Nichimo Spirit FF - The first of a Kind

[silvertriple 3559]

I basically spend quite a few hours yesterday evenning to build a bodyshell using surfaces, but I can't thicken it at the end... (even though I put all the surfaces in the same direction)...

I also had quite a long time to understand that combine become stitch when it comes to Surface environment (but still no way to thicken it).

I really need to take care of building some clusters of parts to reduce the printing costs (black MJF PA12 and red SLS PA12)... Which means the bodyshell and all those elements which require review will be left there until I get back on this.

In the meantime, a bit of fun with a vertical resize (and no, I won't use the perspective view, as the rear wheels look exactly like the front ones in perspective).

Next : take care of the parts printing (I already ordered a bodyshell to TBG for it), build, run and vidéo

[silvertriple 3559]

Tonight, I prepared my cluster of parts. The overall idea is to group the parts together for the prints.

I will have 6 STL files for black parts :
- Chassis (already printed)
- Top Chassis
- Bumper and battery holders set
- Suspension arms
- gearbox
- lost ark (the radiobox :-) )

I will prepare the red parts clusters tomorrow. Depending of the cost, I may print them white sls or red sls (not all providers are proposing dyed red sls).

[silvertriple 3559]

Yesterday, I had a puzzle with all red parts to tackle.

I decided to not decide anything yet for the wheels: the tires are in ok state, but they are old, and they would probably not survive to a run.  Which means I may have to adapt modern/easy to source tire, and therefore redsign the rims accordingly. This will be for later. In the meantime, I may use a set of hotshot wheels...

As the only providers I'm aware of doing dyed sls PA12 are all expensive for each stl file, I decided to take all the red parts I want to print in the same stl.
And I started to group them around the roll cage with some sprues, axles and other tricks relying on joints to capture bodies in the design, and create one single stl that makes it.

At the end I had this :

I estimated the printing cost in many point of time of this by exporting the stl and submittting it. Adding parts in the cluster doesn't climb the price much so it's the good method (same principle as the box I used with the Hunter, but with part too small to be able to use the same way)...

I will order the print for the black and the red parts soon...
 

[Aerobert 2149]

Awesome work you've done there. 👍

[silvertriple 3559]

Another milestone crossed on this project :
All parts are in production now.
- MJF  PA12 Dyed black parts (5 stl files, plus one already printed) are expected to be finished print by April 2nd, and shipment 4-8 days after that
- SLS PA12 Dyed red parts (1 stl file) expected to be shipped by April 11th - 2 days shipment time.

It's now time to take care of another thread/project awaiting the parts to arrive...

[silvertriple 3559]

The black MJF PA12 parts are printed and on the way already...

As said it 6 stl files for the black parts. I repost the pics of the clusters as I had to update some as per the printers requirements:
Chassis halves

Radio box - reinforced sprues

Gearbox - reinforced sprues

Bumper and battery set - unified + reinforced sprues

Suspension arms - unified + reinforced sprues

For the red parts, I reviewed the whole design before submitting it to the printer (IM): reorganized the cluster to get a smaller overall footprint and easier orientation for the key elements, unified some parts and reinforced sprues.

NB: the reorganization of the cluster allowed for a 15% saving compared to my initial estimates.

Black parts were sent from the Chinese provider on Friday. Not sure when it will land here : the estimation I got from DHL express is not in line with the 4-8 days announced when I ordered. With a bit of luck, I get all the parts for my next week of vacations...

On the CAD model itself, I added part of the hardware that was missing (focused on the visible ones only). There is still some missing screws (a lot of them) but it is already driving my computer nuts

Played a bit with the model explosion on web visualizer from Fusion360 - this is a lot of fun

[silvertriple 3559]

The second set of MJF PA12 black parts arrived today.

Effectively, all the black parts are now printed. Only the red parts are now missing, and they are expected to arrive within the course of next week.

In the meantime, and while the cat made my print of the base of my rc workstand fail at 87%, by going on the the touch screen of the printer during the print and deactivated the bed heating, I could not help to do some testing, and  detach the parts form the cluster and do further testing...

