3.4 Starting a Print: the Print Monitor & Menu

Once you start a print from the “Print from SD” menu (Section 3.3), the LCD screen should display the print monitor. By pressing the center key you can exit the print monitor to access the print menu.

If you have not preheated your printer, the screen will display a heating progress bar on the first line, as seen in Figure 3.7.

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Figure 3.7: Print Monitor — Preheating

The screen should also display the current temperatures and target temperatures (in Celsius) of all your heating elements in the form current temperature/target temperature — if, however, the element is not going to be heated, then it will only display its current temperature. Note that for some printers the extruders do not start heating until the platform has heated (such as genuine MakerBots with smaller power supplies). In this case the screen will display “waiting” rather than the temperatures. In addition, the number of heating elements displayed will depend on the number your printer has. Figure 3.7 shows a dual extruder set-up.

Once your printer has finished heating, it will play a short tune to inform you and the heating progress bar will be replaced by a line displaying the name of the print (which will be the name on the SD card unless print commands in the file change the displayed name) and the percentage completed of the print (Figure 3.8). Since the percentage is generated by the slicer, it will remain displayed as 0% if the file does not contain print commands to update it. If a future Pause at Z-Position is scheduled (Section 3.4.3), then an asterisk will appear before the percentage.

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Figure 3.8: Print Monitor — Printing

On some printers with only two heating elements the firmware uses the extra available line to display a running ticker of statistics:

1.
The elapsed build time.
2.
The estimated build time remaining. This will only be generated if the print commands include the percentage complete updates and is, therefore, only as accurate as the percentage markers.
3.
The current filament usage.
4.
The current Z position.

If this ticker is not displayed, the information can be accessed in the “Print Statistics” item under the print menu, Section 3.4.9.

By pressing the center key to dismiss the print monitor, you can access the print menu, seen in Figure 3.9.

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Figure 3.9: The first screen of the print menu

The print menu allows you to control aspects of the printing process as well as monitor the printing progress:

1.
Back to Monitor: returns you to the print monitor.
2.
Cancel Print: as the name suggests, this allows the termination of the print. A confirmation screen will be generated to prevent accidental termination.
3.
Pause: by allowing you to suspend a print and generating the pause menu, the pause option lets you change aspects of the print. If the printer is left paused for over 30 minutes the heaters will turn off even if “Pause with Heat” is enabled (Section 3.7.4.3).
4.
Pause at ZPos: lets you program the print to stop at a certain height. Once the printer pauses, the pause menu will be generated. Again, if the printer is left paused for over 30 minutes the heaters will turn off even if “Pause with Heat” is enabled.2
5.
Change Speed.
6.
Change Temperature.
7.
Change HBP Temp: this item only appears if your printer is equipped with a heated build plate.
8.
Set Cooling Fan ON/OFF.
9.
Set Lights OFF/ON.
10.
Print Statistics: displays the elapsed build time, the estimated build time remaining for prints with percentage complete updates, the current filament usage, and the current Z position.
11.
Cold Pause: pauses, cools off all heating elements, turns off LED lighting, and generates the pause menu.

3.4.1 Cancel Print

To cancel a print while printing, choose the “Cancel Print” item under the print menu. Do not just turn off the printer, as that can damage the printer. Choosing this item will generate the confirmation screen pictured below in Figure 3.10.

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Figure 3.10: Cancel Print Confirmation

Once you have canceled the print, the printer will cease printing and move your print away from the extruders by lowering the build platform. All the heaters will be switched off.

3.4.2 Pause

Pausing your printer generates the pause menu, which allows you to change aspects of the print that cannot otherwise be changed in the middle of printing. The pause is not immediate, as the printer will continue printing until it clears out its buffer of queued work. The LCD screen will acknowledge this and generate the screen as seen in Figure 3.11. Note that, once paused, the build platform will automatically lower by 5 mm.

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Figure 3.11: Clearing Queue

When your printer starts to pause, you should see the screen shown in Figure 3.12.

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Figure 3.12: Pause

Once your printer is paused, the pause menu appears:

1.
Jog Mode: shift the platform or extruder along the X, Y, and Z axes. Be careful not to hit the endstops, as that will cause a loss of registration and the print will not resume in the proper place. The jog mode is identical to “Jog Mode” in the “Utilities” menu; for operation details see Section 3.7.13.
2.
Filament Loading: allows you to load and unload filament. As this is identical to “Filament Loading” in the “Utilities” menu, see Section 3.7.2.
3.
Heaters Off: turns off all heaters. Again, note that if the printer is paused for over 30 minutes the heating units should turn off automatically even if “Pause with Heat” is enabled, Section 3.7.4.3.

To resume printing select the “Unpause” item on the pause menu. You should see the screen pictured in Figure 3.13. Note that if the print has been paused for an extended period, it is best to run the filament load for 10–30 seconds to purge the extruder of cooked plastic. If the extruder is sitting over your print, use the jog controls to move it over a clear spot.

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Figure 3.13: Unpause

3.4.3 Pause at ZPos

This programs the printer to pause when it first attains or exceeds a specified height. Choosing this item will generate the screen depicted in Figure 3.14.

