Machine

[ned]

Thanks Henry, appreciate the info )

@henry Kadzielski - could you link to a product similar to your UPS please? would appreciate it, will save me some time, regards

 

[henry Kadzielski]

here is what i found.
http://www.alphapower.com.au/ups-static-switches/vanguard-ii/product-detail.aspx

These are what I use and have been quite reliable

 

[ned]

Thanks Henry, appreciate it.

 

[ned]

It stands!

not finished welding, but its standing.

 

[ned]

i did a vertical weld, and it doesnt look terrible! ran downhill at a reasonable pace with a slight weave from side to side. Repeated on the other side of the table with better results so its not a fluke, which is great.

welding, grinding flush, welding, grinding flush. the weights are to stop the weld pulling the leg out of square, but im not using that muh heat, 2.5 rods at 90 amps, so it should be fine. Gonna remove the all the braces once its cold.

 

[ned]

got the gantry on. still lots to figure out. gonna start staring at the ballscrew next, or as my girlfriend calls it, 'cock and balls'. She cant separate out the words, bless her.

 

[henry Kadzielski]

I've only got one 'ball screw' and according to my wife don't use them appropriatly, 'bless her to'

 

[ned]

hey all, two things here, 1. there are facebook groups for CNC plasma cutter owners, and they are brilliant!!!!

came across them last week, they are a revelation. ( @AdrianH ) - I started a thread about how shallow a water tray could be, and still be effective, last night, and i think ive got upwards of 60 replies from maybe 15 individuals. Irish people love exaggerating, but the number is close on that i would say. Here is a link to one of them.

https://www.facebook.com/groups/CncPlasmatipstrickssharing/

If you join one, facebook will suggest more, I added them all, and now my timeline is FULL of information about cnc plasma cutting, which is great.

Second, im only learning arc, but I made a vid about getting larger box to bend into shape, seeing as how I couldnt find one when i was looking.

 

[Fintray]

Ned table's looking good but I might be wrong in that unless you can position the castors far enough down so they can rotate 360 degrees you will have trouble moving the table about.

 

[ned]

Cheers Fintray ) I can lock the direction of the castors with the brake mechanism on them, the brake itself is disabled so the wheels move with the brake on, but the direction is locked.

 

[Fintray]

 

[ned]

made some spacers so the gantry can clear the beams. Currently contemplating the ball screw configuration, relative to the rails and relative to the table bed. Im going to attach some posts i found helpful online for the benefit of anyone interested in doing the same.

if i decided to let the ballscrew ride 3 inches under the rails, that would be very easy to do, but, will it alter the movement. thinking bout this currently, will prob take a few days to ponder it. Likely I wont because form follows function, so ill raise the height of the bed and let the ballscrew ride even with the rails.
I'd like to be able to use this as a router too, thinking about making headstones cos theres a lot of cash in that, so there will be forces on the setup.

just need a 10 mm spacer at the back to mount the motor

 

[AdrianH]

HI Ned, I tend to believe you need the drive for the axis as close as possible level to the rails, other wise there will be a tipping action and a possibility of the bearings binding. Now I know that will depend on how far apart the linear bearings are on the rail and as to if it is a problem will be a suck it and see. Could you fit below and see if you can still go full speed.

You mention headstones, that will place some strain on the Z axis, what are you going to use a reciprocating hammer.

Last I am not on facebook.

Adrian

 

[Hood]

I tend to agree with Adrian.
Would it be too expensive for you to get a second ballscrew and either get another motor and drive and slave them or even just a second ballscrew and connect to a single central motor via belts/chain?

 

[henry Kadzielski]

Good evening Ned.
I am not so confident about ball screws for the long travel, they suffer from whip and you are only planning one!
Is there a reason why this is so, otherwise and in the long run it would be far better to run twin drive as suggested above. One thing that others may have not mentioned previously is that there is a speed limit using ball screws. If you intend to plasma cut thin material you need to go fast, much faster than for routing or flat bed milling. This is why most machines use rack and pinion for their linear drives. I am in no way suggesting that what you are proposing won't work but there is alternatives and you won't have limitations later. If funds are an issue, wait, save, don't be in a rush to get it done. Unfortunately I have build many things in the past, it'll do, won't need any more, will and behold later, should have done this or that. So far my machine's problem apart from a faulty operator unit is it was too small and I built it bigger than what I initially intended.
I got the biggest drives that were available, that way if they wern't enough I could say I wasn't my error. I selected servos for speed and planetary reduction gearboxes to get the torque for routing and flat bed milling. There is much mathematics to match weights and acceleration to the drive package, but you need an engineering degree, which I don't have nor the time and patience to calculate that, so bigger is good biggest is best
Anyway my thoughts only, please disregard as if I knew what I was doing, I would be doing something else

 

[ned]

hi guys, appreciate the input ) yah there is a relationship between the work plane, and the gantry center of gravity, and the rails and also the ballscrew.

I'm keeping the ballscrew on the same horizontal plane as the rails. I'm going to start about that this evening.

with a plasma cutter the work plane isnt so important as the plasma never touches the metal, its not pushing anything, however with a router, it is pushing, so yah, im going to have to think about that some more.

my headstones idea got shot down on some of the router groups, apparently granite is not easy to machine, so thats out. Still, there are a lot of things you can do with a machine like this, i just need to happen across them. I would dearly love to make a living from the machine rather than my nine to five. Might be a ways off yet though.

dual ballscrews... Hood I love the idea of driving them with one motor. I also love the idea of driving it with two motors, lol thats a lot of power, already the nema 34 attached to the screw is nearly as strong as me.

I actually got the specs of my ballscrew last night , its a 2510 ballscrew, similar to this one , however mine is 2700mm. Now that I have that info, I could get a second one.

Henry, speed, I just dont know man. Ill build it and see how bad the issue is then. I reckon ill be re-building it at some stage, I'm going to push on for now though.

cash is an issue. our landlord is demolishing our house and building a new, bigger one. So we have to move out for three months, and then move back in.
In the meantime we have to stump up the money for a deposit on a new place, and they will also want a months rent in advance, the usual... this all comes to nearly 3000 euros for the dublin area, average rent is around 1400 per month for three months... its killing me. we cant afford a holiday, i cant afford the CSMIO/IP M. Its a bitch.

I was saying to my girlfriend this morning, when this is over, im going to blow my wages on tools for 6 months. 1000 per month on tools. Thats the light at the end of the tunnel i need to focus on.

 

[slim_boy_fat]

1000 per month on tools. Thats the light at the end of the tunnel i need to focus on.

Just be careful it's not a train.

 

[ned]

ha. my girlfriend is here beside me and ive just re-iterated my pledge, she is fully supportive. lets see in the event though...

the landlord suggested he would extend the shed as well. he is builder by trade, old guy, but he's like a rocket, very energetic. I asked him why he built the shed in the first place, he said he got the notion one day. he just likes building stuff, which we can all relate to I think.

 

[henry Kadzielski]

Good morning ned.
One thing i forgot to mention regarding the long travel 'Y' axis is related to the ability of squaring the machine. The long travel being driven off one ball screw will make it difficult to square up. With two independent drives 'sinked' together you can use two home switches and the machine will automatically square it's self up, once setup. I didn't skimp on hardware deliberately, anyway enough said, it's you machine you build it as you see fit

 

[ned]

Thats clever Henry, I hadnt thought of that, very good. cheers )