What are the advantages/disadvantages of using synchromesh cables instead of belts?
Some 3d printers use synchromesh cables instead of belts. For example, the Deezmaker Bukito (http://bukito3d.com/) and a number of RepRap conversions.
Photo from http://christophergranz.com/?p=449
Are they significantly better than GT2 belts? What are the challenges?
Yeah, I saw that, just curious if anyone here had different thoughts. Terence's answer is a load of crap. (Metric firmware? Yeah right. Gcode coordinates are floating point so it's irrelevant whether the steps/mm is integer or not.)
I noticed that your question has not had much activity lately, are you still looking for an answer to this question? How might we be able to close some gaps?
Looking at the specs for both the GT2 belt and the Synchromesh I'm very hesitant to recommend a Synchromesh over a belt.
The first thing that sticks out is that there are both error and cumulative error specifications for the Synchromesh. For a device like a 3D printer, I don't like the idea that of my axes can accumulate up to ±0.16 in. of error over 100 pitches (the pitch is between 0.12 in. and 0.25 in. so that is 12 to 25 in.).
Contrast this to a belt where the only way you have a cumulative error is if you skip a tooth and I think the winner is the GT2.
Looking at the non-cumulative pitch error both products are comparable but again the belt wins. For the Synchromesh we have an accuracy of ±0.002 in. versus ±0.0003(1) in. for a 2 mm GT2 belt and ±0.0012(1) in. for a 3 mm GT2 belt.
Note: I can't be certain about exact values for error since there are no numbers for the GT2 - only a stupid chart. I also have a hard time believing that error is not a function of total length for both the Synchromesh and the GT2 belt but I'm not the manufacturer. However, since both products are made by the same company I wouldn't be as concerned about them trying to oversell one product over the other.
In conclusion, I don't see of any reason to choose a Synchromesh over a belt if your physical layout is compatible with both. As pointed out in the marketing material for the Synchromesh, it can be routed along 3 axes whereas a belt works best along a single axis. The Synchromesh seems to be a product designed for a very specific application...
I've heard from people that use synchromesh that the cumulative pitch error doesn't actually cause any issues. They say the pitch is consistent and much tighter than the spec, so it doesn't cause any issues at normal printer scales.
@RyanCarlyle, I don't doubt the product may perform better than specifications but choosing components based on "may perform better" does not seem like a wise decision unless there are other motivators. You asked "are they significantly better than GT2 belts?" I answered "not according to the specs".
It's a fine answer, I'm just pointing out that the people using its end to think it's better than GT2, and it would be nice to talk about why that is.