Electronics Enclosure Build

[BobWarfield]

While I have a couple of final tweaks to add to the one shot oiler that I will post when done (see: http://www.cnczone.com/forums/showthread.php?t=53275), I am declaring victory and moving on from basic mechanical mods to the mill.

I have been installing the IH kit (very nice kit, BTW, I like!) and just got the optical limit switches on last Saturday. There is a bit more to do there too, but it's winding down.

So, my attention is starting to turn to the electronics. I want to be able to power up this bad boy that's taking shape so nicely in my shop!

Some time ago I acquired a couple of surplus Rittal NEMA enclosures off eBay very cheaply with the thought they would serve well in this role. They are 19" x 19" by 12" deep. As part of a Labor Day sale, I acquired a Sears Craftsman "Gladiator" rolling cabinet:



Here is what one of the Rittal boxes looks like (back behind some other CNC "finds" from eBay):



These are nice heavy gauge boxes with rubber weatherproof gaskets to seal them.

The first challenge I faced was opening the box. It uses a special theft-proof key:



15 minutes worth of mill and lathe work later and I had fashioned a key from a piece of 12L14 and a 1/8" roll pin I found laying around:



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[BobWarfield]

And here is what was inside yonder box:



That should work very nicely once I clear out that cage!

I drew up a preliminary layout sketch in Rhino3D:



Let me walk you through it.

First, the box will have the following inside:

- A set of 6 "Axis Modules". More on those later, but consider them to be self-contained Geckodrive sub-chassis.

- A power supply. I bought a nice 70V 1000W supply from Antek for a very reasonable price. This is the same outfit I got the toroidal transformer from for another supply I made.

- PC interface. Currently planning on a Smoothstepper.

- Miscellaneous relay and VFD controls, as well as an E-Stop circuit and other auxilliary components.

Here is a shot of the Antek supply I am using:



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[BobWarfield]

OK, now what's up with these Axis Modules?

Here is a 3D model of one:



The module is laying face down in that view. The blue box on top is a Geckodrive--servo or stepper. I'll be using servos for 4 of the 6 channels.

The red box is a heat sink to keep the Gecko happy.

The components directly under the Gecko are (front to rear) a DB-9 connector for the servo encoder, a 3AG fuse holder, and an IES power connector. For my servos I plan to use regular PC power cords to connect them up.

Lastly, the purple object at top is a load meter.

This is basically an ammeter that shows how much current the axis is drawing. I won't include the load meter on every axis, but it is useful for the main X, Y, and Z axis when adjusting the gibs. I came across a procedure for a commercial VMC that recommends adjusting the gibs until the load is about 1/3 of the allowable on the axis servo drive. I think it'll be interesting to be able to monitor these loads over time as well. The meters are cheap from MPJA and I just read the supply current from the DC supply before it gets to the Gecko.

Reading the load in this way has been somewhat controversial on these boards. I'll build one axis module and check it out before bothering with the other 2.

[Jason3]

Bob, that's looking good! Is the screen a touchscreen?

I like the look of the Antec power supply, it's quite tidy and looks well made. I might give them a try next time.

You'll like the Smoothstepper, They're great

Best regards,

Jason

[Runner4404spd]

Looking good bob. i integrated my pc into the control box that way its all in one water proof package. i'm still looking for a good way to bundle all my wires up, but i don't know if i've finalized all the locations yet.

[CarbideBob]

Originally Posted by Runner4404spd Looking good bob. i integrated my pc into the control box that way its all in one water proof package. i'm still looking for a good way to bundle all my wires up, but i don't know if i've finalized all the locations yet.

If you put your pc in the same sealed box with your drives and power supply it's going to get pretty toasty in there and your cpu might not be too happy.

Larger enclosures are better as it's the surface area of the cabinet that determines how much heat is dissipated to the external environment.

You can get an indoor/outdoor thermometer and place the outside sensor in the box and close the door to see how much temp rise you get. If it stays below 110/120 F you should be ok. At about 140/150 most computers will start to get flaky.
Bob

[TOTALLYRC]

Originally Posted by CarbideBob If you put your pc in the same sealed box with your drives and power supply it's going to get pretty toasty in there and your cpu might not be too happy. Larger enclosures are better as it's the surface area of the cabinet that determines how much heat is dissipated to the external environment. You can get an indoor/outdoor thermometer and place the outside sensor in the box and close the door to see how much temp rise you get. If it stays below 110/120 F you should be ok. At about 140/150 most computers will start to get flaky. Bob

Unlike me who gets flaky at 102f.
When that happens apply lots of alchohol

When it comes to enclosures, the bigger the better, especially if there is a cooling concern. Or if you have big hands.

[epineh]

Nice work on the key Bob, shame you live so far away I could have sent you a couple, I have a small pile of plastic ones lying around somewhere (they come with a new cabinet), no matter as they won't have the same "character" as your version

Looking forward to seeing the finished enclosure !

Cheers.

Russell.

[BobWarfield]

Thanks for all the kind comments, and yes, I plan on a touchscreen. In fact, I'll likely build a fancy control panel and integrate the touchscreen at some point, but not until after everything is working and I can use the CNC to make that fancy control panel!

Thought I'd share a bit more recent progress.

Here is a typical Martian War Machine, oops, I mean Gecko Module:



Pretty straightforward job on the mill. The legs are stainless, 304 unfortunately (it's not nice to work with). However, all I had to do was cut the legs to length, and then drill and tap either end for some 8-32's. Fortunately I had some brand new spiral flute taps I had gotten from Enco, and they made even that nasty 304 not such a bugger.

About the only remarkable thing I did to make these guys was to do a template from a 1:1 scale printout from my CAD program and then go on to make a drill jig from a piece of steel plate:



It made drilling all the holes in the heat sinks super easy and fast, and made sure they were all in exactly the right place.

I got my IH optical limit switches installed too:



They're really neat. Oddly, the cast iron was particularly tough on the column. I wound up having to sharpen my drill bits in the Drill Doctor, so maybe it was just that I started with a dull bit. Most of the cast iron is really nice to work on.

Next, I got a nice collection of IES power connectors, 3AG fuse holders, and female DB-9 connectors as well as some 15A ammeters. I ordered it all from MPJA, which is really cheap if they have what you want.

So, time to start thinking about the front panels on the axis modules. First thing was to make another 1:1 template on the CAD program:



I hate making up these panels because its just drudgery. Go buy a hole saw for the big panel cutout. Drill corner holes and mill or nibble for the square openings. When I get the CNC, that sort of thing will be a thing of the past.

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[BobWarfield]

Meanwhile, I could just tee these panels up on the mill and deal with it, or I can look around for a more fun way to do it.

I've toyed with 2 options. First one is to fire up Ye Olde Widgitmaster mini-router for the panels. Should be a fine job for it:



The other alternative I'm considering is putting together a little punch and die action for my 50-ton H-frame. Sure would be nice to have a punch capability on that thing. It'd be a fair amount of work to create a punching attachment, but I'll bet I'd get a lot of use from it.

Will have to think about which of the three options to pursue.

Cheers,

BW

[HimyKabibble]

Bob,

We're practically neighbors - I'm up in Bonny Doon. I've got a CNC'd knee mill. If you need to do those panels, or anything else, let me know. My machine would knock those out in no time. You can contact me at: jagboy@pacbell.net

Regards,
Ray L.

[BobWarfield]

Ray, thank you for the kind offer. I got busy over the weekend and have them nearly finished.

Best,

BW