My First CNC, own design, buidling in progress

[RotarySMP]

Lovely Work Arie.

Just a question, why did you put the X axis Rails on the saddle and the trucks on a small table, rather than opposite?

If you put the rail undneath the table, you would have a larger table for the same travel, the X rails would be covered, and the total material required would be the same.

[arie kabaalstra]

out West here (between OK Corral & Sam's Shoot 'em Up Bar) we call them thar thangs "toe clamps"

Ok.. i think that i don't need to worry 'bout my english, but words like "toe clamp" weren't taught in school

Toe Clamps... Ok.. i Cut off a length of Tool steel ( 2510, almost similar to D2 ), later this week i'll be milling some "baby toe clamps" in Dutch these Things are called "Kikkers" (lit. "Frogs". they never jump, don't ask why )

Lovely Work Arie.

Just a question, why did you put the X axis Rails on the saddle and the trucks on a small table, rather than opposite?

If you put the rail undneath the table, you would have a larger table for the same travel, the X rails would be covered, and the total material required would be the same.

I see what you mean, a bit like the Sieg X3.. that's just what i DIDN'T want.. dirt wil be no problem since i 'm going to fit some kind of Bellows ,and the Threadholes are blind, from the bottom, so even if there's chips on the guides, who gives a *!&%#??
Stability is also an issue here, i want the most stability, considering the work i want to do on this machine, things like this:




most CNC machines are built this way, if i'd want longer travel, i'd have built a Bigger machine!.. the runnerblocks of the Table are far apart, (center to center 220 mm on a 280 mm table, No overhang)

as said earlier, stability is what i need, the weel on the picture is only 21 mm ( less than an inch about 7/8" )

Today, i have been working on the head..



all parts Ground flat, and machined to size... tomorrow will be Drilling-day.. drilling all the holes to put the parts together, i wil also bore out the hole for the motor.

Put on the machine, it looks like this


still no guides, but that's ok.. i'll have plenty of work wiring the motors and the PC, i also have to figure out how, how much, and were to put the end/limit/home switches.
I also wil buy a 4th controller, and a stepper motor to use as a 4th axis, i want to be able to mill my own model tires some day..( and numerous other parts )



this finally, is a daily routine.. clearing up my workbench tomorrows work starts at 7.00 AM, and i dont want to start on a messy workbench, so every day for the past few weeks, all the parts of the CNC are put in this Yellow plastic Crate, waiting 'til 4.00 PM when i start working on mij little CNC again..

[balsaman]

with a spindle speed of 7000 Rpm you'll get a 130m/min cuttingspeed with a 6 mm end mill, with this speed i'd be able to even machine Tool steel, and hardened steel with a solid carbide tool.
30000 Rpm will provide a cuttingspeed of about 50 m/min to a 0.5mm end mill, will do.. a 2 mm end mill will run 188 m/min wich is perfect for machining steel. ( data based on Solid carbide tools) .

It's an awesome machine.

Is the above m/min or mm/min? If it's m/min it's going to be tough getting that axis moving that fast on the drives you are using. I would say your speed will max out at around 150-200 mm/min being that the drives max voltage is 30 volts, using any reasonable pitch ball screw, and coupling them to the lead screw directly.

Eric

[arie kabaalstra]

the speeds in the Qoute are the rotation ( cutting ) speeds, not the table feeds

i had my steppers run @ 22Khz, which gives me about 800 revs on the steppers, with a 2 mm pitch on my leadscrews that'll be around 1.6 M/min or 1600 MM/min table feed on 12Vdc.. needless to say these values will increase with higher voltages..

also, i can always fit "heavier motors".. as long as they're Nema 23 Bipolar ones

[balsaman]

My apologies, in my post above I did mean 1500 - 2000 mm/min, not 150-200, so I guess I was fairly close.

Usually heavier motors are not necessary as they are often slower. Looks like the drive current capability will be a limiting factor here anyways. Bump up the voltage as high as you can safely go for more speed if you need it later.

It's a nice build.

Eric

[RotarySMP]

Thanks for the answer Arie.

Are you going to grind you own spindle or buy something off the shelf?

[arie kabaalstra]

Now What?.. a High precision Bookend?..



Nope.. the head is 'bout finished, only the Clamping for the motor has to be done, and the Nut Brackets for Z and X axis are still to be made..



This is what i got now... almost done, but still a lot to do..



I just bolted on the head, bolts of the vertical ribs are on the same offset, so there wil be no warping under heavy loads.

I will order Bosch Rexroth Ball screws and Ball Rail with 12 Runnerblocks.
Milling motor is a standard router, it'll have to do until it fails..

if the router isn't what i expect, then the design has enough room to incorporate another setup, i can place a motor further to the back ( decreasing cantilever effect ), or i can try another brand of routers.. the bottomplate is removable, so other designs can be tested easy..

@ Balsaman, no worries.. we all do make mistakes sometimes..
if the machine can reach 1200mm/min, it'l mill out that wheel i posted earlier in just 3 hours.. at 0.2mm stepover... i want a smooth finish..

[FPV_GTp]

hi

that is one fine machine

beautiful machine work , when are you taking orders

cheers

[fred klusmann]

This is a great machine.
It is nice to have a lot off machine to build this
I most do everthing by hand , it is also nice to do
But can not do so must als you
fred

[arie kabaalstra]

hi

that is one fine machine

beautiful machine work , when are you taking orders

cheers

Orders?... well.. as soon as i sorted out all "problems i have yet to encounter", i will "clean up" all my drawings, adding Tolerances and reference planes.
convert em to PDF and DXF, write a little manual, and Burn the lot on a CD wich will eventually be for sale through my website : www.pure-scalemodels.eu
till then, you just have to be patient...

hopefully i will be able to order the guides and Ballscrews in a few weeks from now, in the mean time i will be wiring up the steppermotors, and the electronic handwheel, and also designing a 4th axis.

[Trapper14]

looks really impressive! Excellent work thus far, is the under side of the it cross braced at all? Being all steel I am sure it is plenty fine, thats my only suggestion is running something diagonal for extra support. Keep up the great work!

[arie kabaalstra]

a Cross-brace has crossed my mind..

the only "bracing" now is the Motorbrace at one end, and the Spindle bearing brace at the other... but, the slide frame is also more or less braced bij the table, becaus 2 runnerblocks always stay over the middle of it when the table is at one end, and 4 runners are over the middle if the table is in the middle.. there is however some room left beside the y-axisguides to bolt a brace underneath at both sides..

since the design is very compact ( total height of table and cross-slides is under 100 mm ( 4")), the X-axis Spindle nut has a 2 mm clearance over the other parts..