What is the best bit / rpm / feed rate for this enclosure?

[alank2]

Hi,

Hammond Mfg. - Plastic Hand Held - 1599 Flame Retardant ABS Series Enclosures

The datasheet says it is flame retardant ABS plastic.

A bit that could plunge and then cut small circles or squares would be ideal.

Any recommendation on bit, rpm, and feed rate?

Thanks,

Alan

[alank2]

Hi,

I should add that I've been cutting these using forms by hand using a 1/8" bit. I hope to move to doing it with a microcarve. I wonder if a 1/16" bit would be better. Less plastic cut = less heat ?

Thanks,

Alan

[Stowe Figler]

I've never cut ABS, but I've cut lots of acrylic, sintra, kometex, and other types of plastics. Its been a while. It was my last job, in another industry, so my feeds and speeds are bit rusty. I liked using vortex tooling's 2 flute straight edge, and twin O-flute cutters for this stuff. It was mainly a woodshop, but we would get wierd request all the time, and I had a few of these vortex tools for unknown materials. The .25" twin O-flute was my work horse.

Diameters ranging from .375 to .1875. They are my favorite tool company. Tech support is great helping with feeds and speeds. RPM = 15K-18K
F=30-50, and maybe 1/4" DOC. Plunging at a downward angle of about 20 deg. Climb cut for sure. I machined my plastuc parts with a 3 axis onsrud wood router, using the table vacuum for hold down, so my main parameter was making sure the parts are not moving during the cut.

[RomanLini]

I do ABS plastic electronic enclosures from time to time. It's REALLY melty and can get away on you even with the right tool. Some brands and colours of ABS are terrible.

I recommend a 1 flute or 2 flute bit (1 is better) maybe 2mm or 3mm diameter, low RPM like 7000 (which is low for that diameter tool) and a highish cutting feed speed like 35 IPM or higher.

These plastic boxes can vibrate a bit too, so you might find it good to take multiple shallow depths of cut, maybe 0.5mm, this also reduces the heat as well as the vibration as there is less force where the cut is.

Use a compressed air blower onto the cutting tool if you can, it really helps, other wise stop and clear chips and check it does not build up around the tool as that will cause melt for sure.

[alank2]

Thanks RomanLini for the great information - What do you think about this bit:

http://www.amazon.com/Freud-04-096-16-Inch-Diameter-Straight/dp/B00004T7B2/ref=wl_it_dp_o_pC_nS?ie=UTF8&coliid=IBTGJ4IT3MD0V&colid=1XFIZH5HRP9AI]Amazon.com: Freud 04-096 1/16-Inch Diameter by 1/4-Inch Double Flute Straight Router Bit with 1/4-Inch Shank: Home Improvement

Alan

[ger21]

This is probably a much better choice, if you have a 1/8" collet.
1/16"(.0625") single flute carbide endmills for plastic Kyocera Tycom | eBay

[alank2]

Hi Guys,

I've been doing some plastic cutting using the bit I have - which I admit isn't ideal. It is a very tall (probably 2") spiral bit. I've noticed that it tends to drag the bit behind (I'm guessing because it is so long) if I go too fast. It seems to cut a circle that looks nice at 5 IPM, but if I go to 15 IPM it looks a bit oblong. It seems to cut cleaner if I do a single plunge and single pass cutting the entire 0.100". If I do multiple passes, it doesn't seem to cut as clean as a single pass.

Should I look for a better shorter bit? Should I just do the single pass cutting? Should I use a faster RPM with the single pass? Is 5 IPM a reasonable speed?

Thanks,

Alan

[ger21]

What diameter is the bit, and what rpm are you using?
Depending on the bit, I'd say that 5ipm is 15-20x too slow, but the rpm also comes into play here. What's the bit diameter?

My bet is that the oblong holes are the result of backlash or machine flex.

If you can, use a 1/4" bit, single "O" flute. You should be able to run it at 75-100ipm, maybe faster depending on your rpm. And you shouldn't have any trouble with multiple passes, as long as you're going fast enough to not get melting.

[alank2]

Hi Gerry,

The bit is a 1/8" spiral bit. The machine is a Microcarve MV3.

Thanks,

Alan