Make Lehigh Valley Make Hardware, Make Software, Make Art

24Oct/140

Member Project Update: Filament Extruder Project Update

Hi All, the following is an update the Make Lehigh Valley Filament Extruder Project. This update is dedicated Matt Schwarz who recently passed away and who was a co-organizer of Make Lehigh Valley makerspace. Matt was an early proponent DIY 3D printing, filament extrusion and completed prior work at the space in the extrusion of filaments, building of the the space's first 3D printer and other initiatives. Matt's presence at the space will be missed by all.
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Current activities in the filament extruder have focused on the refinement of the heating element and the motor. The oven element heater has been replaced by fiberglass covered nichrome wire powered by a repurposed inverter transformer. The output of the transformer is 6 vac which powers parallel strands of nichrome wire.

A 'slo-sync' 72 rpm motor has been installed to power the extruder. Testing has indicated that this is a little slow and work is underway to either speed up the motor via a variable frequency drive or replace the motor with another type.

Extruder screw modification (3) (Large)

Nichrome heater element with insulation removed

Extruder screw modification (4) (Large)

Overall view of extruder including 'slo-sync' motor

View of extruder auger with housing removed

View of extruder auger with housing removed

Extruding filament at the space testing temperatures and feedrates

Extruding filament at the space testing temperatures and feedrates

Next steps including installation of thermocouples at several locations on the extruder body and building an Arduino circuit to read and display the temperatures. Additional testing will done to refine location of nichrome heating elements and assess whether multi-stage heating of the extruder assembly is warranted. The motor drive is also being redesigned to achieve higher extruder speeds.

Frank Lyter

21Sep/140

Member Project Update: Frank’s Filament Extruder (WIP)

Hi All, the following is an update the Make Lehigh Valley Filament Extruder Project.  Thus far, the concept has been demonstrated successfully with production of several meters of ABS filament!!!

The emphasis on the project at this stage is determining fundamental parameters for operation of key sections of the design.  Key sections of the project include; nozzle design (nozzle diameter, length, inlet & outlet shape), material heater body design (single stage vs. multistage heating, heater element design including material, voltage, current, insulation), extruder design (length of extruder, hopper geometry) and drive mechanism (gear reduction, clutch, drive motor options).

Safety is a key design consideration for the project.  For example, low voltages are planned for powering of the heater element along with interlocks to protect against extruder or motor overload.

Next steps include; refinement of the heater element, incorporation of automatic heater control and testing of motor drive options. Once these items are tested satisfactorily, more sophisticated automation is planned.  The automation is expected to include an integrated control scheme incorporating heater controls, clutch slippage detection, drive motor controls and hopper feed sensing and controls.  Control platform and sensor options are still under review with the emphasis on safety, open source, simplicity, availability, cost and reliability.

Additional project details are provided in previous posts.

Comments and suggestions welcomed!

Frank Lyter

Prototype heater used to refine heater design requirements

Repurposed oven heater element - prototype heater used to refine heater design requirements

Final over heater fit up to nozzle

Heater fit up to nozzle - one of several bend configuration under consideration

Extruder heater test to evaluate operating voltages and currents

Extruder heater test to evaluate operating voltages and currents

Extruder heater testing for voltage and amp evaluation

Autotransformer used for voltage and amp evaluation

Heater element attached to extruder - subsequently covered in fiberglass insulation.

Heater element attached to extruder - subsequently covered in fiberglass insulation.

First filament production!!!  Evaluating various temperatures and pressures - sections with bubbles are when temperature was too high

First filament production!!! Evaluation ongoing for optimum temperatures and pressures - sections with bubbles are when temperature was too high