Filament Flow Error With CubeX

[aceguns1]

A few month ago, I basically replaced everything on my cubex printer; mainboard, breakout board, hot tip, feeding servo, and the z-gap sensor. After everything was done it seemed the breakout board on my printer was fried and that was what was causing the issue. I was able to get a few months out of the printer working just fine until now. I have two issues, that I believe are related. The first being after I do a z-gap align, when it is going back to the home position it is losing its positioning and just slamming into the side of the printer. I have to stop the printer, manually move the printer to the home position and power it down completely to get it to reset its position and work.

The second issue I am having is with just prints now, even with the above problems I was able to get it printing and now that just is not happening anymore. It is having problems laying down layers after the first layer on the bed. I will hear a knocking in the extruder which sounds like it having problems feeding the material onto the print. I believe this is because it is losing its positioning and is to close to the actual print that it is jamming up. Infact after every failed print, after I go and check the print tip visible covered with filament which in turn caused the flow error to begin with. 

So I am curious if others have experienced this type of issue and if they have any ideas on what needs to be replaced or how to fix it. I have ordered a new z-gap sensor that relocated the sensor to another location on the machine, but this will probably not arrive until next week. I plan on calling up Cubify and seeing what they say should be replaced. 

[Peter Gregory]

First, your problem with homing.
Check the magnets located on the left of the X axis carriage and the left rear of the Y axis.
They may have gotten pushed in too far and the sensors are failing to detect them.
You can loosen the screws holing the magnets and pull them out further.

Second, if the print head is mashed into the bed so far that filament won't flow, then it will damage your print bed when the heads move.
If there is any gap at all, some filament will flow.

If no filament at all is flowing, then you probably have a blockage.
Use the temperature control menu to heat the head hotter than usual and turn on the filament feeder.
If nothing comes out, you have a hard deposit stuck in there.
you will probably have to remove the hot end tube, connect it hanging in the air, heat it up to 240c for PLA and manually pull the blockage out.

[Rodney Wells]

The head crashing into the print can be the coupling coming loose The black thing down on the Z stepper motor connecting the threaded rod to the bed.There are 2 3 mm grub screws give them a tighten up.

and if the x or y is crashing into the side of the case when homing you need to adjust the magnets or the reed sensor out a bit usually a 1 mm will fix it.  

I also recommend an optic sensor  for the Z axis stop.  The magnetic field is not reliable.

I use theses on my CubeX

[aceguns1]

Thank you all for the quick responses. I will give these suggestions a go when I get home today. I did have a bit if a question in regards to the prints, the prints do run for a bit and will actually print some of the object but probably an hour or 2 into the print it is failing. However I do hear that jamming sound from the very start, could still be an issue with the z stepper connection being a bit to loose and having the threaded rod drop down just enough to cause a jam on the printer?

I agree the magnets are not reliable at all, where did you get that optics sensor. I have been debating on ordering one of the kits that actually moved the z-gap sensor away from the print head and to the back of the machine.

[Peter Gregory]

I purchased a heated bed that also contains a Z-Gap sensor kit from GRM products.
www.grmproducts.com
I highly recommend them.
A heated bed makes a world of difference with print reliability.

Are you printing using the filament tubes?
I found that bypassing the tubes and feeding from the top directly into the feed hole works much better.
The feed stepper motor doesn't have to work as hard.

You can also increase the bias voltage for the feed stepper from 1v to 1.5v on the main board.
This gives the stepper more power to push through blockages.
They run the X axis stepper at 1.6v, but it gets a little hot.

Are you printing with PLA? How old is it?
I have a few spools with about a year old PLA and they develop hard spots that clog the print head.
I have to remove the print tube, heat them way up and pull out the hard deposit.

[aceguns1]

I actually bypassed the filament tubes completely, I feed it directly in to the feed holes on the top. Do you happen to have any documentation or a link where I could look at increasing the feed stepper up to 1.5 volts, but I could see that being a really big help. The PLA I am using is really new (only a couple weeks old), I am using the Matter Hacker professional line of filament. I have found that the matter hacker stuff runs the best, I didnt like their standard stuff that much; I felt that it was a bit to brittle. However their newer professional material, seems to run as well as the old matter hack through, but its a strong and less brittle print.

