¶ Introduction
TPU 85A and TPU 90A are two different hardness grades of thermoplastic polyurethane (TPU) filaments.
- Hardness: The hardness of TPU is usually represented by Shore A hardness. 85A and 90A indicate the hardness levels of these two filaments, with 90A being harder than 85A.
- Elasticity and Flexibility: Both filaments can stretch and bend over a wide range without cracking and have excellent shape recovery. This makes TPU 85A and TPU 90A perform well in applications requiring elasticity and flexibility.
- Abrasion Resistance: TPU filaments have good abrasion resistance, maintaining stable performance over long-term use.
In terms of applications, TPU 85A and TPU 90A can be used to manufacture shoe soles, sports equipment components, and other products that require elasticity and wear resistance. They can also be used for phone cases, smartwatch straps, and other electronic accessories. Overall, these two filaments are high-performance and widely used thermoplastic polyurethane filaments. Their different hardness levels allow them to meet the needs of various application scenarios.
¶ Printing Guide
¶ Filament General Preparation
¶ Filament Storage Environment
To ensure that TPU filament does not absorb moisture and affect print quality during the 3D printing process or while stored, it is recommended to keep the filament in an environment with humidity below 20% RH. It is advisable to store the filament in a storage box with a desiccant (silica gel desiccant is recommended).
Please place silica gel desiccant in the storage box before storing the filament.
¶ Filament Drying
TPU filament has a high moisture absorption rate and easily absorbs moisture from the environment. If TPU with moisture is used directly in 3D printing, the moisture will rapidly vaporize when heated during printing, causing defects such as bubbles and holes in the printed product, which severely affects print quality and may even lead to print failure. Therefore, we recommend using the following equipment and parameters for drying.
For more details, please refer to: https://wiki.bambulab.com/en/filament-acc/filament/dry-filament
| Blast (Forced Air) Drying Oven | Heatbed |
|---|---|
| 70 ℃, 8 h | 75 - 85 ℃, 8 h |
If using a heatbed for drying, flip the filament every 4 hours and cover it with a PC box or filament box.
Heatbed drying reference: https://wiki.bambulab.com/en/general/bambu-filament-drying-cover
Please be aware of the following risks during the drying process:
⚠️ Spool Expansion Risk
Before drying, the width of the undeformed spool edge is approximately 65.4 mm. During drying, the TPU filament expands when exposed to heat, causing the spool to deform and increase in size. After drying under the given parameters, the width of the spool edge may expand to approximately 69.4 mm.The 4L sealed box can ensure smooth spool rotation with a maximum width limit of approximately 67.5 mm. The 5.8L sealed box can ensure smooth spool rotation with a maximum width limit of approximately 108.5 mm, which is sufficient to allow the filament to rotate and load smoothly after expansion.
Therefore, we strongly recommend using a 5.8L sealed box for loading the filament after drying.
 The right side filament spool is the expanded spool after drying |
 4L and 5.8L Sealed Boxes |
 The maximum width limit of the 5.8L sealed box is approximately 108.5 mm |
 The maximum width limit of the 4L sealed box is approximately 67.5 mm |
Note:
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When drying, using a heat-resistant heavy object to press down on the TPU spool can help prevent deformation. If the spool does not deform, the filament can be loaded using the 4L sealed box.
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If using a sealed box for loading, be sure to use the spool holder to ensure smooth rotation of the filament. Additionally, to reduce loading resistance, please open the side opening of the sealed box.
 Side opening of the sealed box |
 Ensure smooth rotation of the filament |
4L sealed box holder link：https://makerworld.com.cn/zh/models/807064?from=search#profileId-784185
5.8L sealed box holder link：https://makerworld.com.cn/zh/models/437644?from=search#profileId-353897
¶ General Machine Preparation
¶ Hotend
To ensure the best print quality and results with TPU filament, it is strongly recommended to use a new hotend or a dedicated hotend for printing TPU.
| Filament | 0.2 mm hotend | 0.4 mm hotend | 0.6 mm hotend | 0.8 mm hotend |
|---|---|---|---|---|
| TPU 85A | Not compatible | Not compatible | Recommended | Recommended |
| TPU 90A | Not compatible | Recommended | Recommended | Recommended |
¶ Build Plate
The textured PEI plate may become overly sticky after applying adhesive, so it is not recommended to use adhesive when printing with a textured PEI plate.
For other build plates, adhesive must be applied to prevent issues such as poor first layer quality, lack of adhesion, or even print failure.
Using a cool plate supertack to print TPU may result in overly strong adhesion, so cool plate supertack should not be used.
| Filament | Cool plate | Engineering plate | High Temperature/Smooth PEI Plate | Cool plate supertack |
| TPU 85A&90A | Recommended | Recommended | Recommended | Not compatible |
¶ Printer
Check and maintain the extruder (if there are foreign objects or filament residue, disassemble and wipe it clean). If the extruder gear is worn, it needs to be replaced (Otherwise, there may be issues with filament slipping).
