3D printed Frames Question

[Oldmopars]

First, I am not saying these will be offered, more of an question to address the viability of such a thing. 

For Semi trucks, if someone were to offer frames, would basic C channel be desired? Frames with drop fronts, specific truck style frames, etc? 

Next question, what would be MAX length? These would be printed with no holes, just straight frames with possible front details, but just long C-Channel cab back. 

I know someone offered brass at one point, but those were just long bent channel. I was just wondering if frames made to a max length that you could cut down would be of any interest.

Any thoughts? 

 

[DRIPTROIT 71]

Gary Wallace offered styrene frame rails that I believe were cut with a CNC machine. There were a few sizes available to match kit frames. I think that they were about 16” long. I still have some but would have to dig them out. They were slick (no detail) and worked great. If I understand correctly, resin tends to sag over time. I think that is why Dave added metal to his axles. I would be curious as to whether 3d resin would sag on a long frame rail. I know that there is a supplier offering 3d frame extension kits, but I don’t know how well they hold up. 
But to answer your question, I think slick, straight rails that someone could add their own detail to would be the way to go. 

[Oldmopars]

12 hours ago, DRIPTROIT 71 said:

Gary Wallace offered styrene frame rails that I believe were cut with a CNC machine. There were a few sizes available to match kit frames. I think that they were about 16” long. I still have some but would have to dig them out. They were slick (no detail) and worked great. If I understand correctly, resin tends to sag over time. I think that is why Dave added metal to his axles. I would be curious as to whether 3d resin would sag on a long frame rail. I know that there is a supplier offering 3d frame extension kits, but I don’t know how well they hold up. 
But to answer your question, I think slick, straight rails that someone could add their own detail to would be the way to go. 

So, I should have been more clear. My plan, if this were to happen, would be to offer them in PLA, not resin. These would be printed on an FDM style printer. They would be strong, no sag. 

While resin does offer great details, PLA/PET-G/ABS off better structural strength. So, these frame rails would need some sanding, but PLA is easy to sand. 

I would need to expand my printer, or make a new one as my printer is 12in x 12in and would only allow for a few 16in rails at a time. To make it a viable option, I would need to expand it to 18 x 18 to get as many on the bed in line as possible. 

The big thing here is, demand. If there is no demand, it is not worth doing. I can print my own on my current printer. 

[vincen47]

I think there would be interest in these. I’d say they’d need to be longer than your typical kit, because otherwise, just use the kit. So, 14”+ would probably be the target. 16” would be real nice. I like the idea of a little front detail and/or profile where they narrow for the engine, then straight and plain all the way back, cut to the length you want.

Rhino on EBay had some styrene rails available. I think they were 24”. I purchased a pair for a really long scratch built/kit bashed chassis project and another set to cut up for frame extensions because they matched the height of the Italeri Peterbilt 378 rails.

I’d have to say that the market for frame extensions may be a little larger, as I think a completely scratch-built chassis and/or pair of frame rails is not as common as a basic stretch. MTB has some nice looking stretch sections for the Revell 359 and w900. Something like those for the Italeri kits, both the standard Freightliner frame and the Pete 378 could be popular.

I haven’t purchased these yet, but I would feel better if they had a long tab that would fit inside the kit’s rails for a good inch or so for strength, rather than relying solely on 1/2 of the crossmember at the joint.

Either way, whole lengths of frame rails or stretch sections, I would be interested, especially if they were stronger than the typical kit rails.

Edited March 19, 2023 by vincen47

[Sluggo]

After modeling a full frame rail for my wrecker project, a stretch kit opposed to full frame rail would negate the need to model or print any lumps, bumps, rivets, holes.etc. If you use parametric modeling, you could offer on demand custom lengths without the need to make a new model each time.

I just finished modeling and printing these inserts earlier today. They fit great and I can't believe how much rigidity they added to the kit frame, even unglued. At 88mm long i was sure they would introduce a sag or floppiness but they did just the opposite. They also cured the bow in the kit parts. Printed in PLA+.

he

Reason for stretch...

Edited March 19, 2023 by Sluggo

[Oldmopars]

I think you guys are right, frame extensions would be the way to go. Great info, let me mull it over and see if this is something that would be worth offering. 

[carsntrucks4you]

I had printed frame extensions, correct Ford crossmembers, several frames for trucks and trailer on my Mono X. The longest one was a frame rail for a Volvo N88  with 280 mm but that was to brittle . Since then I print the frame  together with the crossmember. This give s more stiffness and rigidity. The 35ft 2 -axle trailer was printed in 3 sections while the 24ft single axle trailer had 2 sections (the pictures shows the first 3 section prototype). The drawbar traler and the 2 axle frame were one piece prints.

In my opinion you are able to design your own correct frame for a particular truck and print it. The problem that i have with the C-channels that you can get from Evergreen or Plastruct that the mostly doesn't have the correct dimensions. 

 

Next frame that I'm going to print is a correct Mack Superliner frame for the Italeri/Revell/amt kit

 

 

 

 

 

Edited March 21, 2023 by carsntrucks4you

[iamsuperdan]

There's a designer who I've purchased files from that has a pretty good solution for a truck frame.

 

You print the front section, with front axle mounting points and engine mounts, then print a rear section again with suspension mounting points, and then there is the basic middle section, that you could print multiple copies of, depending on your desired chassis length.

 

I'll take some pics as I'm doing it.

[vincen47]

On 3/19/2023 at 7:35 PM, Sluggo said:

After modeling a full frame rail for my wrecker project, a stretch kit opposed to full frame rail would negate the need to model or print any lumps, bumps, rivets, holes.etc. If you use parametric modeling, you could offer on demand custom lengths without the need to make a new model each time.

I just finished modeling and printing these inserts earlier today. They fit great and I can't believe how much rigidity they added to the kit frame, even unglued. At 88mm long i was sure they would introduce a sag or floppiness but they did just the opposite. They also cured the bow in the kit parts. Printed in PLA+.

he

Reason for stretch...

Nice work. For anyone wanting to print stretch parts, this looks like the way to go, in my opinion. I like the tabs that fit inside the kit frame rail, and the overall strength is a huge plus.

Are you printing extra crossmembers? I would think anyone buying a stretch kit would want extra crossmembers, too.

[Sluggo]

Yes I plan to incorporate cross members. It looks like only the simple ones are needed in the stretch area. The snow plow kit has extra cross members in it so I can model them up pretty easily or even just alter the kit parts.

In the process of converting the LNT-8000 frame for use as an LT-9000, I discovered that the Italeri LTL-9000 frame is just wrong. Most LTs and LTLs had the 13 inch straight rails. So that kit will need a corrected frame if I ever get around to it.

I'm test printing the wrecker body and mast now to dial in the thicknesses. I will start a build thread when I get some positive results. I'm dead set on taking this thing to the Nats.