First was to take the original gearbox halves and put it on the printed halves.

Perfect alignment. I did further testing after removing the cluster attachment :
- holes size : perfect
- ball bearing fit : perfect
- test fit the original transmission in (no fixation) : meshes perfectly
- fitting in the chassis  : perfect
- fitting with the chassis and motor plate : perfect

Top chassis and  radio box:

A minor defect on the top chassis : while adding some thickness on the top chassis to pass the printer service preprint controls, I forget to apply a recut on the modified area. I used a cutter to repair this, and it is now perfect. Everything else fits perfectly. On the radio box, the important positions are there. However the hinge is not positioned properly : it 1 millimeter forward than what it should be to fit the original other parts. In any case the two parts are meant to be printed together so this should not be an issue.

Suspension arms :


The print is good, but I may have been slightly optimistic for the finish, as the finition is not homogeneous - but to see this, you need to look very carefully. I may want to review my cluster to give more space in between each arms...

Bumper, bumper plate : they work together with the original parts (or the remains of the original bumper). Which means it is another check mark ticked.

overall fitting 

It looks like it is on the good path
I know the red parts are going to work with the black parts. I can't wait the red parts to arrive. Not sure when they will arrive exactly...

[Kol__ 3377]

Those Matt black textured parts look cool mate. What hardware are you using to build it?

[silvertriple 3559]

41 minutes ago, Kol__ said:

Those Matt black textured parts look cool mate. What hardware are you using to build it?

As mentioned in the thread, I'm relying on online printing services to print the final parts on Nylon PA12 using processes based on powder (which means that supports are not required, as the powder is the support). Process being used for the black parts is Multi Jet Fusion, while for the red parts it will be Selective Laser Sintering. I could have get the black parts done in SLS, but it is slightly more expensive than the MJF, and with resistance slightly lower than MJF.

[Kol__ 3377]

8 minutes ago, silvertriple said:

As mentioned in the thread, I'm relying on online printing services to print the final parts on Nylon PA12 using processes based on powder (which means that supports are not required, as the powder is the support). Process being used for the black parts is Multi Jet Fusion, while for the red parts it will be Selective Laser Sintering. I could have get the black parts done in SLS, but it is slightly more expensive than the MJF, and with resistance slightly lower than MJF.

Hey mate, sounds cool. I was thinking hardware as in screws and bolts etc. Are you reusing the original ones or have you sought out replacements for this 3D build?

[silvertriple 3559]

1 hour ago, Kol__ said:

Hey mate, sounds cool. I was thinking hardware as in screws and bolts etc. Are you reusing the original ones or have you sought out replacements for this 3D build?

I'm still debating about this... Still have a few days for that. I may use the original screws or not... Initial plan was to work with all the original metal parts.

[silvertriple 3559]

Today, I finished the Nichimo Spirit FF parts clean up

I will only need to find some o-ring seals for the rear shocks, as the ones I have with me are not of the proper size and one of them is basically dead...

[silvertriple 3559]

Toric joints are an issue for both Samurai and the Nichimo...
Not sure where to find them yet:
- Internal diameter 8, external diameter 10, Tore diameter 1 (3 per Samurai, 2 for the Nichimo)
- Internal diameter 10, external diameter 12, Tore diameter 1 (1 for the Nichimo)

 

EDIT : Found on Amazon, will probably have enough for the next 10 years

[silvertriple 3559]

After the wing and wheels from the Samurai, I received a red cocoon from Belgium...

The delivery was made at the time of my lunch. I was just going to start eating when it happened. I did finish my lunch in about 10 minutes, I believe... I still had some time during my lunch break so I put it to profit.

First was to get all the parts out of the cluster.

