Filament Heads

Hot Flow is our term for filament-based materials which are deposited at over 150°C, depending on the head.

Note that at present, our Hot Flow heads work with 1.75mm filament (actually, 1.6mm to 1.9mm), but not 3mm filament.

Materials for Hot Flow

The following materials can be printed from Hot Flow heads.

• ABS (Acrylonitrile Butadiene Styrene)
  • Flame Retardant ABS
  • ABS - PC Alloy
  • Conductive ABS
  • Smart ABS
• BendLay
• Flex 45
• HIPS (High-Impact PolyStyrene)
• LayBrick
• LayWoo-d3
• MoldLay
• Ninjaflex
• Nylon
  • Taulman 618, 645, 910
• PC (PolyCarbnoate)
• PEI (PolyEtherImide) - AKA Ultem
• PEEK (PolyEther Ether Ketone)
• PET (PolyEthylene Terephthalate)
• PETG PolyEthylene Terephthalate Glycol-modified)
• PLA (PolyLactic Acid)
  • EcoFlex PLA
  • Conductive PLA
  • SS PLA (Stainless Steel infused)
• PlastInk_Rubber
• PP (PolyPropylene)
• PVA (PolyVinyl Alcohol)
• T-Glase
• Ultem

Heads for Hot Flow

Hot Flow is available through the following heads:

• 

  MK1-250

• 

  MK2-250

• 

  MK1-450

1. General MK Series Videos:
   1. MK Series Printing Tips
   2. Post Processing with a Heat Gun
   3. Loading and Unloading Filament in the MK Series head
2. MK1-250 Extruder for Standard Filament Videos:
   1. Overview
   2. Loading and Printing
3. MK2-250 Extruder for Flexible Filament Videos:
   1. Overview
   2. Loading and Printing
4. MK1-450 Extruder for High-Temperature Filament Videos:
   1. Overview
   2. Loading and Printing

Please see our Data Sheets as well.

The following table compares the properties of the various Hot Flow heads, including which heads are recommended for which materials. The MK1 heads drive matieral from one side, with a spring-loaded bearing system to maintain pressure and positioning. The MK2 heads drive the material from both sides, and are designed for more flexible filaments.

Hot Flow Head Properties

Head	Min Temp	Max Temp	Filament Type	Nozzle	Recommended For
MK1-250	150°C	250°C	Standard	.35mm, .50mm, .75mm, 1.0mm	ABS, HIPS, LayBrick, LayWood, Nylon, PC, PET, PETG, PETT, PLA, PP, PVA, T-Glase
MK2-250	150°C	250°C	Flexible	.35mm, .50mm, .75mm, 1.0mm	BendLay, EcoFlex PLA, FilaFlex, Flex45, Ninjaflex, PlastInk Rubber
MK1-450	275°C	450°C	Engineering	.50mm, .40mm, .30mm	PEEK, PEI (Ultem), PEKK, PPSU

Research Papers Citing Hyrel Hot Flow

These are now listed by year here.

Firmware Versions for Hot Flow Heads

As of May, 2018, the following versions should be used for Repetrel versions 2.x and 3.x:

Use _FIL_250_PLAT_1A.hex :

• For MK1-250 and MK2-250 heads.

Use _FIL_450_45A.hex :

• For MK1-450 heads.

Use _FIL_250_RED_235A.hex :

• For older MK1-250 heads with RED RTDs.

Settings for Hot Flow Heads

V2: Non-Hydra units shipping through spring 2017 shipped with Repetrel version 2.x.

V3: Hydra units, and other units shipping summer 2017 through summer 2019 shipped with version 3.x, and should consult the version 3.x tables, below. All units should be upgraded to 3.x when it is available. If you run a head with v2 settings on a v3 install, the background will flash red; please make the changes below, from red to blue.

V4: All units shipping as of late summer 2019 are shipping with version 4.x, which has more fields for the heads. Please see the V4 table(s), below.

Versions 2 and 3

Values for version 2.x will be inicated in this manner.
Values for version 3.x will be inicated in this manner.

Note that you must flash these settings to the head to make them the new default.

Some settings for the MK-Type heads (like temperature, prime/unprime values) will vary, depending on what material you are printing with. Nozzle diameter should accurately reflect what nozzle you have loaded (0.5mm is default) AND what path width you sliced for (recipe path or extrusion width should be nozzle diameter plus 10%). Having said that, here are our default shipping settings:

Settings	MK1-250	MK2-250	MK1-450 (formerly -350 or -400)	MK1-650*
Material
Type	(any)	(any)	(any)	(any)
Color	(any)	(any)	(any)	(any)
Nozzle	0.500	0.500	0.500	0.500
Layer	(any)	(any)	(any)	(any)
Temp Info
Print Temp	240	240	410	800
Power Factor	100	100	100	100
Minimum	(any)	(any)	(any)	(any)
Maximum	(any)	(any)	(any)	(any)
Overrides
Pulses: v2.x (~10nl)	0.78	0.78	0.78	0.78
Pulses: v3.x (~1μl)	78	78	78	78
Feed Rate %	1.000	1.000	1.000	1.000
Prime Please note that Prime values will vary greatly from those shown, depending on the flexibility of your material.
Steps	200	200	200	200
Rate	10,000	10,000	10,000	10,000
Dwell Time (ms): v2.x	20	20	20	20
Dwell Time (ms): v3.x	35	35	35	35
Before Tool Change	2	2	2	2
Unprime Please note that Unprime values will vary greatly from those shown, depending on the flexibility of your material.
Steps	200	200	200	200
Rate	10,000	10,000	10,000	10,000
Dwell Time (ms): v2.x	15	15	15	15
Dwell Time (ms): v3.x	-35	-35	-35	-35
After Tool Change	2	2	2	2
Offsets
Clone Head	Off	Off	Off	Off
X	0,000	0,000	0,000	0,000
Y	0,000	0,000	0,000	0,000
Z	0,000	0,000	0,000	0,000
Head Info
Model	250	250	350	650
RTD Type	1 Meg	1 Meg	1 Meg	1 Meg
Motor Current	High	High	High	High
Step Mode	Sixteenth	Sixteenth	Sixteenth	Sixteenth
Settings	MK1-250	MK2-250	MK1-450 (formerly -350 or -400)	MK1-650*
*In development.

Changing Nozzles

How to disassemble the nozzle from the MK1 head:

1. Carefully:
2. Heat to the printing temperature of the material loaded.
3. Move the manual lever to the left, retracting material until it is free of the hobbed shaft, then remove by hand.
4. Turn off heat to the head and remove it from the yoke.
5. With a 1/4" driver or wrench, remove the nozzle.
6. Inspect the nozzle cavity for any stray material; if found, remove with tweezers, solvent, air pressure or other means.

How to reassemble the nozzle on an MK1 head:

1. Carefully:
2. Ensure your MK1 has no filament loaded.
3. With a 1/4" driver or wrench, attach the nozzle.
4. Use normal procedure for heating and loading filament.