AO Polishing Cassette
Use this document in conjunction with M1/M2 Printer and M3/M3 Max Printer. Please use Cassette Care as your main resource for cassette maintenance.

The AO Polishing Cassette is designed with advanced light scattering technology to smooth the surface finish of parts during printing.
The cassette is available for M2, M3 and M3 Max printers.
See the table below to see how the cassettes are identified.
Printer | Cassette Label | Printer UI |
---|---|---|
M2 | C4 | M2C4 |
M3 | D4 | D4_M3 |
M3 Max | D4 | D4_MX3 |
The cassette label is located at the front of the cassette.

Carbon recommends discussing your application with your CTP to see if it is AO Polishing Cassette compatible.
The AO Polishing Cassette is the same as the standard cassette except for the window.
The standard cassette (C2, D1) window is almost clear while the polishing cassette (C4, D4) window is much more opaque/translucent.

The AO Polishing Cassette is primarily used for certain dental applications. However, it can be used for engineering applications as well. Go to Engineering Applications below to learn more.
When used in conjunction with the proper printer settings, the AO Polishing Cassette can
- increase surface smoothness.
- reduce manual finishing time.
The AO Polishing Cassette has been validated for use with the following resins:
When creating a new project, select AO Polishing Cassette specific resins in the resin dropdown list.
Optional: For most accurate print time estimation select M2C4, D4_M3 or D4_M3X in print control settings.

Resin Dropdown Errors
- When preparing an AO polish build on a printer without an AO Polishing cassette physically present, make sure to select an AO Polishing cassette (M2C4, D4_M3, D4_M3X) as the cassette to complete your print plan analysis.
- Choosing 'Default' as the cassette when an AO Polishing cassette is absent will result in an error prompt.
- Attempting to print an AO polish resin dropdown project with any cassette other than an AO Polishing cassette, will trigger an error message.
- Using non-compatible dental resin dropdowns, such as those not AO Polish or DPR10, will result in an error if a user tries to print the project on an AO Polishing cassette.
For M2d Printer users, the AO Polishing Cassette (C4) is only compatible with software version 1.42 or later.
SPLINTS
Only the vertical orientation has been confirmed for optimal results with the AO-Polishing Cassette.
- Orient the splints so they are about parallel to the platform.
- Rotate the models 90 degrees with the anterior facing the platform. The models should be standing vertically, perpendicular to the platform.

DENTURE BASES
Support creation for parts printed using the AO-Polishing Cassette is unchanged from the standard cassette workflow. Follow the standard support creation recommendations provided in the applicable resin course.
Carbon recommends these settings to deliver the best results for your models when printing with the AO Polishing Cassette.
- Slice thickness should be set to Fine (50µ). This setting is recommended for producing the highest clarity parts.
- Reducing slice thickness will increase print times.
- Standard slicing (100µ) still offers clarity improvements on the AO Polishing Cassette compared to the standard cassette, although parts may exhibit slight cloudiness.
- Adjust slice thickness based on your project requirements.

For Desktop Health Flexcera Base and Lucitone Digital Print 3D Denture Base, setting the slice thickness to 25 µm will not significantly improve surface finish.
This applies only to Lucitone Digital Print 3D Denture Base.
- 5 minute wash in clean InovaPrint Wash
- 5 minutes in clean IPA
Wash other resins according to the standard protocol.
This information applies to all resins compatible with the AO Polishing Cassette.
Green state handling for clarity
- Swabbing/brushing to remove excess resin is not recommended as it will reduce part clarity.
- Not swabbing/brushing will not negatively impact the accuracy of the intaglio surface for vertically oriented parts.

- AO Polishing Cassettes create a shiny surface finish on some vertical surfaces, making it useful for
- customer facing and Class A surfaces.
- surfaces that need plating or painting.
- airtight sealing surfaces.
- improving tearing and cracking in some EPX 82 parts.
- AO Polishing Cassettes mitigate the white dust that sometimes appears when two EPX 82 parts are rubbed together.
- Negligible affect on material properties.
C4 cassettes are compatible with all Carbon resins and work especially well with these materials:
- RPU 70
- FPU 50
- EPX 82
- UMA 90 Black
LESS SUITABLE RESINS
- Accuracy has not been validated and/or the AO Polishing Cassette is not expected to provide significant benefits for these resins: MPU 100, UMA 90, SIL 30, EPU 40 and EPU 41.
- Generally, elastomeric resins see little to no benefit from using the AO Polishing Cassette.
PRINTING
- Small Features: Features smaller than 250 µm, particularly pegs and holes, will not resolve with the AO Polishing Cassette.
- Smoothness: Other than surfaces vertical to the platform, you won’t see much improvement in surface finish quality.
- Print time: The AO Polishing Cassette adds approximately 10% to standard print times.
- Project analysis: To receive an accurate print time estimate in the printer UI, the AO Polishing Cassette needs to be on the printer when the print is being set up. If there is no AO Polishing Cassette on the printer, the print analysis button assumes a standard cassette. If you prefer to just estimate, adding 10% to the print time on a standard cassette analysis can roughly correct for this.
POST-PROCESSING
- Green state surfaces: Parts printed using the AO Polishing Cassette are more easily scratched and damaged in their green state. When possible, we recommend using the Smart Part Washer to minimize part handling.
- Salt baking: Salt more readily sticks to AO Polishing Cassette parts, especially on RPU 70 and EPX 82 parts.