FFG Ultralight Print Heads and INDX mount for use with Full Frontal Gantry mod on Rat Rig printers

Compatibility:
V Core 3 and 3.1 (MFBS hybrid upgrade)
V-Core 3.2h (Rat Rig's hybrid upgrade)
V-Core 4 
V-Core 4 hybrid 
OneBox and 
Enclosure 2
All Ultralight print heads.

Current Ultralight print heads released:
Bare template, for tool changers, etc. plus

Dragon Ace
Rapido 2
Rapido 1
Bondtech INDX (draft)
More coming….

Please note testing of this tool head has now been completed and the results were quite impressive.

I am achieving 40K accelerations on an otherwise near stock V-Core 300 hybrid with zero ringing visible. Videos of this have been posted in the Rat Rig Discord.

This is mod is fully compatible with both the V-Core 3 hybrid and V-core 4 hybrid printers fitted with the Full Frontal Gantry mod. 

The Ultralight core mounting plate template will provide a simple fixutre for a variety of print tools. Print tools could be things like the upcoming Bondtech INDX a pen a drag knife, etc.

Coffee fund
If you download and print this design or get a thrid party such as PCBway to print these parts for you I receive no compensation for my design work or my cost for the CAD software I have to pay an annual license for.

If you decide to make a donation to my coffee fund (which keeps me up late at night doing more of this stuff) I would appreciate it. There is absolutely no obligation for you to do this. My PayPal account is [email protected]

Please remember to post feed back as it is always valuable to me for future iterations.

Many thanks.
Liam Venter
MFBS Design


Caution!!
Please note when installing a Beacon probe on any tool head that you have clearance of your Beacon probe and the top of your leadscrew if you don't there are several strategies you can employ.

1. Use the thinner pillow blocks from the 3.2H hybrid (files available in Rat Rigs on line CAD
2. Print a packer to sit between the top of your rear Z motor and the underside of it's motor mount
3. Cut a couple of mm off the leadscrew with a cutting disc on an angle grinder.

Files for the Dragon Ace Volcano Ultralight tool head are included.
PCBway charge about $32 to print the Dragon Ace Vocano  Ultralight from aluminium (note this price does not include tapping the threads.) Funssor also offer this with the threads already tapped.

https://funssorlab.com/products/funssor-3d-printed-aluminum-dragon-ace-ultralight-mount-with-tapping-holes-designed-by-mfbs

I have now added a spacer that goes between the top of the Dragon Ace Volcano heat sink and the Orbiter extruder. The purpose of this is to stop the heat sink unwinding and loosening the connection between the heat sink and the heater block. The top of this is designed to sit 0.1 mm proud of the top surface of the heat sink cage and be slightly compressed (0.1 mm) when the Obiter is bolted on.


Rapido 2 Ultralight tool head.
PCBway charge about $32 to print the Rapido 2 Ultralight from aluminium. l also highly recommend Funssor's stand off tube kit with this version of the Ultralight.

Rapido 1 Ultralight.
PCBway charge about $32 to print the Rapido 1 Ultralight d from aluminium. l also highly recommend Funssor's stand off tube kit with this version of the Ultralight.

Modular back plate.
I have made the back plate modular. 

1. Top  (includes unmbilical cable mount
2. CPAP pipe
3. Ducts for part cooling.

Making these three parts modular makes it easier to swap these out for alternative part cooling  options.

I have also created drafts of of other Ultralight print heads for the following hot ends that I will update when they are finished:

• Triangle Labs Rapido Ace

• Peopoly Lancer

Belt Wedge-Lock  retaining system.
For the Ultralight tool heads, I have devised a new  belt wedge lock retention system which sares the same Open Source license as all other aspects of this design.

1. The belts are pushed all the way through curved and tapered slots.,

2. Then a short 8mm length of filament is placed in about the 4th belt groove from the end,

3. The belt is then withdrawn out of the slot until the filament and belt jams in the narrowing taper of the slot.,

4. A small section of belt is left protruding out the slot so that when you want to release the belt you can just pull on the section sticking out with a pair of pliers to release the short piece of filament and then fully with draw the belt from the slot.

Pros: 
Initial testing of the Wedge-lock belt retention systemshows that belt retention is very secure. 
The system is simple, compact and does not require any screws. 

Cons: 
A little bit fiddly to fit, but probably quicker than most other systems. 

I did experiment with using a toothed wedge instead of a piece of filament, but the filament worked so well the toothed wedge was just an unnecessary complication and easy part to drop on the floor and loose....so is the filament...but you can always find another 8mm long piece of filament! (edited)

Ultralight:
Depending on the accuracy of the aluminium printed part, which can vary by as much as 0.1mm you may need to fractionally open up the entry point for the belt slots. This can be easily accomplished with a 1.5 mm drill bit.

Part cooling ducts:
I have included an optional UFO duct for people who want to play with it. Both the UFO and the twin horn duct work well, but so far the twin horn duct is the best duct I have tested.