It's the first time I used intricated design. I must report some failures:
- the axis I used for the internal gear and the bevel gears was too thick of half millimeter. Clearance for the small bevel gear and the internal gear was about .25 mm. Not good. It should have been .3mm or more as per the design guidelines. This mistake is mine. I corrected the stl.
- I had some wires intricated in order to prevent things moving too much or breaking while they sand blast it. A wire of 1mm or 1.5 mm is not an issue, really (although they mention 3mm section in the guidelines). But sometimes, the .3mm clearance is not enough. I had .5mm between the wire and the roof support, and it fused. I sent them a mail to get some clarification, acknowledging the fact my print was not only to print things but also to test their printing capabilities

That being said, this is not much an issue, I took my mini drill set, and drilled the parts requiring adjustment. Fixed.

Next, I put the roll cage together with the chassis... I guess anyone in my case would have done this test...

Later on, I had to fix as well my differential case:
- the recess for the axis of the central bevel gears was missing .1 mm or less. I guess it is a tolerance issue, as my design was the right measure. I'll still extend it in the design for the case I'll reprint it.
- I had to use sand paper on the surrounds that goes in the bevel gear as there is a small tolerance issue. I'll increase the diameter inside the big bevel gear

Beside this, it works. It's not set with the screws, but I test fitted it.

And I also checked the overall content of the gearbox...

Again, it meshes :). I will need to put all the bits on a table for a pictures before starting the build... Stay tuned :-)

[NWarty 1325]

Fantastic!

[silvertriple 3559]

Yesterday, before going to bed, I launched a print of rims in red PLA.  Those rims are based on Nichimo original design in a single part, and are adapted to "easy to source" 2 inches tires (with Hotshot tires in mind for my car).

This morning, the print was at 44%, and it finished within the afternoon.

They are not perfect, and there is still a bit of post processing to do on those.

I also printed hex hub to go with this rims.

[silvertriple 3559]

I almost forgot I ordered this some weeks ago

The last bit (aka the missing body mount) arrived today...

Well, there is still stickers missing, but I'm not sure yet if I'll put Nichimo Stickers on my own Nichimo... I may want to do something different, as it is different anyway

[silvertriple 3559]

For this easter, I'm at my parents' place. My father have some tooling that I don't have, and I thought it could be useful in order to correct some adjustments if needed when building the Nichimo. I started yesterday while my son was starting to paint the driver of his Super Hotshot.

 

As I modeled completely the Spirit FF, I thought the pictures of the build have to show up this as well, so I tried to make it visible. Sometimes, I forgot to unhide things on Fusion360 at some steps, please excuse this, I'll try to do better next time

 

First, the differential. I was quite sure it would work as I did test fit and corrected the adjustment for the central axis already.

 

Next step is already known and is requiring to build the transmission main axis. At this step, I had to do some adjustments : once the screws are in place, it was too tight. A bit of sand paper later, and it's no longer an issue.

 

Then all goes in the left gearbox. I had to review the spacers as again it was a bit tight once the gearbox closed and screwed. SLS printing is not as precise as MJF printing when it comes to tolerances (and I knew that already when looking at the ball bearing cages).

 

Next step is to close the gearbox. I thought I lost a part, but it was already clipped on the gearbox: on top of the gearbox there is the support for the way bar, and on the bottom, there is the mount for the bumper.

 

Next is to fix the motor on the motor plate. I used the 15T pinion, which means the center position of the motor (you can go with 12T or 18T). The motor is the original Mabuchi 540 silver can 27T.

 

4 screws later, and you have the transmission assembly…

[silvertriple 3559]

Once the gearbox is completed, the next steps are about the front suspension.

First the knuckles...

And the front arms are joining the knuckles. The adjustment is tight, but is moving. I added some dry lube in the pivots, and it is smooth now. I guess it will improve within time.

Then the suspension arms are joining the gearbox. I used the original screw pins, it should be perfect. Worst case scenario, I'll have to reprint a set of arms and get some axis with e-ring at each ends.

Next is the front damper. I had to use a bit of sand paper on the original piston to get a smooth movement. This is an original part. It is the same for the rear shocks, and they all had the same problem, the piston shocks parts were not cut clean...

