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jacampb2
05-04-2008, 08:59 PM
I spent some time screwing with my CNC mill today. It is now cutting the correct dimensions, the only thing I changed, was to lengthen the direction pulse to 5 uS. Seems to have done the trick. Thanks to Evan and John for pointing me in the right direction (pun intended :) )

I pulled this logo from a PDF of a very old scan of an amplifier instruction manual. It was in pretty rough shape. I used Elgorithm's Magic Tracer demo to convert to a vector image. Decent software, and not a lot of time to get it to do a good trace. I re-sampled the image to some ungodly size, sharpened it some as a raster image in the magic tracer software. Did the vector conversion, and what I found helped the most was to set the line thinning to a very low value. Pretty much followed the tutorials, and got good results.

I engraved the logo in aluminum, and in plexi. I didn't have any proper engraving cutters, so I just gave it a shot with an old drill. Came out pretty good, the plexi was just a piece of scrap.

Here are the pictures:

http://www.rollmeover.com/bronco_fab/amps/amps005.jpg

http://www.rollmeover.com/bronco_fab/amps/amps008.jpg

http://www.rollmeover.com/bronco_fab/amps/amps009.jpg

And here is a link to a crappy video of it cutting the plexi. I have got to remember to take the camcorder to the shop one of these days. Shooting video with a digital camera sucks.

Clicky (http://www.rollmeover.com/bronco_fab/amps/video/PG_logo_plexi.wmv)

Later,
Jason

j king
05-04-2008, 10:14 PM
cool Jason! cant wait

Errol Groff
05-04-2008, 10:23 PM
Pretty neat. Try using a small (#1 or 2) center drill and spinning up your RPM on the AL, use mineral spirits as lubricant.. Keep the RPM under control on plexi to avoid melting the chips.

Here are some photos of CNC engraved clock my students have made.

http://neme-s.org/Clock_Pictures/1.htm

Keep up the good work!!

Ken_Shea
05-05-2008, 12:02 AM
Looks to be a real nice result Jason, always like to see examples of engraving, it is always enjoyable to do, not sure why I don't do more of it just for fun. My last was a "Bugs Rule" license plate for my wifes VW Beetle, still keeps those stupid flowers on the dash, she refuses to grow up !


Ken

Evan
05-05-2008, 09:21 AM
Heh heh. You are on the road to oblivion. There is no turning back. CNC is addictive. It's the modern version of the shaper. Just make sure you don't doze off watching it and pitch head first into the machine. :eek:

Swarf&Sparks
05-05-2008, 09:47 AM
Yup, what Evan said :D

And try cheap carbide router bits. You'll be amazed what you can do with em in ali or brass.

jacampb2
05-05-2008, 12:10 PM
Center drills and router bits! Cool, thanks for the advise guys. I will try them out. I was originally cutting with the spindle set at 3500 RPMs, I believe this is to slow for engraving? However, I didn't want to push the B'port bearings past that. As it was the quill got very hot, and I ended up slowing it down to about 1700 RPMs for all the results you see here.

I made a little stub arbor to hold my 10K RPM trim saw, and was going to lock the spindle brake and give that a shot, but I didn't have any collets small enough for the trim saw... I am going to devote more time to it later. Hopefully I will be able to find some 3/16-1/4 shank bits to fit my trim saw collets.

Later,
Jason

Swarf&Sparks
05-05-2008, 12:23 PM
Jason, if it's purely for light engraving, just attach one o these to your quill.
54000 RPM for $19
http://www.cdcotools.com/index.php
search for "precision miniature die grinder"

for 1/8" carbide burrs, try
http://www.carbidebur.com/18shank/scminiburs.htm

usual disclaimer, no connection, etc....