a Steel Box Section Build with SBR20 & Ballscrews Plus a few questions

[grain_r]

Ah OK so if I had a movable spindle on the plate I can just set the coordinates on the work piece and then even thought the spindle has moved Mach3 would still know where to start from, from that same cutting path, I Wouldnt have to reset back to 0,0 and then get a new cut path. to get a continuous cut.

[EddyCurrent]

Ah OK so if I had a movable spindle on the plate I can just set the coordinates on the work piece and then even thought the spindle has moved Mach3 would still know where to start from, from that same cutting path, I Wouldnt have to reset back to 0,0 and then get a new cut path. to get a continuous cut.

That's right, as long as you tell Mach3 where work 0,0, is you're good to cut.
I've just realised you might be considering moving the spindle in the middle of a job, that's going to give you problems but could be done if planned for in advance, you could split the job up into, 'sub jobs' for example.
I would stick to, one job = one spindle position.

[JAZZCNC]

Hi,

Just looked at machine drawing and it's looking nearly there but 2 things both been picked up on and one Neil pointed out but think you've missed is the Z lower axis bearings conflicting with bolting together. This is a common Err that I and many others have done in the past so don't beat your self up. lol

The Long ballscrew mounting needs some attention.! These are areas where you need some adjustabilty for setting up and alignment so you will be best to mount the End bearings on plates that can be easily adjusted and like wise the mounting point on the Gantry needs to be more accessible. Try not to make the screw go thru the fixed mount but rather have ballnut mount that bolts to the gantry drop plate.
This will make screw alignment much easier and allow finding best performance just that bit simpler.!

Looking good and will soon be time to put the pen down and start cutting.!!

[grain_r]

Hey guys

Thank you very much for the really very useful comments. I thing whilst I'm starting out I might keep the single mounting point for the Spindle until I get how the 0,0 work piece co ordinates work I've got a feeling I would be getting a few odd results with me trying to use it on cuts with moving the spindle and get steps in a continuous lines. Although I think it will certainly be a thing that i will make a new front plate. The good thing is that i can move the work piece around a a little side to side but sounds like I will get a similar problem with the cuttings again.

Hey Jazzcnc Thank you very much for the comments I really didn't spot that with the conflict on the mounting of the bearing blocks fantastic spot. I will move the bearing blocks,
By having the long axis blocks on a plate that will give me the distance that I need to not have to shim the mounting on the gantry. It sounds like I might be best to use 20mm aluminium for the screw connection to the gantry.

I'm still not sure on running the screws with one motor either the only way I can see at the moment is running 2 motors. I don't want to really have the belts running across the rear just in case I want to use long material that can hang over the edge.

I'm really looking forwards to building something that I have plans for now instead of designing on the go.

Thanks very Much

Rob

[EddyCurrent]

With the mechanical stuff I think I got about 90% down on paper, the other 10% got designed ad hoc at the building stage.

[JAZZCNC]

I'm still not sure on running the screws with one motor either the only way I can see at the moment is running 2 motors. I don't want to really have the belts running across the rear just in case I want to use long material that can hang over the edge.

Nothing wrong with using 2 motors provided it's done correctly and they are run well within there capabilty's and using good electronics.!

[grain_r]

Good Evening well I have been lurking on here for a while again and watching everyone making steps forward. I have ordered placed and collected my box section although if I did it again I would opt for 5mm instead of 3mm steel as I think I have given myself a few mini headaches of threading and bolting and would have only been another £50.00 but oh well you live and learn.



The total metal cost was really good I thought I would put the costings on here to help people designing machines as a basis pricing although this price was specific to my machine.

X1 - Cut List – 500 MM 5mm x 50mm Flat Bar £5.00 each
X2 1300.00 mm – Top Rails
X4 550.00 mm – Legs
X2 1032.00 mm Side Bars
X4 287.00 mm Side Uprights
X8 230.4mm Angles
X3 950.00 mm End Support & Mid Supports
X2 95.00 Table Ends
X2 1032.00 mm Table Middle Lengths
X2 850.00 Table Middle Supports
X2 952.00 Gantry Horizontals
X2 200mm Gantry Seats
ALL OF THE BOX SECTION IN 5MM £155.00 LUMP SUM
ALL OF THE BOX SECTION IN 3MM £100.00 LUMP SUM

I had the metal cut because as I said in the email to the company that was cutting it I wouldn't be able to get as accurate as they would, (Well that certainly wasn't true) the cuts are withing 1mm as they said but that just happens to be on the one side they are really out. but at least it did all fit in the car this way oh well.

I thought it might take an eternity to get the accuracy with a file and so I have now purchased a SIP sander & Lanisher (I have always wanted one anyway so a nice justification ) I know it says no metal but it is really good and I am now getting the ends half correct and then finishing them on the Sander it is so well built it doesn't complain at all so I will certainly be buying SIP again.


Well it has then sat there for a while and so the other night I just had to sit there and measure every piece and I have now labelled everything (I should have done this before) and it now makes sense again. also if I had done this straight away when I bought the metal I would have found that my top rail was not in the pile so I will get another and this time I'm cutting it. at least I will get to play with the sander again.
Not a single piece of wood is safe in my garage.


I have been learning tig welding for the project by making a welding trolley as everyone always seems too and I am needing the grinder less now. so its all relevant for the project, I always seem to be going the other way and start making something else to make the next thing in the chain.












Well at least its all practice. I started out wanting a welding trolley and what I have finished with is a welding go cart well al-right nearly finished.

[JAZZCNC]

Hi rob,

Nice to see you back again thou would nicer still to see pics of a welded frame so get the welder fired up and lets see some action. . Lol

Don't worry too much about only being 3mm it still taps and holds threads with smaller bolt sizes. If you need larger bolts in places you can't reach back of then there's other quick and dirty ways like drilling larger hole and inserting a nut weld in place and grind flat.

So now go away and don't come back without pics of a welded frame. .

[JAZZCNC]

. I started out wanting a welding trolley and what I have finished with is a welding go cart well al-right nearly finished.

Grass has nearly stopped growing so rip out the engine and throw it on the trolley and you'll have the CNC machine finished in no time. . . Lol