Thread: CNC Gantry Router #A

Hi Geoff,
Enjoyed your visit and always keen to chat with somebody interested in CNC and shed talk.
I am looking forward to seeing a build from you and your input to our pool of knowledge. Every new machine I see has a couple of different features that make me think I wish I had thought of that.
Most of the people on this forum have been very free with information and advice so for me it is just paying it forward.

Originally Posted by twistedfuse

Maybe greg could post a photo of some 3d off the R&P system?

Here is a video of some 3D carving. One of the samples from the Vector Art 3D site.

This really torture tests the R&P drives when it gets down to finishing pass. No discernible positional error.

http://web.aanet.com.au/greolt/3D%20carve.wmv

Greg

EDIT: Streaming does not work well for me on this file. Plays jerky. Download and view.

Thanks very much for that video. It really reassures me that it will work, i have a pictures somewhere of some work ive done recently of a chevy 327 logo which i converted and engraved into stainless steel. Its about 75mm across and 60mm high. I would still need to do that type of thing on the large machine which is why i as curious as to the accuracy. But i guess it is nearly the same as rolled thread ballscrews. Just a couple of questions about your mahcine. What were the specs of your r&p(pitch etc)? Where did you get them(rough cost if possible), they look like the are mounted to the channel with bolts, which would be best but lately all i can see are small ones which i would have to weld on. Also In regards to your U Channel, how did you surface the channel(home mill or commercial). I would love to use some channel but not having my own mill, it would take ages to surface with my router so i'd have to get a commercial shop to do it, unless i found someone local to do it.

Daniel
P.S I will start a new thread for my ideas and conversations so im not taking over rods good thread. As soon as i get a chance i will do that.

G'Day Rod,

Very impressive pile of raw materials there . It looks a bit different to how you started out Obott ! Not a skate bearing in sight . Could I ask what motors and driver you are using for Morphy ? - this is pretty topical for me at the moment.

Greg, Very impressive 3D cut - what axis speeds were you running for this?

Recieved some rails today to replace the round rails in the earlier photo. Have one of those dustproof electrical enclosures for the electronics. 500 by 400 and 200 deep. See photos.
Had the angles machined yesterday so Morphy has started.

Hi Jason,
I am using Nema 497oz motors and Kelling style 5056 drivers and a break out board. I have a C10 breakout board from CNC4PC but will eventually swap this out for a smoothstepper and go USB.

Hi Greg,
The video didn't work for me the other day and I just tried it again now. I got dizzy watching the Z axis at work.
Great work and you have your machine tuned in very well.
What are you running for drivers, interface ,etc and what do you think has given the greatest improvement in speed?
Spindle looks good as well.

Rod

I have some Geckos in it. They were given to me and that was what started my CNC journey.

Running off the LPT but I think that is about to change to SmoothStepper. Just because I can.

".......what do you think has given the greatest improvement in speed?"

Can rapid at 18000 mm/min but that does not mean much in my book. I have it set about 8000 mm/min. Acceleration settings are far more important IMO. As can be seen in the video.

The number one factor IMO is the overall concept and rigidity of the build. Everything else follows that.

Start with a solid base as per your designs, use proper bearings, resist the temptation of high gantries and keep everything close, tight and solid.

Greg

Well, I havent been on the site for a couple of months now, and wolla look at all the new posts. Rod why doesnt it surprise me your doing another one, Mmm that would be A = 7.

Steve

Gee whiz greg,
I just had a look at that video, is it moving or what. I never run my system faster than 600mm/min, might have to ramp it up a bit more and see what it can do after watching that video, will have to turn the router up a bit faster too
Impressive

Hi Steve,
There is an increasing interest in CNC on this site. Some new ideas coming out of it which we should all benefit from.
Seriously I have lost count on the machines as it has been three years of building them now. Obott the first is still king of the workshop but this build will knock it off the perch. It will be a shame but I might even get rid of Obott after this build.
With a VFD spindle on the new one you will understand why when you see and hear it running at the workshop.

Originally Posted by rodm

... I might even get rid of Obott after this build...

enough of the crazy talk, Rod! Obott will no doubt be a museum piece one day. I am sure you can find a quiet corner of your workshop for the little fella to serve out his days - maybe even a few years on light duties, before retirement

Sorry Jason missed your post.
Yeah Obott has inspired many to build a machine and has made a lot of machines as well. It has served it's purpose well but Morphy will be bigger, stronger and have all the latest design improvements. Obott will cut the granty sides for Morphy so it will be a relative but Obott will be sold off once Morphy is finished. I just don't have the room and my shed, patio and carport are filling up with machines and materials again.
Absolutely nothing to do with CNC but an interesting thought is that the first machine was hand filed on a bench or a product of that process simply because they didn't have a machine to make a machine. I like the idea that we do a similar thing by building these machines.
Progess is happening on Morphy and the Z axis is finished - I actually did two at the same time so it took a litte longer. The steel is cut and I have sandblasted it and primed it. The steel is a lot of work and seems to take forever but it is the foundation and everything is referenced to the base so it is worth the effort.
I'll post some photos this week.

I was clearing the camera and came across this photo of cutting the cross rails for Morphy. As you can see I have stacked all the angle and cut it in one pass. This makes sure that they are all exactly the same length and sqaure. There are 7 pieces of 50mm angle, five at 6mm and 2 at 8mm stacked in that lot.
These bandsaws are cheap and they are incredibly accurate. I use a bi-metal blade and it lasts about twelve months with a lot of home use.
In addition to cutting technique I use a lot of MDF templates to make sure everything is square and accurate during assembly.

After cutting all the steel, cleaning it to bright metal then priming I came unstuck. My mobile bench is too small so assemble the base so I have been back on the bandsaw cutting more steel for a bench. Another photo of the bandsaw this time cutting gussets for each join. Cut 32 gussets out of 6mm plate. 8 plates cut at a time while clamped to the bed. The good thing is I can work on other bits and pieces as the saw does its thing.