I thought the same thing. A couple of things that might account for that
- From other shots in the video later in the process, it looks like the majority of the manholes produced don't have colouring applied
-- The volume of manholes requiring colouring might be too low to justify the expense of automation
- Automated control of a fluid with high viscosity and a tendency to dry/accumulate would be much more difficult than, say, the grinding operation shown earlier. At the very least, the nozzles would require more maintenance
I fully agree though, that it is quite interesting that that step is being done manually. I find most videos of this kind to have the same type of surprise - steps which, to a layman, at least, appear like they could be automated, but are not, despite other steps in the process being automated. I imagine a manufacturing engineer's curse is being able to see a perfectible process but not being able to justify the expense.
- From other shots in the video later in the process, it looks like the majority of the manholes produced don't have colouring applied
-- The volume of manholes requiring colouring might be too low to justify the expense of automation
- Automated control of a fluid with high viscosity and a tendency to dry/accumulate would be much more difficult than, say, the grinding operation shown earlier. At the very least, the nozzles would require more maintenance
I fully agree though, that it is quite interesting that that step is being done manually. I find most videos of this kind to have the same type of surprise - steps which, to a layman, at least, appear like they could be automated, but are not, despite other steps in the process being automated. I imagine a manufacturing engineer's curse is being able to see a perfectible process but not being able to justify the expense.