Sundots 2.85 mm flexible filament has launched. It is compatible with the Bambu Lab H3C, and purchase orders, including bulk, are open now. Bambu Lab has paired an ultra-soft TPU 75A spool with a 2.85 mm diameter and labeled that spool compatible only with the H3C. This article explains why a softer filament is harder to push through a thin path, and it keeps unpublished machine details separate from that listing. The printer details below come from Bambu Lab’s own pages.
What the H3C preview actually sets
Bambu Lab’s Chinese preview page schedules the H3C launch for 22:00 China time on 3 November 2026. Use that page for the event time. A complete specification was not public when this article was written, so nozzle layout, tool-changer details, and the full material list should be read from the official page after launch.
The official forum post presents TPU 75A as Bambu Lab’s softest Shore-labeled material in this launch, and it ties the announcement to 3 November at about 9:00 a.m. US Eastern Time. IT Home, reporting the preview, says Bambu Lab announced the H3C on 23 October 2026 and set the same 3 November, 22:00 China time slot. Those sources fix a date. They do not replace the specification sheet.
What the TPU 75A (2.85 mm) listing confirms
On the Bambu Lab US store the product is named TPU 75A (2.85mm). The page states a diameter of 2.85 mm ± 0.05 mm and says the spool is compatible only with the H3C. That sentence is about this spool. It does not say that every H3C material is 2.85 mm, and it does not say the machine has dropped 1.75 mm filament.
The same listing highlights FlexFeed, a nominal flow of about 10 mm³/s, an ultra-soft wearable use, a natural matte surface, and a requirement to dry the filament before use. Treat those as the vendor’s published points for this grade. Read them on Bambu Lab’s listing for this grade.
The store page also places availability on 3 November 2026. Check the live page for the clock time beside that date, and check Bambu Lab’s current manual before you assume a third-party spool will run.
Why ultra-soft TPU fights a thin filament path
A soft filament is a weak column. The extruder has to push it. If the path is loose, or the filament is very soft, the column buckles instead of advancing. Makers see that as a jam, a grind, or a gap in the line.
Moving from 1.75 mm to 2.85 mm is a geometry change, not a laboratory result measured on this spool. Cross-sectional area grows with the square of the diameter, about 2.65 times. For a round column of the same length and the same material stiffness, Euler buckling load follows the second moment of area, which grows with the fourth power of the diameter, about 7 times. A thicker soft filament is harder to fold inside the feed path.
The larger area also means a lower filament speed for the same volumetric flow. That is arithmetic from the diameter. It is not a promise that a printer will hold the store’s nominal 10 mm³/s, and it is not a measured stiffness for TPU 75A.
What Bambu Lab has not published yet
Community discussion has included a tool-changer layout and the idea of running 1.75 mm and 2.85 mm on one machine. Bambu Lab has not published a full compatibility table. Those points are not specifications until they appear on an official H3C page.
The public store line does not say the H3C uses only 2.85 mm filament. It says this TPU 75A spool is 2.85 mm and compatible only with the H3C. Other diameters, spool formats, and accessory limits are not on that page. They belong to the launch specification and the manual.
A short checklist before you buy H3C filament
If you are planning material around the launch, check the printer’s own pages first. A spool can sit on a holder and still be the wrong diameter or the wrong profile.
- Confirm the diameter and tolerance the manual allows for that material path.
- Dry flexible filament before printing. The official TPU 75A listing says this spool must be dried.
- Check spool width, hub, and winding against the holder you will actually use.
- Keep the official manual and the current firmware next to any third-party profile.
- Match the diameter in the printer manual before you order.
Questions about H3C filament and 2.85 mm TPU
Why is H3C TPU 75A a 2.85 mm filament? Bambu Lab’s store sells this ultra-soft grade at 2.85 mm ± 0.05 mm and names FlexFeed on the same page. The usual engineering reason to thicken a soft filament is column stiffness in the feed path. The comparison of about 7 times above is geometry. It is not a Bambu Lab measurement and not a Sundots measurement.
Does the H3C take only 2.85 mm filament? Not on the evidence published by 2 November 2026. The line ‘compatible only with H3C’ describes this TPU 75A spool. Whether other H3C paths stay on 1.75 mm is part of the specification expected at launch.
Do I have to dry TPU 75A? The official listing says to dry it before use. Follow that page, then the technical sheet for any other flexible grade. For a dryer temperature, use that listing and the sheet for the grade you buy.
Is Sundots selling 2.85 mm filament for the H3C? Yes. Sundots 2.85 mm flexible filament has launched, is compatible with the Bambu Lab H3C, and is open for purchase orders, including bulk. Send us an enquiry for pricing, lead times and available hardness options, and Sundots will confirm the order. Place the order with Sundots.
Sundots 2.85 mm flexible filament for the Bambu Lab H3C is open for orders
Sundots already publishes a flexible TPU and TPE range, including grades launched at WTCC 2026. The 2.85 mm flexible filament is a separate launch: it is compatible with the Bambu Lab H3C and open for orders. Send us an enquiry for pricing, spool options and available hardness grades.
To order Sundots 2.85 mm flexible filament for the Bambu Lab H3C, contact Sundots and name the printer, the 2.85 mm diameter, and the part you have in mind. A bulk or OEM enquiry can carry the same facts. Place the order with Sundots.
Order Sundots 2.85 mm filament for the Bambu Lab H3C
Sundots 2.85 mm flexible filament is launched and compatible with the Bambu Lab H3C. Purchase orders are open, including bulk. Use the contact form on this site to send an enquiry. Send us an enquiry for pricing, lead times and available hardness options.
Sources
Bambu Lab and H3C are trademarks of their owner. Sundots is not affiliated with, sponsored by, or endorsed by Bambu Lab. The names identify the printer and the official listing only. Diameter and flow figures are quoted from that listing. The buckling comparison is a geometric relationship, not a laboratory result. Confirm the current official page, firmware, and manual before you buy or print.
