Broken ribbon… again… I think

Topics around mechanical design, controller and electronics. Mods & hacks welcome.
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Re: Broken ribbon… again… I think

Postby Jetguy » Tue Feb 06, 2018 3:36 pm

This made this cable is meaningless the two resistors are on the side of Extruder

No, this is a misunderstanding. This mounts to the mainboard location inside the electronics bay.
This cable uses locking connectors and the cable is not in flexing situation where it is likely to fatigue and fail.
Again, this device plugs in and mounts directly to the mainboard in/near the base of the machine. It has a short locking ribbon cable with locks at both ends to ensure it cannot easily become unplugged at the mainboard side (the critical side so the mainboard can detect a cable fault). The much longer ribbon cable that goes all the way to the extruder head is what is failing- either from the fact it does not have a locking connector at the extruder head breakout or that it fails from flexing. Because this device is mounted as close as possible to the mainboard, has locking connectors that help ensure security, the location and mounting of it is in a no flex and non stressed location (electronics bay) and even then, they went the extra mile and put a locking socket connector so the existing long ribbon cable to the extruder head now locks to this device. The only further improvement to really be made is a new extruder head breakout board that had the same style locking socket connector.

This is one of the few alternatives to:
Replacing entire mainboard just to add 2 resistors
Having folks send back mainboards to be modified with 2 onboard resistors.
making folks buy entire new mainboards and installing them

Or the ultra impractical- have folks send entire printers back for retrofit.

Again, I even suggested this as one possible way to address this in my own discussions of the problem. Understanding that many folks are not willing or able to modify the mainboard to add 2 simple resistors. So it's either a plug in module to existing mainboards (exactly what this is and attention to details with locking connectors does meet my minimum requirements and guidelines to actually implement safety) or send mainboards back for modification, or replace entire mainboards, or the ultra crazy recall and ship entire printers back and forth for retrofit.
Of all the options, this is easily installed by a user, does provide real safety for the problem, is obviously supported by the company and designed by them.
Last edited by Jetguy on Tue Feb 20, 2018 8:06 pm, edited 3 times in total.

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Re: Broken ribbon… again… I think

Postby Jetguy » Tue Feb 06, 2018 4:33 pm

Again, to make it clear, on one hand, I am happy that Raise 3D engineering saw the problem, saw my suggestions and testing and produced a fix that absolutely I think is a good thing.

What is still bad is that there is a huge silence on even admitting why this was created (the fact there is a limitation and that the lack of cable failure detection can be a serious issue). People are not being told a stock machine has this problem. Then Raise 3D bundled this critical fix with an unrelated item in the store. So they are charging you to fix a limitation in the electronics. Again, if you are a user and owner of this machine, you should not have to jump though hoops and buy a $89 kit with a filament sensor that you may or may not care about to solve a rather much more serious underlying issue that can and does affect printing and can sure as heck confuse users and even tech support. This is the worst of all problems to have. A cable fault that can happen, does happen, and yet the ways to detect and find and properly validate the fault and it's intermittent nature are a huge problem. I cannot stress enough, the nature of this fault is such that when it happens, there is no serial log event. There is no change in reported temperature as recorded in the serial log. So to the firmware, the printer is doing exactly as expected. This absolutely could be why that print the other day failed. You have no idea if you have ever had this fault unless you actually install this device or perform the mod. If you do that- the guessing is no more. If even for a second with this mod there is any break in the connection your printer will report an error, shut down the heater faster than you can blink, and will stop the print in a way that if you can fix the error you can resume the print.

Again, why this matters.
Every other printer on the market has protection against a failed temperature sensor. This is because again, every single 3D printer made has to have wires that go to the moving extruder and as a part of that, either wiring or cable connectors or both can and do fail. Because the mainboard is controlling the heater, it is absolutely imperative that temp sensor fault is immediately detected because if not, the heater can be in and uncontrolled state.
We thought that Raise 3D had implemented all possible safety. What was found was that there is a hole in that safety logic that a cable fault is ONLY detected upon a power on sequence after having been completely off. So if you leave your printer on, if this fault happens mid print, if you don't turn off your printer all the way after a suspected fault and turn back on again, the firmware and serial log may never catch this. Further, if it's an intermittent fault that only happens when the cable flexes a certain way, either pulling on the connector up there with no locks to the extruder head breakout or flexing break in the wires of the cable only happens in a certain spot- likely right in the middle or maybe extreme of print area absolutely can fail and not be detected. It can cause print failures from either overheating or the heater cooling off during the time period where the cable connection is broken. Again, the way the system is made stock, without this modification there are absolutely real world and actual events have happened here to fellow users where this fault is not detected.

I don't wish ill will against Raise 3D, I would hope I would never find such a situation.

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Re: Broken ribbon… again… I think

Postby Squenz » Tue Feb 06, 2018 7:56 pm

Jetguy, i'm fully with you. This ribbon cable is obviously a safety concern and shouldn't be adressed by R3D as they handle it right now.

If we'd talk about a car, NHTSA in US would make R3D come up with a recall to retrofit all their products. Same goes for european countries and i'm quite sure everywhere in the world exist similiar institutions.

