Anyone know about Cams?

I saw this totally bad-ass multi extruder that only uses 3 motors:
[www.thingiverse.com]
I was thinking about making one and I was hoping to redesign it with a standard cam. Does anyone know where you can buy these? When i google search rotary cam, camshaft, etc I get cam shafts for Cars or Motorcycles and I can't find any small ones that would be suitable for this kind of application. I was thinking that if you used 1.75mm filament you could stack a bunch of these cams and interface them to a bunch of j-heads or some other extruder directly.

What do you think? Thanks!

There are so many types of cams out there, can you fabricate one out of aluminum plate?

Or, thin steel; if more strength is needed?

That is a custom turned cam profile.

Work around:
Print an over sized cam profile out of Nylon.
Design a pocket to retain a nut for a set screw.
Press fit the cam over a steel rod, and lock it in place with a set screw.
Then attach a driven gear to the end of the steel shaft to mate with the stepper motor driver gear as depicted in the video.

A2

A2- I am having trouble visualizing what you are saying. You first print the part out of nylon and you make a space for a nut trap. How do you press fit the nylon cam and a steel rod? Both are cylindrical things right? Isn't that just like putting two cylinders together? I don't understand how it helps you.

Metalmann- I am not sure how i could make a cam out of a metal plate. I could see making one out of a metal cylinder but i don't really have the tools for that which is why I wanted to buy a stock cam.

I was mainly concerned with trying to figure out where I could buy stock mini cams that could be adapted for this solution. I saw that someone made a cam out of roller bearings which is cool but I wanted something a little more streamline:
[www.thingiverse.com]


Thanks for the input everyone!

Edited 1 time(s). Last edit at 10/20/2013 02:14PM by A2.

A picture is worth 1000 words, thank you! Would the metal shaft be notched or grooved so that the set screw would get a good grip? Also, why is nylon a better option than PLA?

Edited 1 time(s). Last edit at 10/20/2013 02:28PM by Coherent.

Nylon is a replacement to bronze/brass gears, i.e. it's good for wear and pressure applications.
A flat or a spot drilled hole would be beneficial.

3 more ideas:
Use a keyed shaft.
Use a threaded rod with locking nuts on either side of the cam.
Probably the easiest and strongest would be to simply drill a hole in a steel slug slightly off center, this would act as a cam.

Edited 1 time(s). Last edit at 10/20/2013 03:57PM by A2.

Those are great ideas. Do you happen to know if companies just sell those eccentric cams for putting on a keyed shaft and if so which ones? I would hate to do the equivalent of printing a toothed pulley for the Y axis when you can just buy one that is significantly more reliable. With that said, I will certainly buy some Nylon so I can try this out, thanks again!

Search for:
Eccentric Cam Bolt, I'm not sure how you would get 3 of them to work together.
Wheel Alignment Toe Bolt Kit.




Edited 2 time(s). Last edit at 10/20/2013 06:26PM by A2.