1rst build, time to do next step

[Jonathan]

X isn't long enough to warrant a 20mm diameter screw, so use RM1610.

Gecko G540 is a waste of money - get something like this:
CNC Micro-Stepping 57 Stepper Motor Driver 2M542 2phase 4.2A Switch Controller | eBay
Or better, a higher voltage driver, like DQ860MA - cheap at AliExpress.com - Online Shopping for Electronics, Fashion, Home & Garden, Toys & Sports, Automobiles from China.

These motors are good and probably cheaper than what you specified.

25mm profile rails are completely over the top, so unless you've found some cheap ones on eBay I'd go for smaller rails - even 15mm would be fine for this size machine.

Your gantry could be made a lot stronger without using more material - flat plate is the worst cross section for the gantry since the forces are often in the direction where it is weakest. Box section would be better, or even better remove the gantry sides and have the Z-axis operating below the level of the X-rails.

[Gytis]

Hello Jonathan, and Thank you for your reply !

X isn't long enough to warrant a 20mm diameter screw, so use RM1610

well, you are right., I was thinking same as you., but when I got my first ball screw RM1605 1m long it was bent about 5 mm in the middle, so I can just imagine what will happen with 1.6m long screw

Gecko G540 is a waste of money - get something like this
These motors are good and probably cheaper than what you specified.

I can not argue with you about the drivers and motors, probably you are right .,
but : 1. I already have one G540
2. maybe I have spent to much my time on American forum before I found you guys in the UK (so there is reason why I have chosen these drivers and motors)

25mm profile rails are completely over the top

I'm not sure about 15mm rails, it seems to me that is too weak

or even better remove the gantry sides and have the Z-axis operating below the level of the X-rails.

no, I don't like this design, I want to keep open table design and keep rails & ball screw from dust as much as I can

And finally, this machine will be built not for hobby use, she has to be strong and durable


Thanks

Gytis

[JAZZCNC]

Hi Gytis,

First don't listen to Jonathan the G540 is a great bit of kit for a small machine. There are cheaper but it's a quality unit with great back up and warranty from Gecko and worth the money.

BUT every thing else he's correct about.

I'm not sure about 15mm rails, it seems to me that is too weak

15mm profiled rails will be plenty strong enough and carry far more load than you'll put on the machine.
The only issue with smaller profiled rails is the small bearing blocks can be a pain, esp with making the Z axis has the low height often means using spacer blocks to allow clearance for ballscrew etc. I find 20mm a much better size bearing and plenty on top of the job.

no, I don't like this design, I want to keep open table design and keep rails & ball screw from dust as much as I can

And finally, this machine will be built not for hobby use, she has to be strong and durable

Your design will be substantially weaker than what Jons suggesting and if you want strong and durable then it doesn't get much better.
Has for keeping the screws protected then that's easy enough with a bit of thought regards covers etc. The high sides don't cause any issues in use for most work and actually help contain the cutting mess to the table area instead of slinging it all around the shop.
The advantages of the much increased strength and far better quality of finish on work combined with allowing higher feeds is well worth the sacrifice of bit of access when loading material. End of the day it's the quality and speed of cut that matters.

Both Jon and I have been there done/seen that route so believe me we speak from experience on this.!!

[Gytis]

Hello JAZZ, and thanks for your input !

Your design will be substantially weaker than what Jons suggesting and if you want strong and durable then it doesn't get much better.
Has for keeping the screws protected then that's easy enough with a bit of thought regards covers etc. The high sides don't cause any issues in use for most work and actually help contain the cutting mess to the table area instead of slinging it all around the shop.
The advantages of the much increased strength and far better quality of finish on work combined with allowing higher feeds is well worth the sacrifice of bit of access when loading material. End of the day it's the quality and speed of cut that matters.

now I'm sitting and scratching my head ..,
new design?, short as possible sides?, Z-axis below the level of the X-rails?, Hiwin rails 15-20mm?


Gytis

[JAZZCNC]

Hello JAZZ, and thanks for your input !
now I'm sitting and scratching my head ..,
new design?, short as possible sides?, Z-axis below the level of the X-rails?, Hiwin rails 15-20mm?

Don't despair thats par the course with first machine.!!. . . I had full head of hair before getting into CNC now I'm follicle challenged. . Lol

To be honest I may have jumped the gun slightly because I didn't ask what you intend to cut with this machine.?

If soft materials plastics,softwoods etc then the high sides won't be a problem. There's no disputing the high sides are weaker design than no sides design but they do work ok in soft stuff if rest of gantry is stiff enough.

That said sorry to say your gantry design is very weak and the single piece of plate for gantry is real bad idea. Also the Y axis ballscrew hanging down is just asking to get clobbered with rubbish.

Look around the forum you'll see pics of similar built high side machines with strong gantry's, I've posted pics of similar machines I've built that use profile which is strong design and can handle cutting upto light aluminium work.

[Gytis]

If soft materials plastics,softwoods etc then the high sides won't be a problem

you wouldn't believe me, but I was almost sure that I will be able to cut hardwood and do light aluminum work (now you can laugh of me)

Ok., I think I know what you both trying to say for me..,
so now in my head I have new CNC table plan ( I hope it will cut at least hardwood ).
Version_2 will be here soon

Thanks guys for the advice!

[Gytis]

Hello,

quick update., the Version_2 is nearly done.
now I thinking about X axis ball screw fitting,
my very first idea was to put it between the aluminum profiles, but now I'm not sure or it good idea, I think distance is to big between rails and screw approx.150mm?
what if I run it through the side plate support box?, right now there is few brackets., just one what I do not like, that the screw will be very few cm. above the table.
But maybe I can fix on each side of the box some brush or seal to wipe the dust away from screw ?

btw, what about design? Version_2 will be stronger then the first?

Thanks