[karbunkle1952]

After spending my time researching, since joining in Aug. 2005, I've started construction.

Mind you I'm using the vast knowledge of this group, so I'm not going into this blind, It's more like I have been poked in one eye.
My figurative "poked eye" is the electronics hook up.

I have moved right along building the machine base x axis and z axis. I am now about to fill in the middle y axis.
I have the great fortune of working for a company that has a great deal of "stuff" at it's disposal. Anything I need for construction comes from the scraps from another job.

I am a Prototype Modelmaker and this machine will be used for both 2D and 3D work. Anything from routing Sintra signs to vacuum-form patterns.
I work for a Display Company.

I'll be posting pictures of the progress. I have a few already but, as of this writing they are on the harddrive at work.

Currently, I have this dilemma: How do I make the electronics work?
Let me tell you what I have and please give me advice and links to the information. As noted previously, I've used this forum to get this far, it is my hope that you can help finish it.

Here's what I have:
1. 3 pcs. 640oz/in Model #RHT34-640 Bipolar Steppers from www.homeshopcnc.com
2. 3 pcs. Gecko 201 Drives
3. 1 pc. Magnetek MG1 MODULAR POWER SUPPLY 48vdc 15a regulated (www2.magnetekpower.com/cps/CPS_MG_DS.pdf)

As I understand it here's what I'll need yet:
1. A parallel port interface card (to talk to the Geckos)
2. a 5vdc power source for the Geckos
3. A capacitor (10000uf?) for the feedback EMF from the steppers to the Geckos since the power supply is regulated.
4. A fuse block to protect each Gecko
5. Maybe a Safety Charge Pump (but I'm not sure how that all works)
6. Mach3

Please feel free to direct me (kick in the butt, I'm an apprentice) to the proper vendors.

The capacitor part is confusing me at present.
If I buy one large Capacitor, Can all three Geckos be connected to it?
If so, are they isolated in any way? What voltage Capacitor do I use?

I know from reading the "Stepper Basics" PDF on the Gecko page there is supposed to be at 470uf 100v Cap on each Gecko. But I've seen examples on this forum where just one large Cap is used.

[ger21]

1) www.campbelldesigns.com www.cnc4pc.com www.pmdx.com
2) I **think** you can pull this from the PC.
3) I think there is a formula in the Gecko paper on power supply design, which will give you the cap size.
4) Haven't used Geckos, but this is in the manual, right. Mariss (Gecko owner) is on vacation. Give him a call later in the week and he'll tell you everything you need to know to hook up your Geckos correctly.
5) Works with Mach3, and certain breakout boards (possibly all the above, CNC4PC is an add-on card) to keep motors from moving when Mach3 doen't have control of the system.
6) www.artofcnc.ca Also, watch all the videos at www.machsupport.com

[karbunkle1952]

Thanks Gerry,
It's the whole feedback emf issue that has me a little worried.
According to the Gecko page, if I used an unregulated power supply the feedback wouldn't be an issue since it would be absorbed by the capacitors in the power source. But since I got a deal...$35.00 on this surplus regulated "powerhouse" powersupply... I'd like to use it. (Cooling fans already part of the power supply case!)
I hope Mariss can fill in the Cap question.
-Brian

[ger21]

What I meant, was, to use the formula for the cap as if you were building a comparable size supply as shown in the Gecko white paper, and just hook that up to the output of your supply.

[karbunkle1952]

Here is the progress.
I started with whatever I could scrounge from around the plant.
The framework is made from straight pallet rack rails.
The Rails are 2 inch EMT conduit
The Rails are sitting on Unistrut
The Bearings are Skate bearings sandwiched in Machined Aluminum.
All dimensions are completely made up. I'm Drafting this thing on Cadkey98 as I go along.
That's why I started with the x axis then went to the z axis. It'll be easier to meet in the middle with the Y axis Gantry construction.

[karbunkle1952]

I laid out how the bearings would touch the rails at 60 degree angles.
Then milled the 1 inch stock so in could all be sandwiched together.

This whole works is very Bridgeport intensive.

It's been slow at work so I keep myself busy on this project. It will be used for low volume production.

[2muchstuff]

I think I'm going to like this thread. Any thread that has the word "scrounge" in it is allright by me. I like the idea of using the EMT and Unistrut, makes it simple. Not to worry you but in time the galvanized coating on the EMT will begin to flake off where the bearings ride.

[WarrenW]

I really like those bearing blocks you made! And with the pipes mounted down, they won't flex at all. Can't wait to see the rest.

Warren

[creative_mind]

How did you adjust the bearing block to fit tightly on the EMT?

[swarfmacdaddy]

How did you attach the pipe to the unistrut?

[karbunkle1952]

After I welded up the whole frame, I took a large piece of corrugated cardboard and laid out my hole placement for the unistrut mounting screws. That way I could make sure the holes at least laid out square and parallel to one another. I also laid out holes that would go through and through my welded frame rails.

Now, mind you this is a one of a kind deal. After doing this once I wouldn't build another one the same way. This machine is basically using everyone else's various techniques. I'm just building with the materials I have and adapting on the fly. Back to the story....

The unitsrut is then bolted down to the top of the frame. I drilled and tapped the conduit and installed threaded rod. I bottomed out the threaded rod in the conduit. I added a jam nut up the threaded rod against the conduit. I then dropped the conduit/threaded rod assembly onto the unistrut/frame.

Then it was a matter of using my 48" calipers and working up and down, tippy tapping the conduit left and right until the while works was parallel.

I tightened the nuts onto the threaded rod, continually checking to make sure it wasn't pulling too hard in one area making a big steel banana.

When I'm all finished I may go back and tack weld in areas so the unistrut always stays put.

Check an end view you can see the threaded rod going all the way through.

