Fj60 4wd T-case Vacuum switch 3D-Print

[Seth S]

Best way to learn is go to an industrial supply store and spend some time picking up and playing with calves and switches etc. or go to a junkyard and pulling things apart. Most of the world of engineering is not about building things from scratch but improving or adapting existing designs.

 

[60Works]

Engineering project aside, I'd pull parts from your removed transfer case to mod the new one and eliminate the vacuum shift.

 

[ChaserFJ60]

Engineering project aside, I'd pull parts from your removed transfer case to mod the new one and eliminate the vacuum shift.

I was but keeping it with the vacuum is the easier solution here, i don't want to have to disassemble the tcase again then drill a hole into it, just to put in a lever that i only use like 10 times a year.

 

[ChaserFJ60]

I think i have something here. so the green part has no vacuum nipples, just the rod that the user turns to adjust vacuum output. So as one side has a direct vertical flow path(for vacuum) the other side is connected to the side wall that consists of a channel that follows the valve 360 degrees that will allow for the 4wd valve shifter thingy to vent out its extra pressure. this is just a rough sketch not a to scale model. Sorry for the limited view im on a time crunch right now,

.

 

[Seth S]

Looks like progress to me

 

[ChaserFJ60]

Taking to school on Monday for printing, i dont have stops on how far it should rotate yet but im planning on doing physical tests for that mechanism as I have to test the sealing capability as well.. this isn't a final product its a proof of concept model, so its not being made to permanently fit into my vehicle yet. I would love suggestions on how to handle sealing the top part with the two un-centered ports (as seen in the top piece) I just dont think that O-rings would not hold up to the friction of sliding unevenly across their face over time, im considering putting a flat soft metal as a compression/seal plate? or even trying gasket paper. This is so far really fun just to draw on CAD, using life sized o-rings and valves as reference in a too scale thing is so much fun!

On a side note I realize that a 3d print is not a good solution for a vacuum vessel. my final stage plans include sanding the whole thing smooth, and painting everything with a hard paint to make the surfaces smooth, then sanding down the paint to make it smoother. Even if this doesn't work the main goal here is for a grade and to show my professor that I can use CAD.

 

[davegonz]

Lots of good recommendations earlier. My suggestion is to also do some test prints to see how much your clearance holes shrink (and other features). This is more of a problem with FDM prints. What printers do you guys use at your school?

 

[ChaserFJ60]

Heres a link to my schools printing page.

LibGuides: Collin Makerspace @ Plano Campus: 3D Printers

General guide to the Collin Makerspace in the library at the Plano Campus (Spring Creek). Our services, equipment, and materials are available to current Collin students, faculty and staff only.

collin.libguides.com

but the names of the printers are Polyprinter Ultimaker S5 Form2 SLA
Im still very new with 3d printing so please excuse my lack of knowledge on this subject
Now looking at the the printers specs i see some possible drilling in my near future

 

[davegonz]

The Form 2 rocks. Is has nice resolution.

 

[ChaserFJ60]

Alright i talked the guy into printing with the Form 2 printer and im pretty exited to see its turnout! I have to wait in a queue so i will post back here when i receive it in about one week

 

[ChaserFJ60]

Ok so the form 2 was a great suggestion. I havent gotten it back yet from cleaning but it looks amazing. The lab tech. also printed out an extra pla version that i got to take home and it is nowhere near the precision that i would want. Ill post pics of the form 2 version when i get it later today!

 

[ChaserFJ60]

This is a definate win! Very happy with the results i got. I already have ideas to make this a working part of my truck. I tried to screw on the top but part of the mold cracked. Its a very hard but brittle. Thankyou seth and dave for the suggestions! Heres a video of it working

 

[ChaserFJ60]

Alright so my next testing questions are.
1. What type of lube do i use to prevent too much friction and destruction of the valve & oring. (maybe silicone)
2. Will I use this 3d Material in my final design
3. If I use the 3d print how do i secure the Cap to the cup without cracking the brittle material? (i tried boaring out a hole and putting a wood screw in to secure the lid and the material and it instantly cracked. Im considering doing a Drop through bolt bolt clamp on 3 sides.)

I also would like to add a knob to the final version and a way to seal the shaft and the cup with an oring which should be easy to implement.

These are just base questions that im considering during my next design stage. I will continue to post updates until its installed. when its finished I will post the 3D file along with a basic parts list incase anyone wants to do their own testing. as always suggestions are always appreciated.

 

[Seth S]

In the manufacturing world 3D print isn’t ideal for large quantity builds on something like this. Your results are great and I hope your class grade reflects that. But for practical purposes your 3D printed piece should really be the proof of concept. To build the actual piece that will outlast the truck I’d consider copying the design in aluminum or delrin or nylon etc. something you can machine with ideal properties and that can be bolted or screwed together.

If I were considering mass production I’d be looking at the injection molding route.

 

[ChaserFJ60]

In the manufacturing world 3D print isn’t ideal for large quantity builds on something like this. Your results are great and I hope your class grade reflects that. But for practical purposes your 3D printed piece should really be the proof of concept. To build the actual piece that will outlast the truck I’d consider copying the design in aluminum or delrin or nylon etc. something you can machine with ideal properties and that can be bolted or screwed together.

If I were considering mass production I’d be looking at the injection molding route.

Its just for me, I dont intend to mass produce it or anything of the sorts. The material feels very sturdy, it has a heat deflection temp of 136 - 145° and a hardness of 80. for a one off piece this seems to be alright for me.

 

[Seth S]

I didn’t mean to imply that mass production was your goal. Just pointing out that 3D printing sometimes is better as a proof of concept and prototyping tool and your design works. So maybe got cut metal and don’t worry about the plastic breaking and model it on your plastic prototype.

 

[ChaserFJ60]

I would but unfortunately the only metal fabing tools i have is a grinder, stick welder, and drill press. Having a metal version of this would be amazing But ill just run the 3d for now

 

[The Machinist]

Very cool project!

For improving sealing, (or perhaps seal longevity), you could consider using a labyrinth seal for the ports that run along the center of rotation. Essentially just creating overlapping radial grooves and bosses with the center groove containing the oring and the outer ring boss having a close running fit with the bottom of the "bowl" portion of the assembly.

For retention; drilling layered material (FDM prints) for clearance or tapped holes is likely to fail or cause delamination and on SLA prints the material is often brittle (UV cured resin is usually similar to acrylic), and is easy to crack with machining (i.e. drilling or tapping). Your design looks like it would lend itself well to using nuts and flathead bolts; I would add a hex feature to the bottom of the holes on the "bowl" component and a countersink to the hole on the top plate. You can then press fit a nut into the "bowl" and the countersink angle will act as an alignment feature when assembled.

 

[ChaserFJ60]

I like the labyrinth seal idea! Im going to implement that in my next mockup, and the countersinking nuts will give it a much cleaner look! The part im worried about leaking the most is the cap where the valve slides across its celing. Im going to put in a groove for an o-ring on the shaft to help prevent atmosphereic air from getting sucked in, also im adding a 5th nipple on the venting port so i can put on a small air filter so no dust gets sucked into my vaccum lines. Im considering using a heavy grease on the roof of the valve to act as a "self seal" when i rotate the valve.

 

[Seth S]

In that case.....I recommend epoxying the halves together. When it fails print a new one. Or you could print threads into the two halves and screw them together. Seen quite a few successful 3D printed threaded objects.