hi people, first post here. I am building a router with aluminum profiles.

diycnc-discuss
gplus
(ömer can Inci) #1

hi people,

first post here. I am building a router with aluminum profiles. I got lots of problems with my build. first of all Y axis is vibrating wildy when moving over 1000mm/m. What can it be? I suspect the lovejoy couplers. And I cannot make X and Y square. the angle between x and y is changing when i move Y axis. any ideas? thanks.

(ömer can Inci) #2

i spent a couple of hours to line the base. maybe I should spend more.

(ömer can Inci) #3

@Peter_Plaznik ​ warping is a problem with steel frames and I dont have any exprience with welding.

(ömer can Inci) #4

@chiel_Feuerstein thank you for your reply. I should get to working then.

(Stepan Zalsky) #5

Than you could try to make the Y stepper holder more solid. I see you made it from metal sheet. What bearings is on the other side ? Is there any backlash on a ballscrew bearing ??

(Wing Wong) #6

So you are using linear slides… what are those grey things between the slide carriage and the vertically oriented aluminum extrusions supporting the X/Z axis platform? I’m wondering if there is much given/catch there when you move it by hand? If there is any wiggle, it will most likely oscillate during movement given that you have a top heavy setup. Suggestion would be to power off, manually move the platform along the y axis and feel for any slight change in pressure/smoothness/rigidity, and tweak/tighten. When you move it, move it with force applied from the underside beam to mimmick the force that would be applied by the ball screw drive.

(ShadeTreeCNC) #7

You have have to slow the motor tuning some. You maybe losing steps. I have the same problem with mine.

(Nathaniel Stenzel) #8

You are measuring your diagonals, right? Are you using the Pythagorean theorem?

(ömer can Inci) #9

@Stepan_Zalsky I used bf12/bk12 on y axis. and yes stepper holder is 2mm bent sheet. it is vibrating too.

(ömer can Inci) #10

@Wing_Wong I milled the grey parts. i used those parts to fix the carriage to vertical oriented alu. extrusions. when i force gantry sides to opposite side by hand there is 1-2mm wiggle occurs. I will try what u said about tweaking.

(ömer can Inci) #11

+ShadeTreeCNC I tried slowing down but vibration still exists.

(ömer can Inci) #12

@NathanielStenzel I have a big square . I am not calculating anything :slight_smile:

(Bryan Barnes (BBmech7)) #13

There is a relationship between the inductance of your motors and step rates. I for one bought very cheap motors without looking at the uH ratings on them. Turns out I’m severely limited by my ~14 uH coil inductance. a decent motor(for my specs) should be closer to 3-4 (depending on motor size and coil ampere rating) … oh well. As far as tuning first cut back on acceleration curves then look at max speed. Also if your controller has the option increase the “on pulse time” of the step signal helped me smooth things out. If you find that you shake around 1000 but say for example no around 1500 or 2000 you may be experiencing “Mid band resonance” . If that is the case you will either need a fancy driver or some manner of active dampening.

(ömer can Inci) #14

@Bryan_Barnes_BBmech7 I just looked at my motor specs. They are 2.8A 3.6mH 4 pole steppers from KelingInc. And my stepper driver is geckodrive g540. I dont know about “on pulse time” option? Is it driver or software (in this case mach3) feature? Thank you.

(Bryan Barnes (BBmech7)) #15

I think mach3 calls it “step pulse width”. Your inductance is in a good range. what is the pitch of the lead screws you have. also are they single or multi lead? i think i used this site (http://www.daycounter.com/Calculators/Stepper-Motor-Calculator.phtml) to help me figure out my step rates. (http://www.aquickcnc.com/wiki/Stepper_Motor_Calculations) also has good info on setup.

(Ankur Banthia) #16

Even a small unbalance in spindle can cause huge vibrations. Preferably use heavy sections and also see that at the joints the aluminium are having full contact. If not use more fasteners.