CNC machines

[m_c]

Just a quick comment about motor sizes.
For the vast majority of CNC machines, NEMA 23/24 motors suitably geared will outperform NEMA 34 motors. Unless you spend the money on high voltage drivers for 34's, 34 performance pretty much drops of a cliff once moving at any speed. A low-inductance 23/24 motor suitably geared for the application, will typically give better performance, as it's torque drop-off is less than a typical high-inductance 34 size motor.

 

[Ned__]

if you are thinking about a dual purpose machine, what you are really doing is taking a complicated, difficult and hard project, and making it twice as difficult, hard and challenging.


Getting places with the paint

The ***king thing fell over!!!!!!!!!!!!!

It fell over.

I forgot to tighten the ratchet strap (my fault) and, thinking it was secure, I tipped it on its side, in a controlled fall

But it wasn't controlled and it kept falling.

When it was falling, I remember feeling safe, because I was back out of the way. Time slowed down, as it always does in a bad situation.

And then something great happened - the ratchet strap knotted, and stopped the machine before it hit the floor

 

[Onoff]

difficult, hard and challenging

Aka fun then, it's all about the journey etc!

 

[James1979]

if you are thinking about a dual purpose machine, what you are really doing is taking a complicated, difficult and hard project, and making it twice as difficult, hard and challenging.


Getting places with the paint

View attachment 307655

The ***king thing fell over!!!!!!!!!!!!!

It fell over.

I forgot to tighten the ratchet strap (my fault) and, thinking it was secure, I tipped it on its side, in a controlled fall

But it wasn't controlled and it kept falling.

When it was falling, I remember feeling safe, because I was back out of the way. Time slowed down, as it always does in a bad situation.

And then something great happened - the ratchet strap knotted, and stopped the machine before it hit the floor

View attachment 307656

Coming on well. You have the same storage trays as me

and Tesco

 

[Ned__]

Hiya James, thanking you )

I'm losing the shed, the house is rented. Hence the fire under my a$$ to complete the machine before I have to leave.

Sad to see it go but it has been good to me, was fun while it lasted.

 

[Onoff]

No.

This?

[£77.63 19% OFF]TWO TREES® UNO CNC Kit with Controller + Shield + Nema 23 Stepper Motors + TB6600 + Limited Switches Office Equipment from Computers & Office on banggood

https://banggood.app.link/QlTfWwC6ajb

 

[m_c]

This?

[£77.63 19% OFF]TWO TREES® UNO CNC Kit with Controller + Shield + Nema 23 Stepper Motors + TB6600 + Limited Switches Office Equipment from Computers & Office on banggood

https://banggood.app.link/QlTfWwC6ajb

Depends what you want to actually do.
Motors are probably OK. Lack of full data means they are probably not the lowest induction, which will limit potential speed.
The newer TB drivers are actually OK, as they ironed out the issues with the older TB chips that used to release the magic smoke a bit too easily. They're definetly not high performance drivers, but they're adequate (as long as they're actually decent quality - not all TB drives are created equal!)
Arduino running GRBL is never going to be a high performance controller, but it will operate a machine.

The big issue is the above combination will limit feedrates.
With small cutters, it won't be an issue, but with small cutters you need an accurate machine to ensure you don't end up taking too large a cut and snapping cutters due to flex and/or backlash.
With large cutters, it will be an issue, as you likely won't be able to feed fast enough to actually cut, and you'll end up with the cutter rubbing.

 

[Ned__]

so i welded the spacers for the rail brackets in the middle. Turns out that was a bad idea and either end sprang out.

So I had to press them back down and add weld at either end.

And now the girder is clean and ready for paint

 

[Ned__]

Painted.

Might take a break now. The gantry plates are being milled, so going to screw in the legs and fill it with water I think is next. Might get some beers and do that. Need a rest.

 

[Ned__]

Motors arrived from China, small little things.
Funny - they are more powerful than the other no-name Nema 23 I have, and yet they are the same size

I don't understand very much about inductance etc.

 

[Onoff]

Motors arrived from China, small little things.
Funny - they are more powerful than the other no-name Nema 23 I have, and yet they are the same size

I don't understand very much about inductance etc.

View attachment 308060

View attachment 308061

Got a link? Cheers

 

[Onoff]

Painted.

View attachment 308047

Might take a break now. The gantry plates are being milled, so going to screw in the legs and fill it with water I think is next. Might get some beers and do that. Need a rest.

I'd fill it with water not beer...

 

[Onoff]

@ned whereabouts in Eire are you out of interest? I've to travel over soon and sprinkle Mum's ashes in the Shannon...

Tbh I might just bung the Ryanair lad a tenner and get him to fly low...

 

[Ned__]

You can find the motor details earlier in the thread. I am from Tipperary.

 

[James1979]

You can find the motor details earlier in the thread. I am from Tipperary.

@Onoff thats a long way

 

[Onoff]

@Onoff thats a long way

I thought of that but thought I'm not going to go there.....

 

[Hood]

I thought of that but thought I'm not going to go there.....

Likewise, I thought I should act my age, it was hard but I managed.

 

[Ned__]

hahahahahahahaha

Tell ye what, Tipperary is a pretty place, lots of mountains and forests. I've been living in Dublin the last 8 years, and the landscape up here is featureless. I'm moving back home now and I cant wait to eyeball some forests.

I have an IT job and we are all working from home, so I can move down the country.

 

[James1979]

Likewise, I thought I should act my age, it was hard but I managed.

I failed. I am a child.

 

[ned]

so i got some cans and filled the table. There is a slight bow in the middle of the two beams, the fact that its both beams points to the welding process having deformed them.

I'll probably try placing a massive weight on one beam at a time and try make it flat. I'm thinking a tank of water, like a wheely bin or a barrel, or an oil tank.

There were no leaks at all, anywhere. Took 1.5 hours to fill.

vid