Pulley or Lead Screw

Hey,

I am thinking of making some adjustments to my 3D Printer.

At the moment, I seem to be having some issues with my pulleys on my RepRap i2. I don't get clean edges, they are very rough and at different levels.

Anyway, that isn't the reason for my post.

My reason is this simple question, would it be possible to use lead screws (like for the Z axis) on the X and Y axis also?

I mean the concept is simple, but my only concern is that the motors wouldn't be able to handle the speed in which they need to move?

Any ideas or feedback would be greatly appreciated.

Thanks, ayouden

---

NFireLabs - The World First Modular 3D Printer - At An Affordable Price!

Using lead screws is very possible. The trouble with screws is that they are slow. Terribly slow, unless you find some screws with a steeper thread on them.
Have a look here for lots more info: [forums.reprap.org]
He's building a delta printer with lead screws.

Pulleys:
It sounds like you're using printed pulleys? They are probably one of the most critical parts in the printer affecting print quality directly. If you have sloppy pulleys then I'm not sure how you could use them to print nicer pulleys. I'd recommend buying some. Cheapest place I found was here: [www.tridprinting.com] (Disclaimer: I am in no way affiliated with the site). At 7usd for a set of 3 pulleys you can't go wrong.. unless shipping costs a fortune to your part of the world.

I am currently using aluminium T2.5 pulleys. (see image)

The main reason for thinking lead screws would be a better option is that pulleys bend and need to be reversed quickly, and the sharp turn in speed may make the cable bend therefore giving rough edges.

Thanks

---

NFireLabs - The World First Modular 3D Printer - At An Affordable Price!

tight? are your belts tight. Very tight.

Also,.. what's your idler like at the other end ?
On my printer I have a half twist in the belt as it goes across the bottom, so that it goes round the idler on the smooth side of the belt. I think this helps.

When i built my printer, they advised NOT to do up my pulleys extremely tight, but maybe i should try it and see what happens.

---

NFireLabs - The World First Modular 3D Printer - At An Affordable Price!

Initially I was going to say "oh so you're using T2.5 pulleys" but, just looking at the wiki page and reading this thread it appears it's not a source of backlash if they're setup properly.
The T in T2.5 means Timing. The belt has a square tooth profile and was intended for driving stuff in one direction, not precision positioning. GT2 belt and pulley profiles on the other hand have parabolically shaped teeth, specially designed to avoid backlash. Having a read in the thread it sounds like T2.5 can be used just fine if you set it up right.

At high speeds or accelerations it can jerk pretty hard and show up in the prints. My current repstrap old flatbed scanner mashup isn't the best but it works fine going really slowly at 30mm/sec and with an acceleration of 150mm/sec^2. I haven't got a hot end on it yet (in the mail) but just drawing with a pen you can see the difference by going slower. I find 60mm/sec is fine but slower makes it nicer. Maybe worth to have a play and see what works best for you? A picture of the problematic prints would be helpful.

Here's a picture of what problems with a T5 pulley idler end look like: [forums.reprap.org]