[aceguns1]

I just got home and moved the X-axis sensor out some to hopefully have to register the magnet and no luck. After I align the z-gap is start to go back to its home position in the back right and it just continues to move right until it slams into the side of the printer.

[Peter Gregory]

Here are the instructions for changing the filament stepper motor voltage

[Rodney Wells]

On Thursday, 7 August 2014 09:01:42 UTC+10, aceguns1 wrote: > I just got home and moved the X-axis sensor out some to hopefully have to register the magnet and no luck. After I align the z-gap is start to go back to its home position in the back right and it just continues to move right until it slams into the side of the printer.

If you feel you have made all the adjustments to the magnet or the sensor then you will need to look a bit further.   Do you have any tiny magnets you can hold up next to the sensor 

to see if you get a reading in the screen.    If you are in the manual movement menu where the x,y,z arrow symbols are you will notice the x symbol will appearer if you trigger the X reed switch with a small magnet. Same goes for the others.  This will indicate if there is a problem with the detection somewhere.  The computer is not seeing the trigger.

Also test the other 2, Y and Z and see how they work. 

The optical sensor in the photo is on eBay. You can get them from the 3D Rep-rap Marlin guys that's what they use. usually 2 dollars each or close enough.

I have tried all the magnetic sensors for the z moved it all over the place, the field strength kind of drifts when there is a change in temp not much but sometimes it is just not right.

If you print with a raft not a problem.  I never use a raft. so the first layer needs to be spot on.   

[aceguns1]

It doesnt look like the any of the senors are picking up a magnet against them at all. I put a small refrigerator magnet up to each one and nothing happened, so it doesnt look as if the computer is reading them at all. In addition, i tightened up the screws on the z-axis stepper because they did feel a bit loose and started a print. However I had the same issues as before, the first couple of layers went just fine. But material started to build up on the end of the hot end and my print started looking like what can only be described as swiss cheese. 

[Peter Gregory]

It sounds like it is pushing out too much filament.

If you are using Cubex printer driver, it assumes you are using 1.6mm diameter filament.

Third party filament will vary from 1.7 to 1.8 - so the Cubex printer driver will push out too much filament by default.

What slicer are you using?

If you are using KISSlicer + CubeItMod you can change the filament diameter, flow rate, infill and solid fill percentages.

[Frank Fisk]

Re-flashing the firmware wouldn't be a bad idea.
Follow these steps to update the firmware: 

1. Unplug the power from the printer.

2. Make sure the CubeX software is not open on your computer. Connect the printer to the computer with a standard A-B USB cable and open the CubeX software.

3. Hold the function button as you plug the printer power back in.

4. Release the function button after the machine turns on and you will then be in BOOTLOADER mode.

5. Go to the Settings tab and click the “firmware update” button. Select the .hex file for the firmware version you are updating to.

6. After the update is complete, unplug the USB from your printer as well as the power cord and wait 30 seconds.

7. Plug the CubeX back in and turn it on normally. You will be at the user activation screen and will need to enter the activation code you originally used. (if you do not have this please contact us for the code)

After updating the firmware using this method, check your Z-gap and other offsets. They will likely need to be re-adjusted.

This has worked well for me and after several measurements seems to have solved the repeatability of the Z-gap.

This may solve your axis overrun issues.

Frank

[Frank Fisk]

I Forgot, most of my feed issues have been related to the spools, tubing and sometimes dirty drive block. I've built a re-winder and always take filament from stock spools and rewind onto another to remove any twists or crossovers etc.. that cause filament to bind and unwind inconsistently. Also the tubing can be replaced with slightly larger and much slicker PTFE tubing.  5x3mm is what I have and have not had to feed from the top. I did this with my makerbot R2 and found simple fixes allowed for using the stock filament location without issue.  I use bearings on all my spools which are all the same size and now compatible with both my R2 and CubeX Duo.  The filament should enter the feed tube ASAP after leaving the spool. This will help with the tightly wound filament at end of spool.

