Medical device costing: adding the cost of the production environment
Costing a medical device. Assembly follows electronics, molded parts follow injection molding, plus one category of its own — maintaining the controlled environment, which accrues with time rather than with output.
This industry borrows from two others already covered: boards and assembly follow **electronics assembly**, housings and molded components follow **injection molding**. Read both — together they cover most of the sheet.
What remains is specific, and it has a property that leads people to enter it wrongly: **it accrues with time, not with units**.
Maintaining the production environment
The production area holds defined conditions, and doing so costs money continuously whether you build many units or few: filtration, single-use garments and supplies, scheduled cleaning, environmental monitoring.
Because it runs with time, **unit cost depends on volume** in a way most trades do not experience: the same monthly cost divided among fewer units means each one carries more.
Batch records and changeover
As in **food processing**, cost arises per batch rather than per unit: cleaning between batches, pre-run verification, batch documentation.
So smaller batches cost more per unit — a useful finding, because it puts a number on what splitting an order actually costs. The cleaning and changeover guide covers the arithmetic; only the vocabulary differs.
Three changes from the parent guides
| Category | What changes |
|---|---|
| Material | Add single-use environment supplies — they never appear in the product but they are consumed by producing it |
| Labor | Add cleaning, batch documentation, and gowning time entering and leaving the area |
| Overhead | Environment maintenance accrues with time; divide by the same period's output |
The remaining seven follow the electronics assembly and injection molding guides, depending on which part of the device you are costing.
Related guides
- PCB assembly cost: components, placements and everything the BOM does not show
Costing an assembled board across all ten categories. Two things separate this trade from the rest: the bill of materials dominates the cost, and machine time tracks placement count rather than board count.
- Injection molding cost per part: shot weight, cycle time and cavitation
Costing a molded part across all ten categories. Three numbers dominate everything else — shot weight, cycle time and how many parts come out of each cycle — and getting any of them wrong moves the whole sheet.
- Cleaning and changeover: cost per batch, not cost per unit
Cleaning between batches costs the same whether the batch was large or small — which is what really makes short runs expensive. How to cost it, and what it tells you about batch sizing.