Enables the nozzle to be changed without removing the part cooling duct and fan.
This is a clamp mechanism that fits round the X carriage and bearing rods of a Prusa i3 MK3S to hold the heatblock in position whilst the nozzle is changed. Using this device removes the necessity of disassembling the part cooling fan and duct.
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This design is licenced under the Creative Commons Attribution Share-Alike 4.0 International Licence
(CC BY-SA)
Copyright © 2020, by Eleanor Xanthe Ellis and Cyan Ellis Ltd.. Some Rights Reserved.
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The upper parts are provided in two forms:
First type have assembly holes that are narrower at the bottom and are intended to be tapped M6.
The other type have full M6 clearance assembly holes all the way up and are secured using nuts and bolts running through the whole structure.
Both assembly systems function identically.
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Hardware required
For the threaded upper parts only
2x bolts M6, 40mm to 50mm length OR 2x set screws 40mm to 80mm length
For the clearance upper parts only
2x bolts or set screws 90mm length
2x M6 nuts
For the toggles
2x M4 12mm length
2x M4 plain washer
2x M4 full nut (optional)
For the clamp
2x M4 set screw, 70mm to 90mm length, stainless steel
2x M4 wing nut (optional)
2x M4 full nut
Assembly tools
M6 tap (if using the threaded assembly option)
4mm drill
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Print list:
1x Heatblock Holder Block.stl
2x Toggle.stl
Either
1x Upper Block R threaded.stl
1x Upper Block L threaded.stl
OR
1x Upper Block R full clearance.stl
1x Upper Block L full clearance.stl
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My Settings:
Material Extrudr Greentec Pro
Settings: standard PLA 0.3mm Draft, +10°C additional nozzle temp
For toggles
Standard PLA 0.15 mm Quality
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Assembly
If using the threaded upper parts option, tap the lower part of the fixing hole in each of the two upper parts.
Attach the upper parts to the Heatblock Holder Block using the M6 bolts or set screws
Attach the toggles to the upper parts using the short M4 set screws and washers. Note that the hole for this screw is undersize so that it grips the screw, preventing it from loosening; optional M4 nuts can be used to increase the security of the screws.
Drill out the long horizontal 4mm holes so that the long M4 screws will close free run in the holes.
Insert a M4 nut into each vertical slot in the Heatblock Holder Block.
Insert the long M4 screws through the nuts.
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Usage
Withdraw the right long M4 set screw until the end is flush with the printed block (this provides clearance for the PINDA sensor).
Withdraw the left long M4 set screw until the end is no more than about 10mm projecting from the printed block.
Raise the X carriage to 75% height / 150mm from the build plate (this is only approximate, no need for precision!). Bring the hot end up to temperature for nozzle replacement (typically 285 Celsius).
Working from the bottom fit the Heatblock Holder Block to the underside of the X carriage and move it up to contact the lower bar. Clip the upper part over the upper bar and swing the toggles down to secure it
Screw the long M4 bolts in until they both lightly contact the heatblock, then increase the tension very slightly to ensure the heatblock is securely and symmetrically held (it doesn’t need much force).
Replace the nozzle (again this doesn’t need much force if the temperature is OK).
Turn off the hotend heating and remove the device.
N.B.
The included gcode files are configured for Prusament PLA (rather than the Greeentec Pro that I used).
The author hasn't provided the model origin yet.