Hot Off the (3D) Press: Suspension Upright 3-D Print

The suspension uprights have gone through a long evolution, but I’m zeroing in on the goal.

First Design: Machined Billet Aluminum

This design uses radial-style brake caliper mounting. Needed to be redesigned when someone ordered the lug-mount calipers and had them delivered all the way from the USA. Probably a Freudian slip as they’re less expensive.

Machined Upright

Second Design: Fabricated Steel

Fabricated Upright

Second design was fabricated from steel. Unfortunately, welding will eliminate the temper in the heat-affected zones. The weakening due to this is hard to predict, and can only be eliminated by heat treatment. That would mean days or weeks finding and learning to deal with a heat-treatment supplier.

Mesh Quality

Mesh used for finite-element analysis of fabricated steel upright.

Upright FEA

Finite-element analysis stress plot for fabricated upright. Strong enough, but where are those heat-affected zones?

 

 

Third Design: Cast Aluminum

Here’s the final result of literally hundreds of design revisions, ensuring that the upright is strong enough and as light as possible. This design is made possible by the new technology of 3d printing, which will be used to make the master “plug”, from which molds will be made to cast the actual part. Note that the steering arm is not an integral part of the upright, but is modeled together with the upright because the FEA runs much faster this way.

FEA mesh plot for cast upright

FEA stress plot inner

Cast Upright FEA

View from outside

Finally, the Master Copy

The upright had to be split into four pieces for 3D printing; split vertically so I can make two mold halves and remove the masters from the molds, and split horizontally to fit the 3D printer. The 3D printer extrudes hot ABS plastic in X-Y layers onto a heated Z-axis stage with 0.3mm resolution. The print is slightly rough and the parting plane is slightly warped, which will have to be corrected with auto body putty, primer, sanding, and paint. The cast aluminum blank will still require several machining steps to cut off the gate and sprue, drill mounting holes, bore the bearing hole and retaining ring slot, and mill the brake caliper mounts. Still far better than trying to machine individual parts (or even a mold pattern) this complex, which would be approximately impossible and semi-infinitely expensive.

Beautiful, huh?

One half printed in two colors to highlight the split required to fit it into the 3d printer

Set of 4

Full set of four 3d prints. The cylinder protruding in the upper left is the gate, where molten aluminum will be poured into the finished mold.

Top View

Some people get excited by shoe sales. I get excited by this!

 

 

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10 responses to “Hot Off the (3D) Press: Suspension Upright 3-D Print

  1. Hi, Congratulations for your work. I am based in Bkk, and wish to know where do you intend to use your racing car. I mean in witch racing event, as there is only 2 racings circuits in Thailand.
    Keep on it.

    • My hope is to bring Formula 1000 racing to Thailand, which will probably require organizing races myself among my customers and others who’ve imported cars themselves. Bira Circuit is only four minutes from my shop. What and where is the other circuit in Thailand?

      • Others circuits are in Naklon, not far from Bkk,
        also sometimes clubs organise competitions at Sakeo, on an old army airport. Not a real circuit with track, just cones to delimit the way.
        If you are located 4 mn from Bira, you are not far from (ex) Motorshow and close to Classic garage, Mr Martin, an genuine car lover from Findland, who unfortunately vanished from the place since 1 year.
        Your project to organise races in Thailand is really interesting, because Taki school is doing nothing at all.
        Personaly i’m sure there is something to develop in Thailand in this way.
        Tooling:
        Am not aware about the Bkk flea market, however lathes and milling from China are quite cheap, and you can get discounts during expos (last time Metalex at BITEC BangNa Bkk.)

        Years ago i bought a Takan lathe machine brand new from China in a Yawara shop for 190K thb (460mm x 1000mmm). It was well working. Bought also a milling from Taiwan similar to the one on your photos, and unfortunately it can mill only chocolate with đŸ˜‰
        All gearing teeths came apart.

        Let me know when you progress.
        my e-mail
        utookan@gmail.com

        Fred

      • I did some searching and found the other tracks, and did some updating of Wikipedia entries accordingly. Wikipedia coverage of Thai race tracks hasn’t been updated much in about four years. More to come…

      • Thank’s for updating.

        Once your F1000 will be completed, tested with geometry tuned, you need at least 5 or 6 cars to compete with. How do you plane to organise it ? Building 10 cars, selling or renting them, or propose to others drivers to make their own F1000, to compete with at Bira ? Excepted some supercars, there is no reals interesting races in Bira (in Thailand also), it’s just fun for teams and drivers, so if you can come up with F1000 events, it will draw attention and be welcomed.

        Tech: While cornering, centrifuges forces to oil are obviously differents from car to bike. What kind of dry sump do you use it ?

        Bests Regards Frederic

        On Sun, Jan 13, 2013 at 7:46 PM, ludemannengineering wrote:

        > ** > jjludemann commented: “I did some searching and found the other tracks, > and did some updating of Wikipedia entries accordingly. Wikipedia coverage > of Thai race tracks hasn’t been updated much in about four years. More to > come…”

      • My plan is to sell the cars in Thailand and elsewhere, and to organize races in Thailand that would be open to any car that meets US SCCA Formula 1000 regulations.

        Yes, cornering forces are quite different from bikes, and many engines exploded in the US before they got a handle on the problem. Some cars run dry sump systems, but those are heavy and apparently not necessary. The guys on ApexSpeed got together and developed a flat oil pan with flappy doors that let oil into the area around the oil pickup, but won’t let it out the other side during cornering. Data acquisition systems now show steady oil pressure during cornering and braking, and engines have stopped exploding. I bought mine from George Dean, or you can buy them here: http://www.rilltechracing.com/products/

      • Sorry for the late reply, and thank’s for the link. If you plan to produce and sell F1000 in Thailand, do you intend to import engines and all necessary parts (diff, pan, suspension etc…) or to purchase engines second hand in Thailand, rebuilt them, and sub-contract specials parts as others constructors do actually here ? (usually they are BOI and do not retails theire racing cars in Thailand). Do you have an idea of a turnkey F1000, ready to go, produced by your Cie ?

        Regards Fred

      • I expect that I will sell “rollers” in Thailand due to the difficulty of importing parts. So there would be a list of off-the-shelf parts that would bolt right on and could be purchased by my customers instead of me. These would include engine/transmission, brake calipers, tires, wheels. Differentials probably have to be supplied by me. As you may know, it is currently illegal to import used motorcycle engines, so that’s a big problem for the whole project. All the custom-fabricated parts would come with the car, like suspension, steering, drivetrain, fuel, electrical, and so on.

        Regards,

        -Jim

  2. Hi, im amazed with your work and i wanted to know more about the simulation on the front upright. could you tell me how do you do the simulation using the solidworks. im really a newbie in solidworks and wanted to learn more abt it.

    • Setting up FEA simulations in Solidworks is easy. I think, starting from scratch, I could do the basics in less than a minute. The places where you typically get hung up would be inadequately restraining the model, or having it fail to mesh. For some parts you have to spend a fair amount of time thinking about the proper combination of restraints and applied loads. If it fails to mesh, just take the meshing slider and jam it over to the finest setting, and that usually fixes the problem. If not, you’ll probably find a sharp edge or highly acute angle in the model. For the upright, I have several different simulations setup: one for braking, one for cornering, one to test the bearing snap ring, and so on.

      -Jim

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