Crane's Next CNC

[CarveOne]

Probably just one of the many self appointed "experts". When you ignore them and don't play their game they usually lose interest and go away.

Most of the stuff we use on our machine builds has been around since the beginnings of CNC technology in one form or another. R&P predates CNC, having been used on manually operated machinery of one kind or another.

It hasn't stopped being useful, and never will. ACME resolution is fine as long as the resolution fits within the parameters of what you want to do with it. (not very useful for machining submicron lines in a CPU core though) Wood machines can mill mild steel, but usually not with results like done obtained on a Bridgeport milling machine.

Opinions, are just opinions.

Build your machine as you see fit to, and keep the good opinions in mind. They may someday be useful for a rebuild. (In my case, I ignored too many of the good opinions. It's called learning.)

CarveOne

[Treischl]

But there is this one know-it-all there who is absolutely wearing me out. Every time I make a post he has something to say about my design.

My Solsylva 25x25: Useless for milling steel. Not enough accuracy for precision machining.
Wood frame: Will move too much. Only go with welded steel and heat treat it.
A 6x9 machine: Too hard for the average person to build. I can try, but I will just be disappointing myself.
ACME thread: 2 turns per inch won't give me near enough resolution. I should find as fine of a thread ballscrew as I can.
Open loop system: Unreliable and sloppy. Would never work. The computer needs feedback.
Dual motor drive: Won't work. I need a way to "time" the pulses so they are not out of phase with eachother.
Rack and pinion: Old, useless technology. Better to go with ballscrews on my 7x10.
THK blocks: Junk. Should get rid of my THK's and go with Thompson rails.

Geeeeeez. Just let up already dude. I might believe you except EVERYONE HERE IS DOING IT, AND IT WORKS!!!!!

And he claims to build industrial machinery.

So tell me....is this dude really good at his job and has standards that are way above mine or is he just full of crap and trying to sound important from his grandma's basement??

I read through your thread. Whoever the clown is making the comments does not know what he is talking about. I did design some of the first CNC laser cutters in the late 70's. Back then we used Thompson rails and ballscrews. That is ANTIQUATED technology. Maybe he is antiquated and that is why he thinks he should speak with such authority from on high?

I can give you a HUGE hint here: Turning a ballscrew that long, which has to have a large diameter has huge torque issues. There is a reason that large machines use rack and pinion, it is torque issues and whipping. With a ballscrew that large, we were lucky to get 200 IPM, if that. Truly state of the art machines these days are using linear motors.

As for his comments about a dual motor drive and timing issues? He obviously knows nothing about the electronics or the speed of electrons, does he? Drive a large format machine down the center with a screw and you can watch it twist on the bearings (unless you are doing a moving table with the bearings about 8' apart)

A general comment: There are some people in this world who can only feel good about themselves by berating, putting down, and citicizing others. They rarely accomplish little themselves, because they are themselves afraid of being criticized. They are to be pitied, life for them is miserable. They never get to see a friend smile when they say "Wow, that looks good, or what a great idea, give it a try!"

So my advice to you? Just build your machine, have a good time doing it, and to hell with the critics.

[Jawno]

Crane,
I followed your previous build and am looking forward to following this one too. I am on both lists so I've seen this other persons comments as well. It seems to me like your starting to bring him around to your way of thinking. He's kinda going like "that worked huh? Maybe I should try something like that."
Sometimes simpler is better.
Anyway good luck with this build.

[ger21]

THK blocks: Junk. Should get rid of my THK's and go with Thompson rails.

THK's can carry far greater loads than round rails.

I use a machine right now that uses a ballscrew for 12' of cutting area. It uses a big servo, to spin the nut. It's probably 25-50mm per turn, as the machine cuts at 1000ipm. Using a ballcrew like that on your machine would probably double your budget.

Rack and pinion will work fine.

The one thing I'd have to agree with the guy is milling steel on a Solsylva. If you're doing it, please post some video.

[louieatienza]

So I have been posting the progress of my builds on another forum. Mostly just to share a bit of the CNC world with them, not really to take in info. Most of my questions get answered here, so there it is definitely more of a give situation then a take. Here I feel like I am gaining enough experience with my builds that I can contribute with (at least some) authority.

But there is this one know-it-all there who is absolutely wearing me out. Every time I make a post he has something to say about my design.