After all what i read, as an certified electrician ... this will be my answer if i feel the ribbon cabel starts failing on me or if i got some spare time. ... 8880EN.pdf

I admit, laying this cable up correctly in these kind of connectors will be a sort of a hassle, or probably even a pita, but i'll be doing it only one time in the life of my machine and forget it soon after i have it done.

Maybe someone higher up at R3D acknowledes this, now public known safety issue, and starts to act like a pro (think Takata air bags/GM main switchs/VW Diesel disaster and whatnot else we heard about) and have his engineers come up with a better solution, not only to adress this, but to come up with a solution that not only makes the machines safe but also gives the customer a trustful feeling about his machine and the company they come from. I mean, finding a company who fabs up one meter of such a cable and mount two connectors in a larger scale would cost what ? 10, maybe 15 USD if that at all. Since the customer is basically the service guy and most likely take things in their own hand for one or another reason, there's no extra cost than administration and shipping and handling involved.

I even tend to believe, sending out those cables should be near a freebie, customers pay the outbound shipping or just pack it up with an order of spare parts or filament. As i wrote some postings above, this stupid wire strap on the N1 went away on my machine within a week, not only because it's scraching on the lid, but also because the of the worthless rubber band clamps and the abused, folded up ribbon cable in the wire hose. The cable chain used on the N2 is a much better solution, but the ribbon cable is NOT made made for this kind of movement and it will fail.

EL Cuajinais
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Re: Broken ribbon… again… I think

Postby EL Cuajinais » Wed Feb 21, 2018 4:28 am

Hey everyone. Just getting back into printing with my kickstarter N2. Is the new cable better than soldering the 2 resistors or is it the same? Are there instructions somewhere showing where to solder the resistors? (and the value of the resistors?)

While I'm at it should I upgrade the firmware on main board and LCD screen? I read someone is having issues with the latests firmware. Everything seems to be working fine with the software I had more than a year ago.

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Re: Broken ribbon… again… I think

Postby Jetguy » Wed Feb 21, 2018 12:52 pm

Raise3 just put this on the front page of the home website.
Reserve Your Thermal-Protector Now
Complimentary Pre-Orders for the Thermal-Protector, designed for N-Series printers. Click here to learn more about the benefits.

Free protector.jpg

Free protector2.jpg

It's all up to you how you want to handle this. For me I wanted the protection right away as every day I ran without protection I was unhappy and since I came up with the idea, I had to test it with long term reliability tests.
They both do the same thing.
IMO, the board fix is the "best way", but at the same time, caries the risk of you modifying the mainboard and doing it properly. Not everyone can solder, not everyone knows basic electronics. You have to unplug all the wires, remove the mainboard, solder 2 resistors to the backside of the ribbon cable connector, and then plug it all back in properly. You don't have to do any firmware changes or upgrades, it's just "built in failsafe". It means in the simplest of terms, the circuit now in failure is in a controlled safe mode VS the previous unsafe undetected failure state. Again, for me, I am the owner, operator, and maintainer of my printer, I am responsible for safe operation, my warranty is long up, I know electronics and can solder. In the end, it means the mod cost me pennies and I have absolute confidence in my printer knowing now that in the event of a failure, it will warn me, stop the print, save the event in a serial log, and lastly, allow me to resume the print after a repair and correction of the fault.

This is where the plug in solution fills that gap. The immediate problem is having to wait for it - pre-order of a March? shipping date
Again, the idea that this now free device (Thanks Raise3D for addressing this!!!!) simply plugs and locks in at the mainboard in-between your existing ribbon cable and the mainboard. For mod users, this is the "recommended" fix since it is now free and sanctioned by Raise3d.

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Re: Broken ribbon… again… I think

Postby Noren » Sun Mar 18, 2018 3:21 pm

Vicky@Raise3D wrote: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.

Have attached images if there the brake was this time. I did some delicate surgery and it looks like the whole strand hade a complete break.

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Re: Broken ribbon… again… I think

Postby Vicky@Raise3D » Mon Mar 19, 2018 7:25 am

Thanks a lot for your pictures. Will share with our engineers to analysis.

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Re: Broken ribbon… again… I think

Postby Noren » Mon Mar 19, 2018 7:29 am

The solution that I would like to see. And several has talked about this as well. Is that you could offer a plastic cable chain to be retrofitted to the N1. That would stop the rubbing against the lid. And remove some stress on the cable. That and replacing the ribbon cable with a braided cable seams to be the recommendation from several online.

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Re: Broken ribbon… again… I think

Postby NewbPilot » Mon Mar 19, 2018 3:53 pm

awolf wrote: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?

My N1 cable broke mid last year. The support team sent me a new one, and it fixed the issue. They were supposed to break down (with photos) how to re-route the cable (after removing the broken one). Unfortunately, I never received this. So, I've got my cable snaking out the bottom of the N1 and up the back and am using a Zip-Tie to connect it the the tube and up into the extruder. Ugly, but it works.


(ignore the green piece, that was something my son designed because the tube falls out of the back of the N1, and the print head hits it. So he designed that and it works perfectly.)

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