3D printed Sherman track links

[Adrian Harris]

Thought I'd stress test my 3D printer with some track links:

20 tracks links in one batch, made from TechABS black filament, at the printer's highest resolution and 100% infill.

19 hours down 65 hours to go

Adrian.

[Adrian Harris]

40 hours down 44 hours to go :

Adrian.

[Chris Hall]

Adrian -

Other than time, have you costed materials, electricity, general wear and tear and any other costs ?

I think 3D printing is the future but, like Nuclear Fusion, it's always 30 years away ...

Chris

[Adrian Harris]

I will need to check once the print is finished but I believe the raw cost of the plastic was about £12.

But as you say, factor in the cost of the printer (RRP is around £1200 for this model but mine was secondhand), electricity etc and the cost will jump.

I think the next project will be to use the 3D printer to make masters for lost wax style casting. However, whilst its very easy to knock up a CAD drawing for geometric shapes like these links, parts with lots of compound curves may be quicker to produce with carved masters, due to the time it would take to produce the CAD drawing required. Having said that, once you have the drawing, there's no problem with degradation of the master as you can just run off a new one whenever it is required.

Time is the big factor with this printer. 20 links will have taken 84 hours, and you need 160 for a Sherman, so that's 672 hours of printing if doing batches of 20, or 28 days. I'm seriously considering buying a second printer, to reduce the timescales, but of course that adds massively to the overall cost.

Adrian.

[Dennis Jones]

Are plastic links any good though Adrian ?

Dennis.

[Maarten Schutjes]

Hi Adrian,
Choosing a lesser infill % than 100 also reduces time and plastic.
In my experience it's even stronger than 100% infill mainly because it has some flexibility. 100% infill tend to break faster.

[Robert E Morey]

Adrian,
I didn't know you had a printer!!. Between the CNC lathe and printer you have some neat toys? Are you printing these links for extra detailing or actual RC use? I would think resin casting may be better, and a bit faster? 3D printing is great for making masters. Interested to see what the goal of the project is/was? Sometimes its fun to make parts because "you can".
Bob

[Adrian Harris]

After 84 hours, the links are done:

Dennis - I have no idea but once I get the BARV back up and running, I will give them a test. Because of the Sherman track design, with the separate end connectors, these plastic links never touch the sprockets, so as long as they can take the track tension needed for the Sherman model, the only major wear should be the part which touches the ground.

Maarten - Thanks for the info. I may try a set at a reduced infill but they do need to take quite a lot of tension when running, so I think bulk of material may be more important than flexibility.

Bob - Yup, no kids so lots of toys for me Hopefully they'll be fully operational tracks. I wanted to recreate the look of the Sherman rubber block links, and can't think of any way to do that without using something like RTV rubber and moulds, but each link would still need a metal skeleton for the tensile strength and that would be a pain to get in the right place during the casting process, and I don't think at this scale the rubber would be thick enough to survive turns on rough surfaces without being ripped off the frame.

Adrian.

[Adrian Harris]

Whilst waiting for delivery of the tools I need to get the BARV operational, I seem to have bought one of these:

Adrian.

[Adrian Harris]

This is the first attempt at the T49 link, thrashed out in PLA on the medium quality setting.

I still have to add the end plates and find some way to round off the ends of the treads.

Adrian.