My aluminium CNC Mill/Lathe build.

[digits]

Hi guys - I'm just about to start assembling my new CNC mill which will hopefully also have a lathe on the table

After using a Seig X1 for about 6 months or so, I've come to the conclusion that I need something with bigger travels, more accuracy and a lot more speed.

My plan was to build something with bigger travels than a Sieg X3 but lighter due to aluminium construction. I have however already failed on that design goal - this thing will be a lot heavier than an X3 - desptite being mostly aluminium!

I have also gone way over budget - but having decided that I wanted ballscrews, linear slides and servos, I knew this wasn't going to be cheap!


I will post some CAD renders when I've cleaned them up a bit - I still have some details that I won't have tied up until I have the extrusion in my hands.

[digits]

Replying to my own post may seem insane, but I wanted to start the blogg in a new message.

I got my servos, Geckos and Grex on Saturday, but I haven't had a chance to play with them yet. My first problem seems to be finding the correct connectors for the US Digital encoders - I think I may have to hot-glue some non-latching substitute connectors on.

I also have to design a PSU for the servos and speed control for my Beel DC motor controller, which should be straightforward, but will probably take a bit of tweaking to get just right.

Today my Hiwin linear slides arrived - I've gone a bit overboard and plumped for HGR35's - they are very nice, but very heavy - 60kg!

I also got my ballscrews, and nuts and managed to pop the balls out of three of them, so I spent a very frustrating afternoon trying to find and then re-insert 90 tiny ball bearings into 3 nuts. This wasted afternoon should have been spent designing my PSU and ordering the bits

I'm too annoyed to take any pics of todays deliveries yet, but I'll get the camera out when my huge pile of aluminium extrusion turns up - which reminds me, I don't have any bolts long enough to bolt the HiWin rails down yet...

[digits]

Another day, another delivery - got a load of ER16 collets and end mills today, as well as a tail stock to go with my lathe head

I also spent ages trying to align my mill after fitting my Y and Z-axis column extension:





Why oh why did someone think it'd be a good idea to give the Super X-1 a tilting column? I got the column shimmed nicely front to back, then had to undo the column rotation bolts to fix the left-right tilt - which ofcourse broke the front-back tilt, which required re-shimming, and then the left-right tilt wasn't right grrr!

Anyway, I got it pretty close to true - IMHO there's no point going mad over tramming as every hit on the drawbar to knock a tool out will alter the alignment anyway

So I started making the part that I needed an extra inch of Y for - a 150mm rotary table mounting plate to take a 125mm 3-jaw or 100mm 4-jaw lathe chuck:

First I drilled out the holes with an 8mm drill bit:



And then the mill spent about an hour pocketing out recesses for the cap-screws:



It looks OK in the picture, but the recesses aren't round enough for the M8 capscrews to fit! The recesses appear to be slightly off-centre, but I don't think they really are as nothing moved between toolchanges - I think my backlash is just greater than my hole size tollerance, as I really should have made the recesses a bit larger. I should be getting an M8 counterbore tool tomorrow with my PSU bits, so I will redrill and counterbore the holes tomorrow. I then get to use my rotary table in anger to make a truely round chuck plate, and once I can bolt on a chuck, I should be ready to make a motor pulley for my new X-2 spindle. Phew!

I also ordered most of the parts for powering my Geckos - but I did forget the odd vital thing - like bolts to mount the Hiwin rails! Hopefully my extrusion will arrive tomorrow so I can measure the bolt-length required and send off an order ASAP.

[digits]

Another day, another delivery! I got my PSU parts and ballscrew bearings today - but I still don't have any extrusion to bolt everything to

I did however get my M8 and M6 counterbores today, so I was able to finish the holes in my rotary table/lathe chuck mounting plate. The counterbores are a lot less hassle than pocketing out the recesses

I have also at last used my rotary table in anger - here it is trimming down the chuck-plate to a circleish thing...



