Questions on using a moving gantry style mini-mill...

[Lee Roberts]

The clamp block for holding the spindle to the mill, better made out of one big lump or two plates maybe 12mm thick spaced apart 10mm or so?

My choice would be a single lump or to space them out more if it's for a typical water cooled spindle, 12's a bit thin in my book.

.Me

[Davek0974]

Just realised they would need to be firmly fixed to each other or it would allow twist. Single block it is ;)

[Davek0974]

Will be using two Mach3 profiles. Only one spindle will be in use at any time.

Looking for ways to switch all the control lines needed -

Vfd supplies
vfd control and fault lines
vfd speed lines
limit switches for Z axis in two positions
homing for z axis in two positions
cooling pump for 24k spindle
probably others....

The programming for the CSMIO plugin I gather will need to be the same for both profiles?

[Davek0974]

Odd programming?

I am cutting some plate for parts on my Bridgeport conversion project, had some good success and a couple of oddities. The most annoying one is my motor VFD has shut down twice now with an error that shows as short-circuit on motor phases, each time i reset and it carried on ok, there was a month between faults - the annoying part is i don't have the fault relay in my e-stop loop (yet) so the motor quits and the motion caries on - snap goes another £8 tool :(

The rest of my issues are experience, or lack of, related so in the end i worked them out, but I'm getting pretty good at re-homing and starting over with modified code ;)

[Davek0974]

7000rpm on a 8mm 2-flute cutter too much?

Just been trying to carve a lump of 18mm thick ally for my Bridgeport conversion, using a 2-flute 8mm HssCo tool at 7000rpm, 900mm/min and 1.6mm DOC

All the features went without hitch, the perimeter decided to bog-down after getting about 9mm deep and stalled the axis.

I have a feeling the height of the wall blocked the coolant/air and allowed the tip to build-up. I need to fit two coolant jets i think at 90deg to each other.

I have re-cammed the profile starting from 8mm down and increased rpm to 8000 and reduced step-over a little.

Will see what happens tomorrow.

[routercnc]

Hi Dave,

That used to happen to me a lot. Slot milling over 8mm risks poor chip evacuation and clogging of the tool. I've seen people machine the outside material completely away (i.e. an outer pocket to leave the central island, not a perimeter slot). But then you need to be able to hold the part in the middle which isn't always possible.

Another option is to use something like adaptive machining to mill a larger width slot than the tool.

I tend to reduce the DOC when over 8mm into a slot and that works OK. I vacuum out the slot on every pass and give a quick spray of WD40.

[Davek0974]

Adaptive does look good but none of the CAM software i have can do it.

I tend to pocket the part out, leaving tabs etc to hold it, on the 8mm tool i used a 12mm pocket so two passes, but when the tip is deep in the pocket the air/coolant cant reach it and i was not paying enough attention i guess.

I'll see if i can rescue the part with the modified paths and some extra air blast.