Choosing a belt

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anvoice
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Choosing a belt

Post by anvoice »

Since I'll have to redesign many components of the printer anyway to fit some idiosyncratic parts, I thought I may as well go for a different belt than the 9mm or 12mm belts prescribed in the HD build. Specifically, I readily found 10mm, 15mm, and 20mm fibreglass-reinforced GT2 or GT3 2mm pitch belts. At the same time, my motors will likely have 14mm shafts. I managed to find 40 tooth GT2 pulleys with 14mm bores, but the widest I can find is 10mm. I probably don't want adapters on top of adapters for this setup to improve accuracy, so I was hoping to ask: has anyone seen a 40 tooth, 14mm bore GT2 pulley for 15mm or 20mm belts in the wild? Alternatively, would it be reasonable to use something like a 5mm pitch belt (considering a larger pulley should engage a reasonable number of teeth)?

Small edit: what I found and believed to be "GT3" belt was possibly just GT2 3mm pitch belt... I can't find much info on this, but a reprap wiki said genuine GT3 (i.e. new generation) belt was also available, which perpetuates the confusion between GT2, 2GT, GT3, etc... Am I correct in surmising that the GT3 stuff is trademarked POWERGRIP? Is there any benefit in getting a "POWERGRIP" belt of smaller width vs a regular GT2 of higher width (there seems to be more variety of GT2 available)?

ne0tec
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Re: Choosing a belt

Post by ne0tec »

14mm shaft, that is heavy! How about the motor inertia? Just a thought, but maybe overthink using such motors. It seems to be overkill anyway and making your project-build a pain in the ass. It will be an exotic version though, maybe that it just what you want. Thats ok :)

Take a look at this site, they have good product inventory with technical info and pictures.
https://uk.misumi-ec.com/vona2/mech/M10 ... 002000000/

anvoice
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Re: Choosing a belt

Post by anvoice »

Hi, thanks for your reply! I realize that it's heavy, in fact that's my least favorite part about DMM servos. The rotor inertia is .232 kg-cm^2, more than twice that of the Clearpaths. Which is one of the reasons (other being the small shafts on the Clearpaths) that I'm now leaning towards Clearpath servos after all.

I was going for the 5mm-pitch belts with the DMMs, but now I'll probably be going with 2mm-pitch ones and smaller pulleys with Clearpaths, although I'm finding 10mm wide belts more easily than 9mm or 12mm, so I'll probably go with that. I'll be doing heavy modding anyway so that shouldn't be too much of an issue.

Thanks for the link!

ne0tec
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Re: Choosing a belt

Post by ne0tec »

You're welcome.

I wish I could afford the clearpaths :) I think you won't regret it.
At the moment I'll stick with nema17 steppers, until I'm satisfied with the overall build. Not sure if I go for the clearpaths, since it will be very pricey to get them overseas with all additional costs.

I see a lot of hobby CNC machines being equipped with cheaper integrated servo drives, with pretty good results. Nevertheless I still think that a good BLDC servo drive with an separate controller is a better choice instead. But if I could get my hands on a pair of clearpaths, o yeah!

Just curious, do you or are you going to have a active build log/thread?

anvoice
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Re: Choosing a belt

Post by anvoice »

Yep, they're definitely going to increase the build price by 50% or so...

Depends on the interest. The forum is rather inactive compared to discord, but if there's enough interest I would definitely consider it. It would be a distinctly nonstandard build though: I'm likely to be using some parts from a CNC machine I was hoping to build once, and that's some massive linear rail :)

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