Going over to the dark (CNC) side!

[kvom]

In CamBam, the Cam I use, splines need to be first converted to polylines, and then the equivalent to Fusion smoothing is to do an arc fit with a specified tolerance.

I suppose Fusion can import DXF files, and some CAD programs may generate polylines or arcs with many small segments.  The same smoothing techniques are applicable here as well to reduce the number of segments.

[Jasonb]

next part for the Midget engine that could be done on the CNC were the rocker arms which were cut on the opposite ends of a bit of 1.5" x 0.25" flat steel bar.

First a clearing cut all round with 6mm 3-flute cutter at full depth plus 1.1mm to give the later 1mm R corner mill clearance, this then rises up and roughs out the top contour in 0.5mm steps.

Followed by a 4mm dia 4-flute 1mm R corner cutter working it's way down in 0.2mm steps on the flatter surfaces then 1mm as it gets to the vertical.

Side shot of the work so far.

Then a shot after it was sawn off the bar and held in machined jaws to bring down to 5mm thickness in the X3

Then back with the 4mm bit to contour the other side again held in the machined jaws

Finished parts after a lick with a needle file.

<a href="https://www.youtube.com/watch?v=kO9qIaB77vA" target="_blank">http://www.youtube.com/watch?v=kO9qIaB77vA</a>

[vcutajar]

Nice 

Vince

[Jasonb]

Thank's Vince

I found a bit of time to run the CAM for some cams. In the past I would either have used CamCalc with multiple offsets of the mill at angular increments around the cam or used the inside out boring head method particularly on cams like this with a flank radius. Both of which take a while to setup and in the CamCalc case a long while to cut.

This time with 0.4mm deep x 5.5mm high roughing passes and a slightly slower fed 0.2mm DOC finish pass on the silver steel the cam was done in 2.30secs mins with no need to do any blending with files after. I can't see me wanting to go back the the old ways of doing things.

<a href="https://www.youtube.com/watch?v=LymJwG9oBi8" target="_blank">http://www.youtube.com/watch?v=LymJwG9oBi8</a>

[tangler]

 That's the way to do it.
 

Rod

[Muzzer]

I was impressed by the idea of completing the operation in 2.3 seconds. However, 2.5 minutes is still pretty respectable!

Nice result.

[Jasonb]

Did I not say the video was in slow motion

[Admiral_dk]

Very nice Jason 

I can't remember if you have a fourth axis for your CNC, but if you do, I'm curious about doing the same at 90 degree to what you just did - why - well if you need several cams on the same shaft, it could soon be necessary ....

Best wishes

Per

[Jasonb]

I only have 3-axis but the machine comes with all the boards and drivers for a 4th axis, I also have a Sieg rotary table here so would just need to fit a stepper motor and then plug it into the socket provided at the back of the machine.

[jadge]

I can't see me wanting to go back the the [sic] old ways of doing things.

Blimey, that's a handbrake turn from what you wrote recently on another forum about willy-waving rights when doing it manually. 

Andrew

[Jasonb]

I'm happy to not wave it about as much. 

Having done it both ways I still think those who make their cams manually deserve a right to wave and I would probably still do it for a one piece camshaft with multiple lobes but seeing as I now have the machine it would be rude not to make use of it for certain jobs.

Though I wonder if a short cam could be cut vertically using something like a tee slot cutter to do several lobes Might have to put the Hoglet cam into F360 and see if I can do it. Would certainly make it a lot quicker to play with different cam profiles and timing if you were after performance from an engine.

[jadge]

I'm happy to not wave it about as much. 

Better nip over to the other forum and correct the blooper in your reply to ChrisJ this morning then. I can't imagine many people wanting to hit it with a lump hammer. 

Andrew

[Jasonb]

I can't imagine many people wanting to hit it with a lump hammer. 

Certainly won't do any good to the hardening

[kvom]

I have mentally designed a system to machine cam lobes with a 4th axis, but it requires programming.  The idea is to draw the lobe profile in CAD, and then break the polyline into some number of straight lines.  Each line is defined by the points on its ends, and the pointlist is somehow exported from CAD.

The program code then calculates for each line the A-axis angle needed to bring it horizontal plus the Y and Z axis values  of the line's center once rotated.  Then one can generate G1 moves consecutively for each segment.  If roughing pass(es)  needed, just run the same code with Z values larger than final.

[tangler]

Nobody is much impressed by willy waving (not in my case anyway).  Although I have a proprietorial fondness for CamCalc,  drawing the profile in CAD and then getting the machine to cut it is much less tedious than Manual Numerical Control.  All our skills get superseded - I was really proud of the analysis and plotting routines I used to write for Thermal Analysis and then Excel came along 
Rod