My first Build (2'x3' $1800)

[GlacialWanderer]

I've attached an image of my CNC machine. A detailed parts list, lots of images and more can be found on this page of my blog. The only reason I didn't post everything here is because I didn't feel like formatting all the information and pictures again for this site, but I did want to post my progress here because this site was so helpful getting my engraver built. Thanks guys!

[gerryv]

I think you just raised the bar in terms of both design and presentation. Thank you

[Thazul]

Looks great.... simple, clean design, Very nice!

Keep us posted on how she performs.

Especially those bearings, I have been eyeing them for a plasma project.

Once you get it fired up maybe even a video?

Keep up the good work,

Andy

[blackbeard52]

Absolutely great design. I did notice that the bearings in that configuration was exposed to wood or plastic debris. A simple felt wiper or cover over the bearings wood make life easier. Again great job.


Bob

[Stepper Monkey]

Nice to see you are getting some press on this project, caught it on Hack-a-Day before I saw it on here.

One question though, what do you think of the ideas the folks on there offered about the z travel? It doesn't seem that there will be any functional z travel for you right now, as no matter how far you can retract the router it still can't clear any work because of the z sticking down.

You going to make a drop mount for the router, or flip the slide, or do you have another kind of idea?

[GlacialWanderer]

I don't see the z travel issue as a really big issue like others are. It takes me about 1 minute to move my z axis up or down depending on the length of the router bit and I don't plan to change router bits to increase cut depth often. Engraving drastically different thickness items would also require this 1 minute setup.

It is something I might refine in the future, but I really think this will NOT limit my z travel. It just adds a little extra setup time when I change to a longer router bit for added depth cut. Most of my cutting will be 1 inch or less.

Changing this isn't a trivial problem and I can certainly test what I have without changing this. If I do change this in the future, I'll probably leverage some of the work Ahren is doing on a z mounting plate on this thread. http://www.cnczone.com/forums/showth...575#post484575

[gerryv]

[QUOTE=GlacialWanderer;484946]I don't see the z travel issue as a really big issue like others are... It is something I might refine in the future, but I really think this will limit my z travel. ???

As a relative newbie, I'm likely missing something here but doesn't the current setup limit your Z travel severely? It kind of looks like you had lots of Z clearance and travel in mind but mounted the router such that it will run up and down the track in a mostly unusable way making that great looking Z carriage redundant. My gut tells me that the Z carriage should be run up and down rather than the router... perhaps you moved from a plan to build a router with lots of Z to an engrave only machine after you built the Z?

It's a real nice looking machine so I'm trying to learn from it.

[GlacialWanderer]

I updated my post. It should have read "but I really think this will NOT limit my z travel."

I have it setup for a short router bit in the picture. If my router bit is only 2 inches long then the deepest cut I can make is 2 inches and the current setup is fine. If I get a 6 inch long router bit then I'll loosen 4 bolts, slide the z axis up 4 inches and tighten the bolts. Then I'll be setup for this 6 inch bit. It's a little extra setup when changing to longer router bits, but like I said, that shouldn't happen often.

[gerryv]

Please don't mistake this for rudeness or such, it's not meant to be at all, I'm very impressed with the quality of your work, however:

I'm thinking that you don't actually have any Z travel to speak of. Adding longer bits will not give you any more clearance under the fixed Z column and I'm not aware of there being such a thing as long router bits, especially anywhere near 6". As it stands, I can't see that you will even be able to use it at all as most "common" router bits aren't going to get you close enough to the table to either engrave or route anything that's not raised or very thick.

I see that your X axis moves and your Y axis moves but it seems that you've got your router rather than your Z axis under CNC control negating any benefit other than perhaps a tiny bit of useable working range. Have you actually tried it yet.

But, maybe I'm missing something here so perhaps someone with more experience and knowledge could jump in here.

[ger21]

The issue is that you have a lot of Z travel, but most of the upper end is unuseable because the lower bearing block will limit material thickness. You could have gotten away with a much shorter Z axis and still had the exact same functionality.

[CarveOne]

gerryv

Long woodworking router bits are available but expensive and hard to find.

Long end mills are available and will work in many routers if the shank is 1/4" or 1/2". They aren't as good in wood as in steel and aluminum due to being the wrong geometry in the flute and cutting edges. They do useful work in a pinch though. They will have chatter problems running at 20k+ rpm if there is any run-out in the chuck at all.

Side load flexing and chatter is common in all long cutters of any type.

In the photo, Ahren's roller trucks appear to have about 6" travel (to me) since they roll on the edges of the dark gray steel plate. Behind the vertical extrusion is the edge of a small aluminum plate (Y axis leadnut mount?) that gives the appearance of blocking vertical travel of the trucks but it doesn't do so.

Many cnc routers I have investigated have moved the router instead of moving the whole z carriage and router as one unit. The stepper or servo needs to move less dead weight that way.

With the router at the lowest position, the bottom end of the lead screw protrudes about the same amount as the router's chuck with no cutter installed. This will limit how deep into a mould the cutter can reach without interference. If the router mount is modified to physically lower the router to get more depth of reach below the lead screw the z travel is still the same as it is now.

CarveOne

[GlacialWanderer]

CarveOne, thanks for that explanation. That's exactly what I've been trying to say, but you put it in better words. If people are still confused I might try to draw a picture to show what we're talking about.

The z travel is 5 3/4" so your 6" guess was very good. I do plan to trim the lead screw a little because it actually goes 1/2" past the lowest router chuck position.

I hope to get some real tests run with this machine during the next week, but I've been busy with work so it's slow going. I did get the electronics wired. The next step is figuring out the software. I installed Mach 3 and was completely confused. I need to read a Mach 3 getting started tutorial. Google gave me a bunch of different tutorials to choose from, but if anyone here has a recommendation on a way to get introduced to Mach 3 I'd appreciate it.