P-KPIs

There are many P-KPIs that the platform could report to the dashboard for a given station. Depending on the type of station, a specific subset of P-KPIs might be more appropriate. Note that the following is a superset of all that one might come across on their dashboard.

Yield

Yield is the measure of how efficiently one produces good units vs total units. Yield calculations are based on the result parameter sent when a unit is tracked out of the station. Refer to the result parameter for the track_unit_out() method in the SDK for more details.

$T_{\text{total units}}$ : total number of unique units.

$P_{\text{passed units}}$ : will change depending on the type of yield you are calculating. See below.

First Pass Yield

First Pass Yield (FPY) shown on your dashboard only uses the first occurrence of the unit and its result at a specific station, group, or line and its associated reported result. The following steps are used:

1. Identify the first occurrence of the unit at the specific station or group.
2. Evaluate the associated reported result:
   • A pass or passed result indicates that the unit met all test criteria.
   • A fail or failed result indicates that the unit did not meet one or more criteria.

Final Yield

Final Yield is calculated based on the result of the final test or occurrence of the unit at the specific station, group, or line.

Example 1: Simple

In this example, we'll compute yield for one station with a simple product flow. We'll explore how flows with different retry policies will affect the numbers.

Unit Flow:

• First Pass Yield: Out of 4 units, 2 units passed on the first attempt.

• Final Yield: Out of 4 units, 3 units passed after multiple attempts.

Example 2: Complex

In this example, we'll compute yield for a station group and the stations within. Stations A and B are duplicate fixtures in this station group i.e., parallel stations. We'll explore how flows with different retry policies will affect the numbers.

Station Group 1:

• Station A:

• Station B:

Outcome:

Group 1 consists of Station A and Station B.

First Pass Yield: Out of 10 units, 4 units passed on their first attempt.

Final Yield: Out of 10 units, 8 units passed after multiple attempts.

• Station A:
  • First Pass Yield: Out of 7 units, 1 unit passed on the first attempt.
  $$\text{Yield} \% = \frac{\text{count}\left\{\text{unit 1}\right\}}{\text{count}\left\{\text{unit 1 ... 7}\right\}} \times 100 = 14.3\%$$
  • Final Yield: Out of 7 units, 3 units passed after multiple attempts.
  $$\text{Yield} \% = \frac{\text{count}\left\{\text{unit 1, unit 2, unit 6}\right\}}{\text{count}\left\{\text{unit 1 ... 7}\right\}} \times 100 = 38.6\%$$
• Station B:
  • First Pass Yield: Out of 8 units, 6 units passed on the first attempt.
  $$\text{Yield} \% = \frac{\text{count}\left\{\text{unit 3, unit 5, unit 7 ... 10}\right\}}{\text{count}\left\{\text{unit 3 ... 10}\right\}} \times 100 = 75\%$$
  • Final Yield: Out of 8 units, 6 units passed after multiple attempts.
  $$\text{Yield} \% = \frac{\text{count}\left\{\text{unit 3, unit 5, unit 7 ... 10}\right\}}{\text{count}\left\{\text{unit 3 ... 10}\right\}} \times 100 = 75\%$$

By tracking the results of each unit's pass and fail events at each station, you can calculate and monitor both the First Pass Yield and Final Yield to assess the quality and efficiency of your production process at every station.

Process Capability (CP/CPK)

CP

CP measures process variation.

Coming soon ...

CPK

CPK measures both process variation and accuracy.

Coming soon ...

UPH (Units Per Hour)

UPH measures the rate of production.

Coming soon ...