Need some advice on axis movement systems

Hello, I am currently working on designing my first printer. I need some help deciding what to use for the movement systems. I have seen a lot of pictures of printers with threaded rod systems, but also some with belts. Can someone give me some tips as to the advantages and disadvantages of each. In my head it seems like the threaded rods would be slower, but more acurite(depending on the threading) and belts would be faster, but prone to slipping. If I am wrong please let me know and I would love to hear any tips for a beginner. I am currently living in a college dorm and am not allowed to have appliances with open heating elements, so it will be a while before I get to the actual building.

My current plans include:
1 x Stepper extruder
4 x 17PM-J034-P2VS used stepper motors for axis movement(2 for z, 1 for x, and 1 for y)
1 x RAMPS 1.4 with an lcd control module and sdramps
1 x heated platform

Belts are faster. The belts used in reprap are toothed and so are not prone to slipping but may be prone to backlash if not tensioned correctly and used with the correct pulleys.

Screws are much slower, both in top speed and in acceleration. They are more accurate but belts provide ample accuracy for X and Y axis. Screws are normally used on Z axis which may benefit from the increased accuracy, doesn't require high speeds, and definitely benefits from not being able to fall if the motor loses power.

Theres also cable drive. This doesn't slip since the ends of the cable are fixed to the drums, otherwise its much like a belt drive.

stainless fishing leader line comes in heavy strength and some are using that.
spectra kite string also.
tantilus is a string drive printer. their results are very nice considering the string concept.
It bears consideration.

belts are great. they don't slip. they are very accurate and quiet.

www.econobelts.com has pulleys and belts.

Dave

Thanks, that is exactly what I was lloking for. How much slower are threaded rods than belts, and how big of a cost difference is there? I was planning on doing all three axis with threaded rods, but if I can find reliable belts for cheaper I would probably switch to just using threaded rods on the z axis. Is there a good web site where I could find threaded rods and belts for a good price?

I am looking at this extruder: http://store.qu-bd.com/product.php?id_product=11
Any suggestiond there?

Chelsea and team over at qu-bd has a nice thing going.
would save you from having to create the drive system if you only bought a hotend.
they are selling but might be a queue.


these two videos showcase the benefits of belts versus rods.
Helium frog [www.youtube.com]
rostock [www.youtube.com]

which brings me to some effort saving advice: make a delta printer. far less of every component, easy, fast, fun, the future.

Dave

The delta looks cool, bit it seems like it would be harder to control movement(mainly stay on a level plane). I am also trying to design a collapsable, portable printer similar to the on Ben Heck showed off at Maker Faire. I don't think this would be very easy to do with a delta. It looks like they take up a lot more room hight wise. Those videos did give me a good reference as to the capabilites of belts though and I think I will switch to belt for my x and y.

Well, I agree that you need to suit the project to your needs.
the level plane part is handled by 3 simple equations and a couple of set variables related to the geometry of the delta.

that is already written for you, so don't worry about that. there is a Marlin firmware with it integrated.
those equations just take a standard G-code and hash out a xyz movement for the towers.

Delta is not for everyone.

collapsible would be a first for a delta, from what I see around.

Other constructions are absolutely valid, useful, fun, easy and everything.

I might try a delta later on if I have a place to set up a permanent machine with a large print area. They look like they would handle that well.