just seen this belt-less printer - the prints looked amazing. too bad i could not see it working 
I wonder how well it will hold up to wear and tear.
ehhhâŚ
Belts have proven to be precise and reliable. As with any mechanical system it depends on the design, and also on the quality of the components. Cheap chinese belts and pulleys, sure you can say they have back lash and cause print defects, but I would really like a comparison between genuine quality belt/pulley vs. rack and pinion. The rack and pinion also introduces design challenges due to the limitations of implementation. Motors have to be mounted on the movement planes and the rack must also be precisely in line and parallel to the movement plane. Also I have never had to âre-calibrateâ after replacing a beltâŚ
I like the idea though, I have no doubt a rack and pinion can be very precise and give good results, however, the system requires more precision in the execution of implemented components when compared to belt driven motion systems.
I call bullshit on their video. Iâve got one machine that is on 1600+ hours with the original belts. In a properly designed machine, belt stretch is negligible and wear is very slow. And their belted example is just poorly tuned retraction and the rack and pinion print wasnât all that great. They used a darker color plastic in the video to obscure their problems. Worse yet, they put the motor on the gantry, adding considerable moving mass that wouldnât have to be there if the machine was belted.
Helical racks are fine. Belts are also fine. I donât have a problem with either of those. But I really donât get why these guys threw tons of custom premium parts into the gantry but used crummy round rods. The cost is way too high for the quality they seem to be getting.
Ugghh their website is full of industry fluff jargon âExtruder designed and manufactured entirely in stainless steel for 2.5 more useable lifeâ compared to what?? I bet MSRP is well over $3k.
@Jeff_DeMaagd if you use quality belts, yes. If you use belts without reenforcement (generally steel cable inside) then they stretch. You get what you pay for.
Iâve also seen a few UM2 machines with stretched belts, which was always due to head moving repeatedly into the side of the machine for days.
In some fairness, I counted belt selection as part of the design. Itâs a weird leap for someone to go from cheapie Chinese belt to far more expensive rack and pinion. Thereâs plenty of legit places for rack and pinion, I think they made a lot of counterproductive design choices.
@Kyle1 the msrp is something like 5k if I remember right.
great idea- using a rack and pinion instead of a belt. Too bad they patented it 
I recently started using 3D printed rack and pinions connected to DC motors on two-leg robots. I find that even with PLA they work well, but occasionally a gear tooth breaks.
@Ted_Huntington i will never understand how can anybody patent something like rack and pinion drive⌠i think the whole patent system is a huge screwup
@Cristian_Nicola yeah, itâs absurd- the rack and pinion is very old- but people endlessly argue that there are new variations- like on a stepper motor, on a 3D printer, with slanted gear- and so onâŚto try and make it appear unique or new. But itâs the publicâs own fault for not voting down such a system which they can do through ballot measures and representatives- although its a lot of red tape.
Pretty sure any patent actually granted on this would have to be VERY specific, like the exact arrangement of components or something. Thereâs way too much prior art in CNC mills for any broad patent to get granted here, even by âbad patent examinerâ standards.
But how can you all not be enticed by the extremely brightly painted fingernails demonstrating this?
Marketing paid a model to demonstrate it, really badly with no context, but still a totally disinterested 3rd parties hands were involved and they were painted brightly, so people should rethink their negativity and be attracted to this, because marketing tried so hard to do the same damn thing they always do. Those hands looked familiar, I think it might have been the rep from the TCT XYZ interviewsâŚ
This is hilariously.
I ran my Rigidbot for 3 years with the original belts.
I also use leadscrews on both my lasercutter, CNC and other 3D printer.
Rack and pinion unless cut in metal with high precision profile will provide no benefits over belts and certainly not over leadscrews.
Placing motor within the gantry also means beefing up the linear rails for added support to avoid flex.
I think the patent will likely be useless because anyone with any thought will think of the high end CNC devices and go with leadscrews.
@Ted_Huntington You cannot patent the rack and pinion system - there is no novelty in this âinventionâ. Rack and pinion is used in CNC machines for years and 3DP is just another type of CNC. If you would like you can easily argue with their claims.
@Przemyslaw_Jakubczak I also wander who gave them the patent for such thing - as this solution has been used before (2012): https://www.thingiverse.com/thing:22475
@Przemyslaw_Jakubczak thanks for the link- yeah that is amazing- I wonder how well that rack and pinion configuration works
@Ted_Huntington Here is another example from 2014: https://www.thingiverse.com/thing:383858. Anyone knows what organization should be notified about this patent, as it seems is patenting somebodyâs else idea.
https://www.thingiverse.com/thing:383858
@Przemyslaw_Jakubczak for US patents, there is a process to inform the USPTO that you think the patent is invalid, and they can launch a review. Itâs kind of a pain though. Iâve tried it before and had them reject my challenge because the prior art wasnât documented/formatted right.
For practical purposes, a patent with existing prior art has no enforceability, because it would get struck down in an actual lawsuit. So companies typically donât try to stop infringement when they know the patent is weak.