Thread: CNC Gantry Router #A

At the rate I am going it will be next month before it is finished.

Yeah I might post some of the bench and typical of me it is evolving as I think of things to add. After looking at Zoot's fine drawings I have already modified mine a bit to accommodate the switchboard. I am having trouble with the galvanised angle as it is pressed and not a perfect right angle - that's my excuse anyway.

Are you still one of Australia's homeless? You need to find a shed with a house on the block.

Originally Posted by rodm

At the rate I am going it will be next month before it is finished.

Yeah I might post some of the bench and typical of me it is evolving as I think of things to add. After looking at Zoot's fine drawings I have already modified mine a bit to accommodate the switchboard. I am having trouble with the galvanised angle as it is pressed and not a perfect right angle - that's my excuse anyway.

Are you still one of Australia's homeless? You need to find a shed with a house on the block.

Yes mate I am but found a mate that has a big shed the only problem is we will have to pull the boat out and then if you pull the boat out it wouldn't be good unless you take her out for a fish its a real problem.

Just trying to find the right shed with the right shed to build the next beast but we are getting closer.

Hi Sean,
Not much of a contest fishing or work - hmmm let me think.


Ok because there is not much happening here are some photos of the bench for Morphy. I am only doing an hour or so after work so progress is slow.

Photos show front and side and I am adding ideas as this thing is built. You can see all the gussets I have included from the earlier shots of the bandsaw in action. Lots of drilling and tapping in those.

I still have about a mm of twisting going on in the frame and hope that the slide will take that out. The slide is going to be a sealed compartment to collect all the swarf and sawdust and will have a box at the bottom of the slide. In effect it will add a diagonal brace to the bench and you can see my idea in the photo - it is just clamped there while I ponder.

I have a set of rubber coated cast iron castors on order. They will hold 560kg so I should be OK there.

The drop in the Aussie dollar has stopped any overseas purchases for me so I will have to amuse myself with what I have got in the shed now. Fortunately I have enough parts to finish this machine and one more so things should have improved by then. I got burnt by Western Union and it cost me $90AUS. Apparently they do an adjustment when the person in the country collets the funds. I paid when the dollar was 77 cents and because of a Chinese holiday the funds were not collected for five days. Dollar dropped to 69 cents and that is the rate Western Union did the conversion. I was a bit annoyed especially as I had to pay their fees again to send more money but you can't expect them to take a dive either so it is just one of those annoying things. Needless to say that is why I am not making any overseas purchases until things settle.

Back to important things like CNC. Just so you can get a perspective of the size the bench it is sitting on is 1400 by 710 and the bench being made is 1300 by 1070.

Great work on the bench. I wish i could make mine as neat as that. Im the same with the build tho, very slow going. Im tied up with the machinist putting my job at the end of his list. Ah well i just hope i get a good deal otherwise it wasn't worth it at all.

Anyway, keep up the great work, look forward to seeing this beauty coming together.

Daniel

Thanks Daniel,
You forget I have seen your work and it is of very high standard.
I bet you are glad you got your rails when you did. It would cost you another 30% if you got them today. Just does not seem right to me.
I know what you mean about dragging on and I am just putting up a few posts that I think might be interesting to other CNC'ers to fill in and make me think I am doing something.
I will get on the lathe tonight to make some lock nuts for the ballscrews so looking forward to that.

Rod,

Thanks for that but compared to your work it feels like it is child's play. As for the rails, im very happy i did get them when i did, its was a bummer tho. If i had gotten the tax back quicker and bought the rails when i wanted them it would have been nearly 1:1. Ahwell like you said compared to now im happy but was thinking about a spindle but thats gone for now. Im going to try and budget (got rego and compolsory 3rd party due on the car) and buy all the steel, timing belts and pulleys and buy the 80/20 this month. Thinking of 2 lengths of 40x80 or somethign similar for the gantry. Would that work as good as the solid 60x120? Im just thinking about putting the ballscrew through the middle and that way i can seal it inside with brushes unless i decide to use R&P.

Next month is my birthday so i might have to drop some hints for what i want. lol. Keep up the good work.

Daniel

Hi Daniel,
I don't think the two lengths of 80 by 40 would be much of an improvment on one length of 80 by 40 unless you tie them together like a truss. If they are independant of each other then they are still just 80 by 40. Perhaps the Z axis connection and spreading the load over two beams would help but I am not sure.
Greg and Zoot are chippie/buulders so they will have a better idea of how this works so I hope one of them can chime in.

Spindle can always come later when things settle down a bit. Now you can tell SWMBO how much you have saved by getting the rails when you did.

More impressive stuff Rod. I am always amazed that people can make a cnc machine at home. Saw a nice Mori Seiki the other day 100m/min rapids accurate to one micron has 50 hp machines on 5 axis has a pallet loader and the spindle from memory is only a slow 30,000 RPM. For a mere 700 grand you can have one just like it! I know of one place doing some Aerospace work on a similar just bigger Mazak and they put out parts and are left with scrap Aluminium worth $14,000 every month.

