Thread: G540 & CNC Build

Yep.. Larger rotary jobs will possibly require the depth. I've ideas what I want to do, but not sure if I can actually carry them out . Most of the time the table will sit at the top. I've ordered a 6" Vertex so will be looking for ideas for the modification. Promica's rotary conversion kit for the Vertex (the hardware, no motor) is just on $320... so Im thinking I might look for less expensive options for the moment. Has anyone here completed a self conversion?

Brad.

Well I have been looking at conversions after it was last mentioned honestly I cant see how the Promica model makes any difference to a direct drive model besides looking good and maybe using pulleys for more speed etc and that realy isn't a requirement for us.

Greg can you add into this on your thoughts as your the wizard on this .

I like to K,I,S,S everything so it will be direct drive for me unless someone can give me a valid reason to do otherwise.

Steve (Simso) did a direct drive and it works well. They are a 90:1 gear ratio so no need to have additional pulleys.

The vertex table has a ratio of 90 to 1. This is fairly high for wood or other softer materials. My gearbox is 40 to 1.

I hear a lot of builders adapting wood lathes use about 4 to 1 belt drives.

Presume a max of 300 rpm for the stepper. (you may get higher) That works out to 3.333 rpm max for the table.

A lot of 3D work I do on a rotary, only increments the A axis a little bit every pass of the X axis. The X moves along the rotary axis. So in this case it does not matter.

If it were me I would direct couple a stepper with a helical coupling in between. You can always go to a belt and up the ratio later if desired.

Do you have a spare driver in the G540?

Is the backlash adjustable on the Vertex? Usually done by moving the worm closer to the bull wheel (terminology?)

Greg

Nope.. no spare driver. I'll have to disconnect one from the other axis, so I'll just set up another Mach3 layout depending on which axis I disconnect. Is there an advantage, apart from not have to disconnect it each time for a dedicated rotary controller? I've read on Promica's website that the vertex can be adjusted fairly easily.

Just have to be careful not to disconnect a motor while the power is on otherwise driver lets out smoke.

You can put an additional G251 which are on special for $49 and match your G540 driver. You power supply will not be taxed as you will drop one drive off to use the 4th axis. It might require an additional parallel port or a smoothstepper to get the extra motor output though.

You can have two Mach Profiles for the different setups which saves you having to change your settings each time.

I can live with disconnecting it for now. I'm trying to find some parts to make a stepper mount to the vertex. 4 lengths of threaded tube 50mm long for a 5m bolt . I found Hex nuts but nothing with in a 5mm internal thread. Any ideas where to find such items?

Brad.

You will need to find somebody with a lathe to make them.
Perhaps this sort of thing might be doable in your design. Just use PCB standoffs with a 3mm thread. The 3mm screws are counterbored into the 8mm plate.

I found some. These guys sell all sorts of interesting items.

Pillars - Threaded - Small Parts Mechanical Components

Brad.

Originally Posted by spidey4fun

I found some. These guys sell all sorts of interesting items.

Pillars - Threaded - Small Parts Mechanical Components

Brad.

Looks like its a wait of 21-35 days for any stock.


Just a thought, some round/square/hex stock, drill both ends, tap both ends, stick a bit of allthread in one end with loctite/industrial adhesive/grubscrew/pin and presto a home made riser

Yeah, I was thinking about that too. But I figure Im in no rush on this so will just order some pre-made from these guys.

Brad.

What software would do this? It seems to run on the 3 normal axis and the 4th rotational.

[ame=http://www.youtube.com/watch?v=rrk6wqcB54g]YouTube - High Speed 4 Axis Machining - Hand[/ame]

Brad.

Easy Driver stepper motor driver

http://www.sparkfun.com/products/9402

Interesting.

Heres one I'd seen some time ago

http://www.robotsimple.com/A4983_Ste...Driver_Carrier

Tiny little bugger and outputs quite a bit of power.