My Solsylva 25x25: Useless for milling steel. Not enough accuracy for precision machining.
Wood frame: Will move too much. Only go with welded steel and heat treat it.
A 6x9 machine: Too hard for the average person to build. I can try, but I will just be disappointing myself.
ACME thread: 2 turns per inch won't give me near enough resolution. I should find as fine of a thread ballscrew as I can.
Open loop system: Unreliable and sloppy. Would never work. The computer needs feedback.
Dual motor drive: Won't work. I need a way to "time" the pulses so they are not out of phase with eachother.
Rack and pinion: Old, useless technology. Better to go with ballscrews on my 7x10.
THK blocks: Junk. Should get rid of my THK's and go with Thompson rails.

Geeeeeez. Just let up already dude. I might believe you except EVERYONE HERE IS DOING IT, AND IT WORKS!!!!!

And he claims to build industrial machinery.

So tell me....is this dude really good at his job and has standards that are way above mine or is he just full of crap and trying to sound important from his grandma's basement??

I should probably go to bed.

On a more relevant note, no new progress on the machine. Saving money for steel. Debt is dumb, cash is king, and this machine will be paid for with CA$H!

LOL I think if he's worn you out, then he succeeded at what he wanted to do! Who cares what he says, he's not coming over to your house to make changes to your machine! He can say all he wants, it don't mean a thing!

[crane550]

The one thing I'd have to agree with the guy is milling steel on a Solsylva. If you're doing it, please post some video.

Ran into a steel hold down a time or two.....not very pretty. Actually last time it happened the router bit spun the hex nut right off the bolt. Blew me away.

[louieatienza]

Ran into a steel hold down a time or two.....not very pretty. Actually last time it happened the router bit spun the hex nut right off the bolt. Blew me away.

I was using 1/4" bolts into grommets on my old Solsylava for some guitar fixtures. I had a relatively low z (about 4-1/2") so my rapids height was pretty low like .2 or so. But I had a washer or two under the bolt. The bit skimmed about .002" at rapids speed... the bit never really cut the same again, but the machine was unharmed.

I bet though, if my old Solsylva was on a steel grid base, and I had a plasma torch or 100 watt laser on the carriage, it would cut steel for sure!

[revwarguy]

Ran into a steel hold down a time or two.....not very pretty. Actually last time it happened the router bit spun the hex nut right off the bolt. Blew me away.

I was at a CNC meeting where someone remarked that the nice thing about metal was that there are no knots in it...

I replied that No, there are indeed knots in metal - they're called clamps!

[revwarguy]

Or so I've been told....

[crane550]

I was at a CNC meeting where someone remarked that the nice thing about metal was that there are no knots in it...

I replied that No, there are indeed knots in metal - they're called clamps!

Hopefully that guys machine is strong enough to work thru knots. If not, I would be reconsidering the design! I use cutting board material for my hold downs. I want my machine to be strong enough to eat thru the entire hold down, plus still cut the material without consequence, which is what I do. Cutting boards are cheap at wall world, and just the right of flex/stiffness what I do. Plus its no big deal to tear thru them. Just a 1x3 square with a hole in the middle.

Running into a bolt is a different story.

[crane550]

Well, I hope I do not disappoint too many people, but I am actually going to scale down my plans a bit and go with a 3x7. My wife and I are puting our house on the market and I will be moving out of my shop soon, so space may be an issue in the near future. Plus I am so busy with guitars that I see no real need to build something for sheet goods. Definitely my next build. Thing about it, is the design remains just about the same, so I don't think I am letting myself off the hook any for challenges.

I have been buying parts like crazy. Today I picked up nearly all my steel at the local scrap yard. Cost me $180 for nearly 600lbs. This will take care of my two main beams, some of the cross beams below, and the cross supports where my sacrificial layer will sit.





Also worked on my gantry design a bit. Getting there, but still have a ways to go.



Alex

[crane550]

Working some more on my model for the carriage. I am not sure, I might revert back to the 6x9, I just don't know at this point. Anyways, here are my ideas for the carriage. The 4:1 reduction is already fabricated, and I picked up the large Z plate earlier this week. I want to get this whole thing drawn up on Sketchup before I start fabbing parts for the real deal- just in case I have not thought of something.