Feed Rates and cutters for wood panels

[jimbo_cnc]

The fact is I do listen. Since you said 32mm was too big I've spent a week investigating and learning about machine design. It turns out that 32mm is probably fine, but I will most likely go for the slower speed, higher acceleration 25mm option.

If you tried reading a post now and then instead of flying off on a rant, you would know it's not a 3500rpm machine with 32mm ballscrew.

And once again you throw up barriers that don't exist. I'm not asking for a $4000 machine. I'm looking for best overall value that meets my needs. And that's lifecycle costing, so it includes resale value.

When I add taxes and shipping the machine I'm looking at is about $6000. On paper it meets my needs. So if there was a machine going for $8000 that I thought was a bit betterr, or that I could get sooner, I'd snap it up. A $10k machine would have to be considerably better. As it is I'm happy to go with the best option I've found so far and take the risk that eg the electronics might need upgrading if your predictions come true.

I appreciate you are trying to be helpful, but once you've given out some advice you have to let it go, you can't dictate what I do with that advice.

[JAZZCNC]

If you tried reading a post now and then instead of flying off on a rant, you would know it's not a 3500rpm machine with 32mm ballscrew.

And once again you throw up barriers that don't exist. I'm not asking for a $4000 machine. I'm looking for best overall value that meets my needs. And that's lifecycle costing, so it includes resale value.

Last word that will come from ME just to clear your twisting words.!

My advice was given based on the conversasion on the phone where you was quoteing 32mm screws and 3500mm/min feeds amongst other things.
Advice was 32mm screws are too large and not required. Also 3500/mm/min Max cutting feed was too slow for correctly cutting the materials you planned.
Which you clearly didn't believe or want to hear hence this thread and when other very experienced people confirmed you still didn't believe. Hell only a few post's back you had the arrogance to tell probably THE most experienced DIY and Professional Users on the Net (Gerry) that he was wrong and Torque only dropped after the speed curve.!!

Now I don't give a flying F'#K what you do with any advise I give but I do take execption when you try to make out I'm wrong and try to twist facts/words to show me in a bad light.!

Oh and The $4000 came from you and the quote given not me and you where chasing price from the start because you considered building it your self which you asked me for ballpark figure of components.!

Now Jog on and I'll watch for your RFQ in 12 or so months time.!!

[jimbo_cnc]

You picked some numbers I've said and joined them together to make a machine/requirement that doesn't exist. As you won't allow me to correct you, there's not much I can do about that. Rant on my friend.

You clearly do give a fuck what I do with the advice.

I didn't tell Ger21 he was wrong.

[GEOFFREY]

You most certainly implied that Ger21 was wrong IN YOUR POST no 35. G.

[jimbo_cnc]

I have already mostly explained this, but let me expand.

first, post 33, which is what I though Jazz was on about.

When I say "As I understand it, I'm below corner speed even at max feedrate, so I have full torque available." That's a qualified statement, "As I understand it" means just that, but it also implies a lack of certainty. That lack of certainty is because it's not my domain of expertise and I'm questioning what someone else is saying.

When it's in my domain of expertise and I'm confident I will just state outright "This is how it is"


Post 35.

I can see how you might read that as me saying Ger21 is wrong. But try this for size: It's a link to a document that says something, and below it is a summary of what that page says. It's not me saying that.

I suppose it comes down to attitude, if you want to see that as me telling Ger21 he is wrong, go ahead. You could instead choose to see it as me probing for the correct answer, with proof.

I'm not sure what else I could have done. Someone on a forum, who I know nothing about, states something contrary to all the previous information I've seen. What would you do? just accept it?


I suspect Ger21 understands all this, maybe he's had to explain to lots of people that corner speed is not normally applicable (or whatever the answer is, I still haven't got to the bottom of this one). Or maybe he just works in an environment where asking for evidence is not taken as a personal insult.

[jimbo_cnc]

I haven't received my torque curve yet!

But in the meantime I've done some more thinking about acceleration and realised that torque fall off with speed is not a big problem anyway, at least for cutting profiles on wood. For the design case mentioned elsewhere of maintaining feedrate on curves, the acceleration is out of phase with the velocity, which helps a lot.