FYI: Polymaker ht-pla blues

[Dan Flemming]

I bought a roll of polymaker ht-pla, but it seems something is WRONG with it.

(If you don't see a photo, refresh)

It won't bond to itself, athough I have "calibrated" the filament with Orca Slicer.

This filament seems "dialed in ", according to the calibrations, yet the inner circle of gears I'm try to print wouldn't stick together after a couple of layers (and I get many many holes throughout the infield, like it rejects bonding).

I've tried nozzle temps from 200-250 (calibration was 220).

Plate temps from 60-70 with no good results.

Throughly cleaned plate, bottom 2 layers stick fine.

I slowed the inner hole layers down to as low as 120 and still i get layer separation.

I did print a 200x30x5 mm model that bends more like tpu/petg and makes me think there is something wrong with this filament.

Anybody have problems with this filament?

As you can plainly see, this new ht-pla won't even stick to itself.

(I dried this rolling for 5 hours fresh out of the box before attempting to print with it, my normal dry time, then as I print it's from another dry box with drying on).

As I tried printing the layer separation started getting worse (see photo)

[Sean]

What's your print speed?

Have you tried decreasing the cooling? 

I've had this happen when either I'm printing too fast that the extrusion rate goes beyond the ability of the material to become fully molten enough to bond to the previous layers..

And also when I'm cooling too quickly that the extrusion doesn't have enough time to bond to the previous layers.

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[Dan Flemming]

I've tried reducing fans, increase heat, slowing down print speed, reducing inner/outer speeds.

  Nothing seemed to work.

As you can see, the polymaker pla (red) printed perfectly at my normal pla settings (even tried normal pla settings).

[Kurt A 3d]

If you look here: https://polymaker.com/ht-pla_ht-pla-gf/ and scroll down to Q&A 

"Is it strong?

The layer adhesion is fairly low, not recommended for single wall prints."

So... I guess you are seeing that....

Polymaker has this profile for the snap maker U1:

{
    "type": "filament",
    "name": "Polymaker HT-PLA @Snapmaker U1",
    "from": "User",
    "instantiation": "true",
    "cool_plate_temp": [
        "50"
    ],
    "eng_plate_temp": [
        "50"
    ],
    "hot_plate_temp": [
        "65"
    ],
    "textured_plate_temp": [
        "50"
    ],
    "cool_plate_temp_initial_layer": [
        "50"
    ],
    "eng_plate_temp_initial_layer": [
        "50"
    ],
    "hot_plate_temp_initial_layer": [
        "65"
    ],
    "textured_plate_temp_initial_layer": [
        "50"
    ],
    "overhang_fan_threshold": [
        "50%"
    ],
    "overhang_fan_speed": [
        "100"
    ],
    "slow_down_for_layer_cooling": [
        "1"
    ],
    "close_fan_the_first_x_layers": [
        "1"
    ],
    "filament_end_gcode": [
        "; filament end gcode \n"
    ],
    "filament_flow_ratio": [
        "0.96"
    ],
    "reduce_fan_stop_start_freq": [
        "1"
    ],
    "fan_cooling_layer_time": [
        "100"
    ],
    "filament_cost": [
        "0"
    ],
    "filament_density": [
        "1.28"
    ],
    "filament_diameter": [
        "1.75"
    ],
    "filament_max_volumetric_speed": [
        "15"
    ],
    "filament_minimal_purge_on_wipe_tower": [
        "15"
    ],
    "filament_settings_id": [
        "Polymaker HT-PLA @Snapmaker U1"
    ],
    "filament_soluble": [
        "0"
    ],
    "filament_type": [
        "PLA"
    ],
    "filament_vendor": [
        "Polymaker"
    ],
    "bed_type": [
        "Cool Plate"
    ],
    "nozzle_temperature_initial_layer": [
        "220"
    ],
    "full_fan_speed_layer": [
        "0"
    ],
    "fan_max_speed": [
        "100"
    ],
    "fan_min_speed": [
        "100"
    ],
    "slow_down_min_speed": [
        "5"
    ],
    "slow_down_layer_time": [
        "6"
    ],
    "filament_start_gcode": [
        "; filament start gcode\n"
    ],
    "nozzle_temperature": [
        "220"
    ],
    "temperature_vitrification": [
        "156"
    ],
    "nozzle_temperature_range_low": [
        "210"
    ],
    "nozzle_temperature_range_high": [
        "230"
    ],
    "additional_cooling_fan_speed": [
        "0"
    ],
    "renamed_from": "My Generic PLA",
    "setting_id": "OGFSA04",
    "compatible_printers": [
        "Snapmaker U1 (0.4 nozzle)"
    ],
    "enable_pressure_advance": [
        "1"
    ],
    "is_custom_defined": "0",
    "version": "2.3.1.10",
    "idle_temperature": 0
}

   let us know if you get this dialed in...

Kurt-A

[Dan Flemming]

I'm drying for 15 hours before I start dialing it in agian.

I watched a YouTube video of a guy that said 250 was where ht-pla printed best, but my tests indicated 220 was perfect.

  I tried 250 and I did get atleast a reasonable print, then it turned to crap.

  That's when I did all my calculations and tests but it was terrible.

  I'll know more tomorrow when I start over and dial it in.

To view this discussion visit https://groups.google.com/d/msgid/3d-printing-tips--tricks/98d7bf00-e710-4483-b1b7-4b36f05288a7n%40googlegroups.com.

[3D Printing Tips and Tricks]

All the HT-PLA I’ve printed was from Proto Pasta.

[Kurt Gluck]

Dan,

The config from Polymaker shows 220 - so sounds like you are on track

Kurt-A

Sent from my iPad

On Feb 17, 2026, at 11:13 PM, 3D Printing Tips and Tricks <3d-printing-...@googlegroups.com> wrote:

All the HT-PLA I’ve printed was from Proto Pasta.

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[Dan Flemming]

Update:

I dried this HT-PLA for about 20 hours (on/off, but 15 continuously), then printed a few small items, seems that FIXED the problem.

  Along with increasing the nozzle temp from 220 to 230 and reducing the model fan from 100% to 70%, also slowed the chamber fan from 100% to 70%.

  As you can see this made all the difference...

  That means there are reasons why prints may turn out bad, you as a "Print Master" have to find the reason why and how to fix (at least head in the right direction).

  Experience, experience, where for art thou?

  It's in many mistakes, but the investigative journey divides the "will be's" from the "gone'a be's"...

  Mostly it's about thinking about what your seeing in failed prints, and what the possibilities are that could have caused them.

  Yes, we all make mistakes in diagnosing failures, but understanding what could be achieved by small simple adjustments can sometimes be daunting.

  I hope this helps someone work through a common problem of failed prints...

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