My steel framed router

[pavlo]

I never got round to introducing myself when I joined this site many months ago. I just lurked in the background, reading as much as possible and working out what I would need to build a router with a working area of 600mm x 500mm.

So now I'll say Hi:wave:

I have always been interested in computers and interfacing so a cnc router seemed like the ideal project to have a go at.

I looked on cnczone at all the kits and plans but nothing really caught my eye. I decided to build my own design after ordering a ball screw and linear rail set from China via Ebay.

http://www.homdens.co.uk/router/rails.jpg


http://www.homdens.co.uk/router/ballscrew.jpg

I now had something to base a design around and I came up with this.
http://www.homdens.co.uk/router/routertable-resized.jpg

The base was to be made from 50 x 100 box section with 40 x 40 intermediate supports.

The gantry was to be made from 50 x 50 box section.

I had all these bits laying around as left overs, so I got welding.

http://www.homdens.co.uk/router/DSCF1673.jpg

http://www.homdens.co.uk/router/DSCF1676.jpg

A bit of drilling, tapping and painting later and the frame was done.

http://www.homdens.co.uk/router/PICT1373.jpg

I had wanted to make the z-axis out of aluminium but I dont really have equipment necessary to machine aluminium to any high degree of accuracy. I am builder by trade so my toolkit is jigsaws, grinders, pistol drills etc. I had to choose between making it out of MDF, making it out of steel or getting someone with the right equipment to make it.

A good friend whos owns a cnc factory owed me a favour, so I drew up some dxf files of what I wanted and waited a couple of months until he got round to making them. It was well worth the wait.

http://www.homdens.co.uk/router/PICT1375.jpg

http://www.homdens.co.uk/router/PICT1380.jpg

They are made from aircraft grade aluminium and have been anodised a lovely black colour to avoid corrosion.

Now I could get cracking again.

http://www.homdens.co.uk/router/PICT1377.jpg

[pavlo]

Next step involved spending some more money. So I spoke to Gary at Zapp and ordered 3 nema 23, 3nm steppers and drivers plus power supplies and breakout board. An old pc case was scrounged and I put it together like this.

http://www.homdens.co.uk/router/PICT1381.jpg


Looking at the price of motor mounts scared me so I got some more scrap and made these.


http://www.homdens.co.uk/router/DSCF1674.jpg

Which, when painted looked quite good.



I needed a mount for the Kress spindle I bought so I got my £20 B+Q router out and set to work on more scrap. When it was all put together it looked like this.


http://www.homdens.co.uk/router/PICT1390.jpg


A gift of a decent spec pc with a parallel port meant that I could start to get it working. I installed mach3, plugged it all in and told the program it was 400 steps per mm on all axis. I expected to be doing a log of tinkering and tuning to get it to run well so I was very pleased when it all ran flawlessly. All axis jogged at full speed without any problems at all and the acceleration I could get amazed me, I ended up turning it down a bit because the kitchen table it was set up on for testing was shaking too much (yes my wife is a saint).



I have still got to connect limit switches and and e stop button but I thought I would give it a go.



YouTube"]http://www.youtube.com/watch?v=VhKl0S1JVds (http://www.youtube.com/watch?v=VhKl0S1JVds)



YouTube"]http://www.youtube.com/watch?v=z7uFgeNTnZE (http://www.youtube.com/watch?v=z7uFgeNTnZE)


So thats it. It took about 4 months of grabbing the odd hour here or there to get it done but now I have a good, strong working router for about £1000.



Now all I need to do is find something to do with it.

[dickieto]

wow! looks like a real good machine in only 4 months:clap:could you tell me how easy it was getting slides etc from china, how long did it take?how much did it cost plus delivery?what company did you use?
sorry for all the questions but i am just snooping around internet for best ideas and prices to build my own router.
hope my build goes as smoothly as yours
:beer:Tom...

[pavlo]

Hi Tom.

Getting the bits from China was easy. The price was £412.08 including shipping. I expected to get charged VAT and import duty but I got away with it. I'm sure the quality of the ballscrews is not as good as you would get from some of the sponsors of this site but for my first machine, it made sense to me. The drive couplings didn't last long but to be fair, they were rated for 2Nm and I was working them hard on 3Nm motors. I have replaced them for now with reinforced hose and jubilee clips.

The bits from China took about 3 weeks to arrive but when they were delivered, the small pair of linear rails were missing. I emailed the guy and he sent them out straight away without any argument.

I dont know the policy for posting the details of non-sponsors so I will PM you the guys details.

My build costs were

Rails etc £412.08
Motors and drivers £400.51
Spindle £152.50
4 core screened cable for motors £15.00
and about £50 for machine screws and electrical bits and bobs.
Everything else was given freely or was scrap.


