AMS refers to the Automated Material System, which can work with 3D printers to achieve automated multi-color printing. AMS lite is one of the Automated Material Systems launched by Bambu lab. This article will introduce the modules, main functions and workflow of AMS lite.

Precautions before use

1. The A1 mini can only be connected to one AMS lite, so it can only support 4-color printing at most.

2. The AMS lite is not compatible with X1 and P1 series printers, and the A1 mini is not compatible with other versions of AMS. 

3. The PTFE tubes connected on AMS lite come in two sizes. The standard length of PTFE tube for slot 1/2 is 580mm, and the standard length of PTFE tube for slot 3/4 is 700mm. Be careful not to install the tubes incorrectly.

4. Be careful not to place the AMS too far away from the printer (recommended distance is 50mm, as shown above), as excessive bending of the PTFE tube can cause excessive feeding resistance and result in feeding failure(as shown below).

Unrecommended placement of the printer and AMS

5. The longest feeding distance of the feeder is 1.2m, so if you need to replace a longer PTFE tube, you need to consider it as appropriate.

6. When placing spools on AMS lite, please pay attention to the appropriate weight of the spools in each slot to prevent AMS lite from collapsing during the printing due to the unstable center of gravity. You can place the heavier spools in the lower two slots (slots 2 and 3), with a lower center of gravity to make it more stable.

AMS lite feeding system

From AMS lite to the printer, the entire feed system is divided into the following two parts:

1. AMS lite: First stage feeder + Rotary Spool Holder. Each slot has a feeder and a rotary spool holder

2. Tool head:Filament tangle detection module + Extruder + Hotend

First stage feeder

Each slot in AMS lite has a feeder that feeds the filament into or out of the tool head. It has a filament detection sensor, as shown below:

Filament detection sensor

Each feeder has an odometer, and the odometer wheel is a passive wheel that only rotates when it grabs the filament with another gear and sends it out. So it can be used to determine whether the filament has been sent out from AMS lite, and also to calculate the length of the sent filament.


In addition, each feeder has a speed sensor at the bottom of the DC motor, the speed sensor calculated by the motor speed v1, and the speedometer sensor calculated by the speed v2, comparing the difference between v1 and v2 can determine whether the filament is slipping when feeding.

Motor speed sensor

Rotary Spool Holder

Each slot in the AMS lite has a rotary spool holder for placing the spool. Each rotary holder can automatically turn a certain Angle. When unloading, the feeder will pull filament out of the extruder, the rotary holder will automatically turn a little, ensuring that the filament roll on the spool are tightened and maintain the tension. The maximum Angle of auto rotation is 150°, so it can not roll back too long filament.

The rotary spool holder can auto rotate for a certain angle

Filament tangle detection module

The tangle detection module above the tool head consists of a filament Hub and a feed bracket. The PTFE tubes corresponding to each slot of the AMS lite are connected to the filament hub, which holds the four tubes together. The side of the feed bracket is a small board, and it also has a spring inside, and there is a magnet under the filament hub, when the filament hub and the feed bracket are assembled together, they form a filament tangle detection module. When the feed resistance is too high, the tangle detection module will be pressed down, and the magnet will move closer to the Hall sensor and trigger the alarm.

Filament tangle detection

AMS Lite Functions


When AMS lite is idle, insert the filament into the feeder, the feeder will feed the filament into the PTFE tube about 40cm, this process is pre-loading


Reading RFID

Each slot in AMS lite has a corresponding RFID coil. You just need to place the spool on the rotary holder of each slot and insert the filament to read its information.

RFID reading function can be set on the slicer for update on insertion/startup, or you can also manually click the icon beside each slot on the slicer for reading RFID.

Click here to read the RIFD info

Customize filament information

If you are using a third party filament, you can also manually edit its properties.

Automatic mapping function

When you send a multi-color print task in the slicer, the model is automatically matched to the closest color filament in the AMS slots. You can also customize the filaments in the window.

Filament run-out detection and filament backup function

When you use AMS printing, it still has the filament run-out detection function, which can be divided into the following two cases:

1. Single material printing: When the tool head detects that the filament runs out, it will first check whether the feeder’s Hall switch still detect the filament. If the feeder detects the filament, the tool head will move to the purge wiper, and the feeder will continue to feed the filmanet to the extruder without reporting any error. If the feeder’s Hall switch also does not detect the filament, it will report that the filament runs out and a new filament needs to be inserted.

2. Multi-material printing: There is a special case of multi-material printing, that is, the last section of filament has been detached from the spool. At this time if the filament needs to be switched in the middle of printing, as the filament can no longer be pulled back, it will directly flush the remaining filament, and then switch to another slot of filament to continue printing after the flushing is completed. The screen will indicate that the filament has run out, please wait while the old filament is purged.

3.  AMS filament backup: the AMS lite will switch to another spool with the same filament properties automatically when the current filament runs out. These filament properties include brand, type, color, and nozzle temperature. If the AMS cannot find the same filament, it will display a prompt that the current slot has run out. To enable this feature, please check “AMS filament backup” on the AMS settings page.This function requires filaments with exactly the same properties. It is recommended that Bambu filament be used as a replacement for Bambu filament and non-Bambu filament be used as a replacement for non-Bambu filament.

AMS Workflow

Loading & Unloading

During the loading process, the feeder feeds the filament into the tool head and stops working after the extruder gear grab the filament for 3mm. When the extruder continues to extrude the filament, if the odometer wheel corresponding to the feeder also rotates, it is considered that the loading and grab of the filament is successful.

During the unloading process, the extruder sends out the filament, and the feeder pulls back the filament out of the filament Hub, it is considered that the unloading is successful.

Check Filament location 

When you click load/unload or start printing, if there is a filament inside the tool head, it will check the filament location. The purpose of this check is to see if the filament inside the tool head is coming from which slot in the AMS or from the external spool.

For each slot, there is only one feed sensor, that is, the feed hall sensor. When the four slots are inserted with filaments, AMS cannot know which slot the filament is sent out according to the sensors. For example, after loading the filament of slot 1, the screen /Studio shows that the filament of slot 1 is connected to the tool head in bold, indicating that the filament of slot 1 is in the tool head (as shown below). However, if you cut off the filament from the tool head and pulls it out, and feeds the filament in slot 2 manually, the screen still shows that the filament in slot 1 is connected to the tool head. So it is necessary to check the location of the filament once to know which slot the current filament is from before loading/unloading.

It shows that the filament inside the tool head comes from slot 1

Filament location check logic: When there is a filament inside the tool head, it will try to extrude a small section. If the odometer wheel of the feeder in which slot moves, the filament is coming from this slot. If it can not extrude the filament, each slot will try to pull back a small section of filament, if the sensor of the tool head detects no filament after pulling back the filament in which slot, it indicates that the filament is from this slot. If the above two methods do not find the slot of the filament, it is judged that it is from the external spool or it’s a broken filament.


After AMS lite successfully feeds the filament to the extruder and starts printing, only the extruder pulls the filament during the printing process, and the feeder motor of AMS lite does not work. So at this time the motor inside the feeder is not rotating, and the odometer wheel will still rotate.

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