My upgraded machine and cabinet

[ViperTX]

Nice work Parameter...you'll be fine with any thickness of plexiglass.

[Parameter]

OKay, those PMINMO 3977SED drives are completed and kickin! I just added a 18v power supply and the same setup went from 12 IPM (at 12v) to 30 IPM!!! What a difference. I will change motors pretty soon and get the power supply at 32v. I'd expect around 40IPM.

I'm using 1/2"-10 ACME on X and Y but will go to 1/2-13 All-Thread as I can't make a good ACME tap and cannot find one... The actual nuts are not so clean. The new nuts are all done and seems much better.

I might cast some bronze nuts for 1/2"-10 ACME right and left hand with backlash adjustment... Those would be cast on the screw (with a ceramic microcoating) so fit should be near perfect.

I now cut some foamies for some sign guy that does quite a lot of em. At 30IPM with a 1/4" upcut 2 flutes, it just wheez in at 10,000 RPM for a .9" thick cut in one pass. Having the cabinet is ESSENTIAL with foam, it's incredible how much dust it makes.

Also, if you want to test different plastics, ask the commercial metal and plastic dealer around for offcuts. Most of the time they just sell em at rebate.

I asked a guys for offcuts, I said, just put a couple shovels in a bucket and make me a killer deal... See the pic for what I could get for 20$us. Plus, I had 2 sheet 1.5' x 4' - 3/16" cast acrylic (fumed). Just those are worth more than half the price I paid. In the bucket are UMHW, ABS, PVC, Acetal (Delrin), Polypro, Styrène, some cast acrylic and lexan and some other yet to identify... As always, make sure you have good vacuum on the machine when machining any plastics or foam.

I'm just having a great time. Some peoples helped quite a lot. Phil has been very helpfull and even supplied some components so I could finish the boards without beign ripped of by abusive S&H fees for a few parts.

Those board from PMINMO are really cool and the new PCB's should be an even greater deal. If you look at a nice little driver you can build for very cheap, give em a try.

Enough bragging, back on cutting... Gotta build that 28 x 50 table now and try to get more speed, more more more...

Para

[Lionclaw]

Parameter, what kind of steppers are you using with the 3977 boards?

[Parameter]

As of now, X and Y must be around 90-95 oz-in torque. They're 3.9v, 1.3A unipolars connected as serial bipolars (they're 6 wire so I had no other choice). I set them at about .8A because inductance is now double per phase and will limit the amount of current the phase can take. My power supply is just standard diodes and RFE capacitors.

The darn transfo is expensive... about 20$ US for a 24vAC 4A. That should give me 32v DC which is exactly what I want. WRONG! The transfo output 26vAC so this gives me 36v DC which is over what my drives can take. I'll have to string a few very big diodes (like 6A 1n560x) to bring it down. It's said to be around 1.4v per diode. It would take at least 3 of them to bring it to the level the board can take. Hence I use the center tap to get 14vAC which is 18vDC and this suits my need at the moment. The diodes string should be done this week.

Z is 4v 1.1A, 6 wire unipolars and around 85 oz-in. I run it at .7A. There I only have about 10 IPM on 5/16-18 all-thread but it's sufficient. The head is quite heavy with the dewalt trimer so I might go to 1/2-13 all-thread there too when I rebuild the Z rails support and back.

I love being able to use odd endmills. I got the 5/32, 1/8, 3/16 and 1/4 collets for my dewalt because I found a place for end of stock endmills at killer prices. Sometimes as low as 2$. Those are often new or barely used. Cutting foam is not like cutting steel and it does well for me.

Para

[Parameter]

I changed the Z motor yesterday from a 6 wire unipolar, 4v 1.1 A (which I had to run at .6A in bipolar configuration) to a 4 wire bipolar, 4v 1.4A ran at it's full 1.4Amps.

Well, accceleration went up 3 times (from 3000 to 9000 in 1/8th steps) and speed is now a stiff and torky 16IPM. I really think that inductance in the motors does'nt make running 6 wires unipolars as bipolars such a good deal. Lowering amps also lower torque and the motor does'nt seem to hold to accelerations as good.

All in all, it took 15 minutes doing the move and adjusting the drive and I know I'll recoup that 15 minutes on the next picture I carve.

When doing pic carving, the Z is quite active. I has to be fast. Just the mod above will probably cut as much as 15-20% from previous runtimes.

Parameter

[Ayjay]

Para

Glad to hear you got your machine up and running. I am still trying to get my 3977 boards up and running... just not enough hours in the day!

What kind of pic carving are you doing? Do you have any pictures of some of your work? This is something that I would like to try when I get my machine going.