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Guys
Are there any "rule of thumb" when looking at spindle speeds for different size cutters and for cutting timber? I appreciate that it is not an easy answer but i just need a starting point as I keep finding new ways to fill my workshop with smoke.
Thanks
The key is you always want to be cutting, never rubbing. This is something that applies to any material you're trying to machine.
Spindle speed is a product of how fast your machine can move, recommended surface cutter speed (aka the diameter of the cutter), and spindle power.
Try running some figures through some of the feed/speed calculators like https://app.fswizard.com/
This will give you some ball park figures, but will still need some experimentation for specific cutters/machines.
Usually if your smoking it's because your feeds are too low rather than spindle speeds being too high.
What size cutters are you using and in what material.? Give us some idea of the feeds n speeds your using.
Also, the machine makes a BIG difference because if your machine can't handle the loads or travel fast enough to cut correctly then you always going to struggle. This is why Feeds n speeds calculators don't often work for DIY machines as they assume an industrial spec machine is used.
Good point to check the required spindle power for a planned operation. As well as checking the spindle motor is powerful enough, it's often worth checking how much or little of its capability you are making use of.
Lots of Youtube warriors seem scared to get anywhere near what their machines can achieve and have little idea where that is because they never check. My larger machine has "only" 3kW but when you see what 3kW can do, it can be quite a revelation. If you experiment and go a little too far, what do you have to lose? Cutters aren't expensive and underwear can be washed.
There are a few free f&s apps beyond the fswizard that include spindle power estimates. And many VFDs can display the actual load as a % of max.
I once read a forum entry somewhere that suggested the way to set your feedrate was to increase it until the tool breaks then back off 10% and replace the tool. I prefer to use HSMAdvisor but it's a worthy experiment if you have a handful of 3-6mm tools you're willing to sacrifice. I'm not sure I'd deliberately push my machine that hard with anything larger. Make your own mind up depending on what you have.Quote:
Originally Posted by Muzzer
Regarding the strength of DIY machines, you're better reducing the depth of cut or tool engagement more than the feedrate if you're getting inaccurate cuts since the cause of smoke, as Dean implies, is not moving the tool through the material fast enough. This leads to rubbing, localised heating and smoke.
Material is chipboard (just to practice on) RPM I have varied from 10,000 to 24000 (max) machine is a C-Beam from Open BuildsQuote:
Originally Posted by JAZZCNC
Well, that's two details which don't help.!. . .But you didn't answer my questions regards speeds n feeds your using.Quote:
Originally Posted by Lodds
perhaps this will helpQuote:
Originally Posted by JAZZCNC
Attachment 28980
I am new here, and I am using a Chinese 6040 machine with a 2.2kw spindle, for plywood I run at 10,000 rpm 254 feed and 80 plunge, with a 3mm end mill,and get excellent results, the top edges are very clean.
I intend to try Aluminium next, so some experimenting is needed.
How many flutes ??
That is way too slow. I don't know what machine you have but I would start by triple those speeds ie. 1800mm/min at 14000 rpm
Be prepared to break a few cutters.