# Difference between revisions of "Pulses per Microliter"

(→The MK1-250) |
(→The MK1-250) |
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* A 1.8° stepping motor; | * A 1.8° stepping motor; | ||

** Running in 1/16th microstep mode; | ** Running in 1/16th microstep mode; | ||

− | * And a hobbed (toothed) shaft with an effective circumference (average hob depth) of | + | * And a hobbed (toothed) shaft with an effective circumference (average hob depth) of 5.35 mm. |

The table below explains how a certain number of pulses (or microsteps) on the motor will generate a certain linear advancement of filament. | The table below explains how a certain number of pulses (or microsteps) on the motor will generate a certain linear advancement of filament. | ||

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|+ Flow Calculations for the MK1-250 Head | |+ Flow Calculations for the MK1-250 Head | ||

|- | |- | ||

− | | colspan=" | + | | colspan="2" | [[File:MK1-250.png|250px]] |

+ | | [[File:Nema11 hobbed1.jpg|200px]] <br> close-up of motor | ||

|- | |- | ||

! Component | ! Component | ||

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| NEMA 11, 1.8° stepping motor, <br> so 200 full steps = 1 revolution. | | NEMA 11, 1.8° stepping motor, <br> so 200 full steps = 1 revolution. | ||

1 pulse is a 1/16th microstep, <br> so 3200 pulses = 1 motor rev. | 1 pulse is a 1/16th microstep, <br> so 3200 pulses = 1 motor rev. | ||

− | | The hobs on the motor shaft have an effective diameter 5. | + | | The hobs on the motor shaft have an effective diameter 5.35 mm, <br> so using 2πr (or πØ) gives us an effective circumference of 16.8. |

− | That means one motor rev gives us 16. | + | That means one motor rev gives us 16.7 mm of linear filament advance. |

|- | |- | ||

− | ! | + | ! 1 Rev <br> Calc. |

| 1 colspan="2" | Since 1.75 mm filament has a cross section (πr<sup>2</sup>) of 2.4 mm, that means that for every linear mm of filament advanced, 2.4 mm<sup>3</sup> (or 2.4 μL) will be advanced. | | 1 colspan="2" | Since 1.75 mm filament has a cross section (πr<sup>2</sup>) of 2.4 mm, that means that for every linear mm of filament advanced, 2.4 mm<sup>3</sup> (or 2.4 μL) will be advanced. | ||

− | Therefore, 3200 pulses equals one revolution, which equals 16. | + | Therefore, 3200 pulses equals one revolution, which equals 16.8 mm of linear filament advancement, which equals 40.4 μL advanced. |

|- | |- | ||

! And so: | ! And so: | ||

− | ! colspan="2" | '''3200 pulses = | + | ! colspan="2" | '''3200 pulses = 40.4 μL, or a theoretical 79.2 pulses/μL. |

− | Experimentation | + | Experimentation over the years has produced average results of 78 pulses/μL for ABS at 240 °C and 1800 mm/min.''' |

|- | |- | ||

|} | |} |

## Revision as of 20:55, 30 July 2020

This page will explain the various gearing on our different heads, and how we determine a baseline pulses per microliter value.

## The 27:1 EMO and VOL

The EMO and VOL heads each have:

- A 1.8° stepping motor;
- Running in 1/16th microstep mode;

- A 27:1 planetary gear;
- A 1:1 drive screw coupling;
- A drive screw with a pitch of 18 threads per inch, or 1.411 thread per mm;
- And a reservoir with a 17 mm diameter, or 227 mm
^{2}cross section.

The table below explains how a certain number of pulses (or microsteps) on the motor will generate a certain volume displacement in the reservoir - the pulses/µL (or pulses/mm^{3}) number that we need to control the material advance or displacement. Note that factors like viscosity, compressibility, and nozzle characteristics will introduce some delay from the time of displacement to the time of actual extrusion.

## The 100:1 EMO-XT, KR2, and TAM

The EMO-XT, KR2, and TAM heads each have:

- A 1.8° stepping motor;
- Running in 1/16th microstep mode;

- A 1001 planetary gear;
- A 1:1 drive screw coupling;
- A drive screw with a pitch of 1 thread per mm;
- And a reservoir with a 17.6 mm diameter, or 240 mm
^{2}cross section.

The table below explains how a certain number of pulses (or microsteps) on the motor will generate a certain volume displacement in the reservoir - the pulses/µL (or pulses/mm^{3}) number that we need to control the material advance or displacement. Note that factors like viscosity, compressibility, and nozzle characteristics will introduce some delay from the time of displacement to the time of actual extrusion.

## The MK1-250

The MK1-250 heads have:

- A 1.8° stepping motor;
- Running in 1/16th microstep mode;

- And a hobbed (toothed) shaft with an effective circumference (average hob depth) of 5.35 mm.

The table below explains how a certain number of pulses (or microsteps) on the motor will generate a certain linear advancement of filament.