[harryn]

Well, after a lot of thinking and budgeting, I have decided to postpone the build of a full size cnc router. Nonetheless, I would like to build "something" for education and fun.

Most likely a fixed gantry setup that fits in a 2 x 2 or 2 x 3 ft spot, for convenience. I have also accepted that very little of it will be usable on the larger router.

Now the real challenge - coming up with projects to make on the small router. Making parts for the larger one "might" be ok, but that is down the road.

I have lots of ideas for a 5 x 10 ft cnc router, but absolutely none for a paper size cutting area. Suggestions ?

Harry

[JerryBurks]

For fun (easy) or for money (maybe more difficult)?

Keep in mind the material volume for small projects is a fraction of large ones, allowing you to use nicer materials like exotic woods, metal, etc.

Couple of small things that I made so far. Sometimes it was more important for me to figure out the technique than the result.

[CarveOne]

Well, after a lot of thinking and budgeting, I have decided to postpone the build of a full size cnc router. Nonetheless, I would like to build "something" for education and fun.

Most likely a fixed gantry setup that fits in a 2 x 2 or 2 x 3 ft spot, for convenience. I have also accepted that very little of it will be usable on the larger router.

Now the real challenge - coming up with projects to make on the small router. Making parts for the larger one "might" be ok, but that is down the road.

I have lots of ideas for a 5 x 10 ft cnc router, but absolutely none for a paper size cutting area. Suggestions ?

Harry

Take a good look at microcarve's MV3 and BBX designs for ideas. If you want to use Hiwin or THK rails they can be made to work with some additional structure to mount them on. You can buy the Z axis from John as I recently did for my mini build.

[DonFrambach]

I've made a bunch of small high relief plaques with my small router. Here's three that I just finished:

[harryn]

Lots of nice work on those projects.

The projects that I originally had in mind were building new cabinets for around the house. I was going to cheat and just cut the faces all at once from a ply sheet. Doors would be easy of course.

The other thing I had hoped to make are drawers, which I do very poorly by hand. Mine are nearly useless.

I could make a few circuit boards.

Moving the machine toward Al / light steel use would cut down on size and cutting speed needs, but I am not sure if I really save on electronics or not. Holding things so they don't chatter still takes power and / or precision parts.

Somehow, making the machine smaller drives the projects toward higher precision, small parts, which isn't a low cost machine either. Savings in electronics just push me toward more mechanical costs in precision drive parts, and higher gear reductions, which is not cheap either.

[ger21]

The projects that I originally had in mind were building new cabinets for around the house.

Buy a good quality used tablesaw from Craigslist, and use that to build your cabinets. It'll be a lot faster.

The cabinets in my laundry room were built with a circular saw and router on my living room floor.

[harryn]

Buy a good quality used tablesaw from Craigslist, and use that to build your cabinets. It'll be a lot faster.

The cabinets in my laundry room were built with a circular saw and router on my living room floor.

Hi Gerry, of course you are right, but that also assumes that I have your skills and experience, which I don't. Taking on a kitchen or highly viewed cabinet is also quite a bit more serious of an effort than a laundry room cabinet.

I also only have room for 1 serious size tool, a cnc router OR a table saw OR a radial arm saw, not multiple units.

I did break the piggy bank open this week and ordered some parts to get started with at least the "training" to build a router. A G213V driver and motor to play / experiment with for one axis. It's a start.

I decided on the Geckodrive G213V for "learning" because:
- It has a a wide range of voltage, current, and motor inductance capability
- The inputs can handle both "normal" 5 volt TTL as well as less powerful signals
- It is very well protected
- It can be run in many stepping modes
- Made in USA
- Designed and built by a really great outfit to work with
- It seems likely that it will handle most motors I throw at it, now or in the future

One of the experiments is to see if I can get by without gear reduction in the drive. That would be nice if it turns out to be possible. A good reason to build up one axis for now.

[TrickyCNC]

I've made a bunch of small high relief plaques with my small router. Here's three that I just finished:

Very nice

I've seen the rings show up on here a few times . Do you have a link to the files for them ? I have a friends wedding coming up, and this is one of my ideas for a gift.

Thanks
Rich

[TrickyCNC]

Harry

You could take a look at my build. I used scraps and donations ! my 'Y' and 'Z' can be copied very cheaply. Especially my allthread Z. It works really well.
I even bought some "proper" ACME thread, but haven't needed to use it

Who knows, if you can do it cheap enough, you may be able to go a bit bigger than you thought

Mine cuts 24 1/2 " x 25 1/2 " x 6" and cost me around 250 of your American dollars ! not including PC , but for the software, I use free stuff. Q-Cad / PyCam / EMC2 etc

My X and Y motors and screws were donated though

Rich

[TrickyCNC]

For fun (easy) or for money (maybe more difficult)?

Keep in mind the material volume for small projects is a fraction of large ones, allowing you to use nicer materials like exotic woods, metal, etc.

Couple of small things that I made so far. Sometimes it was more important for me to figure out the technique than the result.

