Total noob Advice on buying

I have been researching for the last couple of weeks what kind of 3d printer would be in my price range, around £300. I have been looking at many PRUSA i3 variant on ebay but it is hard to tell which are good quality. I am in need of medium/high quality parts as I am wanting to print small gears and alike.

I could get 90% of the kit at a very good price having many friends in the engineering business, but having no prior experience of putting one of these things together, I don't know weather I would be better purchasing a kit and then upgrading it slowly to a higher spec.

I have been looking at this as It uses "better quality" machine screw for the axis screws, which was a plan of mine from the start to gain higher accuracy with less backlash.
[www.ebay.co.uk]

Please advise. many thanks Luke

I'm a Prusa i3 kit customer, with no experience when I bought mine. Today if I would buy another kit, I would look forward :

- Quality 48mm nema 17 motors.
- Aluminium frame (or 10mm MDF)
- 8mm leadscrews with brass or derlin nuts (threaded motor axis, the better)
- geared extruder
- branded (or good copy of) hotend : hexagon, E3D, JHead, alike
- Wire management (sleeving)

BUT, it'll be hard to find all into the same kit. You'd rather follow or write your own BOM (bill of materials) with the help of members or a fablab in your neighbourhood. Because all the kits will use rubbish LM8UU chinese bearings, cheap wires, and so on. Better buy better components at each step and build a good machine. Maybe it will cost a bit more, depending of your expectations, but don't be cheap.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

That's what I worry about with the cheap kits. As they give you unrealistic accuracy tolerance numbers like 0.0004mm but I am presuming this does not take into account cheap sloppy fit lead screws, bearings and gears that could easily lower accuracy down to something like 0.5 mm. The thing that is holding me up on being confident to build my own is One, that I want to add my own high accuracy lead screws and equipment but I'm unsure of compatibility to off the shelf plastic parts, and Two although I have a certain amount of experience I have no idea on the electrics setup as Iv never seen one running. Hence wondering if I should play with a cheap kit and upgrade as required.

I see allot of very rough prints online and I don't understand why a very high resolution cannot be attained reasonably cheep so long as quality screws are used as from where I see it even if you had cheap motors and lose a few steps here and there it would not have anyway near a much of an effects as a sloppy gear train.

Edited 1 time(s). Last edit at 03/02/2015 08:46AM by ltaylor88@aol.com.

Well, even here, the accuracy values are theorical and pretty enthousiast. Through, the FDM technology won't give you a 0.5mm overall precision anyway. To give you an idea, in comparison of a plastic injected part, at a distance, a printed will look the same. In hand and looking closely, the parts produced are rough indeed. But it does not realy matter. The important thing is that the printed parts are functionnal and cheap to print. Anyways, repraps are prototyping machines, not production ones. That means you must admit some inperfections, or add a further step on finishing and coating.

So it ain't necessary to overestimate the precision parts needed. For example, a ACME leadscrew with a good nut will do the job with a comparable accuracy of a ballscrew. The fused filament technology won't allow you to see any difference. You need good guides and bearings, but they will never hold a lot of forces, so it won't be necessary to buy expensive linear rails. Keep in mind a 3D printer's head must stay light enough to allow fast movements, with quick acceleration and direction changes.

As you said, you have two choices. First you follow a BOM with the help of a fablab or members here. Seccond, you buy a kit and will improve it step buy step, printing needed parts with it. To me, the first solution will cost you less and at the end it'll be quicker. I still want to improove some clumsy parts on mine. I changed 60% of the provided parts, some were costy, and there's still some work to do, but I'm done. I'd rather start to build a proper printer instead. As you can see, if you're demanding, sooner or later you'll build your own printer. If you're not confident enough to build your first printer, don't waste time and money, buy a proper printer or kit now, like a Makerfarm I3v or an Ultimaker or so. It will cost you approximatively the same than to buy a cheap kit, then uprgrade it. Except if you want to work on the machine itself instead of using the machine on other projects.

Edited 2 time(s). Last edit at 03/02/2015 10:33AM by Zavashier.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)