Acorn for DIY CNC cam grinder on CNC lathe

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vw_chuck
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Acorn for DIY CNC cam grinder on CNC lathe

Post by vw_chuck »

Would it be possible to use Acorn to run a DIY CNC cam grinder using a CNC lathe. Lets say you have control of the spindle via stepper or servo or even a really slow gear motor and a live tool on the tool post. Would this be possible? Where would one get a post processor to run it?
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Re: Acorn for DIY CNC cam grinder on CNC lathe

Post by Gary Campbell »

Centroid is as likely to be able to control the lathe as anything out there. You dont need a post processor, you need a CAD/CAM program that allows you to design a cam.

Note: CAM = Computer Aided Machining...program that generates Gcode from a CAD (computer aided design) program
cam = camshaft

That aside, I would think that any machine capable of doing a good job on a camshaft would be better served by one of the higher end products such as Oak or Hickory
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Re: Acorn for DIY CNC cam grinder on CNC lathe

Post by vw_chuck »

Huh? I use Fusion 360 but the Centroid lathe is only 2 axis. Maybe there is a generic Post processor that will allow me to use my X axis as a Y axis? Anyone ever tried something like this?
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Re: Acorn for DIY CNC cam grinder on CNC lathe

Post by Gary Campbell »

Sure, I do it all the time on wood lathes. For XY operation I set them up as X-Y, which opens up some features. For true lathe operation they are set up as Z-X. Both have advantages depending on the parts being cut. Look this over:


A camshaft would require positioning by adding a rotary axis and using X and Y axes. Similar to this one:
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Re: Acorn for DIY CNC cam grinder on CNC lathe

Post by cncsnw »

If this application is more like a milling machine with a rotary table (e.g. two linear axes plus a precision rotary axis) then you would be better off with the Mill version of the software, even if you build it on a lathe frame.
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Re: Acorn for DIY CNC cam grinder on CNC lathe

Post by vw_chuck »

That is cool but I was just trying to use my X axis with a tool bit or a tool post grinder and a rotary axis(the spindle). Not sure how get it to do it in Fusion 360 and the only way to get it into Acorn would be to digitize it?
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Re: Acorn for DIY CNC cam grinder on CNC lathe

Post by firebrick43 »

Regular CNC controllers cannot actually generate accurate cam profiles. As the wheel is dressed, the wheel gets smaller. This changes the geometry of the lift and fall portion of the cam lobe as its not on center of the wheel as its grinding in those areas.

Commercial cam grinders that I work on, both German made, use siemens controllers and a siemens program called WOPS that handles the geometry corrections as the wheel is dressed.

So I guess the question is, how accurate do you need the cam profiles to be?
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Re: Acorn for DIY CNC cam grinder on CNC lathe

Post by suntravel »

Setting up the spindle as C-axis with the grinder on X should work. If the center of the grinding spindle is on the same height with the C-axis change in diameter of the grinding wheel will not change the cam profiles, only the size which could be easy dialed in after dressing the wheel.


Uwe
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Re: Acorn for DIY CNC cam grinder on CNC lathe

Post by Muzzer »

I've been doing a lot recently in Fusion 360 lathe and there's no way to generate eccentric / cam parts natively.

I'm no expert on cam grinding but from what I DO know, it sounds as if Fusion would need to view this as a "simultaneous 4th axis" milling application. The downside there is that simultaneous 4th axis in Fusion requires you to purchase the eye wateringly expensive manufacturing "extension". I suspect that would rule it out for most people. The basic 4th axis that you get in the paid version of Fusion only allows for indexed (wrapped) toolpaths, whereas a cam requires a true 3D toolpath.
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Re: Acorn for DIY CNC cam grinder on CNC lathe

Post by cncsnw »

On the other hand, a person who know what the cam profile is supposed to be, and is moderately proficient with a spreadsheet, ought to be able to cook up their own CNC codes without requiring any CAD software at all.

Isn't it is just a long list of points, with X coordinates varying through a succession of C angles?
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