That's the fun of it, seeing it evolve rather quickly.Originally Posted by bmorgil
Exactly! That is the nice thing about digital design. Once you have it right, you can do whatever you want with it. Having the proper tools (CNC, Plasma cutter, metal printer etc...), I could machine one that is twice the size of the real one without any more work on the design side.
You are totally right, it takes years for engineers to bring a new design to life. I'm struggling to copy something that was designed so long ago, I can only imagine how complex modern car/mechanic design have evolve over the past 80 years.
There are a few options to strengthen the parts. The easier one is to use more robust filament. ABS, Nylon and some filament engineered for strength already exists. These options will need to be studied. All of them have advantages and drawbacks.
For instance ABS stinks when printed and the fumes are toxic.
Nylon is finicky to print with, it's prone to capture humidity and when it does it prints awful.
Engineered for strength filament is expensive for hobbyist.
Not sure if the Nylon or engineered filament can be painted either. Lots to think about.
On the bright side, newer and tougher PLA is getting on the market regularly. It's just a matter of testing them
For now I will keep overbuilding and cheating when it does not interfere with original look.
One other option that you suggested is to reinforce with steel. I know that some people insert magnets while printing. For instance, they will design a pocket inside the part. They will pause the print where the pocket is halfway done, insert the magnet and resume printing. Using this technique I could embed small metal rods/pins to strengthen the part.
Options are available.
When I say I'm struggling to copy this design, here's the most recent example, Having fixed the front shock and established that the core front axle was fitting, I decided to do the same right away for the rear axle.
Then I noticed that my two axle where not align horizontally.
073.jpg
To get them to align I would need the core of the rear axle to be 1.6 times bigger than the front axle core. That would obviously be apparent when you looked at the two axles. I had two choices, first redo the frame so the front end is lower by 3mm. Second, change the rear springs radius so it is flatter, thus bringing it higher.
I chose the second option.
This is the original rear spring design. A series of circle with the smaller circle at 356mm and the larger one at 368mm
074.jpg 075.jpg
Now how do I get the smaller circle to move up about 3mm. I don't know. I'm sure a mathematician would've come up with the answer and it probably has something to do with PI and all that stuff I was not listening to in school.
My way was a bit longer, I changed the values of the original circles until I got close. It did take a while because the final value of the smaller circle is now 612mm
Now both 10mm axle cores aligns horizontally
076.jpg
As you can see from the picture, it is way flatter. This is one instance where I think I can get away with cheating. And is it really cheating? I don't even know the right dimensions of the spring, I'm working by eye. So most of this Jeep will never be to spec anyways.
Since I need to reprint the spring for toughness, might as well add some features that will be required shortly, namely a way to attach the future axles. Now the U bolts are not an option for me. So I will install a screw from underneath. But I will have fake U-Bolts so it looks the part.
077.jpg
Ok thats enough for this morning.
Reply With Quote