Precious Plastic Extruder

Hint: This work builds upond the precious work of Precious Plastic. We are indebted here to Dave Hakkens. See https://preciousplastic.com/en/videos/download.html

Working Doc

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BOM

• Wood bit - 1" - [1]. 7/16" shank, as in 1/2" version. Local - [2]
• Pipe flange - Menards $5 - [3]
• Pipe flange - pack of 10 - Amazon - $4 ea - [4]
• 1" pipe -

OSE Version Design Rationale

• Slow auger version powered by a Nema 17 with large auger.
• Vertical hang to reduce auger power requirement
• Remove flow control screw and rely on temperature and auger speed instead. PP version doesn't have speed control on motor, so motor control produces additional control required here

Heuristic Calculations

• We want low speed equivalent to a strong corded drill such as [5].

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• Torque Calculator shows this drill has only about 30 in-lb torque
• This is more like it - [6] - 0-600 RPM, same power - means - 140 in-lb.
• PP shredder is 1770 in lb - 10x stronger - Precious_Plastic_Shredder#Torque_and_RPM
• We have experience with Lyman filament maker, 50W, 140 in lb:

• About 140 in lb for motor above. This should be plenty for an extruder application.
• If we take a 1A, 12V motor - Nema 17 - that is 1/4 the power of the above.
• But power for steppers apparently doesn't work like this - as that indicates 600x geardown if we consider power alone. 140 in lb is 140*16 in-oz = 2240 oz in. Then we need 30 geardown for a Nema 17 motor at low speed. That is well doable for a 3D printed geardown.

• Note that Nema motors retain good torque at 300 RPM, so we obtain 10 RPM within the good torque regime.

• Let's move on to Planetary Geardown.

CAD - OSE Version

• This is the OSE version remake. See https://github.com/OpenSourceEcology/Extruder

Filament Extruder

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  Overall Build - FreeCAD -File:Filamenter overall.fcstd

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  Overall Build - FreeCAD -File:Filamenter motor.fcstd

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  Auger - FreeCAD -File:Filamenter auger.fcstd

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  Auger - FreeCAD -File:Filamenter bearing.fcstd

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  Auger - FreeCAD -File:Filamenter flowcontrol.fcstd

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  Auger - FreeCAD -File:Filamenter flowadjust.fcstd

Extruder Controller

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  Overall Build - FreeCAD -File:Filamenter controller.fcstd

BOM Candidates

• Insulator brick - [7]
• Carbon fiber welding blanket insulation - [8]
• Small high torque hydraulic motor - [9] $50
• Type K Thermocouple - [10] - $7
• SSR - [11] - $7
• 1" flange - $4 on amazon - [12] or $5 menards - [13]
• PID Controller - $23 - [14]
• PID with SSR + thermocouple - $14 - [15] - got 3.
• [3] band heaters - 35x45 mm - $4 + SH - [16]
• [1] band heater - 1.75" for next coupler
• 1-3/4" coupler - [17]
• 1.75" heater - [18]

Notes

• 1.75" is 45 mm
• 35 mm is 1.38 in
• 40 mm is 1.57 inches
• OD of pipe union
• 1.25" and 1.75" nozzle heaters are available easily - [19]

Links

• Low-Speed Drill