Routing Aluminium with a Trimmer router

[iwik]

Hi guys,
Have the following small desktop router. The spindle is a Bosch Colt
router with a speed range of 16000 to 35000.
Wanting to cut Aluminum with it, seen others do it but need to know
Feed rate and Spindle speed. Any calculator I use when using a 3mm
bit say my spindle speed min is to high.
I have been cutting 2mm aluminum but the bit seems to get to hot
as seen with it discoloring. Have tried different feed rates. It seems to cut alright but tip life wont be great.
I had been using a HSS end mill but even if I plug in a Carbide bit these
calculators say my spindle speed is to high for the bit size.
Any one using a setup similar to my one and would like to comment,
It would be much appreciated.
Thanks
Les

[Shawn]

Chip load on the tooth is what really matters in the end. The higher the spindle speed the faster the feed rate required to achieve a proper chip load per tooth. I use a single flute endmill for aluminium and plastic to help increase the chip load but I don't spin the bit at the same speed as you either. I calculated 25ipm feed rate for a 3mm two flute endmill in 6061 aluminum? that's pretty fast for a small router table. I use a continuous blast of air to cool the bit and remove chips and that really helps a lot on my setup, better than coolant for aluminum and plastic. The calculators don't take into account how ridgid your setup is, how much backlash etc, its a good place to start but sometimes we just have to take what our tools can give us and live with it.

Shawn

[iwik]

thanks Shawn,
What speed does you operate your spindle at?.
Les

[Shawn]

I have a small milling machine that I converted to CNC so the spindle only runs 4000rpm max but I have added a small die grinder attachment that I use for engraving and it runs between 20,000 and 48,000rpm so I am on the far end of each spectrum.

Shawn

[iwik]

Thanks Shawn,
I have controller I bought a few years back that will allow a Router to operate down to
5000 rpm and still have good torque. So I must hook this into my system, it should help
me a lot.
Regards
Les

[Shawn]

Getting the RPM down and going to a single tooth cutter will make a big difference. When you hit the sweet spot on the speed and feed rate aluminium cuts like butter.

[iwik]

Thanks,
I was wondering about using a single tooth cutter. After what you have said I must try one.
Les

[Westozy]

I use quite a lot of 3mm aluminium for my components and I find the best results are achieved by "economical" cuts. I use a single fluted 3mm end mill and generally choose the speed by ear. I have a Kress spindle in my CNC which can do 6000 to about 30000RPM. I would cut aluminium at 200mm per minute with a depth of only 1mm so therefore 3 passes and I dial in a speed from mid range down to where it sounds like the spindle isn't labouring. This stops the tool from overheating and I find the best finish on the edge is achieved by "climb" cutting. It is slower than machining plastics but this method always gives a good result and the tool bits last for ages. A spray oil such as CRC or WD40 is an excellent lube/coolant although a bit messier!
Cheers Gwyn

[iwik]

Thanks Gwyn,
Are your cutters Carbide?.
Les