Nice work Jerry

[DonFrambach]

I've seen the rings show up on here a few times . Do you have a link to the files for them ? I have a friends wedding coming up, and this is one of my ideas for a gift.

I bought the "wedding rings" from VectorArt3d.com for $10. Here's a link: 3D Model | Wedding Rings (Vector Art 3D, Inc. - Dimensional Clip Art for CNC Routing and Engraving)

[TrickyCNC]

Thanks ... I'll have a look

[harryn]

The Gecko G213V and nema 34 motor arrived on Frday (as promised) but it was Saturday until I could drag my teen daughter over to take a look. I have given her the assignment to help find parts, and that required her to read the gecko manual for power requirement specs.

I was showing her the connecting points for wires, which is a lot easier on the actual part in front of you. Then I was doing a quick explanation of the stepper motors and mentioned that this type is called "bipolar". Quick as a whip, she bonked me with a joke - "does that mean they only work 1/2 the time ?" ROFL.

I figure since she is going into engineering, cnc routers are fair game to drag her into.

[harryn]

I have spent the last 2 weeks thinking about power supplies and how to get decent quality at a reasonable price - normal stuff.

Long term, I see needing to drive 6 motors x 3.5 amps, and at 72 volts, serious power.

Short term, I am in learning mode building up one axis, so I am not quite ready to jump into the longer term power needs.

I also noticed that it is a lot easier to get 24 volt supplies than 72 volts. Are there any (technical) downsides to using linear PS's in an "array".

Example
- 3 each x 24 VDC x 5 amp in series = 72 volts x 5 amps
- parallel these 3 x, and you get 15 amps

Good idea or bad ?

[ger21]

Example
- 3 each x 24 VDC x 5 amp in series = 72 volts x 5 amps
- parallel these 3 x, and you get 15 amps

So you think 9 power supplies would be cheaper???
Just go with the 65V 20 amp that Keling sells, for $190. You're not going to find much cheaper. You're motors and drives will be about $1000, so I'd say the $190 is reasonable.

[harryn]

So you think 9 power supplies would be cheaper???
Just go with the 65V 20 amp that Keling sells, for $190. You're not going to find much cheaper. You're motors and drives will be about $1000, so I'd say the $190 is reasonable.

I wish it were that cheap.

1 gecko nema 34 motor / 1200 oz in / 12 mH / 3.8 amps = $ 190
1 gecko 213v (to deal with the recommended 80 VDC ) = $ 160 ish
total = (corrected math) $ 350 for one set, and that is before the mechanicals.

6 x $ 350 means this is going to be done incrementally. I am still learning, so one axis to start is ok.

In total you are right, I am sure that the price for 1 large PS is less than 9 of them, but I am trying to manage the short term budget as well. I am still studying PSs, and they all have their interesting characteristics, strengths, and limitations.

Also, I am trying to maximize the US made content of this router where possible, rather than adding to the trade deficit.

[CarveOne]

Unless the PSUs are designed for series and parallel operation I would expect trouble of one kind or another when something goes out of the normal loading situation. Suppose one PSU gets shorted on its output, or goes bad from a shorted capacitor. What's it going to do to the other PSUs?

Can the individual PSU withstand having the output floating at 72vdc above its own ground potential when it is not spec'd to do that?

I'm with Gerry, pay the $190 for one PSU that does the job. The KL6520 has 5vdc and 12vdc outputs also.

Same price for the KL7220 that has no extra outputs, but with an additional few turns of wire around the toroid you can add the 5vdc 1amp output with a little effort. Just a small perf board, capacitor, and an LM7805 three terminal regulator. Or find a suitable wall wart for the 5vdc if you need it.

[milhead]

If you're really looking for cheap PS you can build a pretty cheap linear supply from a disembodied microwave transformer and a few components.. I ran 40V at about 10 amps for years on one of these devices... Let me know if you're interested and I can give some links to the How-To

I run my #2 machine on 38V only because I got a smokin deal on an Astec supply on eBay.. I'd have build a big linear supply otherwise.

I've heard tell of using supplies in parallel but it's got to keep supplies of slightly different output voltages from trying to source all the current and entering a latch-off condition.. Probably easier with linear supplies that will lower their output if overdriven and possibly a set of big diodes on each to keep one supply from shorting through another until the load equals everything out. (this is just me speculating, I've not tried it and while I do have some electronics training, it's not in Power Supplies)

[OCNC]

I wish it were that cheap.

1 gecko nema 34 motor / 1200 oz in / 12 mH / 3.8 amps = $ 190
1 gecko 213v (to deal with the recommended 80 VDC ) = $ 160 ish
total = $ 450 for one set, and that is before the mechanicals.

So let me put some money in your pocket...

$190+$160=$350 per set. Savings= $100 per set

[ger21]

but I am trying to manage the short term budget as well

The best plan would be to buy a G540 package, and sell it when you no longer need it. You should be able to get 75% of what you pay for it.
It'll be cheaper than 1 G213, 1 motor, and power supply.
And, it'll probably run your smaller machine much faster.