Active Chamber Temperature Manager (ACTM)

It is a paid feature for the documentation and software config. However, the model itself is free, see the link bellow.

FUNCTION TEST VIDEO

UPDATES

• 260912. Added (in klipper marcro) the ability to control mode and fan speed at every layer change. This is to keep the print volume in the desired chamber temperature range for as long as possible.

PRINT PARAMETERS

• Material: ASA (preferred) / ABS

• Infill: 20% - Gyroid / Cubic

• Number of wall: 3

• Top solid layers: 4

• Bottom solid layers: 3

• Orientated as shown in the .3mf

• Paint-on-support as shown in the .3mf

BILL OF MATERIALS (BOM)

Name	Quantity	Description & Notes	Link
(*) Extra wiring and connectors for the basement and controller board.	n/a	For: - 2x 9733 Blower Fans (cannot share controller port) - 2x 6020 Axial Fan (can share controller port) - 1x Servo (LED port) - 2x Thermistor	N/A
100K Ohm Thermistor	2		https://amzn.to/4eme8yR
24V 6020 Axial Fan	2	For heat extraction	https://amzn.to/4ekndrU
24V 9733 Blower Fans	2	Alternatively, the 12V variant can be used, but not the 5V version. Most 3D printer controller boards cannot product the required Ampere for the 5V variant.	https://amzn.to/4uCCQRH
Activated Alumina / Carbon Mix	1	[Optional] For those who are who need the extra chemical filtration.	https://www.onetwo3d.co.uk/product/zephyr-activated-alumina-carbon-mix/
Carbon Filter	1	To serve as the bottom for the carbon basket	https://amzn.to/43zCnom
JST SM 2-Pin 2.54mm Pitch Plug Male and Female Connector pairs	2	For the trap door 6020 Axial Fan	https://amzn.to/4v9ui5L
Levoit LV-H128-RF	1	HEPA & Activated Carbon	https://amzn.to/4v4LSI4
M3 Nuts	7
M3 spring T-nuts	4
M3 Washer	4
M3x12mm Socket head	3
M3x16mm Countersunk	2
M3x30mm Socket head	2
M3x40mm Countersunk	4	For mount the fans	https://amzn.to/49VAh5J
M3x5x4 heat-set insert	32		https://cnckitchen.store/products/made-for-voron-gewindeeinsatz-threaded-insert-m3x5x4-100-stk-pcs
M3x8mm Countersunk	36
M3x8mm Socket head	2
Molex 8-pin connector pair	1	For terminating the wirings from components	https://amzn.to/4vgrvbc
N52 6x3mm Magnets	8	[Optional] To hold everything together. However, the weight of the unit and form seal is enough by default.
Paper clip 1mm thick wire	1	For the trap door	https://amzn.to/49YFkCv
Sealing Foam Tape 5mm Wide 1mm Thick	1		https://amzn.to/4vbiwI0
Sealing Foam Tape 5mm Wide 3mm Thick	1		https://amzn.to/4vagGaB
SG90 Servo	1	For the trap door	https://amzn.to/4eDxm4h

ASSEMBLY MANUAL

See the attached .pdf file for the full assembly guide.

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CHAMBER TEMPERATURE TEST

For the latest version of this test see:

https://gitlab.com/misschanger/misschanger-v2/-/wikis/6.Q&A/Chamber_temp

Executive Summary

An appropriate thermal sensor location has been selected, through experimentation, which also highlighted that a safety margin of ~5°C must be applied to the reading of chamber temperature. The Active Chamber Temperature Manager (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. The ACTM ability to maintain a cool chamber with layers of filtration has also been shown to be reasonable. However, the best way to keep the chamber cool is still just to remove the panels (i.e. keep the door open). Lastly, the steady state test result shows the complex relationship between ACTM circulation speed and chamber temperature.

1. Abbreviation

Abbreviation table

Abrreviation	Definition
ACTM	Active Chamber Temperature Manger
DIY	Do It Yourself
MCv2	MissChanger version 2
Tg	Glass transition temperature

Terminology table

Terminology	Definition
Chamber fan	6020 axial fan mount at the bottom of the bed
ACTM fan	9733 blower fan inside the ACTM main unit
Glass transition temperature	The glass transition temperature (Tg) corresponds to the point where a polymer changes from a rigid and brittle state (glassy state) to a more flexible and rubbery state. It is a structural transition, different from the melting point.
Temp	Temperature
Steady state	The point at which the machine releases an equilibrium amount of thermal energy into the environment as the heat(s) in it provides, and the internal chamber temperature stabilised.

