Nimble Gnu - System to Adapt the Zesty Nimble Extruder to a Prometheus V2 Hotend Mounted to a SeeMeCNC Balljoint Effector Platform with Accelerometer Probe PCB by slonold

Last crawled date: 3 years ago

Overview:
A system to adapt the Zesty Technology Remote Direct Drive Extruder to a Prometheus V2 Hotend via a SeeMeCNC Accelerometer Probe PCB and Ball Joint Effector Platform. Straps are used to retain the whip connector and there are a pair of 3mm auxiliary holes at each pillar for mounting items such as Berd Air System tubing or a probe etc.
The mounting system makes use of the Nimble to firmly seat the PTFE tubing in the bottom of the hotend barrel. Consequently, "setting" the PTC fitting in the hot end is not necessary which avoids narrowing the PTFE lumen at this point.
If you are interested in a Nimble-Prometheus-Ball Joint Platform setup without the Accelerometer please leave a comment and i will make an option for that sooner than later. In the interim, you could use this system without the Accelerometer PCB provided you place a little spacer between the bottom of the Guide Bushing and the top of the Prometheus to make up the vertical height (~1.7mm) of the absent board.
Required Parts:
M4 x 12 to 16mm button head or socket head cap screws to mount effector platform. QTY 3.Note: Button heads are recommended if using standard Rostock Max v2 fan shrouds.
M4 x 25mm button head or socket head cap screws to secure the Cap. QTY 3.
M3 x 6 to 10mm screws to affix the accelerometer board. QTY 3.Note: Nylon recommended to avoid shorting LED pads.
~ 60mm length of 4mm OD x 1.8 to 2.0mm ID PTFE tubing.
Recommended Tools:
M4 x 0.7 Tap
M3 x 0.5 Tap
4mm(#21) Drill - to size 4mm holes in Cap, Clamp Plate and Centre Plate
3.3mm (#30) Drill to size holes for tapping the M4 threads in the Stand Off
3mm (#31) Drill to size 3mm holes in Cap and Clamp Plate
2.4mm (3/32) Drill to clean out holes for tapping the accelerometer Clamp Plate
Drill bits +/- 4mm(#21) to size Guide Bushing bore to suit your PTFE tube size
1/2" half round file for fine tuning holes and slots to fit hot end
A half inch or similar half round file for finishing and sizing
Sharp knife or razor to trim PTFE tubing
Metal Saw to cut M3 Bolt
Variable Speed Hand Drill Motor
A small jewelers screw driver or blunt probe to install the straps.
Hex driver (Allen) keys to suit your selected fasteners.
Method of measuring hot end barrel depth
Prometheus Mount
Stand Off Sizing
Decide if you will assemble the platform with the ball joint "barbells" on the bottom or top. Bottom orientation will allow shorter (and presumably stiffer) stand offs for a given amount of protrusion below the axis but will place the fan shrouds closer to the bed surface.
For the nozzle size and nut-nozzle zone setup of your Prometheus, decide how much protrusion below the platform you want.Note: Leave enough clearance for the fan shrouds and ball end arms to clear the bed clips!!
For the arrangement determined above, measure the distance from the top of the platform to the upper edge of the lower groove of the hot-end. This distance (in mm) with be the size/filename of the Stand Off model.

Components to Print: Prometheus Mount
one of the Standoffs_XXmm from the StandOffs_32_55mm.zip file
Centre_Plate_1
Nimble_Gnu_Clamp_Plate_71210_Accel_PrometheusNote: ABS recommended for these three parts for ease of post print sizing and natural lubricity for sliding into hotend grooves.
Assembly Instructions: Prometheus Mount
Considerations for assembling the Accelerometer PCB and Prometheus HotendNote that the arrangement of the heater block wiring to the accelerometer plate is such that the wires run up the left side of the hotend when looking down on it from the top and with the fan positioned away from you. See the various photos. The orientation of the cap to accelerometer PCB and the Nimble to the cap is fixed as also is the Clamp Plate to the accelerometer PCB. In order to have the breech block oriented to the front of the machine and the fan positioned towards the back (Z tower), the orientation shown in the photos must be followed. Other orientations may be possible by mirroring the Cap and/or the Clamp Plate before slicing.
When preparing to solder the fan connector headers avoid "pinching" the the pins together for retention. One of the heater wires will likely want to run right between them.
Providing a little (~1cm) slack in the heater and thermistor wires will allow disassembly of the Hotend without undue strain on them.


Through drill the large holes in the Clamp and Centre Plates ONLY to 4mm.
Through drill the holes in the Standoff to 3.3mm to size them for tapping.
Tap holes in Standoff from each end with the M4 tap.Note: Tap deep enough ensure that the M4 bolts will fully seat.
Through drill the small holes in the Clamp Plate to 2.4mm to size them for tapping.
Tap the small holes in the Clamp Plate with the M3 tap.
Ensure upper and lower surfaces of the the plates are free of swarf from drilling and tapping.
Relieve edges and finish slots in the Clamp Plate and Standoff to 12mm and 16mm and the centre hole of the Centre Plate to 16mm.Note: Fit of the Standoff and Clamp Plate into hot-end grooves should be snug but ensure that the Hotend seats fully into slots and that no more than a gentle squeeze is required to bring the bolt holes into alignment.

