Was about to get a toy- then I did some research...

[NeoMorph]

50Vac or 80Vdc Digital Drives with 68Vdc PSU for Nema 23. NEMA 34 with 80Vac or 100Vdc drives. Both using Toroidal Transformer based PSU.

These are proven specs used on machines I build which are used for cutting materials ranging from cardboard to Aluminium and Brass on a daily basis working 12hr plus days 7 days a week in some cases.

*DRRRRRRRROOOOOOOOOL*

I would love drives like these. Unfortunately not everyone can afford drives and controllers that can handle them.

I’m disabled person who had to take medical discharge in my late 20’s because of a deformed gene causing something that is now known as Hypermobility Spectrum Disorder.
So I basically live on a disability pension. Saving up for my Ox took me two years before I could order it... but I’m glad I did. Ooznest manuals are simply the best (especially when stoned on morphine 😂).

[Juranovich]

Well not sure where your getting 1m/min from but giving specifics for sweet spots for things like 3D work isn't really possible because it's material and cutter dependant, plus 3D work requires a slightly different machine setup to get the best from it.

My bad, meant to say 10m/min... effects of nightly writing...

I also put onto isolation into the limit switch lines. I can’t remember the last time I had a spurious signal get through and trip the alarm.

Of what I can see online non-isolated wiring seems to be quite an issue. Luckily, the electronics part is still some time away as that is the part I'm the least competent in (or more accurately "incompetent") and will probably be the most frustrating bit :)

Moving on to great news (for me at least) I’m finally able to post pictures of my design which is heavily based on ideas stolen from this forum! I planned on doing it in the build log section, but seeing the attention this thread has got I figure I might just keep it here (please correct me if I’m doing this wrong!).

So the basics:

- Total dimensions of the frame is 1000x800mm and gantry height 650mm as measured from the bottom of the frame to the top of gantry beam.
- The Z carriage is roughly 450mm high (extending some 150mm above the top of the gantry beam) and 200mm wide with 150mm travel (bearing blocks 300mm apart in the Z and 200mm in the X direction)
- frame consists of 60x120 alu extrusions on the sides and 3pcs 60x60 extrusions across (easy mounting of 20mm round linear rails ;) )
- gantry beam also 60x120 extrusions in L shape
- gantry plates and Z axis made out of 20mm alu, the thinner end plates/stepper mounts are 5mm alu
- the bearing blocks on the gantry plates are 250mm apart
- as discussed above 1610 or 1616 ballscrews drive X and Y, while 1605 will suffice on Z
- NEMA 23 (perhaps 4nm) on all axis as well as 20mm round linear rails
- Haven't decided on the spindle just yet, but should be able to carry something like a 2.2kW spindle (i.e. 5kg or so)

NB! All mentioned dimensions are not precise to the mm, but gives a good indication of the general size. Neither is everything perfectly aligned. I’ll anyway sort out the details as I make the final drawings in fusion. Also- I’ll model the final (balanced) version of the gantry plates as the gantry beam/Z axis design is finalised. Also2- stepper mounting plates will require adjustable fastening slots.





So to the specific questions I have in mind, I'll leave out the ones already previously discussed:

- Frame; I quite like the 60x60 extrusions across the frame as they give me clearance below the table (eg for X axis steppers), but would it be too flimsy? Looking at it now, I have quite some weight on the gantry vs the frame. Maybe worth beefing up the frame with 60x120 instead, or at least the two furthest to the front, leaving clearance at the back for steppers...?

- Gantry/end plates; online consensus seems to dictate 20mm gantry plates, but what about Z mount? Is 20mm overkill and would 15mm do in a machine this size? The end plates/stepper mounts are 5mm (as commercial stepper mounts seem to be in that range). As they're not subject to any excessive forces in my design I suppose 5mm is enough. Essentially they're only carrying steppers and the odd limit switch as well as providing additional stability in the corner joints of the frame.

- Other comments/critique?

[JAZZCNC]

*DRRRRRRRROOOOOOOOOL*

I would love drives like these. Unfortunately not everyone can afford drives and controllers that can handle them.

