An industrial manufacturing cell operates a high-precision 3D printer to fabricate custom titanium implants. The stages required to produce a single batch of implants are listed in the table below.
| Process Stage | Duration in minutes |
|---|---|
| Chamber pre-heat and vacuum pump down | 11 |
| Direct metal laser sintering (DMLS) | 24 |
| Inert gas cooling phase | 8 |
| Ultrasonic debris removal | 4 |
| Extraction and chamber vacuuming | 3 |
At the end of each week, the sintering machine must undergo a comprehensive powder sieving and filter replacement procedure. This maintenance takes 90 minutes.
Construct a general expression to show how many batches of implants can be fabricated in any number of hours (hhh).