Lean Robotics Basics: Lesson 5: Manual Task Mapping

One trap we too often fall into is starting to implement a solution without having clearly identified the problem. We jump back and forth between trying to understand the current process and suggesting elaborate ways of carrying it out with a robot, and it becomes confusing before long.

Manual Task Mapping Steps

According to the Lean Robotics methodology, we start the robotic cell design with a manual task map, which is a static snapshot of the starting point from which we will work to improve the process. Capturing this information will save you time in the later phases.

1. Identify Cell Customer

In a factory, a manual station's customer is the next operation in the manufacturing flow. The customer should be the operator or machine that receives the parts from this station.

2. Define Valuable Output

To define the valuable output, answer these questions: ''What input does the cell customer (next cell) need? As the manual cell's customer, I need it to give me ___ so I can ___.''

Example: ''I need it to give me a 10-layer stack of 20 x 20 cm trays filled with part #DJ2-3322 so I can package them for shipment to the external customer.''

3. Define Input

Define what materials and parts are coming to the station.

Nature of the Parts

Number of a different model of parts
Characteristics of the parts: Dimension, Weight, Material, Other
Variation in time: station changeovers? New parts in the near future?

Document the inputs in a list and their main characteristics and the possible range (min-max size, min-max weight, etc.).

Parts Presentation

Are the parts singulated (individually presented)
How do the parts arrive? (one by one, stacked, side-by-side, place randomly, etc.)
Are the parts packaged?
Where are they? (table, fixture, tray, stacks, chute, bin, etc.)
Are they moving?

4. Describe Process

Describe the steps and process that happens to the parts of the input before leaving to the next station.

Take videos, photos, sketches
Have the operators describe the process
Pay attention to hidden tasks

5. Document Flow of Information

Identify the flow of information that happens between the cell and other parts of the factory and within the cell. Identify the origin of the information, where this information is going to, the format and how it's been used. Use a table like this to gather the flow of information:

6. Measure Cell KPIs

Identify the cell key performance indicators. Monitor all cell KPIs, even if certain are not the main target for improvement by the robot. For example, if your main goal is to increase output capacity you also want to maintain the current cost of production at this station.

Use this short list to identify what you want to improve and the related KPIs to measure:

Productivity: cost of production of parts
Capacity: cycle time, cell capacity
Quality: first pass yield, defect rate
Ergonomy: Occurrence of injuries
Inventory: Inventory at the cell ($ value of input parts, in-process parts, and output parts at the cell)
Human potential utilization: Operator waiting time or non-added-value operations

7. Summarize Map

Summarize the key information in a clear and concise visual representation. Report the information above in the template available at the end of this lesson.

Manual Cell Layout

After summarizing the manual task map, create a sketch to gather the information on the spatial arrangement of the cell. Make a top view sketch showing the main components of the cell. Include all dimensions, clearances and identify the actual entries, exits of the cells. Don't forget to identify the location where the parts have to be processed by a machine like in this example of a CNC Machine cell layout.