Hot end can't go above ~160'c anymore :(

So, I have been printing in PLA for months. No problems.

I tried switching to ABS 220'c without using the Heated bed.

Got some pretty crappy trial prints.

Tried out the heated bed, and it seems to work fine, none of the problems other people have, though I only take it to 80'c.

I try printing with the heat bed at 80'c and the print head at 220'c and the print head drops temperature.

Frustrated as I cant figure out why, I switch back to PLA and still my print head wont hold temp at 190'c.

I do some fault finding and discover I can hold about 150'c all day but anything above 160'c and the print head stops heating and drops to room temp.

Dick around for a while to reset the printer before i can get the hot end to heat after each fail.

So, either what causes this or how do I fix it.

 

Do you have the newer hot end with the four pin Molex connector for the heater and thermistor? I recall posts where Robo support confirmed that some of these have poor crimps that can go open, possibly when the temperature rises. When it is in the 150C state can you jiggle that connector to see if the temperature starts to rise. Try not to burn yourself though .

The other possibility is with the polyfuse on the RAMPS board tripping. Although I think it is usually the bed heater fuse that trips, not the hot end fuse. Did you notice if the bed temperature dropped when the hot end temperature dropped? Do you have a cooling fan on the RAMPS board?

 

You should use the technical support contact on the robo 3d main page. Sounds like you have electronics issue that may or may not require replacement, but Jerry will help get you squared away.

 

I have the older style i believe. No molex connectors in sight on the hot end wiring anyway.

The bed kept temperature. I am happy to try and agitate the connectors. Where are these? I assume they are hidden in the cable shielding between board and hot end?

Yeas tried adding a fan but no change.

I will post in official support as well.

 

Yes then you have the older one which has no connector on the hot end side. I think there are two solder joints a few inches inside the wiring harness with heat shrink around them. I doubt an intermittent solder joint in there could cause it to max out at 150C. Makes no sense. That would have to be a strange failure in the thermistor path to cause it to consistently max out there.

Note that Mike suggested to log a support request at http://www.robo3dprinter.com/pages/technical-support. I don't know if a forum support post is looked at as often.

 

Thanks. But yeah as part of an open community all discussion should be placed in both areas. I have asked for official support but when stuff goes nope, you usually search the forum for simple fixes before bothering the creators.

 

Sorry, I'm confused. No one said don't post this in the open forum. I pointed you there because I am out of ideas. I would always suggest that if support helps (or not) that you post the results for everyone. (So they can use the wonderful search engine on this site .)

 

Perhaps the confusion is that I said "forum support post" by which I meant the private technical support are of this forum. In the past that private area was not looked at by the support team that often. This may have changed recently but they used to push formal support requests to the link Mark gave http://www.robo3dprinter.com/pages/technical-support.

 

Well you didn't build a prusa or a mendal, you bought a robo 3d. It comes with a warranty for a reason and if there's complex electrical issues that they may just fix with a simple replacement wouldn't it be worth everyones time to use both avenues at the same time? They've been tremendously helpful for me in situations where I'd troubleshooted the issue to completion and needed a replacement.

 

Hmmm, some off topic confusion, but,
I believe I need to ask the community first as when most problems occour, (which are common to all of our robo 3d printers), it seems the community is both aware and has a fix for it.

No need to bother the team if they are answering the same question for the 100th time.
Until such time as there exists an official 'known issues and fixes page/thread/guide/email etc' I will always give the community time to review my problems first.

I have created both threads, (here and private trouble shooting), and used the 'contact for support' part of the website.

I just jumped to the second thread and support bit quicker than i usually would as MK has some blue writing under his name which looks important, so i did what he says.

 

Pox, to me it sounds like your issue is a faulty Polyswitch on the RAMPS 1.4 board. http://reprap.org/wiki/RAMPS_1.4

The one you're looking at is the MFR500. I blew mine and it behaved similarly to yours where it would cut off at unexpected temperatures. You'll know it's bad because generally the top will have split open and/or the orange coating will turn reddish.

If you're skilled at repairing circuitry you can probably troubleshoot it on your own. But if your printer is relatively new then getting a replacement part will be far simpler and require less troubleshooting steps.

 

Same thing happened to me on a brand new robo3D just now, failed more and more frequently in midprint until now I can't get power at all. have ordered a new polyswitch, hopefully it solves the problem.

 

If it's new you should have robo3d send you a new one

 

Ye, they told me to dismantle the ramps board and send it back to them (which would take weeks in my case) or try to install new polyswitch. Just installed another polyswitch now and it seems to have solved the problem for me.

 

Good deal

 

Installed new polyswitches but problem persists, power cuts on Arduino board after 30 min/1 hour. I then changed the polys out with bigger ones (12A bed/ 8A nozzle). Same result. I then removed both polyswitches and installed simple car fuses in separate box instead. Thought I had fixed the problem but no! after hours of hours of troubleshooting i found the problem to be a bad connection in the power output port for the heat element (nozzle) at the Arduino board. Power was cut when I applied a lite touch on the screw with a screwdriver. So I suppose I´ll have to dismantle my board and send it back, will take months but I don't think I have any other options at this point.

 

Good point, I´ll order one straight away