If the hotend is not new, check the hotend condition (whether there is residue; if there is, raise the temperature and perform cold pulling 2-3 times using PLA / PETG filament, but do not use fiber-reinforced filaments for cold pulling).
Flushing Operation Steps (using PLA Matte as an example):
- For ease of operation, first disconnect the PTFE tube from the toolhead.
- It is recommended to raise the hotend temperature to 250°C, then insert a segment of PLA Matte filament into the toolhead.
- Press the "Extrude Down" button on the interface and observe whether the filament is extruded continuously and evenly. (This step should be repeated 3-5 times.)
Note: If you want to further clean the hotend to achieve better print quality, cold pull method is recommended. Please refer to this wiki: Nozzle/Hotend Unclogging Procedure for X1/P1.
¶ Operating Precautions and Parameter Settings
¶ Filament Loading and Unloading Prerequisites
All filaments must have the spool elevated (the filament discharge port should be higher than the toolhead's load port) to ensure smooth loading.
The spool holder links are as follows:
https://makerworld.com/zh/models/1155832-tpu-filament-spool-rack?from=search#profileId-1160985
Pre-Printing Precautions:
- Please ensure the filament is fully dried before loading.
- Both TPU 85A and TPU 90A require manual loading; AMS cannot be used for automatic loading.
¶ TPU 85A Loading
Follow the video instructions for loading and unloading:
- Remove the glass cover in advance and detach the PTFE tube from the toolhead.
- Place the sealed box holder in the appropriate position, ensuring the outlet is higher than the printer.
- It is recommended to heat the hotend to 250℃ during loading. Route the filament from above the printer and insert it directly into the extruder (loading from the PTFE tube is not supported). Then, slowly press the load button to ensure the filament is extruded smoothly and evenly.
TPU 85A Loading Instructions:
- When clicking the extrusion button on the screen, do not continuously click it, as this could cause the TPU to get clogged in the extruder gears.
- Once the extruder gears have engaged with the TPU filament, slowly press the extrusion button to ensure the filament is extruded evenly and continuously from the hotend before starting the print.
¶ TPU 90A Loading
Please follow the video instructions for loading and unloading.
- The filament can be loaded from an external sealed box through the rear PTFE tube coupler into the PTFE tube.
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Disconnect the PTFE tube from the hotend, then load the 90A filament through the sealed box’s PTFE tube coupler. Gently push the filament through the tube, and once the front end of the filament has passed through the PTFE tube, pinch the filament's front end and pull out a certain length.
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After heating the hotend (recommended 250 ℃), pinch the front end of the filament and insert it into the hotend. Slowly press the load button until the filament is extruded evenly and smoothly. Finally, reconnect the PTFE tube to the hotend.
TPU 90A Loading Guidelines:
- When loading from the PTFE tube, if there is significant resistance, check if the filament in the sealed box is rotating smoothly and if the PTFE tube has any sharp bends.
- Once the extruder gears have engaged with the TPU filament, slowly press the extrusion button to ensure the filament smoothly extrudes from the hotend, avoiding any clogged caused by the filament getting caught in the extruder gears.
¶ Unloading (same for TPU 85A & TPU 90A)
Automatic unloading is not supported.
TPU 85A:
- It is recommended to heat the hotend to 250 ℃.
- Slowly press the extruder's unloading button and gently pull the filament out of the hotend while following the gear's reversal.
TPU 90A:
- It is recommended to heat the hotend to 250 ℃.
- Disconnect the PTFE loading tube from the toolhead, then grip the filament.
- Slowly press the extruder's unloading button, gently pull the filament out of the hotend while following the gear's reversal.
- Once unloading is complete, reconnect the PTFE tube to the toolhead.
¶ Parameter Settings
In addition to the default parameters, specific parameter settings should be adjusted according to the model's characteristics.
- The recommended print temperature for TPU 85A & 90A is 225 ℃, and the heatbed temperature should be between 30 - 35 ℃. No need to enable chamber temperature.
- Please keep the default volume speed limit during printing, and do not increase the print speed.
- Turn off flow dynamic calibration when printing TPU 85A & 90A.
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- When printing with TPU 90A filament, it is recommended to place the model near the front center of the build plate to reduce friction between the filament and the PTFE tube.
- When printing with X1E, do not enable chamber temperature.
¶ Common Printing Issues
TPU filament is prone to the following problems:
- Under extrusion (Nozzle clogging, loading resistance, filament slipping)
- Extruder clogging (Filament bending, causing a clog in the extruder gear; disassemble the extruder and remove the clogged filament)
- Stringing and oozing (You can use a larger diameter hotend, fine-tune the retraction settings, further dry the filament, and apply post-processing to the model)
For detailed troubleshooting and solutions, please refer to this wiki: Common print quality problems and solutions.
¶ End Notes
We hope the detailed guide provided has been helpful and informative.
If this guide does not solve your problem, please submit a technical ticket, we will answer your questions and provide assistance.
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