Noob Post:Need Help in building a repstrap

Hi Reprappers,
I am an electrical engineer by education and know about the stepper and control aspects of 3D printers but the mechanical nomenclature confuses me a lot. I want to build a rep strap as cheap as possible while not compromising on the key aspects.I have access to a laser cutter in India and can also 3D print some parts provided they are in budget.
I have read the website most of it and really love the revolution it more of a cult that empowers. There are a lot of people selling 3D printers in India but they are very expensive for a student/lab to afford.
I have also build my own stepper drivers based on TI`s DRV88xx series and have tested them to work with bipolar motors. That will greatly reduce the costs as i already have an arduino and hence the cost of electronics would be greatly reduced.I also know some basics of 3D designing in SketchUP and OpenSCAD ! I also got the opportunity to 3D print a Box i made in sketchup while doing an intern that was really exciting.I can also do some 2D designing in Corel (This is becoz my laser cut parts supplier excepts only cdr )
That was my background. Now here are my questions:

1. How to get started? Mechanical know how?
2. I don`t want to concentrate on aesthetics.Low cost and functional is all i want. Can you suggest some standard repstrap/repraps?
3. I have heard a lot of people using Marlin Firmware. Does it run on ARM CortexM4 or only arduino? I can work on porting it to TI's TIVA based processors.
4. Where to source parts for mechanical construction? Do standard hardware/ machinery repair technicians stock them?
5. The extruders ? Is there any one with that can be made with a laser cutter or better comes as it is i.e. you can buy for cheap?

Thanks a lot! Hoping for a reply soon!

Rohit

When I started out trying to figure out what to and how to build my printer I started here [reprap.org] .
I looked through the designs and read the contruction manuals. THen I based my printer off of what I learned from them.

If you have access to a laser cutter and a 3d printer now, things should be easy. You can get the lay outs for parts for the laser cutter, and you can print your exstruder and other parts very cheaply, a 1 roll of ABS ($30 US) would do it. I would look at the Prusa i3 bucause it has a laser cut frame.
For the other parts, look on the internet, there are tons of suppliers, and if there are sellers in your area, that may be willing to sell you the rods and other part.

Thanks a lot for the quick reply!
I got the printrbot LC plans of thingverse it seems pretty easy to make! everything is laser cut. The scraps dealer in my area is selling some HP deskjets for less than $5 . I plan to recover some of the gears and belts from there and also the linear bearing from the print cradle. Which is better i you view? PrintrBot LC or Prusa i3 to assemble and has lesser 3D printed parts as by access to 3D printer i meant that i know a dealer who can print for me the parts i send him.. much like ponko .

Thanks a lot for helping!

I think the prusa is a better printer.. but that is just my opinion. Not sure which has less printed parts, I'd have to look at the builds. Printers are a great source for parts, scanners too.

Personally I prefer printrbot plus v2. I have a friend with an prusa i3 and hes always telling me that he wishes he would of bought a printrbot. Mine has grown as my needs have evolved. I have extended the z and y axis to about 17 inches which is well more than enough for most uses. I have modded it for very cheap and it runs like a dream.

I am currently building a printer called the JunkBot. I took a bunch of reusable and recycled parts to build it. I have about $100 invested in it. I have a build log on the JunkBot as well as all the mods I've done on my printrbot plus v2 hybrid on my site which is linked below within my signature. Either way you go, you cant Go wrong as the prusa and printrbot both have a huge community. One thing that was a big factor for me is how helpful the people at printrbottalk.com

Good luck with your build.

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Thanks a lot for words of encouragement..
Im too currently building one from scraps ! More of Prusa and printerBot mix. I intend to make it print parts for reprap and then make a reprap and convert the older one to a CNC ! Thats quite ambitious but i am working ..

Thanks a lot!!

That is what i did.. just finshed printing the last part to make mine more reprap then rapstrap. I printed a new frog for the bed, x ends and carraige, einstein variant extruder ( my puchased wades was printed very poorly) and i picked up a couple new motors to replace the questionable ones I have been using. Iam excited to do the upgrades, but also a little fearful because it works pretty well now and i may just be asking for trouble.