Broken ribbon… again… I think

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Noren
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Broken ribbon… again… I think

Postby Noren » Sat Jan 20, 2018 9:31 pm

My ribbon cable on my N1 has failed me again. Twice in a year. :(
Today my printer stopped in the far right corner.
The printer said Error 00. Extruder switched off. Mintemp triggered.
Could replicate the error in the exakt same place. Every time. So at first I didn't think it was a bad cable. It was to consequent.
But after checking every connection to see if anything was loose, I located the error to there the ribbon cable and other cables comes out of the cable fastener on the print head.
It is possible that it isn't the ribbon cable. Rather that it is the cable to the extruder motor. I don't know until i loosen the cable fastener and check each cable.

Anyone else that had problem with this?
Or have any suggestions on how to remedy it in the future?
The fastener is sitting really tight. There is really little movement of the end so I don't se exactly why it should break here. It isn't pinched or anything like that. (The last fail of the ribbon cable was at the top of the cable there the bend is rubbing against the top cover. The ribbon cable was really badly installed and folded and twisted. And it had visible breaks).

I did notice though that the plastic filament tubes are pushing against the backside of the print head. And push on the cables on the back. So thats the most likely culprit. And it was in that position that the error was replicated, when the plastic tubes push on the cables from the back.

The circle indicates were I think the break in the cable is located.
And the arrow shows there the plastic filament tubes press against the cables when the print head is in the far right back.
IMG_5113.JPG

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Vicky@Raise3D
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Re: Broken ribbon… again… I think

Postby Vicky@Raise3D » Mon Jan 22, 2018 10:49 am

Sounds like poor connection of ribbon cable with extruder baord.
Hot melts may help.

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Noren
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Re: Broken ribbon… again… I think

Postby Noren » Mon Jan 22, 2018 10:53 am

I took apart the cable "tube".
And the break in the cable were not there i first thought. But rather once again at the top of the bend, there the cables rub against the top cover. Although the outmost care were taken last time i replaced it, it had a kink at that place. And bending the cable in that place triggers the error. Will replace the cable once again.

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Noren
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Re: Broken ribbon… again… I think

Postby Noren » Sat Jan 27, 2018 7:22 pm

Vicky@Raise3D wrote:Sounds like poor connection of ribbon cable with extruder baord.
Hot melts may help.


I replaced the ribbon cable and located the break. Once again it was at the top of the cable tube at the very top of the printer. :(.

I don’t know if the plastic tube is to stiff. Or if it is because it rubs against the top cover. Or just bad luck. It would be nice if the printer could have a system diagnosis test and could tell what part of the printer is at fault.

Squenz
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Re: Broken ribbon… again… I think

Postby Squenz » Sat Jan 27, 2018 9:18 pm

One can't really bend a ribbon cable, there's one way to change direction, that would be folding it at a 90° angle carefully and give the bend area at least a 4mm radius. I carefully made a 90° curve this way and 'curled up' the remainder when i was mounting the bondtech. Not perfect, but works good for me.

The other option, and this is what i would consider with the second cable failing, carefully pull the ribbon apart, seperate each single wire so that the ribbon isn't a ribbon in this area anymore. The ribbon doesn't need to be in shape anymore after the connectors have been fitted. The handlig of single wires is far more easy than trying to get the ribbon where it's needs to be. But you need to be carefull, these wires can't take much of abuse before their strands break or insulation is comprimised, and any excessive force should be avoided.

After you've done the leg work, bring in some special electrical tape which was used at the stock ribbon cable to keep temps in order, like this ...https://www.aliexpress.com/item/19mm-15 ... 76448.html

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Noren
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Re: Broken ribbon… again… I think

Postby Noren » Sat Jan 27, 2018 9:27 pm

Thanks for he tips. I have wrapped it in that kind of tape. But the stock one didn’t have that on mine.

Squenz
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Re: Broken ribbon… again… I think

Postby Squenz » Sat Jan 27, 2018 9:39 pm

Uh, mine does have this tape. It's on the last 10 cm's, but ends about 2 cm before the connector. I felt good about having it near high temp area.

btw, i did away with this nerving wire shield hose about a week after i received the printer and fitted a cable chain. Two aluminum brackets and about 50 cm of 28mm cable chain and you're good to go.

