DIY CNC Camgrinder

The path to success in modern cam design is to write a software that models the shape of the acceleration curve first.
Then integrate to get a velocity and lift curve.
Then write a solver to adjust the dimensions of the acceleration curve until velocity and lift = 0.0 at the end.
Then optimise to get the dimensions you desire.
Then analyze in a CAD/CAE software, it would be a lifetimes work to come close to what they do now.

It would appear that you want to block any progress forward. EG $20K cast iron blocks or Lifetime work to come close.

Can you make some practice suggestion on going forward. We are all on this list because we work outside the square. Helpful comments would be appreciated.

I don't think its a Gcode issue at all.

Get the maths right in a custom component that outputs a count for X axis external offsets based on Z axis radial position and it will look after itself. eg at this point on the circle, the grinder needs to be offset by n millimetres.

Hope I got the axes right!

i would think fusion 360 could do G code for something like this, it has the multi axis functions beyond a simple 3 axis cam software. i think it would fall into a 4th rotary axis strategy. i don't get into much more than 3D tool paths with a 3 axis machine but if i would take a guess the rotary axis is going to synchronize with what would be an X axis on a lathe to follow the contour of the cam profile. i think it would work a lot like the process of of rigid taping in a sense that the spindle speed is set to feed per revolution rather than a linear feed rate so it can follow the thread pitch in that case.

i think in a case like this the the arcs of the cam will be synchronized with a feed per revolution to produce the contour with the rotary axis while the X axis is moving in a linear fashion.

but this is just a guess, i would have to actually program some tool paths and look at the code to see how it actually does the G code. i would need to either find a solid model or make one from scratch to even play around with it so i can see what is going on in the code.

Cam lobes are not made from acrs since the 1950's. Rather than design a lobe, a modern cam designer models the desired motion and then converts that to a file of points typically spaced at 0.1 degrees or 0.01 degrees.

When they were designed from arcs, the motion had discontinuity at acceleration which limited the speed at which they could run. Instantaneous change in acceleration is physically impossible, so the mechanism has to absorb the shock. That shock is amazingly destructive to valve springs.

Here is a web site that explains the history of how cams were designed.

www.tildentechnologies.com/Cams/CamHistory.html

His most modern approach is 25 years out of date though. No one designs cams this way at a professional level.

Even if you live in an out of the way place, I find it difficult to believe that it would be cost effective to build a machine base for what you could buy and transport a commercial one.

When I bought my cam years ago from comp cams a custom grind was only $20 more(no r&d work obviously)

They have a catalog of different profiles you could mix and match what you want plus the LSA and installed centerline and many more I'm sure.

They must be able to punch in the numbers and run a cam core thru with minimal work vs a production grind.