Would you recommend a Chinese 60K rpm spindle for 20K rpm use?

[crazylegsnick]

I was thinking of getting a 60K rpm spindle for use at 20K rpm, because it should be more precisely made than one designed to run at 20K rpm. It should be a cheaper option than getting a European 20K rpm spindle. I want it to be water cooled because they are quiet.

I am going to to be cutting 4mm phenolic plastic sheet with 2-3mm diameter cutters. I need the spindle to be quality enough not to cause the cutter to break from excessive vibration.

Does anyone have any thoughts on my idea.

[Sasquatch]

I did use 0.5 mm 2 flute cutters for pcb engraving at 30000 rpm using Chinese 24000 rpm spindle. Yes 400Hz spindle at 500Hz. No breakages. You're overthinking it.

[JAZZCNC]

Your looking at this wrong way around. The power/torque curve at 20k rpm will be lot lower than at 60K so your more likely to snap cutters from spindle bogging down.
Regards cutters snapping from vibrations then it's often a weak machine frame it's self that causes vibrations rather than just the spindle. Only on very tiny cutters, sub 1mm, will the spindle be to blame and even then it will be mixture of both.

If you want to oversize then spec it so the power curve suits your cutting conditions. IE: if you want to cut at 20K then get spindle with the highest torque is at 20K.
Often that is roughly 2/3rds the rated RPM so 30K would suit.

However, I can tell you without a doubt, because I've fitted in excess of 100,. that Chinese 2.2kw 24K Rpm spindle with do what you want standing on its head 12hrs per day 7 days a week.

[ngwagwa]

I agree with Jazzcnc. I use a Chinese 2.2kw 24K Rpm for cutting Polycarbonate with tools down to 1mm diameter and also cut Ali with these 1mm dia tools

[Boyan Silyavski]

I cut phenolic a lot. I would like to see you cutting phenolic at 30k rpm . One can not evacuate chips at that speed and relative to the size of the bit depth and you will glue and break your cutters.

I cut phenolic at wood RPM and 1/3 the feed for wood, for perfect finish , especially when going deep. Now i can much speed that up HSM and blowing air in the cut, but the only reason i see doing that is serious production. Otherwise one will have to stay there and be like vigilante so the bit does not break. I prefer drinking beer while my robot does the job.

Like Dean said 2kw spindle will do that perfectly. You should worry finding and paying for ultrasharp bits in that size. Cause chinese will not do. I use Kyocera.

[JAZZCNC]

I cut phenolic a lot. I would like to see you cutting phenolic at 30k rpm . One can not evacuate chips at that speed and relative to the size of the bit depth and you will glue and break your cutters

I worked on a large industrial machine for furniture manufacturer which only cut Phenolic board and they used left-hand cutters.

[AndyUK]

I worked on a large industrial machine for furniture manufacturer which only cut Phenolic board and they used left-hand cutters.

For the less experienced muppets here (i.e. me), can you explain how a left-handed cutter improves chip evacuation - or have I missed the point and the left-handed cutters were useful in some other aspect?

[JAZZCNC]

For the less experienced muppets here (i.e. me), can you explain how a left-handed cutter improves chip evacuation - or have I missed the point and the left-handed cutters were useful in some other aspect?

In all honesty Andy I've no idea. I just fixed the machine but noted the cutters and infact I've got one somewhere the operator gave me. They only used these cutters for cutting phenolic boards which is tricky to cut at high feeds.

[Sasquatch]

I worked on a large industrial machine for furniture manufacturer which only cut Phenolic board and they used left-hand cutters.

Do you mean downcut cutters? Never seen left handed endmill(to be spun counterclockwise)

[JAZZCNC]

Do you mean downcut cutters? Never seen left handed endmill(to be spun counterclockwise)

No left hand 3 flute cutters (weldon shank) spinning counterclockwise