Calibration

[testyourdesign]

Well @flytyree after comparing the latest measurements with the first ones you sent it looks like something has caused it to travel a little further than last time. Since some numbers are still short on travel I don't think the cutting forces are having an effect. I am guessing your calibration numbers are a little different since you redid the calibration again. You probably just need to adjust the calibration settings a little to get it closer. Based on your measurements we can get an idea of what to change using those ratios X = 5.5455 / 5.50 = 1.00827 and Y = 0.971 / 1.00 = 0.971

If multiply the current calibration settings by those ratios ( x) * 1.00827 and * 0.971 it should make the X axis travel a little less and the Y axis a little more. Hopefully that will get you back on track or at least give you an idea on how to tweak it.

 

[masso-support]

@flytyree, by swapping the X and Y drives we were saying that to remove the wires from the X drive and Y drives and moving the X drive wires to Y drive, then moving the Y drives wires to X drive. This way from the controller when you move X axis motor it will still move X motor but using the Y drive, and the same for Y but swapping the drives will confirm its not a drive issue. We had a client where a brand new stepper drive was faulty and rotating the motor te wrong steps.

Also you could install a pencil in the Z axis and draw on paper, this way there is no loading on the axis.

 

[flytyree]

Thank you for your input. I have been busy re-calibrating and the results are attached. With the new calibration I cut one side, as before, with NO improvement in dimensions.

I have extra stepper drivers. Tomorrow I will replace first the Y drivers, and then the X driver.

Your help is greatly appreciated.

Clifford

 

[testyourdesign]

@flytyree I think the calibration values you tested were to small to make a significant difference. If swapping out the motor drivers does not help then I would try setting the distance per revolution calibrations to X = 0.5958 and Y = 0.5734 to see if it gets you closer.

 

[testyourdesign]

Any luck with swapping the drives or adjusting the calibration@flytyree?

 

[flytyree]

I am still working this issue. I have changed the X axis and I am running calibration. It looks promising at this time. I have had to many interruptions and that doesn't help when trying to be precise.

Clifford

 

[testyourdesign]

With the level of precision you are looking for I would consider getting a test indicator and a 2-4-6 block. That way you know your calibration measurement is precise to at least 4 decimals. The blocks are also very useful for setups and work holding. The test indicator is great for squaring up your work on the machine.

 

[flytyree]

I have a lot of my Dad's machinist tools; inside/outside mic's up to 12" but I am not familiar with a 2-4-6 block.

 

[testyourdesign]

A 246 Block is a cast iron block with threaded holes. It is precision ground to be square usually within +/-0.0002" and parallel within +/- 0.0003 " on all six sides. It measures 2 inches by 4 inches by 6 inches. Most practical tool in my shop. See photo below.

 

[flytyree]

After changing out the X Stepper Driver box and re-running a calibration there is NO IMPROVEMENT. I have attached the calibration for X & Y as well as the measured values. I am completely blown away with the fact that every finger has a different dimension in both axis. If this difference occurred in only one axis it would be evident that there is "slop" in that axis. With both axis different I am confused.

 

[testyourdesign]

@flytyree it might because of lost steps during motion if the steppers are under powered or over loaded for the application. I noticed in one of your photos that you daisy chained the power to the drivers. That could be the source of the problem. The drivers are supposed to all be connected directly to the power supply and not daisy chained. Can you upload the spec sheets for the driver, power supply and motors so I can better understand your configuration?

 

[masso-support]

daisy chained? where was this @testyourdesign, trying to find it

@flytyree we need to slow down the axis a lot just for the test and only move one axis and measure the results. If you try to move the axis by hand when the stepper is powered and locked in position can you feel any movement?

 

[testyourdesign]

@masso-support take a look on the first page of this post. I see a black and white wire daisy chained on the drivers in his photo. He also has the wiring all bundled together. The VFD wires, driver wires, and motor wires need to be shielded to ground and separated or else EMI will cause problems.

 

[flytyree]

Thank you for your input. Attached is a copy of another cut running at 5 in/min (took 22 minutes).

I will look into the spec sheets and if necessary I will use separate power supplies.



Clifford

 

[testyourdesign]

Hi @flytyree I'm sure we'll get this sorted out very soon. This stuff is not complicated but it does require that we follow a certain recipe. Can you at least tell me the rated voltage and amperage of your power supply, drivers, and the steppers? You need to have enough amperage to cover all the stepper motors running at once.

For now I would simply replace the DC power and ground wires with separate wires for each driver leading back to the power supply. That should provide a move even distribution of power to each driver. I would also physically separate the stepper motor cables from the signal wires to the Drivers and the VFD to eliminate the possibility of interference from the noisy Stepper Motor and VFD Motor cables. That should be fairly easy to adjust since your setup is not enclosed.

 

[flytyree]

Greetings. I too am optimistic that operation will be accomplished.

The four stepper motors specifications are rated at 3.36 V and rated current is 2.8 A. The 24 V power supply is a LRS-350-24 and 24V at 14.6A. This power supply has 3 DC outputs. I put the X and Z axis on their own separate terminal's and both Y axis motors on the third terminal. No more daisy chain. I have purchased 18-4 foil shielded wire and will get this installed late this evening or tomorrow. I trust I can run this shielded cable in the same cable tray with the signal to the motors.

Do I have to use shielded cable for signal wire to the stepper motors?

Thank you for your patience

Clifford

 

[masso-support]

so you mean the cable from the stepper drive to the stepper motor?

 

[masso-support]

Quote from testyourdesign on September 1, 2018, 11:32 pm

@masso-support take a look on the first page of this post. I see a black and white wire daisy chained on the drivers in his photo. He also has the wiring all bundled together. The VFD wires, driver wires, and motor wires need to be shielded to ground and separated or else EMI will cause problems.

thanks @testyourdesign and yes @flytyree please keep the VFD and VFD wires away from all other electronics, VFD's make a lot of electrical noise.

Also as @testyourdesign mentioned that going by steps is very important to find and fix the issue. For example lets say its a VFD noise issue, its best that initially you only run the axis, infact run one axis at a time and confirm that its movement is as expected, dont even run the spindle and keep the VFD powered down. You have to differentiate all combinations that could be making the difference.

 

[flytyree]

I would like to report that success has been achieve but, quite the opposite.

See attached pictures. The daisy chain has been eliminated. Shielded cable has been installed between VFD and motor. The cable has been routed along the coolant lines.

I AM FRUSTRATED.

 

[masso-support]

@flytyree lets do some tests over phone or skype and have a good look at each and every single thing step by step. Can you please email your phone number or skype ID to support@masso.com.au and we will fix a time. Please also let us know what time zone you are based in as we are in Sydney, Australia.