Printer.cfg Overrides
Because a key aim of The FFG Ultralights to reduce the nozzle offset was achieved you need to advise RatOS that distance between the Beacon senosOr and the nozzle has changed.

Place the following in the user overrides sectin of your printer.cfg file.

#Changes for Full Frontal Ultralight printheads.
[beacon]
serial: /dev/beacon
x_offset: 0.0 #for Ultralight
y_offset: 20.5 #25.5 for UFO duct, 20.5 for horn duct

[bed_mesh] # for V-Core 3.5h 300
mesh_min: 20,25.5 #20,25.5 for UFO duct, 20,20 for horn duct
mesh_max: 280,265 #280,265 for UFO duct, 280,270 for horn duct.


To take advantage of the much greater performance offered by the FFG mod you will also want the to override the slow performance capped in  Rat OS.

#Performance changes for FFG V-Core 300 hybrid
[printer]
max_velocity: 800 #This value will be overriden by lower values in your slicer.
max_accel: 40000 #please start and test with a lower value! This value will be overriden by lower values in your slicer.
minimum_cruise_ratio: 0.5
max_z_velocity: 50
max_z_accel: 600
square_corner_velocity: 20



BOM for all Ultralights, except Bonbdtech INDX mount.
4 x M3 threaded inserts (5mm OD x 4mm long) 
https://www.aliexpress.com/item/1005001407970757.html
2 x M3 x 32mm Flat Head Cap Screws (Back plate vertical screws).
2 x M3 x 10 mm Flat Head Cap Screws (Front part cooling Duct mounting).
4 x M3 x 6 mm Flat Head Cap Screws (For mounting the Ultralight to the MGN Carriage).
2 x M3 x20 mm Flat Head Cap Screws (2510 Fan mounting).
2 x M3 x 8mm Socket Head Cap screws (X-stop mounting).
2 x M3 x 8mm Socket Head Cap screws (Orbitor mount).
1 x 2.5 mm x 200mm  Zip tie (Orbiter clamp, optional)

Dragon Ace Volcano Ultralight: Requires tapping of:
2 x M3 x 0.5 holes for X-stop switch mounting.
2 x M3 x 0.5 holes for Orbiter mounting.
2 x M3 × 0.5 holes for fan mounting.

Rapido 2 Ultralight: Requires tapping of:
2 x M3 x 0.5 holes for X-stop switch mounting.
2 x M3 x 0.5 holes for Orbiter mounting.
2 x M3 × 0.5 holes for fan mounting
1 x M3  x 0.5 hole for heat break retention grub screw

3 x M1.6 holes for Rapido heater block mounting.

Rapido 2 Ultralight: Requires tapping of:
2 x M3 x 0.5 holes for X-stop switch mounting.
2 x M3 x 0.5 holes for Orbiter mounting.
2 x M3 × 0.5 holes for fan mounting
3 x M1.6 holes for Rapido heater block mounting.

Bondtech INDX Ultralight Mount, draft only)
4 x M3 x 6 mm Flat Head Cap Screws (For mounting the Ultralight to the MGN Carriage).
No holes need tapping

I have now added a UF0 duct option. This is very much based on the UfO-N-AtoR- Duct design by XrocksaltX but with a few changes to suit the implementation on the Ultralight. At this stage this is very much a draft but shows great promise. I will be testing further iterations of the current version and will update when/if I make improvements to the current design. 

Many thanks to Rocksalt for his advice and supplying the STEP files for me to experiment with this option. Please see the link below for his orignial work. My redesign for the duct inherits his  Creative Commons - Attribution - Non-Commercial license.

https://www.thingiverse.com/thing:6779529

Updates
12/11/25 Very slight cosmetic change to fillets on Rapido 2 Ultralight. 
1/1/26 Added UFO duct option.
25/2/26 Corrected front mounting hole error in both the two horn and UFO ducts.
25/2/26 Increased the length of the heat sinks thread engagement with the heat break on the Dragon Ace Volcano Ultralight. This is a nice, but non critical change. If you have the earlier version there is no need to update.
26/2/26 Added a little clearance for the 2510 heat sink fan to give some tolerance for SLM printing.
5/03/26 Made a number of tweaks to the Rapido 2 UHF to improve its SLM printing.
12/03/26 Added Bondtech INDX Ultralight Mount.
7/04/26 Added Dragon Ace Volcano heat sink spacer.
11/4/26 Changed a couple of fillets on  Rapido 1 and Rapido 2. Cosmetic change only.
30/4/26 Removed UFO duct option. Needs more development to get it to perform as well as twin horn duct.
24/7/26 Corrected belt mount height error on INDX mounts (new files labelled V3)

Copyright
The terms FFG, Full Frontal Gantry, Full Rear Gantry and Wedge-Lock are copyrighted by MFBS Design.