[K_G_B]

Awesome info,
Can't believe cheap prices from stepperonline, its like AliExpress
I shall name my firstborn after you...well maybe not

I was going to go for Nema23 (269oz.in) but weight is 1.2kg whereas Nema23 (178.5oz.in) is only 0.7kg. Less weight equals more stabilty, is 178oz.in enough?

Did you have much issues for getting the basic assembly square?

[ASB79]

I also opted for the 0.7kg motor, time will tell if they are strong enough. I suspect they'll be fine.

I haven't done anything special to get the frame square, when I'm ready to secure it to the table/bench I'll measure it up accurately. Also once the table surface is screwed on it will hold it's shape very well.

[K_G_B]

I started researching heavily into stepper motors and voltages and what I found is a list of rules that when combined come to something like this:
-Power Supply Amp strength required is 2/3 of total motor Amps - no need for higher
-Power Supply volatage to be maximum of the lowest volatage motor - this is reason I'm going to upgrade my Z axis to same motor as X and Y.
-Max volatage is calculated by taking square root of Inductance (usually in 'mH') times 32, therefore: square root of Inductance *32 = max voltage for stepper motor.

Some Nema23 motors have such high Impedence that if ( square root of impedence*32= max voltage) this formula is used I would need 160v to power them at max performace.
I did find a few 260oz.in motors that have low impednce so that max voltage is 40-45v.

In any case, would you mind giving me more info on your ganty plate offer? pricing and shipping to Adelaide?
Can you do Z plate for Nema23 as well?

[ASB79]

Progress on my build has slowed due to home duties but I wanted to share my (experimental) solution for an anti backlash nut on the z-axis.



- - - Updated - - -

[widgitmaster]

Those two nuts will work fine with an adjustment screw to spread them slightly, a spring will work also if the four bolts are tightened after pressure has been applied!
Widgit

[ASB79]

The intent is to only have one of the nuts secured to the Gantry, the second is floating. I'm still playing around with springs to find the balance between holding nut separation under load and binding the threads.

I assembled the z-axis last night, I had a spurt of motivation brought on after seeing my mates machine do some test plots with a sharpie.

I forgot to take some decent photos of the nut arrangement but it all went together well.

Attachment 244880

Those two nuts will work fine with an adjustment screw to spread them slightly, a spring will work also if the four bolts are tightened after pressure has been applied!
Widgit

[ASB79]

Attachment 244882

Also, a tip for current and future builders, use eccentrics on the 3 fixed wheels of the z-axis, just set them all in the same alignment. They offer much more support for the bolts, without them the wheels tend to skew outward resulting in a loose z-axis.

[ledaero]

I purchased on of the router clamps mentioned further up the thread, it will work with the Makita router trimmer I got from Bunnings.

Cheers
Anthony

I couldn't find any mention of clamps further up the thread... this thread, you mean? Anyway, no matter. Hey Anthony, it's Mike - any chance you can throw one of those clamps in the pack with the plates? I have a Makita trim router I will be using as my initial tool and I was wondering how I was going to fix it on

DOH! (EDIT/EEDJIT) I had the forum set to 'newest first' - got that sorted now. And I learned to read! So I understand that the clamp didn't come from Bunnings, so ignore my ridiculous post

[ASB79]

Appologies for the lack of activity here the last few weeks.

Progress on the OX has been slow but steady, the assembly is all but complete. The only tasks left to do are to, fix the spoil board to the base, mount the spindle and work out how to fit the vacuum hose.

Latest updates/changes to my build include;
- Use of a 3D printed clamp for the spindle for weight reduction, estimated 1kg for Aluminium reduced to 190g for ABS.
- Decided against use of Makita Trimmer instead opting for a 1.5kW Watercooled spindle. Mainly for improved accuracy and ability to use a wider range of bit sizes.
- Ended up using a Protoneer CNCShield on an Arduino UNO. This is similar to the gShield but has replaceable drivers, also has 4 drivers so the y-axis does not have to be doubled up.
- Drag chain has been mounted on the y-axis and x-axis, I designed some mounts to fit onto the Stepper motors. They are on Thingiverse if anyone wants to use them.

Won't be long until I can make some cuts.

Cheers
Anthony


Attachment 249584

[ASB79]

For all intent and purpose my machine is now done.

Just some final comments about the build.

The printed clamp has been working well, but I will probably change to an Aluminium mount to improve stiffness. I noticed that holes I've tried to cut have come out a little oval, I suspect this may be related to the stiffness in the gantry assembly or belt tension.

I used the machine to drill a grid of holes in the spoil board, into which I installed t-nuts from the underside. This allows for a very flexible clamping arrangement.

The belts tend to slip if secured using only the screw and T-Nut. Find a way to anchor your belts securely!