Slide and fully seat the Standoff into the lower groove of the hotend.

Place the Centre Plate over the top of the Hotend and onto the Clamp Plate.

Clock the Clamp Plate as shown to accommodate LED, thermistor and fan wiring.
Slide and fully seat the Clamp Plate into upper groove of Hotend.

Note: It is not necessary to "seat" the PTC connector, it can be left loose. The Nimble will hold the PTFE tube firmly at the bottom of the Hotend barrel.
Ensure Accelerometer PCB fits flatly and easily into the recess in the Clamp Plate.
Temporarily install 4mm x 25mm screws through top of Clamp Plate into Standoff to ensure alignment of Clamp Plate.
Then firmly snug down 3mm screws to secure Accelerometer PCB.
Ensure soldered wires do not protrude more than 2mm above the PCB.
Arrange fan wires as shown in order to clear Cap.

Nimble Adapter
Components to Print: Nimble Adapter
Nimble_Gnu_Cap_Prometheus_71210_Accel_Rev1Notes:PETG is recommended for strength of thin sections and thread robustness.
Best printed upside down (as shown in stl model).
Support for the countersink holes is recommended
Set xy support clearance to at least 0.3mm to maintain countersink clearance for the screw heads.
Guide_Bushing_Prometheus_Rev1Note: ABS recommended for ease of post print sizing and natural lubricity for passing PTFE tubing.
Strap QTY 2Note: TPU (NinjaFlex) recommended - you will likely get a much better result after installing the Nimble!
Assembly Instructions: Nimble Adapter
Trim ONE of the 40mm bolts that came with the Nimble to 35-37mm.
Through drill the large holes in the Cap to 4mm and ensure bolt heads fit freely in the countersinks.
Through drill the small holes in the Cap to 2.4mm to size them for tapping.
Tap the small holes in the Cap with the M3 tap.
Ensure all surfaces are free of swarf from drilling and tapping and that the centre hole of the cap is free of protrusions.
Square one end of the PTFE tube and chamfer the OD slightly.Note: Be sure to thoroughly clean the PTFE tubing of any fragments after cutting or shaping it. You do not want discover any unmelted shards in the tip of a small nozzle because by the time you excavate them, your sense of humor will be long gone...
Drill out the bore of the guide bushing so that your PTFE tube passes smoothly through it with a little force. The PTFE tubing should NOT be loose in the Guide Bushing.
Size the OD of the Guide Bushing so that it passes just freely through the centre hole of the cap.Note: You may want to employ the poor person's lathe for this purpose.

Measure the depth of the barrel in the hot end and the length of the PTFE tube.
Insert the squared and tapered end of the PTFE tube into the hot end barrel and seat it firmly.
Measure amount of PTFE tube protruding and verify tube is fully seated in the bottom of the Hotend barrel.
Install the two straps (can be done once Hotend mounted in printer so these could be your first print).Note: Judicious use of a small screw driver and a fingernail will avoid bloodletting and savagery.

Install the cap with the M4 x 25mm bolts.
Place the Guide Bushing over the PTFE tubing and seat it on top of the hot end.
Set the Groove Mount Adapter on top of the Guide Bushing. It should sit flat against the top of the Cap. Shorten the Guide Bushing from the Bottom if necessary.
The height of the top of the Guide Bushing should be just below the height of the rear locking tang (drive end) of the Groove Mount Adapter.
The smaller diameter "pin" of the Guide Bushing should fit snugly into the upper part of the Groove Mount Adapter.

While firmly pressing the PTFE tube into the bottom of the Hotend barrel , trim the PTFE tubing so that it slightly protrudes above the top of the Guide Bushing (0.3mm or about the width of a razor blade).
Mount the Nimble. Use the 40mm bolt with the Sleeve Clamp (or a 3mm spacer for fit testing without the drive cable) to avoid damaging the Accelerometer PCB.

Gentle tightening of the Nimble Mounting bolts should cause the Nimble to seat squarely on the Groove Mount Adapter and the entire body of the Nimble should seat squarely on the top of the Cap.
The PTFE tube should contact the bottom of the filament guide groove on centre without distortion. Re-trim the PTFE tube if necessary.Note: If you cut it twice and it is "still to short", START AGAIN with a new piece of tubing. You do not want the PTFE tube to be able to move vertically re the dread filament jam at the bottom of the barrel...

Once satisfied with the fit, snug down the Nimble mounting bolts.
Install Hotend in printer, strap down the whip.

Remember to revisit your slicer retraction settings. It is a whole new world without the Bowden tube.