2. Reference

No.	Title	Link
1	Glass Transition Temperatures of PLA & PETG	https://facfox.com/docs/kb/glass-transition-temperatures-of-pla-petg
2	Nevermore StealthMax	https://github.com/nevermore3d/StealthMax

3. Introduction

3.1. Background

The management of heat is an essential aspect in all form of manufacturing. That is no exception for 3D printing. However, there is a unique challenge for designers and creators in this field; and it is not the complexity of the designing a heating solution. What makes a 3D-printer difficult to design for and around is the shear flexibility of it. The same machine can be used in the bedroom of a hobbyist (working with common material like PLA) or it can be integrated into a industrial fleet (running 24/7 with exotic engineering, like Nylon). These materials requires drastically different working environments; thus, reasonable compromises must be made, and/or targeted features developed for specific use case. It is best shown around the topic of 3D printer chamber heating.

For a period time, environmental heating is not a major concern for consumer-grade 3D-printers. In the era of open-frame bed-slinger, putting a DIY enclosure around the machine is often done to get the chamber conditions needed for materials like ABS. These make-shift enclosures and low-power (~250W) PCB bed heaters do not allow the chamber temperature to be high enough to cause any material failure of the components in it. Thus, the broader 3D-printing community has adopted the idea of "higher is better" for chamber heating. And, when needed, just remove the enclosure for lower temperature materials.

But, time has chanced. Starting with DIY enclosed system like Voron, and then the success of the BambuLab X1C. The 3D-printer space is now populated with many machines that are fully enclosed with higher power heaters inside (~600W), allow the system to get much hotter than ever. Furthermore, valid concerns have been raised over the years about to potential harm of the emissions from the molten filaments. It is a modern expectation that a printer comes with an enclosure. Lastly, the recent growth of tool-changers, many are finding the need to manage emissions of materials like ASA in an filtered chamber while controlling the chamber temperature, so that it can be combined with materials like TPU.

3.2. ACTM Design History

3.2.1. The predecessor

Before the Active Chamber Temperature Manger (ACTM), there is the Nevermore StealthMax. The Nevermore3D team has contributed greatly to the topic of air filtration, and the Nevermore StealthMax is their attempt to have a system that can either recycle or extracted the hot-air from the printer, for better heating / cooling. Tested on a Voron 2.4 350, the air cycling of the system has been shown to dramatically improve the chamber heating performance of a printer (enough to melt some ABS parts, and fans). However, further testing has shown that it is insufficient for keeping the chamber at a low enough temperature. Hot air was not extracted fast enough for the chamber temperature to go down, and the system slowly get too hot to print with materials like PLA / TPU / PETG. Thus, a more powerful system is needed.

3.2.2. ACTM specifications

The ACTM system is designed around a pair of 9733 blower fan; Power: 4.8W, Air Pressure: 17.07mmH₂O, Airflow: 19.94CFM. Together, they can purge the entire volume of a Voron Trident 300 up to 9.7 times per min. Further design considerations had also been made to improve the print-ability of the ACTM components, and create flexibility in the configuration of the unit. These optimisation includes:

• Have multiple smaller sub-component

• Built-in supports

• Multiple config options

No extra heater. The ACTM system has been designed without including additional heating elements to the system. This is to avoid adding extra un-needed complexity.

The final design for the ACTM main unit is shown in the following picture.

3.3. The Key Challenge

3.3.1. Define "chamber temperature"

It is hard to measure the temperature of air. Air has extremely poor thermal conductivity. Thus, depending on where the temperature sensor is positioned relative to the source(s) of heat and air flow, drastically different temperature made be detected. This is true even for locations that are only a few centimetres apart. Making things more complicated, there is no standard as to where the chamber thermal sensor should be mounted. Thus, it is not possible to directly compare the chamber temperature reading between machine, unless they are identically built.

3.3.2. Manage the chamber temperature

The amount of thermal mass in the chamber also present a difficult challenge, both for testing and daily usage. In a Voron Trident 300, there is ~40kg of mostly metal inside the chamber. This thermal mass acts like a dampener, that prevents the chamber from rapid heating up or cooling down. It takes hours for the system to reach thermal equilibrium, one way or the other.

The biggest challenge for the ACTM is not to get higher printing temperature, but rather to cool the chamber down to a temperature that is usable for many common materials like PLA / TPU / PETG.

3.3.3. Peer review

Due to the nuances above, discussion between community members have also been proven to be difficult.

3.4. Scope of work

This document aims to provide the details and results of test, that will allow the:

• Identification of a reasonable estimate for "chamber temperature"

• Quantification of the performance of the ACTM unit in different operation mode

4. Method

4.1. Test platform

The machine on which the tests had taken place is a Voron Trident 300, with the MissChanger version 2 (MCv2) upgrade. The most notable different between the test platform and a stock Trident is the gap at the top back, which is needed of umbilical management. It is assumed that will have a considerable reduction on the machine ability to heat up, but better cool performance, when compare with a stock Voron Trident.

