I finally have the time and most of the parts to contemplate building the my CNC router. I stacked up most of the parts last night to get an idea of the thing. The motors are the cheap Clifton servos as per the "my cheap servos" thread. The z axis are THK NSR20TBC that I got for a song on ebay. They are 640mm (25"). The y-axis is a thomson superslide with a 5mm lead ballscrew. The screws for the x-axis are IKO rolled units, two start 10mm lead, both will be coupled with belts, I have bearing blocks for these also. The z axis is a Aerotech with 5" of travel, has a ground ballscrew with 2mm lead. That will probably be stepper driven, not too sure.

For noise I am adding a 900W Kress router, they are really nice and not too loud.

I'll add pictures as I do stuff however progress may be slow as I have run out of cash at just the same time having some time to do the work.

Graham

This is a 3D sketch of the proposed layout. I am sorting out the proper CAD now.

as I have run out of cash at just the same time having some time to do the work.

LOL, Graham there is not a sole on this forum that cannot relate to that, It will all come together in time.

Here is another fact of life:
To late smart, to soon old :D


Ken

"To late smart, to soon old" :(

But it looks like you've gotten off to a very good start, Graham! I like it!

Arvid

With those pieces, you should have a very well built, ridgid machine. What material are you using for your frame?

That is a good question. I have some large pieces of extruded ali for the two uprights, this stuff is 80mmX160mm and has internal webbing and a thick wall. I'll add an aluminium doubler for mounting the rails on. I can get these milled true with respect to the base on the mega sized milling machine in the department .

For the base I am still thinking, I really liked the egg box torsion style contruction but not sure how to go about it, this is one idea I had attached Not eggbox but I think it would work OK I think, the sides might be 80mmX40mm extruded ali and the cross-pieces 40X40mm. There would be a top and a bottom, the former t-slotted. Not sure I am getting much stiffness for the weight, I can't make it too heavy, my workshop is in the attic with a horrible little spiral staircase up to it. I would really like the webbing of the base to be made from say 5mm sheet upright and welded into a criss-cross but the welding is the problem in that I can't do it and the access to the joint lines would be limited anyway.

Other things I am stuck on is the gear ratio to the screws. Thanks to the new FAQ I can do the calcs and Mariss from gecko also posted info on matching these motors to a ballscrew however I am leaning towards accuracy so encoder choice and pulse rates all come into it, I am also not sure what I want. Then I wonder if I am really going to acheive any more accuracy than most due to the rolled screws.

The use of the machine other than general routing in wood and ali is mouldmaking and 3D milling jobs. I make propellers and such things and would like a good degree of accuracy so things can be made to fit together.

Generally confused but I now have time to work through the confusion.

Graham

p.s. Reason I have no cash is the 25W CO2 laser sat on my bench, another reason to finish the router!

great start graham and welcome to the wonderfull world of pulling out your hair,oops i mean cnc.no realy it will all come together and you will be gladly missed everytime you run for the work shop.like my wife says,the only time i see you is when your hungry or when your hungry for it.L.O.L. cheers.

try some 8020 ,if im not mistaken your rails might fit the slot designed into them.

This is my first router but I'm not new to the hair pulling :)

I don't live in the US so I am not sure 8020 means much over here. The slots are slots so you can always bolt a rail over them I just think a doubler should be used to ensure a flat surface and full contact area, I'll also mill it so it has an edge so I can have a reference slide as per the THK recommendations.

"Maximum overkill" may be the name of my router I suspect.

Graham

Sounds good graham cant,t wait to see what your router will do.Just talked to a chap who knows of you and he said you you are very knowledgable.I think I,m going to try 24 volt setup as you described and see what comes about .If you don,t mind me asking ,where in the UK are you situated.My wife is from there,other side of the Mersey from Liverpool.Sure miss the place.Anyhoot post pics as you can .Cheers,Corrie.

You can't say something like that and just leave it, who do you know? What have they been saying? Its not true, I was let off with a caution! ;)

I am living in Nottingham origionally from York (the old one).

Graham

What can I say, change of plan:

Picture1: The old config showing the large overhang from x carriages to tool.

Picture2: Flip the slide vertical and it is reduced. I have removed bearing blocks from the ends of the thompson rail, these will be built in to 1" thick gantry ends. This ties it all together much better but involves boring which is not only boring but I find easy to mess up. Still it builds character.

Have ordered the 1" thick ali and should be starting to make the 1/2" thick parts tommorow. Oh joy.

Graham

To show I am doing in something. Close up of the plate that sits on the carriages, also the 1" thick gantry end and the combined butress and ballnut mount. If the butress does not look like it sits flat on the ali then it is because it doesn't. Some shell mill action required I think.