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Noren
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Re: Broken ribbon… again… I think

Postby Noren » Sat Jan 27, 2018 10:05 pm

Squenz wrote:Uh, mine does have this tape. It's on the last 10 cm's, but ends about 2 cm before the connector. I felt good about having it near high temp area.

btw, i did away with this nerving wire shield hose about a week after i received the printer and fitted a cable chain. Two aluminum brackets and about 50 cm of 28mm cable chain and you're good to go.


Could you post some pictures of the setup with the cable chain?

Squenz
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Re: Broken ribbon… again… I think

Postby Squenz » Sat Jan 27, 2018 10:43 pm

Here we go...
Attachments
IMG_20180127_233850.jpg
IMG_20180127_233922.jpg
IMG_20180127_233941.jpg
IMG_20180127_234006.jpg
IMG_20180127_234016.jpg

Jetguy
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Re: Broken ribbon… again… I think

Postby Jetguy » Sat Jan 27, 2018 11:27 pm

"It would be nice if the printer could have a system diagnosis test and could tell what part of the printer is at fault."
It does already have this in code, but I tried to warn the group several times, unless you perform the mainboard mod or buy the new "safety" board, a ribbon cable fault is NOT detected in operation. The only time it can detect the fault is starting up from a cold start of no power.

That's why I made such a stink in the other thread about the bundling of the safety board (that does the same thing as adding the 2 resistors to the mainboard). Resistor mod discussion viewtopic.php?f=4&t=3524&p=18990&hilit=resistor+mod#p18989

You can buy the off the shelf plug in fix from Raise 3D, but it's currently bundled with the filament sensor mod https://www.raise3d.com/collections/acc ... ent-sensor The issue is, you are paying $89 to get a safety mod you really should get for free or a really low cost to us owners. The mod of 2 resistors is about $1 on it's worst day if you had to buy a pack of resistor and beg a friend to solder it for you. Not everyone is willing to solder the mainboard, I get that. The alternative is the plug in system but that does mean that you folks need to start asking for this and putting pressure to sell it separately.

Again this part "fixes" this exact detection failure.
thermal-protector_filament-runout-sensor.jpg

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Noren
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Re: Broken ribbon… again… I think

Postby Noren » Sat Jan 27, 2018 11:44 pm

Thanks for the picture and the information. :)

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Vicky@Raise3D
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Re: Broken ribbon… again… I think

Postby Vicky@Raise3D » Mon Jan 29, 2018 2:17 am

Noren wrote:
Vicky@Raise3D wrote:Sounds like poor connection of ribbon cable with extruder baord.
Hot melts may help.


I replaced the ribbon cable and located the break. Once again it was at the top of the cable tube at the very top of the printer. :(.

I don’t know if the plastic tube is to stiff. Or if it is because it rubs against the top cover. Or just bad luck. It would be nice if the printer could have a system diagnosis test and could tell what part of the printer is at fault.


May I ask a picture of the broken point of the ribbon cable? So that I can ask our engineers to pay attention also on our side.

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awolf
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Re: Broken ribbon… again… I think

Postby awolf » Thu Feb 01, 2018 12:23 am

After a few days of trying to figure out why we were getting intermittent problems on our N2 Plus (fans turning off, filament jamming, etc.) we realized that the problem was in the main cable. My assumption was that a connector was loose, so I pulled the main connector (that is held on with white elastomer) and the 3 pin connector, and made sure they were replaced tightly. The issue still exists, at least based on watching the fans—we can move the head on the XY axes and watch the fan cut in and out, or leave the head stationary, and turn the fans on and off by flexing the cable. I didn't want to think that it was a broken cable, as this seems an odd failure for a machine with only a few hundred hours printing on it. But—does this happen? Is there a visible sign of the break? (Should I open the chain to get the cable out?)

