big budget cnc

[pet30]

Hello

I am peter 30 from belguim.
first of all sorry about the bad english i don't typ it a lot.

I am thinking of building a cnc and i hope you can help me with the design.

The idea i have is a machine of about 3000x 1600.
Why this big ? because i have a small company and i make kitchens ,dressings,TV cabinets etc.
this way i can lay down a sheet of MDF of melamine and cut the pieces .

But the thing thats special about the machine is the next thing:
i want the gantry to be 3000 mm, so basicly a big gantry and smaller X axes then normal.
i was thinking for the gantry 160 mm high and 80 mm deep.
is this enough or do i need to make it bigger so it do's not flex?

Instead of linaire rails i was thinking a strip of steel or alu and then ball bearing rolling on the alu or steel rail.
the reason why is simple.
I want to start with a budget machine and later in the future upgrade it with better linaire rails like hiwin etc but for know i don't have the money to spend on expensive linaire rails.
for now i will use a bosch router but also in the future a spindle.

For the drive i was thinking rack&pinion module 1 is this enough or do i need to use 1.5 or 2?
the motors and R&P will be mounted on the rails on top.

i was thinking to use these motors.
Nema 23 stepping motor 57BYGH627

is this strong enough or not?


i made some drawings in sketchup.

Sorry for the many questions but i just want to be sure before i start building.

[Robin Hewitt]

Your machine has so many mistakes I don't think your kitchens will fit together very well.

Have you considered copying someone else's working design and fixing their mistakes rather than inventing your own?

[pet30]

what are the mistakes?

and do you reccomend someone else's design?

[mekanik]

Hi pet30
Welcome to the forum
I can't see any logic in having your gantry that long the machine would normally have the gantry spanning the shortest width.
trying to construct a gantry that length you are on a hiding to nothing, have a look through some of the build logs.
Enjoy the forum.
Regards
Mike

[hanermo2]

Forget the round rails and bearings.
I tried it circa 2006..

Steel frames, sand for smoothness / non-binding,
increase section sizes 2-5x,
glue in with industrial goops and bolt if you want, ..

For accuracy, a steel or granite machinists reference edge/plate, vertex 1000 mm is cheap to 0.04 mm / m,
sand with wide belt sander to remove most of the bend/curve.
Then assemble/build, with non-binding free-running linear guides.

You probably cannot make a good commercial-level cnc router for cheap --
no-one can.
Look at mechmate. 8-10k for parts.
I will likely make one for a local business for full-sheet 2.5 x 2 m size .. and will charge 20k€ or so.
It MUST have a toolchanger to be useful/profitable.
Likely, it will be horizontal, like the more productive modern CNC machining centers.

Most likely, the 20k€ cost is paid in 1-2 months.

[pet30]

and if i was to change the gantry to 1600 mm so just flip the design?
could i then use ball bearings etc?

is not my fulltime job , i make kitchens etc after hours. so the machine do's not need to get super fast speeds.

and could i use the same system as this machine? he uses rack&pinion and round rails


http://www.rawcnc.com/

[pet30]

Hi pet30
Welcome to the forum
I can't see any logic in having your gantry that long the machine would normally have the gantry spanning the shortest width.
trying to construct a gantry that length you are on a hiding to nothing, have a look through some of the build logs.
Enjoy the forum.
Regards
Mike

i need the gantry to be this way because my workshop( ist at my parents house) and if i go home then my mothers car is parked in the garage so i this way i can still have a cnc .

[Desertboy]

i need the gantry to be this way because my workshop( ist at my parents house) and if i go home then my mothers car is parked in the garage so i this way i can still have a cnc .

3m's is just too long though and you will be creating yourself a world of trouble, there are plenty of machines out there with 3m gantries they are very very chunky and use serious slides the cost of the gantries are far beyond what most of us spend on our entire cnc machines.

If you build it like you suggest it will not work very well at all and you will spend a lot on a frame you can't use.

https://www.kickstarter.com/projects...foot-cnc-machi

This seems like it might be more useful to you although I would never consider this suitable for real production (I thought it looked crap but mate thought it was ideal for a small workshop for occasional jobs.) It might be something that ticks your boxes given the lack of space and tight budget.

There is another choice you could make the gantry 1.5m's and mount the CNC so it folds to the wall when not in use you can get more space and only use when the cars is not there.

You probably don't want to cover your mum's car in sawdust anyway if you still want the cnc machine their in a months time ;)