Cylinder Cam Model PLEASE!!!

I hope there is someone here who can help my company out on machining
issue. We priced out some cylinder cams with some fairly large machine
shops, and when the quotes came back my boss almost had a heart attack.
We are in desperate need to apply reciprocal motion to a slide. The
tolerance for the motion must be held within .005". The range of motion
can be anything from 1/4" to 3".
If there is anyone here with knowlege of cylinder cams, (or barrel
cams), your response would be most welcome.
Mike

 

how is asking for a model going to help you with a machine shop quote?
they will still be setting up and doing the same work and charging the same
for it surely.

 

http://www.3dcontentcentral.com/3dcontentcentral/ this place will
have what you need already modeled, good luck.

 

Mike,
First thing that you should know is that anything relative to a
helicoil shape, involves a lot of time, which of course translates into
high cost. Secondly, you are not commited to a cylindrical cam in the
first place to accomplish what you are looking for, linkage governed by
an excentric cam is almost as effective as a cylindrical, or barrel
cam.
If the quotes that you received are unusually high, you were probably
being quoted on a cylindrical cam being machined from a solid block.
The only machine shops that can do this are the larger companies that
are equipped with machining centers. These larger job shops, with
machining centers have no choice but to bill our their machine time at
$175.00 per hour plus. In this machine and tool climate, such as it is,
you may be much better off finding a shop that can fabricate the cam
from two components, the cost of which will be much less prohibitive,
and equally as effective. I personally have made these fabricated cams
and used them for years without any problems whatsoever. They are
traditionally made from oil-hard tool steel, and heat treated to a
58-59c Rockwell, and with proper lubrication, will last a lifetime.
The accuracy of your throw, (you require .005" repeatablility), is
accomplished by your slide hitting an adjustable dead stop, which will
give you repeatability in the .001" range.
The equipment needed to make this type of cam is a vertical milling
machine, equipped with a dividing head that is ratio geared to the
traverse screw, needed to machine the helicoil profile.
I have published to my website some photographs of the cam that you are
looking for. Feel free to download them and give them to your vendors
for quote. You can substitute your own dimensions as your needs
require.

http://www.deangelistool.com/help/fabcam.zip

G. De Angelis
www.deangelistool.com

 

The reason a model is needed is so it can be presented to a Rapid
Prototype company for 3-d printing. There exist some 3-d printers
that can replicate a Solidworks or Rhino model into a Cast Urethane,
then ultimately into metal. We are in hopes that this process is less
expensive that the traditional machining process which was out of
reach, however without a 3-D Model, a Rapid Prototype company will not
quote.
Fortunately, we were introduced to a second option by a member here
who recommends fabrication of the part. Hopefully, between the two, we
will be able to get our cam made and complete our project.

 

Hey,

This is how the part should be modeled. Kudos to J. Mather.

http://home.pct.edu/~jmather/content/DSG322/solidworks_surface_tutorials.htm

Now you know how to model yours. Hope this helps.

Reaper.

 

I would question the tolerance you stated. Are you sure you need that
close of tolerance? I don't think you will achieve it with your RP
method.

 

This is how the part should be modeled. Kudos to J. Mather.

I stole this method from Jeff Howard. I have made a lot of money off
of the method.
;~)

 

Mike,
I have made the model for the fabricated cam that you need to submit to
the Rapid Prototype Co, or a Machine Shop, suitable for quote. If you
need a sketch of the linkage and mechanical stop used along with this
type of cam, get back to me and I can provide it.
Bear in mind that the metal that you will ultimately receive your
prototype in is on the order of cast zinc or an alloy, and therefore
not very durable for industrial use or continuous duty. Also, the
process is not cheap.
The design offered by the tutorial of Dr. Mather, is of course Classic
and a very excellent design, but there again, this is a design that a
machine shop would have no choice, but to machine from a solid
cylinder of steel, and you would in the same fiscal situation that you
were in originally.
Whatever you decide, I have published all the files that belong with
the assembly for the cam that I propose on my website. Here is the
link.
www.deangelistool.com/help/fabricatedcam.zip
Good luck
G. De Angelis

 

I stole ...

Nah.
That was the result of public domain collaborative thought and effort.
One of the few idle time persuits I enjoy more than public domain heckling.
`;^)

 

Mike,

They're usually not that hard to machine using "A" axis mapping (axis
substitution), hold better tolerances too. I've done several of them myself.
You want to model the cylinder using sheet metal functions so you can unwrap
it into a flat pattern. The contours are programmed in the flat state, and
wrapped onto a cylinder using a single line of code in the program. Actually
very easy. What is it made of and how big is it ??

It sounds to me like the shops you got quotes from didn't know how to do it,
and subed it out to someone that did.

Mark