I hope your build goes well

Paul

[Lee Roberts]

Looking good pavlo!

I'm using the TBR type supported rail for the new machine i'm currently working on as well, i'm hoping to start my build log VERY soon.

How much did the lovely anodised black cost to have done, somthing i picked up on from your build was aluminium and corrosion, this is somthing i didnt really think about.

Thanks,
Lee

[pavlo]

Hi Lee

I was fortunate enough the get the black anodised bits made for free.

I dont know much about aluminium but I do know that some grades will corrode very easily, especialy if steel screws are used.

[Lee Roberts]

Hi Pavlo,

Ok no problem mate, i hope i wont have any problems but i guess i could look into this and let you know. Maybe some undercoat and a top coat maybe in order!

Great !

[irving2008]

Indoors in the dry aluminium needs no protection as the film of aluminium oxide that forms with oxygen is sefl-protecting. However this does give a dull finish. Anodising provides a nice surface finish and looks better but isnt necessary.

See http://www.keytometals.com/Article14.htm for more info.

[Lee Roberts]

Pav your images have stoped working mate?

[pavlo]

Thanks Lee

sorted now I hope.

[monza]

Yep sorted. Looks like a beefy machine that one :)

[F.O.X]

hey pavlo,
amazing work !!
I think I just found the design of my router (well,,,almost!)
I wish if you could send me your design ,I'll start a new thread soon after finishing the initial design of mine.

I'm thinking of ACME (multi-start) instead of ball screw and aluminium (tube) for frame

3-axis upgradeable to removable 4th-axis (rotary)
with a working area of 400mm x 300mm and 2 N.m steppers
I'll order the steppers kit soon
this is the link
http://cgi.ebay.com/4-Axis-Nema-23-Stepper-Motor-287oz-in-Driver-CNC-Kit-/280612072407?pt=LH_DefaultDomain_0&hash=item4155c86bd7
chinese , can't imagine the life without them

hope to hear from you soon

excuse my bad english ,it's not my native :)

[Jonathan]

I'm thinking of ACME (multi-start) instead of ball screw and aluminium (tube) for frame

Why aluminium tube? Surely steel is easier to join (by welding) and stronger for the money...


3-axis upgradeable to removable 4th-axis (rotary)
I'll order the steppers kit soon
this is the link
http://cgi.ebay.com/4-Axis-Nema-23-Stepper-Motor-287oz-in-Driver-CNC-Kit-/280612072407?pt=LH_DefaultDomain_0&hash=item4155c86bd7


I think you'll find that kit to be of limited value. The stepper motors have an extremely high inductance (18mH), which combined with the low voltage that driver runs on will really limit your motor speed.

[F.O.X]

Thanx for your replay Jonathan,,
The fixed work table from steel but the gantry is movable and steel's density is 7850 Kg/cu.m compared to AL 2650 Kg/cu.m .
it's easier for me to use steel for all the body but I'm not sure if the 2N.m motors can handle it ,I didn't finish my calculations


about the kit,, I'll consult my friend ,an elec.eng. , I hope it can be tuned.
I'm short of time and money and the drivers are more expensive than the board , I can switch later to better drivers
Right now I'm in big trouble , I can't find screw lead (ACME) and slid rails in the market , that's why I didn't finish calculations , my last hope is printers' scrap .

Does anybody knows website? with international shipping? or another way? :S

[pavlo]

Hi FOX

Glad you like the router, I will PM you with as much information as I have regarding plans and suppliers.

One thing to bear in mind is that although aluminium is about a third of the density of steel, it's Young's modulus is also a third of steel's. This means that for the same geometry, you need to use three times as much aluminium to get the rigidity of steel. The benefit of aluminium is that the geometry of extuded sections have a high second moment of area (I) which gives good flexural rigidity.

[Jonathan]

One thing to bear in mind is that although aluminium is about a third of the density of steel, it's Young's modulus is also a third of steel's. This means that for the same geometry, you need to use three times as much aluminium to get the rigidity of steel. The benefit of aluminium is that the geometry of extuded sections have a high second moment of area (I) which gives good flexural rigidity.

That's what I was referring to, but you put it better.
Also steel is 1.7x more dense than aluminum, which is something to consider with regards to resonance.

[wiatroda]

Hi Pavlo
Great job with your router. Looks like we have similiar ideas about building CNC's. I built mine from 50x100 and 50x50 steel profiles like you did. Frame of mines is 120x150cm. Steel construction is rigid enough to mill steel, so I think steel construction is right way to go
Regards
Mariusz

[F.O.X]

I see

So steel it'll be

thank you all for your replays