MAX MPCNC FEEDRATE?

Hello

what is the max feedrate of the MPCNC in the firmware setting?

is it the same for all supported board?

thank you

1 Like

#define DEFAULT_MAX_FEEDRATE

Search for that in your Configuration.h file. The values there are listed in mm/sec.

Ryan has his firmware with the following as downloaded from the Github page:

[quote]/**

• Default Max Feed Rate (mm/s)
• Override with M203
• X, Y, Z, E0 [, E1[, E2[, E3[, E4[, E5]]]]]
*/
#define DEFAULT_MAX_FEEDRATE { 120, 120, 30, 25 }[/quote]

Ok thank you.
so the max feed rate for X & Y is 120 mm/s

And what is the max X & Y feedrate that we can consider in the most optimistic case for this machine? if you consider having the easiest material, the most efficient milling cutter and the most efficient spindleâ€¦

It is just to define the very optimistic up limit for a excel calculator tool

Thatâ€™s not really how it works. Every machineâ€™s feeds will be different since every machine is build slightly different. You could probably run full speed in something like foam insulation though.

Yes I know, but it was just to use the software max speed rate into some formula using Vc, Vf, n, Z, fzâ€¦ in excel, to have a reference point for the speed that the formula will give me.

as you speak about it, can you give me the max speed rate that you could use for MDF cuting with a 1/4 " 2 flutes, because in this case the formulas gives me a speedrate which can be beyond of 40mm/s and I think itâ€™s a lot for this machine.
it seems to me that between 20 and 30 mm/s it can force too much for the rigidity of the machine when I cut MDF 15mm. Of course by adjusting the rpm of the spindle â€¦

1 Like

Not really. I generally donâ€™t cut with quarter inch end mills. 1/8 or 1/16" is what I use. I have a 2mm depth of cut at 10mm/s set in estlcam right now, but I canâ€™t remember what it was for. Iâ€™m pretty sure it was my mystery barn wood. Which is either 200 year old oak(when it was used), or 200 year old pine(again when it was used). I very rarely cut MDF. When I do, it will usually be half thickness depth of cut at 10 to 15 mm/s. I can slow it down if I need to with repietier.

1 Like

There is a number that says cutting force. find what you machine can handle well, then you know how to set up every cut. You choose the right values and make sure it does not exceed the cutting force your machine can handle. As you can see there are many many variable s but that one numbers tells you what they all add up to at the end of the bit.

Then, you need to take in account your depth of cut, as that effects what you machine can handle the most. If you can handle 1kg at full extension you should be able to handle double that number at about half extension of the Z. (it is reverse of that for the LowRider)

Speaking of this, I have wondered and meaning to ask a while back, if itâ€™s possible to have the â€śfeedrateâ€ť on the LCD work, just like we do in 3D printing, so we could adjust the speed simply with the knob if we need to during a job. I have tried mine and it does nothing. I reckon that would be very useful. How do we turn it on?

No idea on the lcd, I do it in repetier. I do know not to speed it up too far, it will overspeed the z axisâ€¦ Thatâ€™s the real problem.

1 Like

It does, or at least should. Are moves are much longer so you will not get a response until the buffer catches up. A printer can do ten moves and clear the buffer in a fraction of a second, it can take ours mills minutes (or longer) to do the same. I think the buffer has something like a 12 line capacity-ish.

Ah that must be it then. Thanks Ryan

where can i see the cutting force there? that would be really interesting, since thats the consistent value, no matter what material you use, if your cutting force is within the limits, there you go.