I have two of each of these parts

Graham

hello mate looks great,whats the thickness on your pieces,looks real sturdy are you sure you,r not building a tank L.O.L. no seriously beautifull workmanship and look forward to seeing more.what size ball screws?turns per inch?

Yes it is a little tank like but I want to use it as a mill as well as a router :)

ballscrew details are in my first post.

Graham

Did a bit more, was away last week and busy the week before.

This shows the Gantry almost done. You can see one glaring mistake, I made the holes in the ends of the gantry for the rails the wrong size. I carefully centre drilled and step drilled to the biggest drill that would fit in the normal chuck. I then carefully selected a drill from the stand on a taper that would be just shy of the required size for final reaming. I then picked up a drill I had used earlier and used that instead, DOH. I'll just add brass bushes so it should still look pretty good in the end.

The rails need to be trimmed (will use wire EDM). and the far end of the ballscrew needs remachining. I also need to make the 1/2" thick back plate that is held by those M10 bolts.

Graham

Looks great mate ,sorry to hear about your over-sized holes,bushings would be the answere to that.Live and learn I say.Looks very profesional,I like your work,keep posting pics. :cheers:

Graham...

Nice work so far.. gantry is looking great, very sturdy. What width is the gantry.

What type of bearings are you going to use on the Y?

How are your Y rails secured in the sides of the gantry, couldn't see in the pics.

Have you milled the Alum plate yourself?

I will be watching your build with interest.

cheers

Do you mean the sides of the black bit of the ends that I have machined?

I have done all the machining myself but with plenty of advice from my mentor in the workshop when things need to be just right (for example using slip gauges to ensure that the holes for the rails are the correct distance from the back plate. Shame the holes were made the wrong size.

I now have the back plate made, will post pics later.

Graham

Here is the base so far as seen in the main router forum, just thought I would add pics here for completeness.

All steel, 6mm outline, 3mm uprights, 25mmX25mmX3mm channel. The surface is going to be 6mm thick plate which will then be slotted to form T slots (well V slots).

Graham

WOW it has been a LONG time since I last posted, heck almost a year. Well in the mean time I have been doing some work on the router and also finished off my PhD. Here are the results to date. The bed was a massive undertaking and could be better to be honest. If I knew then what I know now it certainly would be. The V-slots have ended up being rather shallow because I had to take quite a bit of material off the finished frame to bet it flat. I then had more machining trouble with the surface as well but hey it is finished and it looks OK. And yes it is very heavy!

Still some work to do but the end it in sight at last.

Graham

Hello mate welcome back,looks awsome.You can see that it,s heavy,oh and congrats on your PHD.So whats next,drive train ,power supply,sending me a Mini,my wife misses her old one.L.O.L.Keep up the great work and keep posting pics.

Thanks

Well after I have got the rails aligned properly and done a few small jobs I want to mount the dual lead screws. Then I need to work out how to drive the things together with belts. These are details I have avoided as all costs.

Like your router too, trying to steal the limelight are you? ;);)

Graham

Na no lime light for this boy ,I didn,t build this one,bought it .It,s you who deserves the light .What type of leadscrews are you going to use?Also what are your bearings ,they look like hywin,s. :cheers:

Graham, that machine looks almost exactly the one I was planning as my second router! :) Seems to be very rigid design.

However I ended up doing my router in different way due to expensive linear guides (see my homepage (http://www.students.tut.fi/~kontkant/jv2.php.html) if interested).

Corrie, see my first post but when I say z I mean x. I.e they are THK rails.

Xerxes, nice little machine. Stiffness does not just come from the bearings though. If you support something over only a short area then it is more likely to flex away from the support. That is another reason the bearings tend to be used in pairs. In your case it seems to have turned out fine.

Graham

I thought I should post that my router bed ended up being scrapped. The workshop in which I was building it had to be emptied and it was too heavy to get into my attic (via the spiral stairs) it also turned out less flat than I had hoped so the weight was not worth it. I'm moving house later in the year if all goes to plan, hoping to get more shop space then, I'll build a new bed with just t-slot extrusion and some cast tooling plate then let it true itself up.

Graham

I liked that bed it looked good. Looks like the way you put that bed together would also make an awesome bench top. Was that all welded?

It was, the problem is basically that to prevent severe warping during the welding the steel used would need to be thicker, I struggled to lift it as it is so that wasn't an option for me. I got it normalized and machined the top flat on a huge mill but clamping was difficult and it was not quite as flat as I would have liked. Bearing in mind I wanted the router to be be very accurate for mill type operations. Its all good experience.

Graham