Feed Rates and cutters for wood panels

[jimbo_cnc]

Don't worry Jazz, I'm having square profiled rails on mine.

Seller will build to what I want, but his opinion is 32mm screw rather than 25mm. He says 10000mm/min will vibrate with 25mm screw. Thisimplies 2510 ballscrew to me. There is no belt on the drive, so that rules out the simple double the pitch and use pulleys to keep the same motor speeds.

He also susgests that 3kW spindle is not powerful enough for 10000mm/min at 19mm depth anyway.

[JAZZCNC]

Seller will build to what I want, but his opinion is 32mm screw rather than 25mm. He says 10000mm/min will vibrate with 25mm screw. Thisimplies 2510 ballscrew to me.

Argh Probably because he's got a pile of 32mm screws he wants shut of.!! . . . You won't find many other reputable builders recommending 32mm screws with a single central screw at this width and using steppers.!! . . . . . However You will find many machines this size running 20 and 25mm screws without any trouble.

Also 3Kw will easily push cutter thru MFC at 19mm with correct cutter/size but if your in no rush what does it matter if it's done in 2 passes.? Proper spec'd machine will do 2 passes quicker than one only capable of 3500mm/min.!

By the sounds your sold on the machine anyway, so no point saying anymore really other than good luck.!

[jimbo_cnc]

Don't be like that Jazz,

I'm here for help to get what I want. Although all I seem to be doing is pissing of all my potential suppliers :)

Those machines you mention are running 2525 or 2020 I assume ?

...and 1 pass at 6000 is quicker than 2 at 10000 :)
Again, this could be my mistake for mentioning cutting at full depth when that might not be an actual requirement.

[Shinobiwan]

Your going to need a beefy machine to do 19mm in one pass at 6m. I wouldn't fancy doing that with 6mm tool either! Cut quality would be shite with all the chatter and that's if it didn't snap. 10mm would be where I'd want to be at really.

[jimbo_cnc]

OK, so that was a bad thing for me to mention as a requirement to the supplier, I'm correcting that now.

I have some 6mm wide grooves, and 19mm wide grooves, both about 6mm deep. I was hoping to cut the whole thing with one cutter but swapping is no biggy either.

What do you recommend if I had 3kW spindle and 6000mm/min ?

The whole job with 6mm cutter and DOC= 6mm?
or 6mm cutter for narrow grooves, 10mm for wide grooves and multi-pass for cutting the profile?

Multipass rough cut the profile, then a full depth finish pass with compression cutter?


I will be hot glue edgebanding the cut edge, and I've got a choice of chipboard or mdf for the core of the melamine board.

[Ger21]

If you need both the top and bottom edges clean, then you want to cut the profile with a compression bit.
If you can, I'd try to go up to a 4-5Kw spindle, which should let you cut the profile in one pass with a 10mm compression bit. Machine rigidity will dictate how fast you can go, but I've cut 19mm board in one pass at ~17m/min with a 10mm compression bit.

If your limited to 3Kw, then I'd probably try using a 1/4" compression bit for everything. Cut the profiles slightly oversize in 3 passes, with a final cleanup pass at full depth, removing about .5mm.

[jimbo_cnc]

Thanks for that.

I'm not limited to anything. I'm just looking for the most economic way to cut 200 boards per year.

[JAZZCNC]

Don't be like that Jazz,

I'm here for help to get what I want. Although all I seem to be doing is pissing of all my potential suppliers :)

I'm not being or have been anything other than helpful with sound advise.!! You on the other hand appear not to be listening and hell bent on that particular machine so I wished you good luck. Nothing more than that.! . . . . I still wish you good luck.

[jimbo_cnc]

I'm listening and using the advice I get.

I'm not hell bent on that machine, but no one has suggested any alternative yet. That's not a criticism, just a
fact.

And it appears to meet my needs. Even if it doesn't meet your idea of how fast I should cut wood. (I'm up to about 6000mm/min now, just in case you think I'm still at 3500)

As to ballscrew size, I've asked for 2 proposals from the seller, 25mm ballscrew and 32mm ballscrew, with details of motors and drivers. When I get that info, I will try to analyse the overall performance of the options. Apart from acceleration, what else is there to consider?

[jimbo_cnc]

as anticipated, next question is acceleration.

I've got some specs:

Motor: 85BHX450B current：4.0A resistance: 0.5Ω, inductance：3.0mH, torque：6 Nm
can't find that on google, but I can just use the values given.

Driver: Leadshine MA860H


I've plugged the values, along with some guesses on gantry weight into the motorcalc spreadsheet, and for 25mm ballscrew it all looks good.

I deconstructed the spreadsheet so I can see the acceleration being used is based on time to achieve feed rate. This results in 0.57g requirement for my cutting.

Is that an appropriate value for this machine?

I'd also like to use this machine for my small plastic parts. I haven't paid any attention to acceleration settings on my 6040, although I might have followed some advice without remembering it. I'm going to run some of my cutting jobs in Mach3 with different motor tuning to see what difference it makes.


32mm ballscrew:
When I plug in the 32mm ballscrew, it's clear the ballscrew dominates. I can get about 0.3g from the motor above. Or I can ask for a larger motor. I was quoted +$100 for 32mm ballscrew, but wasn't given a price for a bigger stepper.