Back on planet earth I am still stunned what you guys manage to do at home. Just a thought but do you always fix the table and move the gantry? Has anyone ever tried fixing the Gantry and putting the table on rails so it runs back and forth under the gantry? This is the way your typical double column Machining Centre works. Table gives you X and Y and the column/gantry Z. They do this to get a more rigid structure, maybe it would help with what you are doing?

Studley

Thanks Studley
I would love to have a manual Mori Seiki as I think their lathes are the smartest looking beasts you could have in your workshop. There is a magic web site where a bloke has 5 (I think) fully restored Mori Seiki lathes and not a spec of dirt anywhere. Very different to my workshop where I bruise my hips on machinery all the time and are forever picking swarf out of my feet. Yeah I know my workshop safety standards are not as good as they should be.

There certainly is some very impressive CNC gear out there and at my scale it is hard for me to to imagine some of the photos I have seen let alone $14,000 of scrap ally a month.

I have looked at building a bridge gantry with moving table but being a bit tight in the pocket I always come back to moving gantry. Much longer travel for same size rails. I have a big slab of 20mm ally plate and an R8 spindle with variable speed DC motor that is begging for a moving table design so it might happen one day. This will be geared more for milling than routing but I have enough to keep me busy for this year.

Building these machines is not hard but you do need patience. It takes me about three months to build a machine and the most tedious part is setting up and adjusting everything once it is built. A couple of dial gauges, a pocket full of shims, some good music and plenty of time is the key to making a good machine. My method is to overbuild so it is rigid and has mass and the rest is just basic metalworking skills.

Nice work ROD. I know how much of a pain it can be working with inaccurate angle, its even worse when it has a slight twist due to bad transportation. And yet aluminium angle is so perfect.

Any reason the frame was not welded? Also I wanted to ask is the above with the triangle pieces what you were refering to in my post so that the frame would not twist?

Yeah this duragal is all over the place and I have a bit of trouble convincing it to go where I want it. Lots of clamps and plenty of measuring to make sure it is right.

I am primarily a woodworker so welding in a woodworking shed is not a good thing to do. In any case I would not weld this stuff as it is galvanised. The triangular gussets are there to make the joint stronger but will not remove twisting. Twisting can be from the joint but is more likely caused by flexing in the length of the mateiral. A diagonal brace from bottom corner to top corner will remove that.

I have to fit in an electrical panel, a coolant tank for the spindle, a vacuum pump / tank and an aquarium pump into the base so lots to do yet.

Mate you left out the ............

Hello Studley and Rod

I think the size of the machines that most here build is why we go for a fixed bed / moving gantry, most ?? machines seem to be around the 1200mm X axis length, with a moving bed that would be at least 2400mm, the shed size available to us would be the major issue, having said that I have finished the design of a 3.6m machine so where there's a will there is a way.

I had a cousin who was a sheet metal worker and he said when weld gal steel part of the award was some milk to drink at smoko and lunch, apparently the milk negated the fumes from the weld. I have just done a quick google and the milk theory has some propents, most are saying work in a well ventilated area.

Finally, I approached Triton recently to see if they had any plans to have as an accessory a weld visor for the powered respriator they have, they don't but I wish they did, they are on the net but the $$$$'s aren't good.

Ed

The aluminium they are using to get all that scrap Rod is 7075 so high end aerospace stuff. It isn't cheap.

Sounds like you are on all the right paths about being rigid and getting mass into your machine.

Mori Seiki grew up making Toolroom Lathes. High precision stuff was always their thing. I do know of Moris that are 25 years old and still just bang on. The hubs they use in V8 Supercars come from a place here in Adelaide and are made on Mori Seiki SL 2's or 3's. (CNC Slant Bed Lathes) I think they go up to around 4000 on the SL 2 and 2400 RPM on the SL 3. Rapids are about 10 m/min and tool change two to three seconds so they are way below state of the art speed. They make lathes with 0.2 second tool change now and 100 m/min rapids. Frightening stuff. Spindle Speeds aren't that much faster as you need tools to handle the speed. Similar sized machines these days go to 5000 or there abouts. Small ones I don't know the old Mori SL OH of 1980 had 8 hp and 6000 RPM spindle they might go to 10 or 12,000 now but I don't know.

Mills are getting really juicy, spindles that run at 30,000 RPM and on light machines up to 100,000! Can you believe that? They run them at 30,000 and 10 m/min feedrate and just obliterate billets into finished parts. Mind you the guys doing that are using HSK spindles, and shrink fit tools as well as some pretty expensive balancing gear as well.

That stuff all fits into what they call High Speed Machining, the basic idea of which is that you run high speeds and feeds and light cuts. Very possibly that is the sort of stuff that might be interesting to guys with CNC Routers. The result of High Speed Machining is much higher output and much lower loads on the machine. It might be beneficial when you have a light machine without that much power.

Studley