Build CNC camshaft grinder
Not sure if I'm posting in the correct area. I'd like to build a CNC cam grinder. Building the machine itself won't be difficult for me, but instead of having to use masters to grind the lobe profiles, I would like to be able to program it into the CNC.
The way I envision this, is to have an encoder motor on the cam that tells a stepper motor to move the grinding wheel / X axis away and closer to the cam lobe depending on the position of the cam.
Being a bit of a novice on the electronics side, I am a bit unsure of how to properly set up / program the timing vs position. I wish there was a simple way of telling a machine: "IF cam position is "---"degrees, send "X" axis to "-.--" position. Then you would simply build a lobe by programming the X position for every one of the 360 degrees or how ever many pulses you have per revolution.
The other way I can see this happening, is setting it up with the cam rotation motor to only travel 359 degrees, reverse back to zero (home).
I expect some severe criticism in my idea here, and am prepared for it. But would certainly like the input from others. My plan would be to use generic stepper motors and drives with a basic CNC program.
Thanks in advance.
Re: Build CNC camshaft grinder
Quote:
Originally Posted by
studman
Being a bit of a novice on the electronics side, I am a bit unsure of how to properly set up / program the timing vs position. I wish there was a simple way of telling a machine: "IF cam position is "---"degrees, send "X" axis to "-.--" position. Then you would simply build a lobe by programming the X position for every one of the 360 degrees or how ever many pulses you have per revolution.
Thanks in advance.
It's even simpler than that from a software perspective. Just draw the cam profile in any CAD program, and the create the tool paths in almost any CAM program, the load the resulting G-code into the CNC controller and press GO. A little bit more to it than that, but not much.
Another way would be to describe the cam profile mathematically, somewhat as you suggest above, and simply output the result as G-code. Pretty easy to do with simple programming or could even be done in an Excel spreadsheet. Just let the computer best fit the arc between the points to get best resolution and a smooth profile.
In either case, the resulting G-code will be much like that for a lathe with a C axis.
The hardware might be a bit more of a challenge, but not that difficult to do. I would start with a machine that was designed for grinding round stuff like a cylindrical grinder or maybe even a cam grinder if you can find one.
The controls and motors are readily available from many vendors. To grind accurate cams you are going to want good resolution accuracy, and repeatability, so good hardware is going to be required.
Re: Build CNC camshaft grinder
Quote:
Originally Posted by
studman
Not sure if I'm posting in the correct area. I'd like to build a CNC cam grinder. Building the machine itself won't be difficult for me, but instead of having to use masters to grind the lobe profiles, I would like to be able to program it into the CNC.
The way I envision this, is to have an encoder motor on the cam that tells a stepper motor to move the grinding wheel / X axis away and closer to the cam lobe depending on the position of the cam.
Being a bit of a novice on the electronics side, I am a bit unsure of how to properly set up / program the timing vs position. I wish there was a simple way of telling a machine: "IF cam position is "---"degrees, send "X" axis to "-.--" position. Then you would simply build a lobe by programming the X position for every one of the 360 degrees or how ever many pulses you have per revolution.
The other way I can see this happening, is setting it up with the cam rotation motor to only travel 359 degrees, reverse back to zero (home).
I expect some severe criticism in my idea here, and am prepared for it. But would certainly like the input from others. My plan would be to use generic stepper motors and drives with a basic CNC program.
Thanks in advance.
You would want to be using Ac Servo motors not stepper motors with high count Encoders ( PPR ) for best results some to look at DMM | Technology Solutions | AC SERVO DRIVE | AC SERVO MOTOR | ROTARY ENCODER
Re: Build CNC camshaft grinder
Might get some ideas from Sherline, don't know how large your cam shafts are.
https://www.sherline.com/product/8650-cnc-cam-grinder/
Larry