4.2. Assumptions

4.2.1. General assumption

1. The critical point of concern for the chamber temperature is the approximate glass transition temperature of materials like PLA (between 55°C and 65°C), i.e. at the temperature does PLA become soft.

2. It is assumed the temperature of the unheated T0 extruder is similar to the temperature of the filament within the tool-head during print time.

3. The temperature of the filament is assumed to be highest within the tool-head during print-time.

4. Room temperature stay constant though out each experiment.

4.2.2. Configuration assumption

1. The bed is at Z = 50 mm.

2. Normal bed operating temperature is to 100°C.

3. The extruder fans will stay off, through out the experiments.

4. T0 is at the centre of the build area.

5. T1 and T2 is docked, at the front edge.

6. The tools are not heated for the tests.

4.3. Hardware Set-up

4.3.1. Sensor Location

The thermal sensor are placed is shown below. They are named:

• "chamber_air_x_temp" for the reading of the sensor on the x gantry

  • This sensor aims to represent the temperature of the filament in the tool-head, which is where heat creep can often occurs.

• "chamber_air_b_temp" for the reading of the sensor at the back of the printer

  • This sensor aims to represent the temperature of the filament in the umbilical.

• "chamber_frame_temp" for the reading of the sensor inside the y gantry

  • This sensor aims to measure the temperature of the frame.

4.3.2. Fan Location

There are two 6020 axial fan attached to the bed frame, blowing air at a 45° angle to the bed and toward the back. They are mounted on a 45° hinge (it can go to 0°, i.e. flat, at max Z). These fan are referred to as chamber fans.

There are two 9733 blower fan inside the ACTM main unit, referred to as ACTM fans. They are connected to a servo controlled duct, that can be switched between ventilation or circulation mode. They pull air through a Levoit LV-H128-RF filter and a 3D-printed carbon pellet basket. Each fan are rated 19.94 CFM (~565 cm^3 per minute), and together they can cycle the entire volume of the Trident 300 ~9.7 times per minute. However the filter and carbon basket will cause that number to reduce.

5. Test Procedure

5.1. Control Case

1. Make sure the gantry position is as assumed in section 4.2.2.

2. Turn all fans off.

3. Set bed temperature to 100°C.

4. Record the temperature of the sensors, when the bed average state is between 20 and 25% power (i.e. the machine is heat soaked).

5.2. Chamber Temperature Estimation

1. Make sure the gantry position is as assumed in section 4.2.2.

2. Turn the chamber fans and ACTM in circulation mode on, at 100%.

3. Set bed temperature to 100°C.

4. Record the temperature of the sensors, when T0 (extruder) is hit 55°C.

5.3. Heating Assist

1. Record room temperature.

2. Make sure to start at room temperature, at least ~25°C.

3. Make sure the gantry position is as assumed in section 4.2.2.

4. Turn the chamber fans and ACTM in circulation mode on, at 100%.

5. Set bed temperature to 110°C.

6. Record the time needed for the system to reach different temperatures.

5.4. Cooling Assist

1. Record room temperature.

2. Make sure to start at room temperature, at least ~25°C.

3. Make sure the gantry position is as assumed in section 4.2.2.

4. Configure the ACTM for the relevant test case.

5. Turn the chamber fans off.

6. Turn the ACTM in ventilation mode on, at 100%.

7. Set bed temperature to 100°C.

8. Wait 30 mins.

9. Record the chamber temperature.

5.5. Steady state chamber temperature

1. Record room temperature.

2. Set bed temperature.

3. Set ACTM mode and speed (at different rate per run)

4. Wait 1 hour.

5. Record steady state temperature delta.

The following code is used to automate the this process. However, it is not functional without the [gcode_macro ACTM_CONTROL].

