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Belts - Whats the best you can buy?

Posted by DjDemonD 
Belts - Whats the best you can buy?
May 25, 2017 05:08PM
Most of our printers use GT2 belt. So whats the best GT2 belt you can buy? I've tried steel cored it didnt work for me as my pulleys are too small (16t), and the steel wires break.

Can you actually buy Gates original belt in this size?

Does anyone know if a carbon reinforced/kevlar reinforced version exists? and where do you get it from?


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Belts - Whats the best you can buy?
May 26, 2017 12:47PM
No one? We strive for ultimate precision in almost everything but we are happy with £1/meter belts from China? They are a vital component.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Belts - Whats the best you can buy?
May 26, 2017 01:20PM
could be what we have for £/M gt2 belts is good enough... only other belt I've seen is MXL "on the overlord" but do we really need kavlar belts.
Re: Belts - Whats the best you can buy?
May 26, 2017 01:23PM
I'd say my two larger machines were both better with steel/pu belts they just didn't last very long.

I just find it odd that we all spend a lot on rails, motors, machining, tooling plate and then settle for cheap belts, so either they're good enough, which I'm questioning, or we are overlooking a core part of the system that we could improve by spending ?£3-5/m instead.

Edited 1 time(s). Last edit at 05/26/2017 01:46PM by DjDemonD.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Belts - Whats the best you can buy?
May 26, 2017 01:54PM
Quote

I'd say my two larger machines were both better with steel/pu belts they just didn't last very long.
yea I was surprised to read you managed to break cables inside been/was considering them for an upgrade.


Quote

or we are overlooking a core part of the system.

dont think it being overlooked they are what they are and we dont have to pay a premium for it. just something I dont come across a lot " folks having to swap out belts because of being worn out!. think we would but how many us associate degrading print quality to worn/stretched belts. I haven't read of anything better than GT2 on repraps and when they do go they're cheap enough not to think about.

one could ask do we really need belts? lorenz
Re: Belts - Whats the best you can buy?
May 26, 2017 02:01PM
Neoprene Fiber Glass Reinforced


Polyurethane Steel Cords

Re: Belts - Whats the best you can buy?
May 26, 2017 02:32PM
I think testing the quality is quite hard...we rely heavily on manufacturers specs for this which just arnt available, or are false if you get from cheap Chinese .
Re: Belts - Whats the best you can buy?
May 26, 2017 02:40PM
Thanks for the link on the "Gates" belts, this might be what I'm looking for, if they're genuine, much obliged.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Belts - Whats the best you can buy?
May 26, 2017 02:56PM
I'm currently leaning towards 9mm 3GT belts (gt2-3m) for my large design to fight against stretching and what-not. still not sure if that will sacrifice on backlash or not though...but that could be another option.
Re: Belts - Whats the best you can buy?
May 26, 2017 03:22PM
I've decided to go with 2.4A 0.9deg steppers, 9mm PU/Steel belt and 32T pulleys (for a delta I'm putting together so I don't have much experience). I do think 9mm wide belt maybe a little overkill as PU 6mm steel reinforced belt I have seems very strong but for $15 extra (for larger belt and pulleys together) I just went with the 'bigger is better'.

Edited 1 time(s). Last edit at 05/26/2017 03:38PM by newbob.
Re: Belts - Whats the best you can buy?
May 26, 2017 05:56PM
Ive run the steel PU2.5mm belts in my printers for year. The main thing to remember with the steel reinforced belts is they don't like small radius's and benefit from toothed idlers, other than that i find them a great belt once tensioned.

I also had a Delta that I ran with fibre reinforced belts as it was only a mini and could not justify having the bigger ends just to get a bigger pulley for the PU belts. The thing i found with the fibre was that it took a wile to settle, as in, I was continuously applying more tension for a couple of weeks till the fibres settled out.
Re: Belts - Whats the best you can buy?
May 26, 2017 07:19PM
What kind of drive?

How many moving hours on belts?

confused smiley
Re: Belts - Whats the best you can buy?
May 26, 2017 08:15PM
Quote
cozmicray
What kind of drive?

How many moving hours on belts?

confused smiley

Yeah good points, Its not something I keep on hand (I guessing most people dont). My recommendations above are based on light usage, maybe 15 printing hours a week, with my longest prints an average of 6 to 8 hours.

I always give the printer a quick once over before a print and dont really have any preventative maintenance planes or keep a printing log, after over 10 years of building and running these types of printers i sort of have a good idea of what will fail when.