Next is the sway bar. My links unfortunately are too tight, and I did not succeed to get them in, I used the original ones. I'll rework them with a tool I have at home, with a bit of luck, they will work.

Then come the steering rods and the servo saver. I used my father drill presse to adjust the servo saver holes so it moves freely (again SLS tolerances are not as good as MJF). The front train is now together and next steps will involve the chassis...

 

[silvertriple 3559]

Once you have the front train done, it is time to join the bottom chassis. The gearbox is snapped in the chassis (the radiator plate goes in the opening for it), and there is 4 screws to fix the gearbox (no particular difficulty here, as it was test fitted anyway).

 

Then, you start to add a few things at the rear : the battery holders, the shock towers and the bottom of the radio box '(aka the lost ark :-) )...

 

Next step is focusing on the bottom of the chassis. Battery door fist, and the radiator and the under guard. There was a small half millimeter issue for the underguard : the holes did not lined up perfectly with the radiator plate (maybe my chassis a slightly too thick there... I decided to drill the radiator plate with an increased diameter : this is going to ease the lining up of the holes, and won't change anything if I reprint a chassis later on.

 

Next is the bumper plate and bumper. The bumper plate is mounted with two spacers at the rear end, and 2 o-rings in the center, fixed on the gearbox... The bumper lines up perfectly, and the front end of the chassis is finished.

 

After this, you go back to the rear side, to mount the sway bar, and the rear arms...

 

Then comes the rear shocks, where I had to do the the same as the for the front one to get a smooth movement (the non smooth movement, may have led to the chassis breaking, I don't know).

 

It is then time to go for the electronics. I noticed that I completely forgot to take the connectors within my stuff when I packed things for the week-end. I had to find a way: I searched thru the stuff in my father's place, and only thing I found that could be used reminded me a lot of those chassis I got recently, where people did not solder anything. I did apply this method temporarily (it will be enclosed anyway, so it is fine). I also made a mistake when designing the red servo horn: I did it based on one of the metal heads servos, and the plastic head servo head as not the same diameter, so my new horn did not work. I had to use the original horn... The switch of the Tamiya TBLE-02S enters perfectly in the radio box opening, which means it is perfect.

 

Time to close the chassis with the top end. There is no more MJF printed parts on my table...

[silvertriple 3559]

Time to add the wheels. There is pins and hub on rear axis as well, probably because that's the way they thought it would be easier to remove the wheels...

 

And then, it was the time for the roll cage... There is a lot of screws. Everything lines up perfectly...

 

I could not wait more, took the battery, and discovered that although I planed for 138mm, the gap between the chassis and the door is too small so my 4200 mAh lipo pack does not fit. I added two washers for the door hinge. I will revise the chassis slightly in order to make it possible for more lipo pack possibility if I reprint it. The 4000 mAh battery pack fits perfectly.

 

I did a quick run of 1-2 minutes on asphalt to check everything was fine. First it works perfectly. I'm really surprised how easy to control it is in curves: the front drive and the rear follow. And what impressed me the most is how this thing is fast at cornering... Can't wait to try on a slippy ground, actually

 

Later on, I took the time to trim the body shell and the wing... I don't have the paints with me, so the paint will be when at home. And I still need to think about something special for the paint

[silvertriple 3559]

And a quick run video...
https://youtu.be/yht1v2TDRK0

[NWarty 1325]

Absolutely brilliant

[silvertriple 3559]

Had a very nice discussion today with an Australian about the Nichimo Spirit FF and it's awesome aggressive fantastic box art look... And the car being among the the ugliest when you see it in person  ... I decided following his suggestion to do the original roof in my CAD work...

I may tell more about this Australian guy later on when time will come :-)

[silvertriple 3559]

I got a lot of feedbacks and some unexpected help thanks to this Nichimo Spirit FF project. I had some hesitation to publish the parts, but some recent turn of events convinced me this is the right thing to do. The parts are now on Thingiverse (only plastic parts and not clustered).
https://www.thingiverse.com/thing:5373562