I hear what you are saying but £40-45 isn't a massive amount of money for a good drive. I've used lots of these low budget machines they are great value and work great. They cover a large range of motors including Nema32 upto 8Nm.

https://www.ebay.co.uk/itm/2DM860H-2...72.m2749.l2649

[JAZZCNC]

Going to show you some machines I've built that are all the same design but slightly different in size or Z-axis type/length etc dependant on usage but all share the same profile size. 45 x 90.
These machines were designed solely for woodworking and range in cutting area size from 600x400 to 1300 x 700 with a mixture of single or twin screws. However, all of them will happily cut aluminum as you'll see from a couple of pictures sent to me by customers.

Now I'm not showing you these and saying this is how you should build your machine but what I am showing is that this kind of profile size will easily do what you need so don't go stressing about if your 120 x 60 is strong enough or not. What's more important is how it's used ie: L shape gantry bolted together etc.
Some of these machines are used for business and running 12hr days 6 day weeks and have been doing so with minimal maintenance for several years.

Can I also strongly advise you to drop the round rail and go with profiled Linear rail. It's much much better and far less hassle. Don't spoil a potentially great machine for a few Euro more. You'll also get the extra back when you come to sell it as you'll be able to ask more for the machine and it will appeal more to those who know what to look for.

Also, move the ball-screw on the gantry to the top and motor below to keep the length of the drop plate to the shortest possible. Another thing you need to be aware of and one of the reasons why I use the Bosch Rexroth style profile with slot spacing at 45mm is that it suits BK/BF12 bearing bolt spacing. This means you won't have to make mounting plates or mess around drilling the profile.
It's these little details that can easily screw your ideas up or make things much harder than they need to be.!!

[Juranovich]

Going to show you some machines I've built that are all the same design but slightly different in size or Z-axis type/length etc dependant on usage but all share the same profile size. 45 x 90.

[...]

Can I also strongly advise you to drop the round rail and go with profiled Linear rail. It's much much better and far less hassle.

[...]

Also, move the ball-screw on the gantry to the top and motor below to keep the length of the drop plate to the shortest possible. Another thing you need to be aware of and one of the reasons why I use the Bosch Rexroth style profile with slot spacing at 45mm is that it suits BK/BF12 bearing bolt spacing. This means you won't have to make mounting plates or mess around drilling the profile.
It's these little details that can easily screw your ideas up or make things much harder than they need to be.!!

First off- those are some slick looking machines! Also, I never considered using a cross beam under the frame for dual stepper set-ups.

The round vs profile rail debate is one that has had me torn the most. Undoubtedly profile are superior in theory, in practice, however, I've been somewhat put off by the many worst case scenarios people have posted about when ordering the Chinese kind (which I strongly suspect is the only kind my budget allows). Second, being a first timer, I was hoping to get slightly more parallel mounting tolerance with the round rails (bc self alignment), and they provide more room for mounting ball screws on the same face (although that could also be achieved by spacers on the profile carriages). I'm curious though, in what way do you find profile to be less of a hassle?

Considering cost, downsizing to 45x45/90 extrusions might free up some funds that could be used on profiles... I might just have to bring out the famous abacus!

With regards the bk/bf12, I thought bolt spacing was something like 46mm in which case standard t-slot nuts wouldn't work? Or is it merely a case of using good ol' force?

I long favoured flipping the ball screw and stepper positions, but figured ball screw placement as centrally as possible relative to the gantry rails took precedence over drop plate length.

[JAZZCNC]

The round vs profile rail debate is one that has had me torn the most. Undoubtedly profile are superior in theory, in practice, however, I've been somewhat put off by the many worst case scenarios people have posted about when ordering the Chinese kind (which I strongly suspect is the only kind my budget allows).