As for the drive, like most people, direct drive from the motor.
Re: Belts - Whats the best you can buy?
May 27, 2017 01:39AM
I want to drive the ballscrews of my CNC mill with 1:3 closed loop belt reduction.
I was thinking of HTD3M 9mm belts and pulleys. ( IIRC they are PU/fibre type )
What's good enough for digital_dentists CoreXY is good enough for my mill. At least I think, that's what he was using for his z-table...
Re: Belts - Whats the best you can buy?
May 27, 2017 02:28PM
X, Y, Z Drive configuration?
Core XY?
Belt X over Y?

How long the belt?

Complete belt failure or just wear?

perhaps "non-use " degradation
Perhaps un-tension while not in use

Perhaps accept belts need to be replaced every 100000 hours?


How often do you inspect / replace the belts on your car?

confused smiley
Re: Belts - Whats the best you can buy?
May 27, 2017 02:44PM
A maintenance schedule is a great idea and RRF and marlin come with some log writing built in but we still don't have a odometer to help us know when to service.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Belts - Whats the best you can buy?
May 29, 2017 08:55PM
I've had the same set of neoprene/glass MXL belts driving the spindle (1000-3000 RPM) of a homemade milling machine for about 15 years. I don't worry much about belts wearing out.
Re: Belts - Whats the best you can buy?
May 29, 2017 10:08PM
Quote
LoboCNC
I've had the same set of neoprene/glass MXL belts driving the spindle (1000-3000 RPM) of a homemade milling machine for about 15 years. I don't worry much about belts wearing out.

I would have to agree with this statement, Unless you are printing 24/7 with some massive loads on your carriages I dont think you would need to worry too much about the belts (as long as they are installed correctly, ie. no rubbing and parallel). You might get some wear on some of the teeth if you continue to pint the same size object, but you can just rotate the belt to counter act that. I would say more design thought needs to go into the belt path, tentioning, masses and motor selection then the belt itsself.
Re: Belts - Whats the best you can buy?
May 30, 2017 04:29AM
LoboCNC, Scottybfg I take your point on belt wear, I am sure these belts can remain functional, in the situation above driving a spindle, for many years. However that's not the criterion I am considering, which is belt accuracy. To be told by a few people now, a gt2 belt isn't even 2mm pitch unless its under quite a bit of tension, and that they might indeed stretch, just makes me question why little care or attention is given to them, we take them for granted.

Its a bit like tyres isnt it? On a normal run-around car, premium tyres are not really worth it, but on a high performance/race car and they are probably the most important part on the vehicle.

Edited 1 time(s). Last edit at 05/30/2017 05:56AM by DjDemonD.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Belts - Whats the best you can buy?
May 30, 2017 09:05AM
To me the most important specifications when choosing the belt were backlash and repeatability. I picked GT2, 2mm pitch for lowest backlash and 10mm width for repeatability.

As per sdp-si.com, GT2 2mm belts have lowest backlash (equal to or slightly better than trapezoidal belts), that is much lower than GT3 3mm or HTD belts. GT3 3mm and HTD belts are more suitable for CNC machines than 3D printers.

Edited 2 time(s). Last edit at 05/30/2017 09:08AM by newbob.
Re: Belts - Whats the best you can buy?
May 30, 2017 10:20AM
I've been using genuine belts (Misumi/McMaster/SDP-SI/Gates) just because they are pretty cheap and these suppliers keep a wide inventory of belt lengths. I have noticed that open lengths of belt are quite unusual in industry and are sometimes quite expensive - You can only buy genuine 3mm/15mm Gates in 100ft rolls and they list for >$400USD.

Steel core belts aren't really ideal for low force applications like 3d printing, and they also require larger pulleys or the wires will fatigue. You see them more often in large CNC routers that deal with high cutting forces.

Fiberglass has one of the best overall combinations of properties which is why it is so commonly used. It is actually quite stiff, the main drawback is poor shock handling.
Re: Belts - Whats the best you can buy?
May 30, 2017 11:10AM
Quote
691175002
I've been using genuine belts (Misumi/McMaster/SDP-SI/Gates) just because they are pretty cheap and these suppliers keep a wide inventory of belt lengths. I have noticed that open lengths of belt are quite unusual in industry and are sometimes quite expensive - You can only buy genuine 3mm/15mm Gates in 100ft rolls and they list for >$400USD.

Steel core belts aren't really ideal for low force applications like 3d printing, and they also require larger pulleys or the wires will fatigue. You see them more often in large CNC routers that deal with high cutting forces.