[karbunkle1952]

Great, none of the pictures I have so far show how the blocks snug up to the rail.

Here's the theory....The bearings on both sides are attached to the aluminum the same way on the same 60 degree angle. One side is actually made up of two pieces bolted together so the entire assembly can be tapped to the correct distance.

I'll get a better photo on Monday.

[karbunkle1952]

Using a little of this and that, I made up a mongrel Y Gantry of 1.5" pipe, birch ply and extrusion.

The pipe is screwed down to the wood and sits in little saddles like the other torsion box designs on this site. That keeps it all lined up true and parallel.

The square extrusion is bolted to the wood.

If you're wondering how it's attached...it's not yet, I just have it laying on the x axis.

[karbunkle1952]

I went to the Axeman, A local surplus place. They have everything.

I picked up a 48v 15a power supply. It's a Magnetek. $35.00 It has a bunch of pins to use on the back.
I'll attach a drawing.

Please give me your Ideas on firing it up.

I say on the output module I have to put a SPST switch between pins 3 and 4.
But what are the rest of the pins for?

On the Input module I say I have to put a SPST switch between 8 and 9.
But what are 1 and 10 for?

Mouser had all the proper connections. I just have to wire it up correctly.

I do understand it is a regulated power supply. I guess that means Ill have to use large capacitors to take up the excess emf from decelerating motors.

I'll be asking about that in further writings/ramblings

Please advise.

[CJL5585]

As I understand it here's what I'll need yet:

1. A parallel port interface card (to talk to the Geckos)
2. a 5vdc power source for the Geckos
3. A capacitor (10000uf?) for the feedback EMF from the steppers to the Geckos since the power supply is regulated.
4. A fuse block to protect each Gecko
5. Maybe a Safety Charge Pump (but I'm not sure how that all works)
6. Mach3

The capacitor part is confusing me at present.
If I buy one large Capacitor, Can all three Geckos be connected to it?
If so, are they isolated in any way? What voltage Capacitor do I use?

I know from reading the "Stepper Basics" PDF on the Gecko page there is supposed to be at 470uf 100v Cap on each Gecko. But I've seen examples on this forum where just one large Cap is used.

First of all, You will need 3 each 470 uF 100 VDC capacitors. These capacitors will be installed across terminals 1 (Gnd) and terminal 2 (+48V) on each of the Gecko 201's.

Additionally you will need a filter capacitor (Some may say you don't, but you do) across the regulated output of your power supply. I would recommend a 10,000 uF (or larger) rated at 100 Volts DC. This is not based on a formula, just experience. The reason for the filter capacitor is that the majority of these supplies are switching supplies and can have some switching noise or ripple in the output voltage when supplying high currents. The filter capacitor will kill ALL the noise and almost all the ripple.

You will need an external 5 Volt DC supply. A 500 ma. (1/2 Amp) will be more than sufficient. Some people use the wall wart type. They work just fine.

I think that the charge pump is built into the Campbell breakout board. The charge pump is only required if using Mach 3. It disables the electronic signals from the parallel port to the Gecko's during the computer operating system boot-up process. The charge pump is a safety device for Mach 3 software.

The power wiring for the Gecko's should be in this order:

The filter capacitor should be across the outputs of the power supply. You should also have a bleeder resistor (a 5000 ohm 5 watt from Radio Shack works great) across this capacitor to bleed off the voltage when the power is off. Otherwise you will have +48 Volts on the Gecko's and could mess up a drive by removing a motor lead etc.These two wires should then go to some type terminal block(s). From the 48 volt common (some people say Gnd or -48 Volts) run a wire to terminal #1 on each Gecko. From the +48 Volt stud or block, you should have 3 each 5 Amp fuses. After passing thru the fuse the +48 Volts should be wired to Terminal #2 on each Gecko. Remember that the 470 uF Cap. also goes across these terminals when you are wiring these.

Hope this helps answer some of your questions. I have built a few (about 6) systems and wired them as above without ANY problems.
Jerry

[CJL5585]

I say on the output module I have to put a SPST switch between pins 3 and 4.
But what are the rest of the pins for?

On the Input module I say I have to put a SPST switch between 8 and 9.
But what are 1 and 10 for?

Please advise.

The ONLY connections you need to make are the utility power connections as follows:

On Jl
Power cord GND (Green in the US) to terminal #1
Neutral (White) to Terminal #2
120 Volts AC (Black) to Terminal #3

Connections to the 10 pin connector are not required in normal operation.

The inhibit inputs are to shut down the outputs of the power supply.

The sense pins are designed to be used in a special wiring arrangement and compensate for voltage drop in long runs of cable.

I only wrote down the important pin #'s which I have addressed above. Special care MUST be taken in wiring anything to the 10 pin terminal.

Hope this helps.
Jerry

[karbunkle1952]

I decided to mill a couple of pockets at 45 degree angle to make the carriages for the z axis.

[karbunkle1952]

I built the uprights from 1/2" birch and filled it with 2" urethane 10 pound sculpting board.

Drilled all the holes then milled off the bottom of both pieces at the same time with a killer end mill.

[CJL5585]

Karbuncle1952

I really do like your ideas and methods.

Looks good.

Should give you a nice system.

Jerry

[Mike F]

Karbuncle1952,

I like your ideas of the birch ply either side of the polyurethane foam - it will give a really rigid yet reasonably lightweight structure. This is also the thinking behind my composite machine where I will use carbon fibre where you use the birch ply.

One thing to be aware of though is localised areas of stress where you may be bolting things together. These areas need reinforcing with something a little more resistant than the polyurethane foam. I did notice in your photos that there is a central spine but no other areas of reinforcement. Are you sure there will be no give in the ply when it is all bolted together?

Mike