I have a ticket started, based on what we had as an initial problem (prints needing to be stopped after a few hours in, when the filament was no longer running through); but I'm pretty certain that the issue is with the fans (and possibly other parts) cutting on and off depending on the cable flex. There was mention in this thread about a unit generated report that could be sent in, which sounds like it would tell if there were communication breaks like this. How does one get that report to send in?

Behold
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Re: Broken ribbon… again… I think

Postby Behold » Mon Feb 05, 2018 5:32 pm

I want to make sure this is correct... the filament run out sensor is that "safety board"?! @jetguy was talking about?

Jetguy
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Re: Broken ribbon… again… I think

Postby Jetguy » Mon Feb 05, 2018 6:17 pm

No, they are bundling 2 totally separate devices but they bundled them as one product. They assume that if you are going to print for a long period of time then the safety board makes sense and then also filament runout detection. That is the complaint, the safety modification board/cable set should be something flat out given to anyone not willing to make the safety mainboard mod. It should be a recall. Barring that, they should be selling separate, telling you newer users why you need it.

Again, someone at Raise 3D understands this fault, enough so, they made a product that is based on work I gave to the group.
The issue is, tech support is doing a poor job of telling you users about it. You'd think they would be trying to sell it and help you.

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Re: Broken ribbon… again… I think

Postby Jetguy » Mon Feb 05, 2018 8:49 pm

So from the marketing page https://www.raise3d.com/collections/acc ... ent-sensor

While this is a bundle, there are 2 totally separate and not exactly related parts here.
THIS is the filament out detector
filament_runout_sensor_02_1024x1024.png


In this picture included in the bundle that really should not be a bundle is this.
thermal-protector_filament-runout-sensor.jpg


While both will plug into the mainboard, they are NOT plugged together or related in any way.
The filament detector just detects if filament is in the middle of the that sensor. That's all it does. If turned on and printing and that sensor detects no filament, it pauses the print.

The OTHER safety board is a totally different story. It plugs in at the mainboard and the ribbon cable then plugs into it.
It's purpose in life is to correct a safety limitation of the mainboard in that it cannot detect when the ribbon cable is broken or unplugged mid print.

Again, let's really get to the crux on this.
Cables can and will fail. You can say all you want that it should be engineered better, but across every brand of 3D printers for the last 10 years, there is one thing in common and that is cables that flex (and since the extruder must have cables to it and when it moves, they flex over and over and eventually will wear out or fail).
The second part is, that locking connectors should be used on all cables- especially ones that flex. The ribbon cable to extruder head breakout that is carrying the super critical temperature reporting information of the hotends does NOT use a locking connector as currently supplied on all raise 3D N series printers. There are details that are printer version specific on cable routing, but all of these printers are subject to both flex failing of the ribbon cable and unplugging of the connector at the extruder head breakout.
The third part that makes this a problem is that the cable fault may not be detected mid print. This is where this goes from an annoying failure to outright dangerous failure. This is due to an overall architecture design of both the mainboard and the extruder head breakout board. Again, the issue is that at the very most basic logic level of just reading the voltage on these pins, if the cable comes unplugged or broken wire connection mid print, the mainboard still thinks it got a valid temp report. No firmware update can fix this hardware failure to detect a fault. What this means is that mid print, if you have an intermittent connection in this critical cable, that OBTW has no locking connectors, and flexes every time the extruder moves, the firmware may go trough periods of time where it has NO idea the actual temp of the extruder heaters. However, it is still able to power those heaters and turn them on based on the simple logic of what is the reported temp (which in failure is the last temp read) is that higher or lower than setpoint? That in turn determines the power sent to the heater. This is why we see BOTH types of failure. If at the time of the break in connection, if the heater was 2 degrees below setpoint or even one degree, the firmware thinks it should be heating up trying to reach the setpoint. However, over time, since it is not getting a feedback of the rising actual temp of the heater, it just keeps on heating well past the desired setpoint. The other way it happens is then say it connects for a second and gets this now too hot temp report. That stays and keeps reporting it's higher than the setpoint thus turning off the heater. But the cable is broken or not connected. So the real temp is dropping like a rock, the firmware thinks all is normal and you are near the setpoint and you eventually get a jam because the extruder cooled off.