#--------------------------------------------------------------------
[gcode_macro TEST_STEADY_STATE]
gcode:
    ## Assumptions
    ## 1. Bed is at 100*C
    ## 2. [temperature_sensor chamber_air_x_temp] is in the config above
    ## 3. [gcode_macro ACTM_CONTROL] is in the config above
    ## 
    ## Variables
    {% set interval  = params.INTERVAL|default(3600000)|int %}    # default: 3600000ms (1h)
    {% set bed       = params.BED|default(100)|int %}
    {% set vent      = params.VENT|default(False) %}
    {% set room_meas = printer['temperature_sensor chamber_air_x_temp'].temperature %}
    {% set room_temp = params.ROOM|default(room_meas)|float %}
    {% set max_x     = printer.toolhead.axis_maximum.x %}
    {% set max_y     = printer.toolhead.axis_maximum.y %}
    ## Working
    RESPOND TYPE=echo MSG='[ACTM] room: {room_temp}*C'
    # _TEST_STEADY_STATE_COLLECT_DATA TEMP={room_temp} SPEED=0
    M140 S{bed}
    G1 X{max_x / 2} Y{(max_y-10) / 2} Z50
    {% for i in range(6) %}
        {% set speed = i * 20  %}
        ACTM_CONTROL VENT={vent} SPEED={speed}
        G4 P{interval}
        _TEST_STEADY_STATE_COLLECT_DATA TEMP={room_temp} SPEED={speed}
    {% endfor %}
    M140 S0
    ACTM_CONTROL VENT={vent} SPEED=0
#--------------------------------------------------------------------
[gcode_macro _TEST_STEADY_STATE_COLLECT_DATA]
gcode:
    {% set room_temp    = params.TEMP|float %}
    {% set speed        = params.SPEED|int %}
    {% set current_temp = printer['temperature_sensor chamber_air_x_temp'].temperature %}
    {% set delta_temp   = current_temp - room_temp %}
    RESPOND TYPE=echo MSG='[ACTM] speed: {speed} | chamber: {current_temp}*C | delta: {delta_temp|round(2)}*C'

6. Test Cases

Cases name	Description
Control Case	To identify the test platform inherent ability to manage temperature, without additional fans.
Sensor location	To identify a reasonable estimate for "chamber temperature".
ACTM Heating Assist	To identify the time needed to reach certain chamber temperatures.
ACTM Cooling Assist no filtration	Maximum cooling performance.
ACTM Cooling Assist carbon basket	Carbon filtration only.
ACTM Cooling Assist carbon basket & HEPA filter	Maximum filtration performance (during ventilation mode).

7. Results

7.1. Control Case

When bed average state is between 20 and 25% power, and all fans are off, the sensor readings are as shown bellow.

Sensor	Sensor reading	Temp delta | Room temp: 23.8°C
chamber_air_x_temp	43.2°C	19.4°C
chamber_air_b_temp	40.1°C	16.3°C
chamber_frame_temp	32.2°C	8.4°C

7.2. Sensor Location Test

When the T0 (extrude) is at 55°C, it is assumed in to be the same temperature of the filament in the tool-head, as stated in section 4.2.1. The sensor readings are as shown in the table bellow. The x-gantry thermal sensor may have received more heating due to it's approximation to the bed. Given its position, the temperature detected is most-likely similar to the extruder's cold-side. However, it is still ~2°C colder that what the filament may experience during print-time.

Overall, the chamber_air_x_temp reading should be used for the "chamber temperature", with the understanding that it is slightly colder that the actual temperature if the filament in the tool-head, and a safety margin of ~5°C should be apply.

Sensor	Sensor reading	Temp delta | Room temp: 23.8°C
chamber_air_x_temp	53.2°C	29.4°C
chamber_air_b_temp	51.1°C	27.3°C
chamber_frame_temp	44.2°C	20.4°C

7.3. ACTM Heating Assist Test

The time taken for the system to reach specific chamber temperature is recorded in the table bellow. It shows that a temperature delta of 28°C (chamber 52°C) can be achieved within a reasonable period of under 30 minutes. Further heating, with maximum assistance from the ACTM shows the steady state temperature to be 61.8°C (temperature delta of 38.6°C), after 2 hours. For large / tall ABS prints, it suggests that the chamber should be pre-heated to 40°C or 50°C before starting, such that thermal expansion has been stabilised. The printer will then slowly climbs to the steady state as the print progress.

The following 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.

Chamber temp	Temp delta | Room temp: 23.4°C	Time taken (from room temp)
30°C	6.6°C	5 minutes
40°C	16.6°C	14 minutes
45°C	21.6°C	19 minutes
50°C	26.6°C	27 minutes
52°C	28.6°C	31 minutes
54°C	30.6°C	33 minutes
56°C	32.6°C	38 minutes
58°C	34.6°C	49 minutes
60°C	36.6°C	67 minutes
61°C	37.6°C	85 minutes
61.8°C (steady state)	38.6°C	120 minutes
61.8°C (steady state)	38.6°C	140 minutes

7.4. ACTM Cooling Assist Test

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.

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).

Configuration	Steady state chamber temp	Temp delta | Room temp: 23.8°C
With filter & carbon basket	46.7°C	22.9°C
With carbon basket	45.8°C	22.0°C
Fan only	32.0°C	8.2°C

7.5. Steady state chamber temperature

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.

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.

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.

Fan speed	Temp delta Bed: 100°C	Temp delta Bed: 70°C
0	23.28	-
20	24.08	-
40	22.05	-
60	24.92	-
80	28.61	-
100	30.33	-

8. Conclusion

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.

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.

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).

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.