Attachment 362846
So if you've been following 1Jumper10's build log, I now include inertial effects in my performance estimation. The "I" or inertia values of 0.0002 and 0.0004 kg*m^2 are properties of the reducer gear and we don't know what they will be yet. From what I've seen, for the power output required, the required gear will have a value in this range.
The estimation does not include:
Cutting forces, extra acceleration required for backlash compensation, etc, etc. not included. Any mistakes that I may have made may be unaccounted for also. I'm fairly confident but have not been fact checked by a second party. I came up with this yesterday and was fine tuning it today. I changed one small thing from yesterday to include the inertia from the reducer in the optimal gear ratio calculation, which is something I missed before.
I think the advice you were given by DMM is good, but rushed. I actually took the time to make the graphs. You're welcome.
Feel free to invite the person from DMM to come and look at this thread. I wouldn't mind that.
And I think 1900 ipm on a Z is more than excessive. Your Z would work with a Nema 34 and a 5mm pitch ballscrew up to a speed that any sane person would run it at. Or perhaps I'm wrong?
The clear winner for 1800 IPM is the 7:1 at at 2 inch pitch circle diameter. That is about 0.35G above what the advice you were given according to my graph. Next is 7:1 at 39.79mm pitch circle diameter.
My spreadsheet shows the optimum Gear Ratio based on inertia. Pinion size and gantry weight change this ratio the most.
For 5:1 - 27mm the optimum was between 5 and 6
For 7:1 - 39.79mm the optimum was between 7 and 8
For 10:1 - 50.8 the optimum was between 9 and 10
For 7:1 - 50.8 the optimum was between 9 and 10
I'm guessing that means that all of those options have good inertia matching and that you don't have to worry about over or under shoot or any strange effects like that.
I was thinking about this earlier today. A 750kW with a larger reduction ratio. I was thinking of 16 for some reason. They can go up to 5000 rpm. I had to get the manual out again to pull the numbers for these graphs
.
The only concern I have is I can't see any data on those reducers as far as input speed or continuous / max load output. Perhaps I missed it?
I wouldn't buy one without that information.
If you look at this gear for example:
Gear Reducers | In-Line | PE-N34-010G | GAM
It's on a Nema34 frame and it has a max acceleration output torque of only 24 Nm. It wouldn't last too long. Not sure about the other ones. If you knew the weight of them, you'd could have an idea of the load capability........
I'm out for the next few days. Tired of graphs, much work to do. Talk to you guys later. Good luck Ramsey with whatever you choose. I'm sure it will be fine.