And here is where the user can get confused and very frustrated. You turn off the printer or reboot and suddenly you may or may not have a bootup failure for mintemp. This all depends on if the extruder is moved to a point where the wires flex or the connector makes contact again or not on bootup. Power on from completely off is the ONLY time that a ribbon cable fault is detected. This is because the system starts up from off with no voltage. If the cable is not connected then it never gets that first voltage signal for a valid temp across the cable. However, if the cable is flexed just right, or the connector is just barely making contact- then the firmware boots thinking all is OK so you start a print.

Again, it's all about failure detection. The system can and will detect if the thermocouples are disconnected from the extruder head breakout. This is because the onboard chips that read the thermocouple on the tiny extruder head breakout board constantly check the thermocouple. Again, if that connection breaks it is detected. But if the ribbon cable between the 2 boards breaks connection, that is NOT detected mid print.

So that is what the safety board is all about. That board and locking cable set plugs directly into the mainboard for the ribbon cable. Then the ribbon cable going up to the extruder then plugs into the locking connector on that board. Basically it puts the device inline in the circuit. The idea is that since this DOES have locking connectors, is installed at the mainboard where it does not flex or bend or vibrate, the device has a low chance of breaking connection to the mainboard and as said before, this is because the mainboard cannot sense the loss of connection by itself. However, that device changes the circuit and the isntant the cable to the extruder head breakout fails in any way, now a maximum temp voltage is sent to the mainboard and read by the firmware. That does 2 important things. #1 it instantly turns off the heater output because reported temp is way higher than set temp. Even if no other safety code invoked, by the shear nature of what that function does it fails safe. The second part is, by exceeding the maximum safe reported temp, the system knows there is a fault and stops the print. Rather than like before dragging on and still trying to print, now in a fault, we have a proper function and stop.

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Re: Broken ribbon… again… I think

Postby Jetguy » Mon Feb 05, 2018 9:01 pm

Again, this board and cable set will plug into the mainboard here.
2016-07-07_21-28-56.jpg



You can even see the silkscreen marking when you zoom in. "To Extruder" is again, where the ribbon cable going to the extruder plugs in. The other end with the short ribbon cable connects to the mainboard "To P1 Connector"
markings.jpg
markings.jpg (18.68 KiB) Viewed 985 times

Behold
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Re: Broken ribbon… again… I think

Postby Behold » Mon Feb 05, 2018 10:34 pm

Thank you. I appreciate your response

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awolf
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Re: Broken ribbon… again… I think

Postby awolf » Mon Feb 05, 2018 11:42 pm

My N2 Plus is back in business, with a replacement cable that is currently running outside the umbilical. (Want to see a day plus print work before going in and re-routing it.) Is there any posted information of replacing the cables?

I was also sent a replacement control board, and may replace that, but truly don't think that's the issue.

Mouser has a replacement flat cable, mil-spec, that is possibly overkill for this; but 10 feet is $40, plus connectors and a crimp tool. This is very tempting to me; if this cable is prone to failure then getting one that is of higher engineered standards makes a lot of sense.

Jetguy—thanks for your well written explanation. I've already ordered 2 of the upgrades, mainly for the filament run out, but now that I understand the cable notification, this makes the package more worthwhile, and I agree with your acessment regarding being charged for it.

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Re: Broken ribbon… again… I think

Postby Stanislav » Tue Feb 06, 2018 3:23 pm

Jetguy wrote:

You can even see the silkscreen marking when you zoom in. "To Extruder" is again, where the ribbon cable going to the extruder plugs in. The other end with the short ribbon cable connects to the mainboard "To P1 Connector"
markings.jpg
Image

Jetguy I want to ask something
This made this cable is meaningless the two resistors are on the side of Extruder '' WHY '' the idea is that the resistors are independent of the cable and so they become part of the problem cable.
If cable break in the field of resistors, the protection will not work
Fix me if I'm wrong
Stanislav

there is always a smarter man than you


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