Re: [CAD_CAM_EDM_DRO] digitizing engine camshafts...

You can find out everything you need to know about the camshaft manually.

Place the camshaft between the centers of a dividing head and tailstock
mounted on a mill table. The table. Install a dial indicator in the
spindle and lock the spindle so it won't turn. The dial indicator needs to
have enough travel to go from the highest point to the lowest point on the
cam.

Raise the table, rotate the cam to somewhere on its lowest position. Zero
the dial.

Now start rotating the dividing head. As soon as the dial comes off zero,
stop and write down the travel. Rotate the dividing head in equal
increments and plot the changes. When the cam gets to it's highest point,
it may remain at that point for a few degrees. By plotting the entire cam
you'll get a pretty good idea how long the valves will be open. Of course
you'll also have to take into consideration any play in the valve train to
be absolutely sure at what point the valve actually opens and closes.

Do this for all the valves. The exhaust cams will probably be different
from the intake cams. Also you can average the readings between like cams.

Next plot this information in a CAD program and use it to develop a smooth
curve in a vertical plane. Now your ready to generate g code for cutting
the cams using a fourth axis CNC mill.

Smoke

----- Original Message -----
From: "Doug Fortune" <pentam@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Tuesday, November 06, 2001 11:59 PM
Subject: [CAD_CAM_EDM_DRO] digitizing engine camshafts...


>
> Another list I am reading has posts like the following:
>
> > does anyone out there have the specs on a stock EA-81 Cam?
> > From the Fuji Heavy Industries manual I have been able to
> > determine the max lift, but I have not been able to find:
> > Duration for intake and exhaust
> > Lobe centerline (max lift)
> > Lobe seperation
> > any help would be welcome.
>
> Well of course it is easy for a machinist to determine the
> max lift, and probably also the degree it occurs at.
>
> But it strikes me that once we get cnc digitizing under
> control we could put the cam in a rotary table on a mill
> (or put the cam in a digitally controlled lathe spindle)
> and digitize the profiles directly.
>
> Doug Fortune
> http://www.cncKITS.com
>
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