Up Date on EF Error

[jwa1156]

Fellow Botters
The VFD error “EF” gremlin is still haunting my Desktop.
Tech support and I agree that this may be caused by the Spindle Overheating.
We have pretty much eliminated the normal electrical issues.
My Desktop has an HSD Spindle, with what I thought was a fan attached to the top of the spindle.
I removed the black end of the spindle thinking it was a fan to send to Shopbot for testing. When I actually removed the end cap of the spindle I discovered that it was not actually a fan. The black end cap was covering an impeller attached to the end of the spindle shaft and turned with the shaft.
When turning at even 14,000 rpm I can’t determine any airflow being generated from this impeller. Are any desktop owners equipped with a HSD spindle able to determine any air flow or does it seem to only rely on the movement of air by convection?
My HSD spindle is also reaching temperatures of 160-170 degrees F, tech support say it should not be over 140 degrees F. Do any of your desktop spindles reach 160-170 F? How does your spindle get cooled?
Thanks

[Brady Watson]

Those little HSDs have shaft mounted fans as you have found out. Only the larger HSDs and Colombos have electric fans. The electric fans allow for a cool down when the shaft stops turning, the little HSDs do not...which is why they should be run at lower RPM for a little while when machining for prolonged periods.

The flow is low on these. If my memory serves me correctly, the electric fan on a Colombo 5hp is only like 140 CFM. The air is blown out of the 4 corner holes on the bottom of the square spindle housing. If 140 CFM is enough to cool a 5hp motor, a 1hp motor (really 0.9hp) *should* be able to be cooled by 28 CFM, or 1/5 X 140 CFM.

Since it is shaft mounted, there isn't too much to go wrong there in terms of the fan not working mechanically. So...here are a few things I would suggest.

Using compressed air, blow out the spindle from the top down, through the cooling vent, in the event that the channels are blocked by debris. While blowing, put your hand under the exhaust ports and see if you can feel the flow. You may find the exhaust on your shopvac to be an easier method. You want to make sure nothing is impeding the flow.

Inspect the spindle itself by 'feel'. Turn the shaft by hand. Does it feel smooth? Do you hear any noise, like ball bearings? Does it feel like the bearings are galled?

Turn on the spindle - does it sound labored? Take a piece of paper (remove collet and nut first) and see if it flaps like a fan tassel when the spindle is running, underneath. Is air blowing the paper around?

-B

[jwa1156]

Brady
Thanks for the great suggestions
I don't think the bearings are bad, the spindle is smooth when turned by hand
it is quite when running
I will check the air flow IN the correct location after I flush out the spindle.

on the RPM for cutting are you suggesting maybe varying the speed during long cuts?
I have thought as a last resort could just hit the space bar and let the spindle cool off then
I have a small IR thermometer to get the reading, so I do not have to touch the spindle.
also have looked at may attaching some cooing fins on the outside of the spindle housing?

[Brady Watson]

I've run mine full tilt for 10hrs straight at a time on very detailed 3D stuff. It is toasty as you would expect any electric motor to be running that long, but I would not say it was hot.

No, my suggestion was not to stop it to cool (the whole idea with a spindle is high duty cycle); the idea is to run the spindle by itself after the cutting is done at say 8000 RPM for a few minutes to allow it to cool down. Everything gets heat soaked and just like your car, when you shut it off, the temp rises.

-B

[scottp55]

Feeling kind of dumb that I didn't know the fan was shaft mounted, and I've been checking the flow for 2 years to make sure the "Fan" hadn't died:)
Jerry, Don't have a thermometer, but VERY familiar with 140F(paraffin) and 150F(beeswax) temps by touch as we heat soak our buttons and remove excess before they cool.
Most recent continuous cut was 5 hours(but if memory serves one 22 hour cut was the same) and spindle temp was way under those temps by touch, maybe 120F? Our normal cuts are 20-50 minutes with a 45-60 second break to change blanks out and spindle stays cool over that 3-6 hours.
We blow out top of spindle at the end of every day,and spindle cone at every bit change(probably cleans ports a little too as nozzle is about 4" away).
Thanks Brady, May start doing a C5 at 8K at end of long continuous cuts.
If shaft mounted is the only thing I learn today, it's still a good day:)
scott

[Brady Watson]

We blow out top of spindle at the end of every day,and spindle cone at every bit change....


Did 'you people' get that? When was the last time you properly wiped out the taper in your spindle or router?

A little WD40 will 'quench' the metal and keep it from oxidizing/rusting. Just lightly dampen a clean rag or paper towel and wipe it out. I think many of you will be surprised as to how much junk is in there if you haven't wiped it out recently (have you ever?)

Pursuant to cleaning...Your machine will look new again with a quick wipe down. Instant detailer and a microfiber cloth, available at auto parts store, works great to wick up the grime and buff it all shiny blue again. You will be amazed...

-B