Do robots eliminate the need for lean manufacturing?
With COVID-19 your factory has been having high absenteeism, struggling to attract new employees, and having higher employee turnover. So, is now the time to implement robots? You have heard that robots are good at replacing repetitive tasks. Should you just find a repetitive operation and replace it with automation? No, not if you want to get the most benefit from your automation. Going from having limited automation to using robots is a bit like being a weekend jogger and deciding to run a marathon. There is a lot of training and strengthening that needs to occur before race day.
While the cost of robots and the ease of programming them have both improved you should still take a more holistic approach to your manufacturing process and how you automate it. For example, if you do not evaluate the process first you may automate an operation that is not necessary or could be eliminated. Even if a shiny new robot is doing it an unnecessary process it is still waste.
The goal of Lean manufacturing is to remove waste from a process. Using Lean Manufacturing tools is a great way to evaluate your manufacturing process and identify waste. This gives you the ability to eliminate waste prior to automation or use automation to further eliminate waste. Looking at the capabilities of automation after first going through the lean manufacturing tools such as value stream mapping and spaghetti diagrams is a great way to increase the return on your automation investment.
The goal of a current state value stream map is to make the process and the waste there visible. Lean manufacturing has several tools to eliminate waste, such as Kanban, supermarkets, SMED. I believe that automation can be considered one more tool in your Lean Manufacturing tool kit.
When people talk about factory automation they tend to think about robots and a factory like Tesla's. However, there are many levels of automation all of which improve productivity. Robotic automation has become cheaper and easier to program, but there can still be significant hidden indirect costs. These costs may keep it out of the reach of smaller companies or companies requiring more flexibility. Some of the costs to consider when looking at implementing a robot are:
o The cost of programming
o The cost of integrating the robot with your material flow
o The cost of designing a part for automation
o The cost of designing the workstation for the presentation of the part
o The cost of maintaining and reprograming the robots
o The cost of training or hiring the required skills to maintain and program the robots
For larger companies with high volume and fewer products, higher levels of automation make sense, but what about small and medium-size companies? Is there an automation option for them? Yes, the good news is that automation has many levels. The Lean Enterprise Institute book "Creating Continuous Flow" by Mike Rother and Rick Harris defined 5 Levels of automation (chart below). This is a great way to look at automation as it does not look at how you automate, but more about what you automate. They break a typical manufacturing process down into 4 steps: load machine, machine cycle, unload machine, and transfer parts. Based on their experience getting to Level 3 is easy. This is where the machine cycle and machine unload are automated. Then moving to Level 4 you hit what they call "The Great Divide". The process of automating machine loading and the movement of parts between workstations is significantly more difficult to automate.
Let us look at Level 3, the automation of the unloading of the part from a machine. The unloading process can be quite simple. It only requires that the part be removed from the machine to present the operator with an empty machine (nest) to load the part. The savings in doing this can be significant and the skills to design it are not complicated. Often operators or team leaders working with maintenance can develop and execute the concept. A simple actuator to push the part out of the nest is enough. There normally is no need for orientation or alignment of the part in this case.
Now compare this to Level 4 with automated loading of the machine. For Level 4 you need to present the part to the machine properly oriented so that the machine will be able to load it correctly without jamming every time. This requires a consistent way of presenting the part to the machine. The machine needs to know that a part is present or not. A way for the machine to take the part and load the machine with the right orientation. This normally requires a manufacturing engineer with programming skills and larger capital investment. While "The Great Divide" gets smaller as the cost of robots drops and programing them becomes easier this is still significantly more complicated than Level 3.
Just like a runner wanting to run a marathon, start with assessing where you are. Evaluate your overall process condition with Lean Manufacturing tools. Then create a training or conversion plan to reach your target over time. Just as with beginning to run, the early gains are the easiest. Getting your processes to Level 3 automation will give you the greatest return on your automation investment and start to strengthen your organization. Having done the work to get to Level 3 you are prepared with a better understanding of your process and your capabilities to move to Level 4 where robots will start to add value.