Fiberglass has one of the best overall combinations of properties which is why it is so commonly used. It is actually quite stiff, the main drawback is poor shock handling.

Magnitude of force is not the reason to go with a steel reinforced belt, but rather belt stretch at elevated temperatures. I'm curious why shock handling is an issue when you write that 3D printers don't handle high forces?

Edited 4 time(s). Last edit at 05/30/2017 11:15AM by newbob.
Re: Belts - Whats the best you can buy?
May 31, 2017 02:20PM
Quote
newbob
I'm curious why shock handling is an issue when you write that 3D printers don't handle high forces?

I just noted it in a general sense, its not a drawback for 3d printing so fiberglass is a good choice for us.

In general I'd assume that overall frame and stepper compliance contribute significantly more error to the average printer than its belts.
Re: Belts - Whats the best you can buy?
May 31, 2017 05:54PM
Quote
691175002
Quote
newbob
I'm curious why shock handling is an issue when you write that 3D printers don't handle high forces?

I just noted it in a general sense, its not a drawback for 3d printing so fiberglass is a good choice for us.

In general I'd assume that overall frame and stepper compliance contribute significantly more error to the average printer than its belts.

I'm sure you're right, but how much? We spend a lot of time and money on frames, motors and controllers, very little on belts.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Belts - Whats the best you can buy?
May 31, 2017 07:21PM
Quote
newbob
To me the most important specifications when choosing the belt were backlash and repeatability. I picked GT2, 2mm pitch for lowest backlash and 10mm width for repeatability.

As per sdp-si.com, GT2 2mm belts have lowest backlash (equal to or slightly better than trapezoidal belts), that is much lower than GT3 3mm or HTD belts. GT3 3mm and HTD belts are more suitable for CNC machines than 3D printers.

What about GT2-3mm, aka 3GT? Not sure if the GT3 that you mentioned is the same as what you mean.
Re: Belts - Whats the best you can buy?
June 01, 2017 11:21AM
Quote
shortyski13
Quote
newbob
To me the most important specifications when choosing the belt were backlash and repeatability. I picked GT2, 2mm pitch for lowest backlash and 10mm width for repeatability.

As per sdp-si.com, GT2 2mm belts have lowest backlash (equal to or slightly better than trapezoidal belts), that is much lower than GT3 3mm or HTD belts. GT3 3mm and HTD belts are more suitable for CNC machines than 3D printers.

What about GT2-3mm, aka 3GT? Not sure if the GT3 that you mentioned is the same as what you mean.

From what I read, larger the ptch - higher the backlash hence GT3 2mm is better than GT2 2mm but GT3 3mm is worse than GT2 2mm (for backlash, for speed and power GT3 3mm would be better). This makes sense to me so I stick with 2mm pitch.
Re: Belts - Whats the best you can buy?
June 01, 2017 11:56AM
For what it's worth, I just measured the backlash on my big (350x350mm) H-drive printer that uses MXL belts at less than 0.01mm. Belt stiffness and structural stiffness are going to have a much bigger effect on accuracy than the timing belt backlash.
Re: Belts - Whats the best you can buy?
June 09, 2017 12:19PM
Just a followup to what I posted earlier...

After putting 32t pulleys and 10mm PU-steel belt to use I would only recommend it if you have a very sturdy frame and mounts. PU-steel belts are rather stiff and need much more force to tension them adequately (compared to rubber belts). I don't have a problem since in my printer idle pulley and stepper are attached to the same profile but I can see it being an issue with other configurations. Increased tension force also puts more strain on stepper's ball bearings which may shorten their life.
Re: Belts - Whats the best you can buy?
June 10, 2017 11:23AM
My only concern with 32 tooth pulleys and 1.8 degree motors would be that you've effectively reduced your resolution by 4 times, compared to 0.9deg motors and 16t pulleys (I accept 16t and 20t pulleys used with polyurethane/steel belts is a bad plan). So do you feel the improved belt performance makes up for the resolution loss?


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: Belts - Whats the best you can buy?
June 13, 2017 03:14PM
Posted this pic on my CoreXYU build thread:
Using 6mm GT2 PU steel cord belts, using 40T and 1" smooth pulleys. Geared down 2:1 from a 20T pulley with standard 9mm GT2 belt. Red pucks tension white PU belts, grey 4 bolt pulley sets slide to tension 9mm belt.
Reduced tension on stepper, higher resolution final drive, more torque, and increased reliability.

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