This is the problem people only focus on those who have had issues, probably because they shout the loudest, but for everyone that as an issue there are 100's more who haven't and work perfectly fine.
Chinese VFD's and spindles being a classic case, I've lost count of how many sets of VFD/Spindles I've fitted and I've had about 3 failures in 10+yrs and those weren't all due to quality but more user error or wiring issues.
I was probably one of the first in UK to use the Cheap Chinese Linear rails and again I've fitted dozens of sets without any issues, Now I fit Hi-win because the price difference isn't too great, but both come from China so don't be put off. Either of them are far superior to round rail and worth the extra, trust me on this you won't regret buying them.

Second, being a first timer, I was hoping to get slightly more parallel mounting tolerance with the round rails (bc self alignment), and they provide more room for mounting ball screws on the same face (although that could also be achieved by spacers on the profile carriages). I'm curious though, in what way do you find profile to be less of a hassle?

Not quite sure what your meaning by Less hassle.? Less hassle than what.? Compared to using steel it's lot less hassle for obvious reason, try drilling and tapping 150 x M5 holes in steel and you'll understand this quickly.! . .Lol

If you are referring to my comment about using 45x90 because of the slot spacing being less hassle. Then I mean it's less hassle than having to make plates which first bolt to the profile so you can then mount the BK/BF bearings onto. Or having to Drill and tap the profile directly, which don't advise doing because never works out good. Like on this gantry that uses 40mm spaced slots and BK15 bearings with larger hole spacing.

With regards the bk/bf12, I thought bolt spacing was something like 46mm in which case standard t-slot nuts wouldn't work? Or is it merely a case of using good ol' force? .

The holes allow just enough wiggle room so that it works ok.

I long favoured flipping the ball screw and stepper positions, but figured ball screw placement as centrally as possible relative to the gantry rails took precedence over drop plate length.

I find comments you've seen made like these are made mostly by armchair theorists who have probably never built a machine.!
Because in the real world the difference between them is so negligible that you'll never see or notice any difference in how the machine performs. I've built all kinds of machines in all possible configurations and I've yet to see one that stands out to even slightest degree that says that's the best way.

End of the day if it fits your design best to have it raised up a little higher then go with it because you won't notice any difference if struggle on and have it the so-called "Optium" position.
The reason I say move it up is that being shorter it won't vibrate as much, which then goes into the screw, which then goes into the motor etc.
Also because the bracket is actually fastened to the top bearing plate anyway, the so-called optimum center position doesn't apply because the forces are being placed on the top bearing plate, not into the center of the Z-axis rear plate which is considered the Optimum position. So having it short means the forces are moved closer to the actual bearing plate which is what's being moved and makes everything that little bit stiffer.

Again don't stress over this stuff because it's not a game-changer or disastrous if not in the optimum place, you WON'T notice any difference. The little details like being stiffer or better-placed screws, motors, switches, etc make for a better more reliable machine than if a ball-screw isn't quite in the Optimum place.

[Boyan Silyavski]

First off- those are some slick looking machines! Also, I never considered using a cross beam under the frame for dual stepper set-ups.

The round vs profile rail debate is one that has had me torn the most. Undoubtedly profile are superior in theory, in practice, however, I've been somewhat put off by the many worst case scenarios people have posted about when ordering the Chinese kind (which I strongly suspect is the only kind my budget allows). Second, being a first timer, I was hoping to get slightly more parallel mounting tolerance with the round rails (bc self alignment), and they provide more room for mounting ball screws on the same face (although that could also be achieved by spacers on the profile carriages). I'm curious though, in what way do you find profile to be less of a hassle?
.

The square rails for me are may be the most important part of the machine in the long run, so there should not be any doubts about that. In fact better buy a smaller size square rails than round rails. mean 15 instead of 20 size , if machine is not intended for heavy duty use . You can always use one carriage more as they are cheap. rail is heavy hence expensive to ship. You get what i say?

About the Chinese square rails, if you buy from a good factory they are same or very similar quality like the Hiwin. You may need to clean a carriage or similar, but most important is to be from a good place.

I buy from these guys https://es.aliexpress.com/store/822038 12 and 15 size. Have not bought from them 20 size , but their rails are very good quality and price. Custom size also, contact them. make sure to buy the long carriages.