I'm a firm believer in starting simple and when that fails start throwing money at it replacing sensors and boards. 

Frank

[Frank Fisk]

Lets try that picture again.

[Frank Fisk]

Attached is a picture of the rewinder I built from my MakerbotR2 overhead spool mounts.  The white spool was my 1st CubeX print.  I have different size inserts for various size spools.  I found trying to straighten tightly wound filament a waste of time. Its easier to mount the PTFE tube closer to the spool so the filament has no chance of wrapping around itself.  Bearings are a must and will eliminate any spool and mount friction issues.

Off the top of my head below is a partial list of procedures I follow religiously.

1. Always HOME after adjustments and before any new adjustments made or alternate function screen is activated. 

2. Magnetic sensors don't always work in MOVE mode and will allow the carriage to slam into the gantry or housing as you described.

3. Be sure the X & Y Magnets are positioned so when HOMING the carriage moves as far left and back as possible without hitting the X stepper or the back where the fan bumps up against wiring and filament feed tubes. This should get the z sensor closer to the center of the build plate magnet.  A good whack to the X will break the stepper gear as it is plastic pushed onto the aluminum mount which has splines that do not extend the length of the shaft and only engages the gear at its ass end.  Epoxy fixed mine as the gear is not available by itself, only with the stepper.

4. Level build plate using a digital level with alternate "0" function. I use a SPI-TRONIC Pro 360 model SPI 31.038-3. Always level from the X & Y gantry rods.

1st measure the x gantry rods and if necessary use alternate "0".  set the back 2 leveling screws so X is at 0 then do the same for the Y and repeat as necessary.

5. Set Z gap without anything on build plate.

6. Be sure the Z coupler has engaged the stepper shaft at its flat and hasn't slid down onto the stepper body itself.  

[aceguns1]

Thank you all for the suggestions. I will try a firmware refresh tonight and see if that will fix the issues I am having. Currently I am using the Kisslicer +Cubeit method when doing my prints and am using a 3rd party filament over the cubify cartridges. Would you recommend changing the flow rate in the actual software?

[Peter Gregory]

Try using CubeItMod.

It gives you control over more than just flow rate.

It also lets you set different flow rates (using percentages of base rate) for filling, infilling and stacking.

The latest version is 4.8

Be sure to install the language file - it uses some of the existing fields to let you tweak rates.

[aceguns1]

I have tried the suggestions and nothing seems to be working. Cubify is sending me a new X-axis senor which may resolve one of the issues, but ultimately I believe the problem to be either the breakout board or the main board yet again. 

[bikejunky98]

Hi FF,

Awesome spool holder! Would you be up to sharing the stl?

[min....@googlemail.com]

As you said, cubex Extrudermotor has maybe too low voltage setting.
Voltage in datasheet for stepper Motor(m42sth47-1684s) was 2.8 volt (max).
(see http://www.motioncontrolproducts.com/pdfs/nema17-stepper-motor-42mm.pdf )

i will try up to 1.5 volts.
thanks you.


2014년 8월 7일 목요일 오전 12시 43분 20초 UTC+9, aceguns1 님의 말:

[Jetguy]

NO, man, you guys really need to read a data sheet properly.

The motor rating of 2.8 volts has NO BEARING on the answer of what voltage to adjust the Vref which sets CURRENT AKA AMPS output to the motor.

The motor is rated at 1.86 Amps per the data sheet you linked.

Look, I know you didn't know but when you guys haul off and make such a bad assumption, you are going to cause more problems than you solve. If you crank up Vref too high, you will heat both the motor and the driver chip potentially causing the driver chip to go into thermal shutdown or just flat out burn up. Do it right or don't do it at all.

That is the target current AKA AMPS level you want to tell the driver to put out. If you then read the datasheet on the driver chip, then you would know you also need to read the value of current sensing resistors on the mainboard and then the datasheet give you a formula how to calculate what Vref should be to tell the driver to output 1.68A or less (and we should use less because MAX may heat the motor too much.).

