SolidCore CoreXY: Belt Routing & GT2 Belt Tensioning
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- เผยแพร่เมื่อ 7 มิ.ย. 2022
- SolidCore CoreXY: Belt Routing & GT2 Belt Tensioning
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CoreXY Belt Routing
One of the most important parts for corexy movement is belt routing. Here’s a guide to the mechanics of corexy belt routing pulley layout in order to get accuracy and constant belt tension.
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Belt Routing Methods
There are two main ways to implement the corexy belt path. Either a stacked pulley arrangement or a crossed belt also known as a belt twist. The crossed belts design allows for each belt to take different paths, creating an x-shape configuration The stacked belt path simplifies alignment and belt tensioning. There is an increased complexity in this routing due to having two different height motor shafts, but it also eliminates belt tensioning issues.3d printer resolution may be affected when the toothed belt runs on a smooth idler as it results in a curtain effect pattern also known as ripple.
Crossing Belts vs Stacked Belts
While both belt routing methods can be equally effective if implemented correctly. But belt path designs that move the belt teeth against smooth idlers, and designs that run teeth against the teeth of the idlers
It is possible that the toothed pulleys produce more noise and some people claim that the teeth against the smooth pulley causes irregular offsets in their printing from belt stretching but a smooth belt surface on a smooth pulley reduces ripples and may be a simple way to increase the print quality, as it would allow for more of an even printing process. This routing path has its negatives in relation to artifacts within printed parts that could appear on one side of the gantry; however, this route also allows for straight belt paths without any twists which might give off smoother prints and have less risks when compared with other designs.
Stacked Belt Path - Offsetting The Stepper Motors
Offsetting the stepper motors with stacked belt path pulleys may give the belts a clean run and simplify belt alignment. A printer’s motors can be offset at different heights so that the belt routing runs a straight belt path and doesn’t have to be twisted. But this corexy belt routing path would also mean that on one side of the gantry the belt would have the teeth on the side of the idler wheel which wouldn’t run as smooth and could lead to artifacts within printed parts.
Crossing Belts - Twisting The Belt Cross Over
The Railcore design had a lot of influence on the SolidCore 3D Printer. The belt path of both machines cross in an “x” shape, but many people prefer the stacked belts approach. Twisting the belts can cause the belt to ride on the flanges of the pulleys which causes wear on the belts. However, there are many corexy designs that work very well with this mechanical arrangement. The main concern is that belt tension varies from one height level to another because it has different lengths created by varying tensions depending on how tight they are wound around their respective pulleys .
Belt Layout & Belt Tension
Many people prefer the stacked belts approach. Twisting the belts can cause the belt to ride on the flanges of the pulleys which causes wear on the belts. However, there are many corexy designs that work very well with this mechanical arrangement. The main concern is that belt tension varies from one height level to another because it has different lengths created by varying tensions.
Parallel Belt Paths
The corexy belt path must be parallel to the linear guides as the carriage moves along the axis. This means that there is a x-shape configuration with two points of contact at both ends. The length of the belt may vary in tension. Belt tension may increase or decrease as it moves along the axis. The length of the twisted segment must maintain constant tension, otherwise the twist will cause the belt tension to vary. Mark Rehorst has an excellent blog that explains the corexy belt routing. Mark Rehorse’s Blog.
CoreXY Kinematics Explained?
The corexy kinematics mechanical arrangement includes a unique motor movement where the X or Y motor move together or opposite of each other to move the carriage from left to right or towards or away . If you were to move just one motor you would see the print head move diagonal.. If the two motors move opposite of each other the print head will move along the X-axis, If the two motors move in the same direction the carriage will move along the Y-axis. - วิทยาศาสตร์และเทคโนโลยี
Came here to find out how to tension my belt, left without any good info.
😂👍
did you find any other good source?
@@Prashanth-yn9zd No, but I used a sound frequency analyzer on my phone (Spectroid on android) to have both belts tuned at the same frequency and I increased the tension progressively till the quality improved, but not to the point when you can see the pulley teeth marks on the print (ringing). There isn't a one fits all frequency for all printers, so even if you have two identical printers, you need to tune them at their own frequency... if that makes any sense.
@@L3X369
Thank you,
Could you please share what belt tensioning mechanism did you use?
I saw one where the position of the motor can be slightly adjusted to increase/decrease the tension. I am looking for other possible methods to adjust the belt tension in the core-xy setup
In hurry to see a complete kit. Are you going to make this a complete open source kit with all CAD files and manual ? How is it expected to cost (ready-to-print) once completed ? I am looking towards a 400x400 up to 500x500mm build volume in a coreXY platform
It is unclear to me why you don't want to mash the teeth of the belt on the other side of the carriage.
If I'd be making a printer from nicely machined parts, I wouldn't attach the belt with tie wraps like on a $300,- printer. There are so many nice timing belt clamp designs available.
👍😂
Why actually? Say your belt came undone, you always have an extra ziptie, but you can't just easily fire up the printer to make yourself a new clamping device. The idea behind machined parts is that they aren't going to fail and leave you stranded, because realistically from the mechanical perspective, you don't need them, you have the space to make plastic pieces as rigid as needed and then some; zipties are pretty resilient, and if they do fail, they won't leave you stranded either.
@@SianaGearz This machine is made of aluminium mostly. Personally I'd make nice aluminum clamps as well. They would not fail in a 1000 years under normal circumstances. It would be mostly for aesthetics. Also for more easy adjustment and replacement of the belt. But the time making clamps probably doesn't make up for the time saved on mounting. But hey, making a machine from scratch is not very time efficiënt to begin with.
Any reason why you need two axles for the idlers on each side? couldn't they be stacked on top of each other? Is it because they often rotate in opposite directions? Since they are on separate bearing it should be fine no? anyway, thanks for sharing
I am not him, but the answer is trigonometry, Belts need to run in parallel with the movement. Only way to use one axel, is to use idlers of significant different diameter on the crossing, for his type of setup.
Aluminum extrusion below the x-Axis linear rail is not required. These rails are sturdy enough for a 3d printer if you use them for mounting. Like you have done.
Bit late but the rail is definitely not stiff enough unless youre running a sub 250mm rail and a bowden config with a short and light hotend.
And even then you can improve your is graphs by adding a backer to the rail.
Ok nice -so this is the corexy - i still dont know how to derive its kinematics - but why is the xy plane so high? What is this device meant to do so high - is it a 3d printer with lowering ground level?
the xy plane moves up and down... bed is stationary
How did you determine that the tension was even for both lines. I did this similarly and had no “tight spots” but still ended pulling it out of square?
You want to remove any slack in the belt and tighten the belt until you can pluck it like a guitar string. What did you pull out of square?
Email me and I'll get you some documentation on tensioning the belt if you're still having trouble.
You should be using a belt tensioner tool. Belts cannot be properly tensioned by hand. Most that Ive seen have over the years have been too loose. One of the many reasons I’m not a fan of belts but when done properly can provide adequate diy results.
Belt stretch must be a huge issue with this style printer.
All of that work to end up using belts and lead screws. Too much flex and loss of resolution with belts for my end use.
Besides that you cant use them with an FDM if you expect them to last. Soon as the oven (enclosure) heats up the belts they get soft, stretch, and are shot.
We are building High temp composite precision ball screw printers. Enclosures are t stat controlled hvac air filtered systems. Very complex in nature and need to meet high use precision requirements.
As long as you have happy customers that is all that matters.