Overall I am quite happy with the machine but there is obvious flex on the z-axis if you lean on it. I didn't glue the two 20x60 rails together I suspect this deflection could have been reduced if they were. I'm not going to any heavy duty cutting so it shouldn't affect me too much in any case.

With the built up table mod there is not a lot of space to work with, if I did this again, I would leave the 20x40 in place or use 20x60 instead of 20x80.

Overall I am very happy with the build, was very straight forward, even the arduino and GRBL setup was painless.

I'm using ESTLcam to generate my gcode, it is super simple to use and it surprisingly capable. It is also very reasonably priced for what it is. I'm not affiliated with the creator of this software, I've just found it very useful as a beginner to CNC.

I've attache a pic of the first things I've made using parts off the router, just to prove it does work

Please contact me if you have any questions about the build.

Attachment 252568

Attachment 252566

[ledaero]

Great stuff, Anthony. I am still struggling with getting parts. Robocutters have proven to be less reliable, after having banked my money.

Two incomplete/incorrect shipments so far... I wonder if they will get the third one right, or even if I will ever get a third one. He has gone suspiciously absent in the communications department.

[duke149]

*removed duplicate

[duke149]

What steppers did everyone end up going with?

I was thinking about these Nema 23 CNC Stepper Motor 2.8A 1.26Nm(178.5oz.in) 23HS22-2804S - US$

Would they be suitable?

[K_G_B]

I think so, you can always reduce speed of CNC machine to cover the lack of torque (if there is going to be any).

not an expert but researched this a fair bit so here is my 2 cents:

Inductance is good on that stepper, only 2.5 which gives it a max voltage of 50v
so If you get a 48v power supply you're in bussincess. Also make sure that power supply and the board are in sync. Some boards can only take 24v or30v so buy power supply in accordance to your board.
Less voltage than 50v just means that stepper will not be able to perform at its very optimal, but that is ok.

I went with very expensive option and am regreting it simply because I am an amateur and will never need that much power or stability but hey its a learning process, and for $15 per stepper you can't go wrong.

[duke149]

Inductance is good on that stepper, only 2.5 which gives it a max voltage of 50v
so If you get a 48v power supply you're in bussincess. Also make sure that power supply and the board are in sync. Some boards can only take 24v or30v so buy power supply in accordance to your board.
Less voltage than 50v just means that stepper will not be able to perform at its very optimal, but that is ok.

Thanks for the reply.

Are you able to explain what how the Inductance of 2.5 gives 50v?

I assumed that being 24-48v steppers at 2.8amps would mean that to run 4 steppers I would need say a 24v power supply @ 12amp?
Is there something else I need to take into account when running steppers?

Edit: Ah is the 2.5 the voltage drop? So it would drop 50v to closer to 47.5v in the working range of the stepper?


In terms of the control board I am looking for something I can use with an Arduino.
I have 3 stepper motor controllers already. I think I will give them a try first.

[K_G_B]

If you read throug Gecko website support info it should give you a clear picture of what is required.
http://www.geckodrive.com/support/st...or-basics.html

Inductance is under Section 6

Basically formula is
square root of inductance * 32 = max voltage stepper can take
so sqrt (2.5) * 32 = 50.59v

On Gecko's support page they explain maximum Amps needed for all steppers and I think it was something around 75% of total amps required - don't trust me on this one, I'm probab;y wrong but it is mentioned in there somewhere.

Arduino board is 24v so make sure you buy adequate power supply.

[duke149]

Thanks. I will do some reading.

In regards to power, I think I will use my bench power supply. That way I can see what its drawing and buy something that matches better.

[ledaero]

What steppers did everyone end up going with?

I was thinking about these Nema 23 CNC Stepper Motor 2.8A 1.26Nm(178.5oz.in) 23HS22-2804S - US$

Would they be suitable?

I went for these: Nema 23 CNC Stepper Motor 2.8A 1.9Nm(269oz.in) 23HS30-2804S - US$

Only a little higher resistance, all other figures are close, but with 35% more torque.

[ledaero]

Arduino board is 24v so make sure you buy adequate power supply.

Mine is 5v...

My motor controller board is 24V.

[ledaero]

Thanks. I will do some reading.

In regards to power, I think I will use my bench power supply. That way I can see what its drawing and buy something that matches better.

For what you are proposing, anything north of 250W will suffice. I have a couple of 350W and a 400W and a 500W all at 24V - any of them would deliver enough power.

For peace of mind, get the 400W supply from Switching Power Supply 400W 24V 16.7A for CNC Router Kits 115V/230V S-400-24|S-400-24|Power Supplies - it will more than cover your needs and the price difference between that and the 250W one is minimal.