Before you choose
- Define refresh rate as fresh mass divided by total blend mass.
- Use the recommendation for the exact grade and process.
- Track recovery and exposure history; a percentage is not a reuse-life guarantee.
Define the percentage before doing the math
In the planning example here, refresh rate means the mass fraction of new powder in the final fresh-plus-used blend. A 10 kg blend at 30% fresh contains 3 kg fresh and 7 kg used powder. The percentage and batch mass are editable examples, not instructions for a JoySpool grade.
A recovered powder has a history
Thermal exposure, time, contamination, storage and recovery methods can affect the condition of powder that was not fused into parts. Follow the exact grade and equipment instructions for recovery, screening, blending and permitted reuse. Different material systems can require different approaches.
Distinguish powder charged from powder consumed
A build may contain powder surrounding the parts as well as powder fused into them. Some material is recovered and some can be lost or rejected. A part mass multiplied by the raw-powder price does not describe all of these flows.
| Quantity | Meaning |
|---|---|
| Build charge | Powder needed to prepare a build |
| Part mass | Powder incorporated into printed parts |
| Recovered powder | Material collected for the approved recovery route |
| Fresh addition | New powder required for the approved blend |
| Loss / rejected material | Material unavailable for reuse in that workflow |
Ask for the operational assumptions
For a purchasing comparison, request refresh guidance, packing assumptions, recovery losses and storage conditions. Keep a record of the incoming lot and the blend/recovery history. Only use a blend that meets the process requirements; the calculator below performs mass accounting alone.
MASS BALANCE EXAMPLE
Build a fresh-plus-used powder blend.
Here, fresh percentage = new powder mass ÷ final blend mass. Values are illustrative; use the approved requirements for the actual grade and process.
Fresh 3 kg
Used 7 kg
Enter a positive blend mass and a fresh percentage between 0 and 100.
Fresh mass = total × fresh % ÷ 100. Used mass = total − fresh mass.
This tool checks arithmetic. It does not qualify recovered powder, determine reuse cycles or override storage, recovery, contamination or process requirements.
Questions buyers ask
Does 30% refresh mean a powder can be reused three times?
No fixed cycle count follows from that percentage. Reuse depends on the grade, exposure history, recovery process and required part quality.
Can I apply another supplier’s refresh rate to PA12 powder?
PA12 grades and equipment conditions vary. Obtain the recommendation and validate the process for the actual material.
Sources
- Formlabs — powder usage and packing density
Fresh/used powder mass accounting in a defined SLS workflow.
- Formlabs — SLS cost per part
Packing, build height, refresh requirements and process costs; examples are specific to the referenced system.
- Formlabs — powder care, storage and disposal
Grade and equipment instructions govern powder handling and recovery.