[the_canuck]

Bad news.

My Hitachi WJ200-022LF 3ph 3hp VFD died a spectacular death tonight after a max of 15 hrs of use. I was 10mins. into a 3 min cut in AL plate. I was running only about 70% of max speed and had all the safety over current parameters setup and tested. I'm out over $350. I've had it sitting on the shelf too long to RMA it.


Andrew

- - - Updated - - -

[pippin88]

Bummer. Try contacting the dealer and manufacturer anyway, you might get lucky.

[the_canuck]

I figured out why the VFD died the other day. The connector on the top of the spindle is arcing. Time to replace it!

I got a ground fault error when powering up my new replacement VFD and I went searching and found arc marks inside the connector.

Currently the spindle has a 3 wire round style connector. I added a separate ground to the spindle. What are other people using to replace the round style connector?

[mactec54]

the_canuck

You should be able to find a cannon Plug male/female for what you need to replace

[the_canuck]

I started by cleaning up the carbon soot out of the connector with some alcohol then re-soldering the female pins, adding a dielectric grease, and was still getting arcs during AC power up to the VFD. Arcs were occurring inside the connector from the male pins to the connector housing. Next I removed the ground to the housing and that finally stopped the arcing. The standoff inside the connector is not high enough for the voltages seen during start-up. Connector is same as the one Mactec54 shows above.

Andrew

[ger21]

Here are part numbers for an Amphenol plug that I've seen others use.
http://www.cnczone.com/forums/diy_cn...tml#post978212

[the_canuck]

Thanks for the link!

I made some table surface progress tonight. It's now attached to the machine!

[the_canuck]

Quick update on the Machine. I did some measuring tonight to see how close I am to where I want to be.

Here's where I stand.

Cutting Area 24.25" x 73"

On that area I'm +/- 0.0025 wost case from nominal flat. I'm +/- 0.001 on the x axis on the extremes of y-axis travel. The center of the plates is where I have the worst numbers. I did notice that the plate is not sitting down against the spacer in the middle and I can slide in a 0.0015 shim between the spacer and the plate easily in the area I get the worst flatness measurements. I'll have to add more hold down bolts (currently only have 2 per spacer except the middle spacer where I added an extra in the center) to get it better than what I have now.
Not bad on such a large table area. It's better flatness then the table on the Eagle Knee mill I used to make many of the parts.

The plate is +/-0.001 in thickness on it's own which I can't really do much about.

Now for tram. I did a bit of work on the y-axis which as off about +/- 0.010 at the start. After some tapping on the spindle mount I'm now +/- 0.0005 total both x and y 1.5" from center of rotation. I think that's good enough for now.

[Arbo]

Pretty close in cutting area to mine, but it will be a heck of a lot more accurate no doubt.

[the_canuck]

Drill! Drill! Drill!

I made a bunch of progress this weekend.

First I started with engraving 2" x2" grid over the table yesterday.

Today I drilled a 4" x 4" grid of hold down holes. They will eventually be tapped to 1/4" 20. I first used the cnc to center drill all the holes, then came back with a #39 drill all the way through. Then by hand I used a #7 drill and finally the center drill to d-bur the holes. There's 124 total holes so it took a while. I don't have any 1/4 20 taps so the next laborious task of tapping all those holes will have to wait a couple of days.

Fun! Fun!

[the_canuck]

Tap! Tap! Tap!

[FannBlade]

I don't envy that task at all!! I think I would rather mow the grass with scissors instead.

[the_canuck]

Did a test run in MDF today for a small wing mold.

Results are decent. Some minor things to tweak.

More pics on facebook.

www.facebook.com/Canuck.Engineer

Andrew

[mactec54]

the_canuck

Great to see your machine is working well, it's a great achievement, when you cut your first parts,on a machine that you built yourself

[the_canuck]

Playing with Corian today. I now have a set of usable molds for a small free flight glider 19" wingspan.

0.25" 2 Flute solid carbide ball mill running at 24K rpm cutting at 50ipm. 100ipm I could smell the Corian was getting hot so backed down to 50 ipm for the molds.

Still need to work on the tuning issues. Corian is harder than MDF and shows the oscillation problem even more prominent in the cuts.

Andrew

[Arbo]

24k rpm? were you getting corian dust? I usually cut it at like 11k down to 8k rpm, get nice flakes.

[the_canuck]

I was getting chips. Not much dust at all.

[ger21]

100ipm I could smell the Corian was getting hot so backed down to 50 ipm

Actually, it works the opposite way. Slowing the feedrate down will actually create more heat.
Corian smells nasty regardless of the feedrate

[the_canuck]

50ipm gave me good results and no smell. 100ipm I was smelling it more. Maybe because I was cutting with no vacuum or compressed air for the chips.

Andrew

[Arbo]

I was getting chips. Not much dust at all.

Well, that's good. If I up the rpm like that I start getting dust, so I always cut it at a lower rpm. Interesting.