Planet CNC Mk3 4Axis Controller for a lathe

[richardandtracyParticipant @richardandtracy]

After a while using one of the Chinese 6040 CNC router/engravers for a while I have come to the conclusion that I need a cnc lathe. I have found a fairly new Clarke CL430 that will do the job, having the advantage it's functionally identical to the lathe part of my Warco WMT300, so tooling will be common and I will only be confronted with learning 'Lathe CNC' and not the quirks of the machine. I now have to choose a controller etc.

Has anyone any experience of the Planet CNC controllers?

I am most interested in the 4 axis Mk3. I understand it can be run on its own without a computer having been set up correctly. I do hope this is actually the case – my workshop is unheated and I have an array of dead XP PC's to testify just how fast the conditions kill the PC's. It strikes me that a tablet can be used to load a SD card in the warm, then that used to plug into the controller.

I really want, as a long term goal, to control the spindle so I can engrave the surface of turned work using a router as an optional lathe tool. This means having cnc control of the spindle. Does anyone know if the Planet CNC controller will allow a lathe spindle to operate with a stepper drive (can one go fast enough?) or if I will have to be able to swap between the standard motor and a stepper motor? The plastic materials I turn can happily be turned at 950 rpm or a little less, and the power demand is usually less than 50W from the motor. I realise I will have to use ball leadscrews to eradicate backlash before this is possible.

Sorry if it doesn't make much sense at the moment. I am just starting to get my head around what is needed to convert the lathe.

Regards,

Richard.

[richardandtracyParticipant @richardandtracy]

[Clive FosterParticipant @clivefoster55965]

The run on its own via G code data on a SD memory card concept looks to be more about running proven programs than completely doing away with the control computer. As I read it you will still need a computer to do all the de-bugging, development et al needed to get decent parts off the machine. Once the program is sorted it can then be put on the SD card and run on a computer-less system. Great if you are using a multiple cheap machine model to produce certain numbers of components. Not much help for onesie twosie stuff. I'd be unsurprised if there were some limitations as to what G Code can be processed too.

Clive.

[richardandtracyParticipant @richardandtracy]

I hope to be doing small numbers of fountain pens, so there will be a number of common parts involved. The section (bit where the nib goes in), cap and barrel finials, cap lip and cap rings will be common to all. And quite frankly, they are the least interesting bits to machine, so I'm happy to prove a program, and knock off a few at a time of each. I understand about not being able to do away with the computer completely, and don't expect to, but if I can reduce the number of times I need one in the workshop, I'll have dead computers less frequently. And, with a USB controller, I can actually use a Windoze tablet which will be very convenient to take out – The Planet CNC controller seems to take the processing load off the computer.

I can work around G-Code limitations. Probably. I'd expect to do the basics long hand. I'm much better at software than I am at lathes…

Regards,

Richard.

[Martin ConnellyParticipant @martinconnelly55370]

What you are proposing sounds like what is usually referred to as the fourth axis on a milling machine. It may actually be easier to treat it like one and add a stepper operated fourth axis to the lathe. Keep the standard spindle set-up for high speed machining and have a fourth axis that can be mounted on the lathe to do the slow speed rotation needed for your engraving. The lathe X and Z axis would stay as they are and the fourth axis would be either Y or A axis. To have high speed with enough power for normal turning and the control needed for the engraving would probably require a big servo driving the spindle. This may be harder to achieve by modification than an add on axis.

Martin

[richardandtracyParticipant @richardandtracy]

I rather thought as much.

I've a 4th axis on my cnc router. It has been, um, not entirely successful. The gearbox drive is a bit of a micky-mouse affair, isn't concentric to the faceplate it drives, there is almost no meat to machine back to cure that and the best thing to do is ditch it. I had thoughts of modifying my rotary table, but the size of the table is such that the gantry can't clear the table and there is barely enough room under the gantry for an ER32 collet chuck, so a tailstock support would be needed to keep the gantry away from the table. The tailstock would have to be lightweight to avoid the gantry… The net effect is I'm heading back into micky-mouse territory again.

Thanks for the confirmation of what I was thinking.

Regards,

Richard.

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