[min....@googlemail.com]

Thanks for your Opinion. But I did not write Let's use the maximum value(2.8V).
I wrote that i will try to 1.5V. What was (my) bad assumption?

i use now 0.2 nozzle. and it needs more Torque in low speed. As aceguns1 said, 1.5 volts is in the acceptable range. isn't it?


2015년 2월 28일 토요일 오전 9시 45분 4초 UTC+9, Jetguy 님의 말:

[Hugues]

Hi,

I tweak my voltage to 1.6 without error during long print. The standard was 1.1 from cubify but it's not enought to push filament higher than 1.7 diameter.

[Jetguy]

2.8 V has nothing to do with this. It's NOT the correct max spec. You do know the motor is being fed 15V directly from the PSU through the drive chip right?

Heaven forbid we should educate ourselves here.

Go ahead, just try whatever value you want, because you obviously have no clue how that relates to rated current for the motor.

For those of you who want to learn, the motors are all rated at 1.68 A. I don't have the resistor value handy on the board but the datasheet for the driver gives the formula.

Simply work back from the desired set current of 1.68A, plug the resistor value into the equation, and then you would know what the proper max Vref is. Then you can willy nilly adjust to some value below that spec or right at the spec.

Or, you guys can keep flying blind in the dark adn just adjust to some arbitrary value because someone said it was OK. Look, Even the document from 3D systems is just a "suggested" value with no math to back it up.

file:///C:/Users/vbarry/Downloads/CUBEX%20Measuring%20Stepper%20motor%20chip%20voltages.pdf Given that Y motors are the same physical motors- in theory 1.6V Vref is safe- however, we still have no idea where that actually is percentage wise of comparison to rated motor current specification VS driver output current regulation based on the Vref value.

Here is the driver data sheet http://www.allegromicro.com/~/media/Files/Datasheets/A3979-Datasheet.ashx

Per the data sheet, the formula is 

The maximum value of current limiting is set by the selection of RS and the voltage at the VREF input with a transconductance function approximated by: ITRIPmax = VREF/8RS

RS is the resistor values. By looking at the board, we see the giant current sensing resistors near the chip are marked R100 http://www.mouser.com/ProductDetail/IRC-TT-Electronics/LR2512LF-01-R100-F/?qs=8k2Nf0ft%252bwguafT9kteOCg%3D%3D basically we know they are precision 0.1 Ohm resistors.

So using the equation again, our target is max allowable current of 1.68 Amps per the data sheet for the motor.

We know we have 0.1 Ohm current sensing resistors. 8 times RS is 0.8 

Basically, whatever Vref is voltage wise, times 0.8 (8 times 0.1 Ohms) = output current.

1.6V vref times 0.8 = 1.28A

This is why I wanted you to do the math and understand what is logical here.

1.6V is a safe V ref voltage, but it's ALSO not the max Vref voltage that equated to maximum rated torque for the motor.

In order to reach rated torque, YOU MUST feed the motor with rated 1.68A of current.

In other words, given the motor spec, given the data sheet, and given the resistor populated on the board, in order to get maximum torque out of the motor, you can set the Vref as high at 2.1V

2.1V times the RS factor of 0.8= 1.68A

A quick check if 1.68A is max, and 1.28A is a setpoint, then that only equates to 76% of maximum rated torque.

See, isn't it better to actually KNOW and calculate rather than go off what somebody posted that they used???

Again, for you, I would go somewhere between 1.7V to 2.1 volt with the understanding, the closer you go to 2.1, the hotter both the driver and the motor will get. The driver has a flan blowing right on it- the motor does not.

[Hugues]

Hi Jetguy,

You're right about everything, i just tried completely blindless...but keeping in mind the 1.68v value.

Thanks for this precious help, and i really like your sailfish cubex. Is it hard to convert it like you did ?
I'm tired of non acceleration feature compared to open firmware...