Building My First CNC Router, Looking for Advice & Other Info

[Clive S]

Yes it's good for the spindle but make sure it's CY not SY cable this is very important as SY cable is not at all flexible. Also SY is a lot more expensive (It's armoured). I use a company called Rexel Senate for wiring you could see if you have a branch locally. Prices were similar as ebay but without the postage and of course you can get it today/tomorrow.

http://wfsenate.co.uk/

http://www.cablechoiceguide.co.uk/ca...ontrol-cables/

The differences between the three cables are as follows:
CY Cables are used when interference-free transmission is needed. The CY Cable has a Multi-core Flex and a tinned copper wire braid and a PETP (Polyethylene Terephthalate) separator. All these work together to protect the cable from external electromagnetic influences and mechanical stress.

YY Cable works well within light mechanical stress and is suited to most environments. It is very versatile so can be used outside when protected and in dry and moist conditions inside.

SY Cable is the strongest cable from this family. It offers reliable mechanical protection and the galvanised steel wire braid makes it ultra strong and durable.
Control Cable Similarities
All three cables have similar properties. They are all highly flexible Multi-core cables with copper conductors (Class 5) and have a voltage rating of 300/500V.

[AlexDoran]

...now you must practice how to set the orientation right. The pictures are nice but they are all (even the videos) turned 90 degrees... ;) I mean, the videos are supposed to be taken with the phone in horizontal orientation otherwise you are wasting image surface area.

Anyway, it is really a very nice machine you are building. The only thing I notice is that you seem to have made the same mistake I did regarding the Z plate. The linear bearings should be the other way round, the rails moving up/down and the bearings fixed. If not too late you should change that. For me it is too late now, but it sure will be the first thing I'll correct next time I upgrade my CNC.

Lol I took the photos portrait and they are portrait on my PC, so not sure why they have uploaded rotated! Schoolboy error on the video though haha

That's an interesting point about the Z Bearings, so is the point of this to be able to spread the bearings further apart?? Maybe I could change the design, I'll have to have a play around with the CAD model.

The machine looks good, it seems you are getting close now!

Thanks, still a way to go yet I feel!

Thanks

Alex

[Neale]

If you look at the geometry of the Z plates and imagine both ways of positioning rails and bearings, you will see that you get better support of the moving plate through its full travel if you put the bearing carriages on the fixed plate. It feels wrong at first, but it's the right thing to do! The rails also provide a slight stiffening effect on the moving plate as well, although if you use the usual 20mm plate, that's not going to matter much.

[Zeeflyboy]

While I agree, it was pointed out to me that it can make the Z-axis less versatile... it can limit the ability to retract the Spindle and tool above the gantry base height which can cause problems when using long tools and/or tall stock.

Just worth considering if that sort of thing is on the agenda.

[Neale]

No argument there - good engineering is all about compromise, and understanding the trade-offs so you pick the right compromise is important.

[AlexDoran]

Having had a QUICK look, im mot sure that will work for me as I need to be able to get a 80mm tall workpiece in there and machine at least half way through,l. I will have a more detailed look tomorrow. I am probably going to space the carriages out slightly more and sacrifice travel at the lower limit as it will currently reach below the horizontal braces with a tool in the collect.

Thanks for the advice guys I appreciate it.

Alex

[AlexDoran]

So i adjusted some of the components of the Z Axis to hopefully improve how rigid it is, previously that blocks that connect the Spindle Mount to the Linear Carriages were shorter than the Spindle Mount, in order to try and maximise Axis Travel, however in reality this meant that the spindle could reach well below the bed even without a tool in the collet, so i decided to make the Connection Blocks longer and increase the spacing of the Carriages.




I started looking today about how i need to properly Ground the Spindle at the VFD side, whilst looking for information i came accross a forum post on CNCZone that said many of the Chinese spindles do not have their Ground pins connected to anything inside the Spindle, so i decided to take the top off and have a look - and not much of a surprise as the Ground pin was not connected to anything. Where can i connect this to? Should i just drill and tap a hole so that a connector can be screwed to the casing and soldered the correct pin?



I've also been scouring the net today trying to find some nice proximity sensors to be used as limit switches, i think the DDSCV1.1 can use 12v limit switches? Could be wrong any advice would be appreciated.

Also waiting for the Cable Drags and breakout boards to arrive so i can design some brackets and a portable enclosure for the controller.

Also been searching for the correct resin to fill the extrusions with, anyone have any personal experience / recommendations?

Thanks

Alex

[Clive S]

Where can i connect this to? Should i just drill and tap a hole so that a connector can be screwed to the casing and soldered the correct pin?

I just changed one of the socket hold down bolt to one a bit longer and put a connector on that with a nut.

Make sure you clean the water holes and put a little silicone around them to make a good seal when you put the top back on.

[AlexDoran]

I just changed one of the socket hold down bolt to one a bit longer and put a connector on that with a nut.

Make sure you clean the water holes and put a little silicone around them to make a good seal when you put the top back on.

So simple - yet so brilliant ;) :D Thanks i will do that.

Thanks for the silicone tip i will pop out and grab some tomorrow.

Do you have any idea about the resin for the extrusions?

Thanks

Alex

[Desertboy]

I was considering filling the extrusion with resin but I asked around the forums and was told it was a waste of time.

I also spoke to a fibreglass guy who told me to use polyurethane with metal filler.

In the end not going to bother this time but will consider it in future.