# The Human Performance Impact on OEE in the Adoption of New Production Technologies
## 3 Framework Proposal
### Proposal of the OEE Measurement Methodologies  
This subsection introduces two different OEE measurement methodologies which allow distinctions to be made between human and technical factors. Both methodologies originate from the TPM OEE and can therefore be easily traced back to the framework reported in Table 2.  
In addition, it should be highlighted that the methodology aims at differentiating the technical factors from the human factors, namely human errors and process configuration errors that can be traced back to the human activities. In this way, it would be possible to effectively consider the gap between technical performances and human performances, and to identify potential improvements for the ramp-up period. Note that the proposed measurement framework strictly requires the possibility of implementing a data tracking platform in a digital and interconnected industrial environment. Indeed, the platform must track all the relevant parameters for the OEE calculation: operating time; downtime events and the time taken for recovery; and the count of compliant, non-compliant and processed products. The fundamental requirement of the data monitoring platform is to accurately track the flow of raw materials within the plant and the process, recording every type of physical movement and temporal duration of the materials. Moreover, it is assumed that the data tracking platform is able to distinguish between errors due to human activity or due to the machinery product processing. Without this digital platform and environment, it would not be possible to adopt the proposed framework. Table 3 shows the definition of the metrics used in the OEE evaluation methodology. From the previous definitions, it is possible to obtain the following metrics, which will be adopted for the OEE calculation:  
\[\text{Uptime}=\text{PT}+\text{IT}+\text{BT}+\text{ST} \tag{5}\]  
\[\text{Downtime}=\text{F}_{\text{proc}}+\text{F}_{\text{mac}}+\text{OM}+\text{ ST} \tag{6}\]  
\[\text{Non}-\text{compliant}\text{products}=\text{P}_{\text{nc}}=\text{P}_{ \text{nc, proc}}+\text{P}_{\text{nc,mac}} \tag{7}\]  
\[\text{Potential}\text{products}=\text{P}_{\text{pot}}=\text{P}_{\text{pot, proc}}+\text{P}_{\text{pot, mac}} \tag{8}\]  
\[\text{Target}\text{products}=\text{P}_{\text{target}}=\text{P}_{\text{c}}+ \text{P}_{\text{nc}}+\text{P}_{\text{pot}} \tag{9}\]  
where it is possible to observe that, considering a constant machine processing time (constant machine cycle time; expressed as CT), the following equivalency is obtained:  
\[\text{Uptime}=\text{CT}\cdot\text{P}_{\text{target}}=\text{CT}\cdot\left( \text{P}_{\text{c}}+\text{P}_{\text{nc}}+\text{P}_{\text{pot}}\right) \tag{10}\]  
Figure 1: Representation of the OEE time model from Schiraldi and Varisco (2020) [37]. Table 4 represents the OEE assessment methodologies, where considers all the inefficiencies that may occur during the production phase (namely inefficiencies due to the machinery, process configuration or human errors) and where considers only the inefficiencies due to the machinery, excluding the ones attributable to process configuration or human errors. Note that both calculation methodologies assume constant processing times (constant cycle times) and the possibility to implement a tracking platform, while the following assumptions are provided for the calculation:  
* All the inefficiencies and time lost due to process configuration or human errors are considered as additional processing time for the machinery;
* During the additional processing time, no machinery losses are present;
* All products obtained in the additional processing time are compliant.