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Figure 3.14: Pause at ZPos

To change the Z position use the up and down keys, and to set the Z position press the center key. Pressing the right key once changes the Z position in larger increments, a second causes larger increment still, but a third time will set the value by which it increments back to the original; it is actually doing this in units of steps, but still displays units of millimeters. Pressing the left key cancels any changes to the Pause at Z-Position value.

Note that the printer continues printing while you set the Z position.

Since you can include multiple pauses at specified Z positions within the printing file, the printer honors the last pause it has received. Therefore, if it encounters a pause within the printing file after you manually set one, it will replace the Pause at Z-Position that you have set with the one in the print file. Likewise, if you have included pauses within the print file, they will be replaced by any subsequent pauses you enter manually.

If you set a Pause at Z-Position and later wish to cancel any such pause you can either allow it to pause and then manually resume right after, or set the Z position for the pause to a value not attained by the print. Note that each print starts without a Pause at Z-Position set — the changes are not retained between prints.

When using Pause at ZPos it is important to note that the slicer probably started your model a few hundredths of a millimeter above zero so you need to account for this difference when setting a pause height.

Once the print has attained the specified height, the pause menu (Section 3.4.2) will be generated and the build platform will be lowered by 5 mm.

3.4.4 Change Speed

This item allows you to change the printing speed by a multiplicative factor (see Figure 3.15). As you enter the speed, it starts percolating through the queue of already buffered work.

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Figure 3.15: Change Speed

To increase the speed use the up key, and to decrease it use the down key. The center key will set the speed and return you to the print menu while the left key will cancel any changes and return you to the print menu. Note that pressing the left key will not necessarily return the speed to 1.00, rather, it reinstates the scaling factor which was in effect when the screen was entered.

3.4.5 Change Temperature

This allows you to change the temperature of the currently active extruder while printing. You cannot use this menu (see Figure 3.16) to change the heated platform’s temperature or the temperature of an inactive extruder.

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Figure 3.16: Change Temperature

To increase the temperature use the up key; to decrease it use the down key. You cannot set the temperature above 280 C and, naturally, you also do not wish to set it too low or else the filament will not melt.

Unlike the change speed item, the temperature changes do not take effect until the center key is pressed. Pressing this key sets the temperature and returns you to the print menu. Note that if you change the temperature by more than 10 C at a time the algorithm used by the temperature control will reset, which can cause temperature instability for upwards of a minute. Pressing the left key cancels any change in temperature, resetting the temperature to what it had been, and returns you to the print menu.

3.4.6 Change HBP Temp

If you have a heated build platform installed, this menu (see Figure 3.17) will appear to allow you to change the temperature of the platform while printing. You cannot use this menu to change the temperature of any of the extruders.

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Figure 3.17: Change HBP Temperature

To increase the temperature use the up key; to decrease it use the down key. Note that you cannot set the temperature above 130 C.

Similar to the change temperature item, the temperature changes for the heated platform do not take effect until the center key is pressed, which will then set the temperature and return you to the print menu. Again, note that if you change the temperature by more than 10 C at a time the PID state is reset, which can cause a wide temperature swing. While increments of about 5 C work best, any value of 10 C or less will work. Pressing the left key cancels any change in temperature, resetting the temperature to what it had been, and returns you to the print menu.

If you do not see this menu option despite having a heated build platform installed, you will need to navigate to the “HBP Installed” option under the “General Settings” menu of the “Utilities” menu when you are done printing, which is discussed in Section 3.7.4.8.

3.4.7 Set Cooling Fan

This allows you to change the state of the print cooling fan on printers that have such a fan. Note that this has nothing to do with the heatsink cooling fans. If the cooling fan is currently off, then the option will read “Set Cooling Fan ON” as depicted in Figure 3.18 below. Likewise, if the cooling fan is on, then the option will read “Set Cooling Fan OFF”.

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Figure 3.18: Set Cooling Fan

Note that some slicers generate many commands to turn the fan on and off throughout the course of the print. When you turn the fan on or off with this item, any subsequent print commands to change the fan’s state will be honored — this option does not override all further print commands regarding the fan.

3.4.8 Set Lights

This option allows you to change the state of the printer’s LED lights mid-print if necessary. If the lights are currently on, then the option will read “Set Lights OFF”. Similarly, if the lights are off, then the option will read “Set Lights ON”. You can change this state by scrolling to the option and pressing the center key.

3.4.9 Print Statistics

This item (Figure 3.19) allows you to see the progress of the print as reflected in four items:

1.
Print Time: the elapsed build time.
2.
Time Left: the estimated build time remaining. This will only be generated if the print commands include percentage complete updates and is, therefore, only as accurate as the percentage markers.
3.
Filament: the length of filament used so far in meters.
4.
ZPosition: the current Z position in mm.

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Figure 3.19: Print Statistics

If your firmware has auto-leveling, then the last line will alternate between auto-leveling status and Z position, displaying one for a few seconds and then the other.

3.4.10 Cold Pause

This option allows you to pause the print and automatically turn off the heaters and LEDs. This will also generate the pause menu, Section 3.4.2, and lower the build platform by 5 mm.

2Commands to pause at specified heights may be placed directly in a print file; see Section 9.7.