Drive systems
There are some different drive systems:
I like the spindle the most, because of stiffness & precision. Pitch is available from 1 to 25 [mm/rev].
Speeds & accuracy
Difficult to know the right speeds etc, suppose the next specifications:
- 1000 [Hz] speed: 25 [mm/sec] with resolution of: 0.1 [mm]
- 10K [Hz] speed: 150 [mm/sec] with resolution of: 0.1 [mm]
- 10K [Hz] speed: 25 [mm/sec] with resolution of: 0.01 [mm]
- max speed spindel: 500 [rpm]
- full step: 200 [Steps/Rev] (changeable by stepsize of driver)
The table below gives some options of different pitchs:
High pitch values give you the next benifits:
high speeds @ low step rates (100 [mm/sec] half step 25pitch @2000 [Hz])
accuracy could always optimized by micro stepping (when using fast step rates)
Conclusion:
Best choice is highest possible pitch rate. This because if you need large lengths (2 [m]) you don't want to wait for ages.
(2 [m] will still take 20 [sec] with 100 [mm/sec] and then you need a second line to create and a third..)
Pitch should be 20 or higher [mm/rev]:
1K [Hz] frequency: 100 [mm/sec] (Full Step)
10K [Hz] frequency: 166 [mm/sec] (Full Step)
accuracy: 0.1 [mm] (Full Step)
accuracy: 0.01 [mm] (Micro Step: 10)
Diameter & Lengths:
A spindle of 2 [m] are available in different diameters: 16, 20, 25 [mm].
- Weight [kg]:
- D16 = 3.1
- D20 = 4.9
- D25 = 7.7
- Critical bending speed [RPM]:
- D16 = 1750
- D20 = 2200
- D25 = 2700
- Critical torsion speed [RPM]:
- L0.5[m] = 1800
- L1.0[m] = 900
- L1.5[m] = 600
- L2.0[m] = 450
- L2.5[m] = 360
- Critical axial force [N] (I'll propably need less forces ;) ):
- D16 = 1600
- D20 = 4000
- D25 = 9000
Conclusion:
- Chosen dimaters (max of 600 [rpm]):
- X-axis: 25 [mm] length 2.0 [m] (or smaller)
- Y-axis: 16 [mm] length 1.5 [m]
- Z-axis: 16 [mm] length 0.5 [m]
These values are for a general calculations methods when creating a drive shaft. (Hopefully spindle doesn't differ a lot.)
Additional graphs: Critical spindle speed & buckling load
