CNC Router Build

[mike os]

My adopted unfinished project is a 2x1m heavy, accurate CNC router that I am assembling, probably completing the design and building for a friend. The job was started probably 2 years ago, by a tame engineer friend but abandoned because of other commitments.

The pile of bits.... weighs a bit!... x axis ballscrews are 32mm!!! , 30mm Hiwin rails on x, 20mm for y&z, Servo motors rather than steppers all round...

Tapping 28 M16x50 and 48m8x30 by hand because the monkeys that machines the sides "forgot"

Think it has been good for my hand as I have had to work with both hands... still a total PITA though as for most I am having to work left handed.

First time together..... useful as one of the cross rails has been drilled & tapped about 2mm off... could do with some suggestions as to a sensible repair, don't want to open out the holes and counterbores unless it is the only real solution

Nice chunky parts.... 160x30mm .... weighs a bit though, about 160kg on there

 

[Robotstar5]

A good start to what will be an interesting thread.

 

[mike os]

Certainly interesting for me... loads to learn

 

[CRB]

A good start to what will be an interesting thread.

Poor fellow has to fix something before he has got the frame together. A bit unfair to call it 'interesting'

Regarding the design trauma though, cut a section of material into which the correct thread is cut. Remove the offending duff hole and weld or pin the repair in place.

TaDaaah

 

[mike os]

Holes are into the end of one of the cross rails, think it is a 6xxx series ally but don't know could do without having it totally remade but may be easier

Thinking drill out to about 24 mm, tap for 100% thread and insert ally screw cut for minimum clearance, stud lock in and then redrill, could be pinned too I guess

 

[CRB]

Sorry, I do not enough about the material to know whether or not it will be easy to drill or cut.

I had assumed that the problem was the end of the cross rails, so redrilling seems a bit awkward, hence cutting a section out and inserting a threaded block.

Drawings always help, but I thought that pinning through the joint would be possible.

 

[mike os]

Drawing helps a lot... hoping to get one for the rest of this one day soon

 

[MattH]

That's some heavy duty components.
What spindle are you intending to run?

 

[julianf]

How come you used plate and not extrustion (eg minitec) ?

 

[mike os]

That's some heavy duty components.
What spindle are you intending to run?

2.2kw watercooled, its what is already supplied

How come you used plate and not extrustion (eg minitec) ?

I did not design it... there are some extrusions for the gantry and bed, not even unpacked those yet

 

[mike os]

Been playing in a friendly engineering shop for a couple of days.... cant believe they let me loose on their kit, must have made a good impression as I am welcome back, some great lessons from a pro to help up my game a lot... after 2h "induction" with the owner (at my insistence as I did not wnt to fubar his equipment by being an amateur & making a stupid mistake,) not used a mill in anger for a good few years so really pleased with how well I did, good finish and all to within 0.05mm of required sizes I am 500% more confident in what I am doing and probably 300% better too.

one of the nicest Bridgeports I have ever used, no discernible wear or backlash... just as well as all the finishing cuts had to be climb milled for a decent finish...



no way I can go on to a "lightweight" mill now... just going to have to keep looking for something decent and make room

Need to tidy up the curves and a few other bits, whats recommended for grinding/shaping of a 4.5 grinder?

I guess flap wheels to finish but any particular flavour?

Next about a hundred holes to drill, counterbore and tap......should only take a day or so to mark out

 

[skotl]

That sounds like an excellent day, Mike.

How did you persuade them to let you loose on their kit? Do you know someone who works there?

 

[mike os]

they are in a unit behind the guy I am building this for/with, we have dealt with them for a while. As he is busy we suggested I helped, and if he was happy I could cope and not break his toys we would just get on with it. More my concern not having used one for a while I did not want to muck up his only vertical mill....

whats best disks for grinding ally? (ie for not clogging up every time you blink)

 

[mike os]

wow cant believe it has been so long... time flies when you are having fun

load of boring stuff... machining ally plate to size and drilling holes/counterbores and threading, couple of hundred m16 & M12 all deep and blind

y axis risers are finished..

Upside down but shows how it interlocks with the gantry rail

Quite pleased with myself as these fitted with no adjustment and no play

 

[mike os]

Nest was the bearing carriages to attach the above to the x axis, despite several hours debate and playing in 3d cad we could not decide the best way to attach the bearings and ballscrews together so made a mock up in timber (old fashioned method but still has its place)

the answer was immediately apparent...... both of us wondering what the hell the problem was....

gantry riser, bearings and ballscrew assembly

Mocking up allowed me to redesign the bearing carriage to include a top web, increasing stiffness and removing the potential for any bending during assembly, and also allowing for a registration face for the hiwin bearing blocks... will make assembly more accurate and simpler but will make machining more difficult... oh well....

 

[Wedg1e]

Proper job

 

[CRB]

Next was the bearing carriages to attach the above to the x axis, despite several hours debate and playing in 3d cad we could not decide the best way to attach the bearings and ballscrews together so made a mock up in timber (old fashioned method but still has its place)
the answer was immediately apparent...... both of us wondering what the hell the problem was....

When cardboard is not enough.

Top job.

 

[DanielW]

Wow! that ally bed must have cost a bomb alone.

Did you not think it would have been cheaper to have the bed welded up in box section? think the weight would have been less as well.

 

[mike os]

see first post.. not my design.... welded steel has distortion issues, this should be as stiff when finished with adjustment and less resonance.

Cost has not been a consideration at any stage I don't think....more a case of as good as it can be without going totally overboard... (if you dismiss 30mm hiwin profile rail & 32mm ballscrews for a 2m x axis )... servos rather than steppers and cs labs controller.... gearboxes are 250+vat each

Cardboard is not so good for 3d CBR

 

[MattH]

Just finishing off my cnc controller rebuild after swapping out the servo drives and motors. I went with a CS labs unit and I must say that it is top notch, I also have an ESS and Kflop and the CSMIO is a pleasure to us in comparison.

I have cut aluminium and steel with mine. Yours with all that aluminium plate will be very capable but you might fine you run out of spindle power before any machine limitations. I run a 4HP spindle and I glad I do.