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figure shows the trend of the between the temperature delta versus the time to reach it. The figure shows that the higher the different between the chamber temperature and the ambient temperature, the longer it will takes to reach it.

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Chamber temp

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Temp delta | Room temp: 23.4°C

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Time taken (from room temp)

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30°C

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6.6°C

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5 minutes

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40°C

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16.6°C

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14 minutes

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45°C

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21.6°C

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19 minutes

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50°C

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26.6°C

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27 minutes

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52°C

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28.6°C

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31 minutes

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54°C

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30.6°C

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33 minutes

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56°C

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32.6°C

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38 minutes

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58°C

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34.6°C

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49 minutes

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60°C

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36.6°C

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67 minutes

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61°C

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37.6°C

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85 minutes

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61.8°C (steady state)

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38.6°C

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120 minutes

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61.8°C (steady state)

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38.6°C

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140 minutes

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7.4. ACTM Cooling Assist Test

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With the table bellow, the ACTM has been demonstrated to rapidly loss it's ability to maintain a cool chamber with more layers of filtration. As shown in the table bellow, only when there is not filter in the way did the ACTM was able to keep the system cooler than the control case (43.2°C). In other cases, the air flow generated by the ACTM actually cause the chamber to get slightly hotter than the control case. Thus, when printing with materials that does not product harmful fume and can benefit from a cooler chamber (such as PLA or TPU), it is recommended to remove the filters, or just keep the door open.

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Nevertheless, the maximum steady state temperature at 46.7°C, with both filter & carbon basket on. This is still well bellow the glass transition temperature of PLA. Therefore, This is still a reasonable compromise for multi-material prints, that combine materials that need filtration (like PETG or ABS) with PLA (or TPU).

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Configuration

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Steady state chamber temp

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Temp delta | Room temp: 23.8°C

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With filter & carbon basket

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46.7°C

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22.9°C

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With carbon basket

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45.8°C

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22.0°C

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Fan only

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32.0°C

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8.2°C

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7.5. Steady state chamber temperature

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The steady state chamber temperature test records the steady state temperature at different bed temperature and ACTM fan speed. The table and chart bellow shows the complex relationship between ACTM circulation speed and chamber temperature. The chamber delta is used to normalise the room temperature different between different days, and can be added on top of future room temperature to extrapolate the absolute achieved chamber temp.

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It shows that there is an interesting zone for the fan speed, between 20% and 60%, where the temperature delta drops. This is because there is enough air flow to disrupt the hot air pocket at the top of the printer and mix it with the cooler air bellow, the air flow is not enough to extract extra heat from the bed.

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Nevertheless, there is a considerable temperature delta, even without the ACTM. With the full assistance of the ACTM, an additional ~7°C can be gained.

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Fan speed

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Temp delta Bed: 100°C

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Temp delta Bed: 70°C

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0

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23.28

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-

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20

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24.08

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-

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40

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22.05

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-

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60

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24.92

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-

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80

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28.61

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-

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100

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30.33

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-

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8. Conclusion

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Sensor location. The location of the chamber_air_x_temp has been shown to be the most appropriate point to collect temperature reading. As it approximate the temperature inside the tool-head, which is where the filament experience the high temperature and failures due to heat creep tends to occur. However, the experiment has also shows that a safety margin of ~5°C must be applied to the reading of chamber temperature.

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Chamber heating. The ACTM has demonstrated that it can enable a maximum temperature delta of 38.6°C (over room temperature) and rapid heating to ABS printing temperature in less that 30 mins.

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Chamber cooling. The ACTM rapidly loss it's ability to maintain a cool chamber with more layers of filtration. Thus, it is recommended to remove the filters, or just keep the door open, where possible. Nevertheless, with the maximum steady state temperature at 46.7°C, the ACTM is still a viable option for multi-material prints, that combine materials that need filtration (like PETG or ABS) with PLA (or TPU).

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Steady state. The steady state test result shows the complex relationship between ACTM circulation speed and chamber temperature. Nevertheless, with the full assistance of the ACTM, an additional ~7°C can be gained, when the bed is at 100°C.

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