After a couple of hours cutting, I am about 12mm through this 19mm disc:


I think I might try a bit more aggressive cutting tomorrow - this was 0.1mm/pass, 10mm end mill @ 250 degrees/minute and 2000 rpm.

Assuming I get the chuck holder done tomorrow, I might try cutting a bearing block on the rotary table - the finish looks way nicer than my interpollated holes have been, but the setup is more tedious on the rotary table...

[Kipper]

I'm looking forward to reading your experience with the GRex Gecko's etc....Oh don't forget to say where you got the servo motors from :beer:

[digits]

Originally Posted by Kipper I'm looking forward to reading your experience with the GRex Gecko's etc....Oh don't forget to say where you got the servo motors from :beer:

So am I! I had a little set-back with the Geckos, I had planned to put them in a nice 2U 19" rackmount case with the PSU - unfortunately the PSU is so masisive that it's going to need a 2U case of its own. So I've ordered another one and some heavy duty power-connectors to link the two boxes. Thinking about it, it's probably safer to have no A/C in the box with the Geckos in it - I'm less likely to kill myself while tuning the servos!



I also finished my lathe-chuck adaptor for my rotary table:





The spiral finish was done on the rotary table, not by interpollating the sprials.

I also had a very nasty setback to the whole project - I still have no aluminium extrusion

The servos and Geckos and Grex all came from homeshopcnc.com - the $2/£1 makes it an attractive option, though it is bad for my carbon footprint and very good for the customs men and Parcelforce who charge an extra £13.50/$26 per parcel for 'holding on to them' until I pay the tax - Grrr.

[Kipper]

Thanks for the link I notice we're rotary table twins As for the mail/customs charges....we're British and as such are used to being bummed by the taxman :lol:

[aspenelm]

why so many geckos? how many axis will be present on the machine? would like to see your cad drawings posted when you get a chance. will be watching this thread to see what develops.

[digits]

Originally Posted by Kipper Thanks for the link I notice we're rotary table twins As for the mail/customs charges....we're British and as such are used to being bummed by the taxman :lol:

I can handle the VAT and the duty, and charging VAT on the duty is pure genius , but I really don't like paying £13.50 on a £30 tax bill to the Post Office, just so they can delay my package for another 3 or 4 days!

As for the rotary tables, mine's a Soba 6" - it's pretty well put together for the money, but could do with proper thrust bearings - that little stepper is working hard

[digits]

Originally Posted by aspenelm why so many geckos? how many axis will be present on the machine? would like to see your cad drawings posted when you get a chance. will be watching this thread to see what develops.

It's a 4-axis machine + Lathe, but I have twin-screws on the Y and Z-axes. The CAD is on-hold until my extrusion arrives, and I am working on the massive powersupply at the moment. The new 19" rack case for the Geckos & Grex has arrived, so I'd better get a move on and cut holes in the front pannels for all the connectors!

Cheers.

[digits]

Well, it's 15 days late, but my extrusion has finally arrived! I actually got most of it on Saturday, but the useless courier sent the parcel with all the brackets and T-nuts 200 miles in the wrong direction, so it only arrived today - losing me another 3 full build days

On the brightside, the extrusion is very nice - the cuts are very,very clean and the cast-brackets make pretty rigid joints

No time for a pic today, got to work on the CAD for the bearing mounts so that I can try and pocket one out tomorrow after work.

While waiting on the extrusion I've been working on the two PSU boxes - and now that I've got some pesky M3 nuts and bolts to fix the connectors, I should be able to do some wiring while my X-1 cuts the bearing mount.

[digits]

Well, I've been scratching my head on how best to make the bearing mounts. I can either pocket out large holes to leave plenty of clearance round the bearings and then just secure them by the screws on their mounting flanges, or I can try and bore fairly accurate holes for a friction fit, but that would mean cutting them on my rotary table which is a bit more fiddly to set up.

I also need to get decent accuracy between pairs of bearing holders so that the screw runs perfectly parallel from end to end, but I'm not sure whether to aim for precision manufacture, or just to allow a lot of adjustment during assembly - or perhaps both!