Bondtech LGX™ Lite - Large Gears eXtruder Without Motor

The Bondtech LGX™ Lite is a filament feeder based on the LGX™ Large Gears eXtruder and uses Bondtech's new Dual Drive Technology based on larger drive gears.

8 features of this Bondtech eXtruder:

• Larger drive wheels, for increased filament grip;
• Filament pre-tension lever, for repeated results;
• Drive wheels’ maintenance windows, for easy cleaning;
• Compact, light & centered filament path, for increased performance and compatibility;
• Multiple mounting hole patterns, for easy and flexible setup;
• Compatible with Nema14 round stepper motors;
• Craft boxes without bleaching & no coating.
• Nylon housing with no dyeing or other chemical post processing.

STEP Files to Download

Technical Specification

• e-steps value : 562 using 16 microsteps; 1124 using 32 microsteps.
• Drive wheels : hardened steel;
• Materials compatibility : abrasive; rigid; semi-flexible; flexible; and soft.
• Mounting holes : M3
• Mounting patterns : bottom (4 points); right (2 points), front to motor (2 points), top (1 point)
• Hole at the top of the LGX® Lite : 5 mm depth
• Holes on the side of the LGX® Lite : 5 mm depth
• Holes on the bottom of the LGX® Lite : 5 mm depth
• Max tightening torque on the extruder screws is 0.3 Nm

For Klipper users

rotation_distance = full_steps_per_rotation * microsteps / steps_per_mm

rotation_distance = 200 * 16 / 562

rotation_distance = 5.7

The above calculation assumes the following parameters:

• stepper motor is a 1.8 degrees motor hence 200 as full steps per rotation;
• microsteps are set to 16;
• e-steps value recommended for the LGX® Lite is 562.

• retraction speed : 35 mm/s
• retraction distance (bowden) : ~5 mm (0.4 + tube length[mm] x 0.015)
• retraction distance (direct drive) for rigid materials : 0.4 mm
• retraction distance (direct drive) for soft materials : 3 mm
• Max Environment operating temperature : 90°C
• Max stepper motor running temperature : 120℃ / 750 mA
• LGX® Lite net weight : 48 g
• LGX® Lite with motor net weight : 141 g
• Package measurements : 80x103x73 mm
• Package weight : 85 or 185 g

Custom Stepper Motor for Bondtech LGX™

• Connector: JST-XH 4-pin connector
• Motor gear : 10 teeth
• Motor length: 20 mm
• Motor Diameter: 36mm
• Weight : 93g
• Max Current : 1.0 A / phase

To use the LGX, run the stepper motor with currents between ~0.45 and ~0.65A:

Be vigilant regarding the stepper motor surface temperature.
Keep it cool enough to touch. Lower Vref otherwise.

• Leads Length : 1m
• Step Angle : 1.8 degree
• Max Torque at : 1800 PPS
• Potential Flow Rate @ Max Torque : 120mm^3/s
• Class: H, rated peak temp 180℃
• Max operating Temperature / Current :
  120℃ / 750 mA
• Manufacturer : LDO
• Manufacturer SKU : LDO-36STH20-1004AHG(XH)

How to change the Current using Vref

It is very hard to read the current being fed to stepper motors. To determine that current we rely on the Vref value. The Vref value is a voltage reference measured in VDC that can be read using a multimeter. It helps us setting the current output of the stepper motor driver.

Different 3D printer mainboards use different stepper motor drivers. Each type of stepper motor drivers has its own formula to calculate the required Vref to get a specific current. Here are some examples:

• TMC stepper drivers.
  The formula for these drivers is Vref = ( I * 2.5 ) / Imax
  Where I is the target current value measured in A; and Imax is 1.77 on regular mode and 1.2 on SilentStepSticks mode.
• Pololu A4998.
  The formula for these drivers is Vref = I * 8 * R
  Where I is the target current value measured in A; and R is the Sense Resistor value, that depends on what board are you using. Melzis use 0.1,the Creality Silent boards use 0.15, ...

Mounting Patterns & Info.

Extruder and Stepper Motor go together

Preferably, you should always use the extruder attached to the stepper motor when you mount it on a printer.

If you need to put a plate in between the stepper motor and the extruder please notice the max supported thickness is 3mm.

To use a plate in between the stepper motor and the extruder, you need to replace the stock rear plate of the extruder with the printer’s plate (thicknesses between 2 and 3mm, preferably 2.5mm).

Don’t use a plate in between without removing the rear plate.

MULTIPLE MOUNT PATTERNS

The LGX® Lite features 4 mounting patterns:

1. 4 holes at the bottom;
2. 2 holes at the right hand side;
3. 1 hole at the top plus the filament entry that may be used as anchor.
4. 2 holes across, to hold the stepper motor

All except frontal mounting holes on the LGX® Lite require to place a M3 square nut inside the housing to act as reinforcement. The holes with square nuts are M3 thread and 5 mm deep (till bottom of the square nut).