Making a car pattern from a 3D modelling programme

[kurtiejjj]

Thanks for that SZ, that's great stuff! very much the things I wanted to know. very good to know that there is a programme which can transfer CAD thingies to machining code. I will look into this more in the weekend when I have some more time, thanks again!

[Carlos]

Xylotex includes driver/circuitboard/modules and motors. Great! Solsylva is a redirect to David Steeles's 3 axis CNC plans. A variety of CNC tables can be built. Simpler and more straightforward than one might think. These sites are informative & definitive. Look's amazing what these machines can do and how building is something that can be accomplished with general skills - without being a millwright or IT code expert. Inspiration and enough advice to build a machine.

Good to have you onboard SZ. Very Generous - Thanks



http://www.solsylva.com/cnc/cnchome.html

[SZ]

cheers, though no thanks to me, thank the people that put time to compile good plans (it's a lot of work). i'm just happy to pass on knowledge )and keen to see results )

always work with the mentality that there's a cheaper, more effective way of doing things, and life is pretty sweet...

[kurtiejjj]

again thanks for pointing to the links,might be good for the future when I want to have my own CNC thing.

But for now I think it would be better to concentrate on the CAD design part which is difficult enough on its own. Regarding what materials to use to make the pattern I'm not too sure any more about foam as it's not something flat and with a clean shape I mean I will have to finish that of with some kind of resin before I can take a mould from it. Which will of course that the pattern's size will be increased by 1mm or something like that in the progress. Which will of course affect the size of the end product, as it's bigger as intended.

To solve this maybe aluminium would do better, however more difficult to work with and more expensive it will be mainly a flat surface when finished and if neccesary after polishing.

However what about other sorts of plastics any ideas?

[SZ]

it all depends what you want to work in as a material for the part.

foam is seriously OK for a good surface finish. of course the top layer won't be foam; it's an acrylic filler. so the foam is undercut 5-25mm (depending on the part), the filler is sprayed on, and that's cut again (e.g. CNC) to the final finish. a skilled operator may opt to skin that with a very fine layer of fibreglass.

if it's a really small part, craftwood (or any wood that's easy to machine in any direction without splitting, and that gives a nice, hard finished surface) is OK too. to take a mold or a part i'd actually have the plug machined in wood, then sand, spray paint/seal, mold release wax/PVA/both and take off a fibreglass mold. you can use a tooling gelcoat for your first pass in making a mold and back it onto fibreglass. just be sure to take the mold in as many parts as you need to have it come off (and not stick).

you could even do the above by making the master yourself in wood at home, if the shape is not too complex.

most composites to make tools from are either very expensive (e.g. tooling grade composites) or are a real --- to cut (as they overheat, melt, etc, so to avoid this you cut rough and fast, defeating the point). you could try in delrin though the tolerances aren't fantastic with it and you're cutting very fast and very fine for a good job. it's also not cheap (unless you want a round bar of it).

soft grades of aluminium (3xxx, 5xxx) are actually not too hard to machine, but yes, the tool cost can be excessive and the surface finish not wonderful. if you have machine swirl in there that you didn't want, good luck sanding it out!

if you really want an inexpensive plastic part, one that has to be super flat, i'd not make the job complicated. make a plug from a flat piece of wood and whatever else you need machined on, finish it how you like and fibreglass to your heart's content. with due care and attention - not a great deal of skill, just care and attention - you can make mirror finish molds in your backyard.

my 2c... if you can post a vague drawing of what you're trying to build maybe we could help out a little better. would be happy to try.

cheers
SZ

[kurtiejjj]

Sorry that it took so long, but to give you an impression what my idea is here a blueprint of a toleman:



Now of course you can't design this in one piece in CAD. I was hoping someone could do the tub in CAD, as I found out I can't do it without learning it for a year (which I will), but for the moment it would be great if someone could help me out. I will give them a little something if that would help .

I know this drawing isn't detailed enough and ideally you should have one seperate drawing of the tub and other parts, I'm on to that, not of this toleman but of the F2 toleman. I know a few people who might have these drawings, so fingers crossed I can get a copy.

I have a few detailed photos of hart turbo engines and again know someone who could help me get a few drawings, as he rebuilds these things from time to time beside his main work on rs500 engines.

Great thing about doing this CNCing is that I can learn from it for when I design something myself in the future.

Well I hope I've updated you enough on my plans.

PS. is Tom interested (check PM)?

[SZ]

yes, you can build it all in CAD using a 3D printer, it'd just be horrifically expensive

if you're not planning on making money from this i would suggest you get yourself an educational copy of solidworks (may need to enrol in a class or similar). very easy to use, considerably inexpensive for proper 3D CAD and more than powerful enough to model this.

if you plan on generating drawings, making a model from a fully dimensioned drawing is pretty easy.

this isn't unreasonably difficult, with more specific drawings quite easy even.

PS (anyone) aren't there freeware 3D CAD packages out there?