2mm Pitch 6mm wide belt profile

[Anonymous]

I am making a turntable that is 6 inches in diameter. I want to use it with a 2mm pitch, 6mm wide belt like those used in 3D Printing. I am learning Fusion 360 and am not sure how to go about making a 6 inch (152mm) disc with the correct pitch profile. I would like to eventually have those parameters set up so that I can vary the diameter. Any help would be much appreciated.

I will 3D Print the 6 inch diameter disc that is 10mm wide, 4 mm for the edging to allow the belt to stay on, 6mm for the belt.

[dean.dekovic_gideon.brothers]

Hi,

try finding the correct timing belt, using maybe SKF belt calculation software or other. 

http://www.skf.com/group/knowledge-centre/engineering-tools/belt-drive-design-calcalutions-tool.html

Then find the correct belt profile, sketch it correctly on the front face, extrude cut, and circular pattern of the extrude. 
Parameters in Modify tab can be used when creating the features 

https://www.youtube.com/watch?v=ZakT54JIhB8

https://www.youtube.com/watch?v=khG4Zk5XZrw

https://www.youtube.com/results?search_query=using+parameters+in+fusion+60

Also, google search bar is your best friend in this case. Timing belt systems have many details that must be taken care of.

Dean

[davebYYPCU]

I work in metric, 

you need to divide the Circumference by 2mm for the number of teeth, and for 6 inch = 152.4mm = just short of 480mm circumference

I went up a bit to 480mm circumference, divided by pitch being 2 = 240 teeth = 152.769mm diameter  (480 / pi)

Made a disc, and waited, waited  and waited for fusion to produce the model.

Pattern cut with tangent arcs, took a while but does work.

Might help.....

[etfrench]

Attached is a dxf with the profile of several teeth of a 240 tooth GT2-2mm pulley.  It would be best to convert one tooth to a spline, extrude it, then use a circular pattern to add all of the teeth.  Grounding the pulley component after combining the teeth will make Fusion 360 more responsive.

A 6mm belt needs a pulley thickness of 7mm or more.  The 2mm flange thickness should work fine. 

I currently have a 3d printed 7" GT2-3mm pulley on my Rose Engine and it works quite well.  I used a .125" aluminum plate for one flange to add strength and to keep the plastic from warping.  Here's a screenshot of a Fusion 360 model of an early version (The aluminum flange isn't shown and it was GT2-5mm).

 p.s. You may want to consider using G2-3mm as it will be easier to print accurate teeth.  The tops of the teeth in Gt2-2mm are only about .7mm wide which is near the minimum line width for 3d printing.

[Anonymous]

Dean, Great info. Thank You.

Dave thank you for the effort.

ET thanks but how do I load a dxf file into Fusion 360?

Thank you all for the help, I am still not computing how to go about this correctly. I should use Modify/Parameters for this project so I can change the features quickly since I am not exactly sure of the speeds, etc, of the other components involved. This is a standard GT2 3D Printing belt and I am pretty convinced my printer will handle it. So 1 mm top, 1mm bottom for a 2mm pitch and the depth is about .75mm as well. For a 153mm diameter circle, I need about 940 teeth to meet that requirement. I am in WAY over my head. Thank you again!

[etfrench]

Your approach is guaranteed to fail.  The teeth on the pulley must have the correct profile. 

You can either upload the dxf from the Data Panel or use the Insert DXF menu item from the Insert menu.

p.s. GT2-3mm belts are about the same price as GT2-2mm belts.

[Anonymous]

I am here because my approach is guaranteed to fail. I have the belt sitting in front of me. I am using 2mm because that is what I have tons of already for my 3D farm.  I have made plastic ones before from someone elses design, but they are way too small for this project. There HAS to be a better way than doing each 1mm division by hand.

[davebYYPCU]

I pinched the tooth profile from the internet, copied the dimensions for one tooth, 

Extruded the 4mm ring one side of the sketch,

extruded the base of the belt track, the other side of the sketch,

extrude cut the tooth valley,

then circular pattern that tooth cut, with 240

if you zoom into my photo, about 2 o'clock in the pic, is my sketch.

Will check your file a bit later, 

We often don't know the posters abilities, happy to answer question as they come by.

Later...

[Anonymous]

Imagine no ability whatsoever. I can do simple things, but this is very very complex. I do not understand why revolve doesn't work on the plane I want, circular pattern should do this, but I am missing some crucial information apparently because I can't get that to work either. What would be nice is if I could figure out how to imprint this pattern on any diameter circle so we can change the speed of the rotation. Seems like an extremely useful effort for anyone using Nema 11 or 17 steppers for creating just about anything.

Also, the pattern needs to be on the edge of the disc with 2mm side guards to keep the belt from falling off in the horizontal plane.

[davebYYPCU]

I agree with your sentiment- and could be done.

I have not used a gear generator, or scripting, so my expertise in those areas, nil.

To model my example I used one sketch.

I will review your file, then have a go at parameters for you.  They work well in Fusion.

Shortly....

[etfrench]

Pulley tooth profiles change with different tooth counts.  Using the belt profile will get you in the ballpark, but it won't give you the correct profile for a pulley.

p.s. The flanges need to be created in a separate sketch, then Combined with the tooth component.

[Anonymous]

Thanks ET. I will review this tomorrow, but I agree there will be differences in size of pulley vs the profile.. but a mathematical formula should compensate for that since the curvature would be linear. I know what I am asking is difficult but it would solve a gap in our arsenal of mechanical solutions for belt driven steppers. And, it would be movable into 3mm, or any other size solution easily once the parameters were correctly set up. Not that I have a clue what I am talking about. 

[davebYYPCU · Accepted solution]

Changed my file to be parametric, I like a challenge, and so far has not broken the file, by changing the parameter for the Circumference, about the limit of my math skills,

other than, Parameter Ccfn = Circumference is found by Diameter * PI.

Used these dimension, most are static, only the three circles and two tangent arcs (indicated in red) are what changes for the differing disc size, the rest of the profile slides up and down the centre line.

Change the length of the circumference, and you get your new disc.

Changes to the disc construction, edges either side can be done, but not with my parameters, this demo is as requested, 6 x 4 mm disk.

File attached, 

[Anonymous · Accepted solution]

Dave this is really good work! I can use this to test my contraption. I am in the middle of watching videos on Fusion 360 trying to learn how this stuff is done for myself, but I have a long ways to go. I will be reviewing ETs instructions too. Thanks for this!! Good call not putting the upper edge on the disc. 3D printing this would be harder with an overhang. 

[etfrench]

Flanges can be printed in place easily by adding a chamfer to their inner edges. 

[Anonymous]

I just wanted to get back on and thank you again. I just printed out this solution (been stupid busy lately) and it fits the belt perfectly. This is the perfect solution for parametric GT2 belts. I printed one in half size and it worked just as well. 

[Anonymous]

@Anonymous Thanks for this. What would I need to change in order to make it fit the GT2 3mm profile? (Where would I even find a spec for that profile?)

[etfrench]

GT3 belts are designed to fit GT2 pulleys.  There are no GT3 pulleys.

[Anonymous]

@etfrench I'm talking about the 3mm pitch for GT2, and not GT3. ARen't these different? (GT2 has 2mm, 3mm and 5mm profiles, as far as I know).

[etfrench]

Sorry, my reading skills are sadly lacking   This site has the belt spec for GT2-3mm.