Adding gear teeth to arc spiral gear

[Anonymous]

Hi,

I am trying to add teeth to a spiral shape to 3d print a spiral gear. I have tried to make my sketch coincide with the arc of the spiral, but it never seems to do it how I would like. I have the correct tooth profile sketched and just want to position it so that the tooth sits flush on the surface of the spiral. Every time I try to coincide the endpoints to the spiral, it only changes the radius size instead of moving/rotating the whole sketched profile.

If I enclose the shape it gives me an error.

I am a student and none of my professors have been able to assist me with this, so any help would be great. I have attached my file with the shape and profile so you may see what I am trying to do. There are also screenshots if you wish not to open the Fusion file.

[etfrench]

Usually, Pattern on Path would be used for something like this.  However, it doesn't keep the teeth aligned to the path properly.

Component3 in the attached file is a lograrithmic gear created in Gearotic.  Perhaps it can help show how the teeth must be spaced.

Notes:  Try working in Timeline mode instead of Direct Modeling.  See @TrippyLighting's Rule #1.

[davebYYPCU]

Blue sketch lines should keep you awake at night. more constraints and dimensions

Your sketch distorts because it is not fully constrained, measure the angle between the two face lines,

highlight the parts to move, select move tool, 

The base line is attached one end, set the move pivot there,

rotate the tooth part of the sketch to overlay the black line, by putting the angle value in here.

That fixes the sketch.

Because the tooth is not in a component, and you are Direct Modelling, the tooth doesn't go with it, 

So move the tooth the same way, and it looks like the sketch and tooth were moved before I saw the file.

Beginner mistakes because you are new to Fusion.

Capture Design history for easy updating, 

Fully define sketches, you are patterning the body on the path, set it up correctly.

Stuck, send the file back with new questions....

Might help.....

[davebYYPCU]

These settings are looking Ok.

Might help....

[TheCADWhisperer]

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@Anonymous wrote:

I am a student and none of my professors have been able to assist me ...

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Can you ask your professors to join this discussion?

Have they covered the techniques of using the Timeline and history-based modeling?

Have they covered the techniques of fully defining sketches (the basic foundation topic of parametric modeling)?

[chrisplyler]

I often get the impression that there are people out there teaching Fusion 360 without having any logical sense of how to use it themselves.

[etfrench]

Perhaps this site  or this one can help you design a proper gear.

[Anonymous]

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@TheCADWhisperer wrote:

Can you ask your professors to join this discussion?

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The professor I spoke with teaches in NX by Siemens, not Fusion 360. The school does not allow students to obtain copies of NX on our personal computers so I am using the education license provided by AUTODESK. I have tried to search everywhere, but I cannot find how to go to timeline mode.

[g-andresen]

Hi,

here:

günther

[wmhazzard]

Click on your name and select preferences/ design/ design history and select capture design history so it will be default. 

[Anonymous]

I rotated the tooth over flush with the gear using the move function, but when I use pattern on a path, the orientation changes the farther around the gear the teeth wrap. I assume this is because the one end of the tooth and gear are not constrained together.

I attached a picture of what I get when I add all the teeth.

How can I fully constrain the profile of the tooth, in order to "attach" the tooth to the profile of the gear? The way fusion handles constraints is vastly different from the previous modeling program I used. If there are any good videos or resources you recommend for sketching and constraints.

[etfrench]

The end points on the tooth are probably not coincident with the path.  Try making them coincident in the sketch before extruding the tooth.   You may also need to start at the second tooth as in @davebYYPCU's example.

p.s. Attaching your file will work much better than a picture for debugging problems.