Thermals and the Rambo

[n9wxu]

I have been fighting layers moving over like a stepper is loosing a few steps. The problem seemed to get better if I run a fast fan directly on the stepper controllers. At the suggestion of a friend with another Rostock Max I bumped the currents from 175 to 195 this seemed to help some but the steps did come back. So I brought home a thermal camera and it has told the complete story.

Note the Extruder stepper controller is at 127C.
The Z axis stepper is at 121C (different picture not attached).
The fan dropped the temperatures to 81C but it is moving LOTS of air (a heat gun in cool mode). The QFN package is not very thermally efficient. It relies upon the copper on the PCB for heat extraction. This copper is not that great especially when each controller has about 1 sq in of area before the adjacent controller's copper starts.

I have ordered these : http://www.amazon.com/dp/B004CLDIHK/ref ... 1_ST1_dp_1" onclick="window.open(this.href);return false; heatsinks. They will go on the stepper drivers and the heater MOSFETS. I measured the bed heater at 91C. MOSFETS are generally not an issue at these temperatures but the stepper controller will start to reduce it's drive strength as part of its thermal protection.

[int2str]

Very cool! (no pun intended)
Would love a FLIR camera!

[geneb]

SCIENCE! It works, bitches.



g.

[bubbasnow]

i want

[Eaglezsoar]

i want

I want too! Must be nice. We are all scrimping to buy a thermocouple meter and he shows up with a Flir! AND I AM JEALOUS!

[GarageBay9]

I have encountered this issue on my Max with long prints as well. I suspect that it is primarily an issue with people printing ABS and running the Onyx at 90-100c, rather than the much lower levels used for PLA. I have only ever printed ABS in my machine.

Mayhaps this can be integrated into the stock version, or mentioned in the manual? Sounds like it's a potential weakness in the design that's easily fixed.

[n9wxu]

All of my prints so far have been PLA. I am still in the "make a birds nest" phase of 3d printing.
My standard settings seem to be 230C layer 1, 205C other layers, 60C bed. These settings stick to glass. To go colder I must use blue tape.

The heat in the stepper motor drivers has nothing to do with the temperature of the extruder or bed. The heater MOSFETS are at the top of the pictures. The bed is the hottest MOSFET and it is located just under the corner of the 81.0C grey box in the first picture. It is warm but not as bad as the stepper drivers.

Skips start on my machine with the Z tower after about 3 minutes unless I use a high performance fan (no heatsinks). With the good fan, the skips start after 10 minutes.

I estimate that the temperature hits the temperature shutdown limit (165C) within seconds of power up even with a good fan but no heatsink.

[n9wxu]

The small MOSFET heatsinks previously linked arrived and dropped my peak temperatures 20C.
With a 60mm fan blowing into the equipment bay, the max temperature is below 55C. Quite an improvement.
The FLIR autoscales the colors. In this picture the white color is 52C. It looks like the old pictures but it is better.

[dpmacri]

How did you attach the heat sinks?

[n9wxu]

The heatsinks came with a double sided thermal tape.
This stuck fairly well but it would have helped to clean the drivers with alcohol. There are extra thermal tape squares provided in case you must remove and restick the sinks.

[dpmacri]

Cool, thanks! I went ahead and ordered a set because I started having some stepper skipping when I enabled a second print head.

[foshon]

I have used the Antec ceramic non-conductive epoxy to glue these on since my Gen7. Be warned it is as permanent of a mounting solution that is out there. Works fabulous, chip heat worries are null and void. I added a fan to the door of the MAX just because I had one laying around. Never needed it.

[brbubba]

I have used the Antec ceramic non-conductive epoxy to glue these on since my Gen7. Be warned it is as permanent of a mounting solution that is out there. Works fabulous, chip heat worries are null and void. I added a fan to the door of the MAX just because I had one laying around. Never needed it.

I think non-conductive is key in this type of application. I've ruined some, thankfully cheap, equipment with arctic silver epoxy. Once it goes on there's no taking it off again to see if you did it wrong.

[Eaglezsoar]

I have used the Antec ceramic non-conductive epoxy to glue these on since my Gen7. Be warned it is as permanent of a mounting solution that is out there. Works fabulous, chip heat worries are null and void. I added a fan to the door of the MAX just because I had one laying around. Never needed it.

I think non-conductive is key in this type of application. I've ruined some, thankfully cheap, equipment with arctic silver epoxy. Once it goes on there's no taking it off again to see if you did it wrong.

Most people use far too much epoxy and it squishes out and makes a mess. You only need a tiny amount of the stuff on each heatsink.

[brbubba]

I have used the Antec ceramic non-conductive epoxy to glue these on since my Gen7. Be warned it is as permanent of a mounting solution that is out there. Works fabulous, chip heat worries are null and void. I added a fan to the door of the MAX just because I had one laying around. Never needed it.

I think non-conductive is key in this type of application. I've ruined some, thankfully cheap, equipment with arctic silver epoxy. Once it goes on there's no taking it off again to see if you did it wrong.

Most people use far too much epoxy and it squishes out and makes a mess. You only need a tiny amount of the stuff on each heatsink.

You also run the risk of using too little with something this small. Tis better to just get the non-conductive stuff and not worry about destroying your electronics, the performance is almost identical anyway. I did get the heatsink kit and ended up just using the included thermal pads, they seem to working just fine. If they fall off I'll bust out the adhesive.