A new project - Nichimo Spirit FF - The first of a kind

[Dadio]

I always use sprues to link parts , I know some will let you use loops but I've never looked into it , I've had times when I've connected two parts that work separately but together they fail , then I've had to change their orientation slightly , link them again and it works , I think it's to do with the post print clean up , they sand blast the parts to clean them up and if they can't clean them properly they reject it , it's just a guess .

[silvertriple]

Well, reworked all my sprues, and the way to snap parts together... In some cases, I included loops to secure the stuff... Hope they will accept them this time. worst case scenario, I'll rework them again...

[silvertriple]

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]

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]

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...

[Dadio]

looks great having only two minor adjustments to make is really good I've said it before and I'll say it again "measuring is hard" .
Can't wait to see it being assembled .

[silvertriple]

looks great having only two minor adjustments to make is really good I've said it before and I'll say it again "measuring is hard" .
Can't wait to see it being assembled .

Taking into consideration that the first minor adjustment was not an issue in the original design (I reworked each part separately of the bigger file for the print files - I just made a mistake there). And for the other, I had to do estimations based on broken parts (even the 1 mm I mention is an estimation based on the two broken parts I have - I would need one of the part being perfect to measure it correctly, so the easy way is to get both printed together...)

[silvertriple]

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...

[Dadio]

Is the inverted spur gear metal or plastic ? looking at the pictures it looks plastic , I had assumed it was metal .

[silvertriple]

Is the inverted spur gear metal or plastic ? looking at the pictures it looks plastic , I had assumed it was metal .

It is plastic, and apparently fragile. Not sure what plastic it is, but I will run a SLS PA12 printed one.

[silvertriple]

Toric joints are an issue for both Samurai and the Nichimo...
Not sure where to find them yet (figure in mm):
- 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]

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

[Dadio]

Great work , well done , tolerances are a pain , for home FDM printing they need to be way bigger than for SLS but they still need some in places , good that you could overcome the issues .

[silvertriple]

Well, maybe I tried to much to attend the limits of the printer capabilities

[silvertriple]

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.