help requested in routing .040 aluminum license plate blanks

[iSign]

yep, a great tip.
Actually, I wrote this post (even though I already had done the job, as a way to have my notes somewhere... as well as to try to generate some feedback. lots of great feedback here already, so many thanks to everyone...

I guess I had thought of what I would post before I called a few of my friends instead, so I forgot that I hadn't mentioned that this "exercise" was mostly to learn in my spare time. It was a small part of $600 worth of signs for a new Zipline company, and the other 10 full color digitally printed signs were done on 12x18, and 18x24 aluminum blanks, with stock blanks having .75" radius corners.... so, even though I sold them on square corner blanks hacked off my RE riders on the panel saw.. I just decided to go the extra mile for them, since we will be doing several hundred, if not several thousand dollars worth of additional signage in the coming months.. byt the way, I got 5 free trips on their Ziplines this morning WOOHOOO!!! sometimes going the extra mile pays off in unexpected ways!!

 

[signs2trade]

Ive cut 100's of sheets of aluminum over the last year and I have to agree its probably my least favorite thing to cut. Here are some of the things Ive learned.

1. I use the Onsrud 63-620 UPCUT router bit. It leaves a nice clean edge even on coated aluminum. It seems that the shorter 3/8 cutting length of this bit helps reduce heat and increase longevity of the bit. I can generally cut 10-15 sheets of aluminum before the coating on the edge of the aluminum starts to look rough. At this point I usually switch to a fresh bit as the time required to file the edges exceeds the savings of continuing to use said bit. I run in the Climb direction.

2. I don't have a vacuum table and I really hate using tape as it can be time consuming to remove and can gum up the tip of your bit. I just use self tapping screws and screw the sheets directly to the MDF. This does take its tole on the corners of your MDF after a while. I occasionally just fill them with bondo and all is good again. Clamps work good as well, my table just does not allow for using clamps.

3. I only use water in my mister. I have the mister set to give a very small burst of water about ever 5-7 seconds. Generally just the air it self is enough to help cool the bit, the burst of water is a nice bonus though. This amount of water is not enough to cause problems with your MDF spoil board.

4. Bridges are a must especially if your cutting smaller pieces. I make them small enough (.1") and can use a pair of wire cutters to to free them from the sheet once the cutting is complete. 2 bridges per piece should be sufficient if placed correctly. If cutting rectangles place bridges a few inches from apposing corners, this will prevent material from twisting. Bridges can be removed with a 1" belt sander very quickly. Bridges not only hold your pieces in place, they will give the over all sheet more strength. Without bridges the 4x8 sheet can become very week and be very difficult to manage.

5. Ramp in whenever possible. Not only with this increase tool life it will prevent burs or scratches at the entry point.

6. My sweet spot for .040 is approx 55ipm at 18,000rpm. This gives me extremely good edge quality with good tool life. For .080 I drop the speed to around 40ipm at 18,000rpm.

7. It is extremely important to setup your cut order properly. I always start at the front of the sheet (X0/Y0). All pieces start cutting from the top right or left corner depending on if I'm cutting conventional or climb. Basically you want your last cut to end on the strongest part of the material. If your cut ends near an another cut the material may flex enough to mess up your piece.

8. Empty your shoes often.

Hope this helps some of you guys out.

 

[iSign]

That is an excellent post I-45... Thanks!!