upgrade onyx heat bed help

[geofferyrb]

Hi, i have just made my first 3d printer (Rostock Max) that has a 480w power supply and i am hoping someone can direct me to a post that explains how to upgrade the onyx heating bed. Right now i am maxing out at 95c and am looking to reach 120c. any help greatly appreciated.

[lordbinky]

If you have any fans in the base, cover the circular hole in the base underneath the center of the onyx.

The simplest ways to achieve higher temperatures are to insulate the bed, adding a glass plate to the onyx should get you to 110 easily although slowly. Beyond the new limit the glass plate allows you, you'll have to either insulate the bottom of the onyx and maybe get a bit more, or get a 24V power supply for the bed.

[lordbinky]

Oh, and making sure the wires to your bed are of the correct number and gauge as the manual states is important. Bigger/more wires can make a noticeable difference for the onyx, just keep it reasonable and avoid poor connections and wires that get in the way of the melamine snowflake under the onyx sitting properly. I had to cut out a chunk of the snowflake for it to sit correctly because of the onyx connections.

[geofferyrb]

I did fallow the guide for the wires, (I used the supplied wires, four 12 gage if I remember) I put a piece of paper under the heat bed but it only raised the temp to 103 degrees Celsius after 15min and that with a 1/8 inch glass on the top of the onyx bed.

I should state that the reason why I am trying to get the heat on the bed is because i am trying to get abs to not warp.

I think I would like to try the 24v power supply method.

[lordbinky]

Hair sprays with polymers works really well on glass as well as UHU glue sticks. I can get away with no warping on glass with hairspray at 60°C for parts without heavy infilled bases otherwise I need to bump it to 80°C.

[geofferyrb]

Thanks for the advice, I will try that. What temp are you extruding your ABS at? I am using 230C.

[edward]

Blinky gives good advice. Ensure there are no drafts or airflows to start. The next check would be the EEPROM bed PID max value (or somthing like that - NOT the drive max). Make sure it is set to 255 or else you won't be outputting full power to the onyx. With the stock setup you should have no trouble reaching 120 after a long warm-up, but I can't agree that you need to.

Try the spray or glue for low temps, or get some Kapton tape and you'll be fine around 100-105. If you *need* 24V with just the onyx and the glass, something is seriously wrong.

[dsnettleton]

My wife came up with a pretty simple solution for drafts, as long as you're making a smaller print.
I posted it in the mods and upgrades section a while back.
http://forum.seemecnc.com/viewtopic.php?f=35&t=2499
Pay careful attention to the caveats. You don't want your cheapskate bearings crashing into the wall!

[edward]

I remember seeing this. You should take the credit

My next major mod is going to be an enclosure using some lexan. I essentially want to make doors for each of the three sides to keep the temperature more favorable.

[geneb]

You might find it easier to find a diameter of Sonotube that will cover the machine and then just make a curved acrylic door that you can put in the side of it.

g.

[edward]

I like that idea. Right now it's just a thought. Like you I have things that I need to use my printer for these days rather than continually upgrading it

[dsnettleton]

You might find it easier to find a diameter of Sonotube that will cover the machine and then just make a curved acrylic door that you can put in the side of it.

g.

That's the sort of solution I was looking for until my wife pointed out the foam board. I find it much more elegant, though not, in fact, easier.

[Jimustanguitar]

Like you I have things that I need to use my printer for these days rather than continually upgrading it

I'm stuck in that rut... (sorry this is off topic). I bought even more parts at the Ft Wayne Maker Faire...


The heated bed is pretty much the only thing that I haven't upgraded. I'll have to try the paper trick and taping the air holes shut.

[edward]

You could do even better by putting some sort of insulator across the entire back (bottom) of the Onyx. That is, do what you can to allow the heat to only go up, into the build surface.

[dsnettleton]

Like you I have things that I need to use my printer for these days rather than continually upgrading it

I'm stuck in that rut... (sorry this is off topic). I bought even more parts at the Ft Wayne Maker Faire...


The heated bed is pretty much the only thing that I haven't upgraded. I'll have to try the paper trick and taping the air holes shut.

Further off-topic. I was at the Ft. Wayne Maker's Fair too! And I also picked up some new parts. My wife bought me the tricklaser arms for my birthday. Can't wait to hook those babies up!

I don't remember seeing Mugato there, so I didn't recognize you... I'm one to talk... Mayhaps I should change my avatar.

[geofferyrb]

Thanks for the tip about the hair spray. It took care of the warping. dose anyone know of a good source for accuracy printing? right now i am trying to print a bolt and nut and get the threads to work. right now my bolts threads look round and the nut dose not fit. i have tried moving the layer thickness down to .05mm and have slowed the travel rate to 15mm/s. i have also been playing with the diameter of the thred in slecer (i measured it first, but i was off, so now i am trying to find tune it through experimentation.)

on another note, i now have this problem right before a job starts were the hotend will heat up within a fraction of the print temp, and stay there, causing the job to not start. if i block the air flow of the fan it will reach the print temp, but as you can imagine, this is annoying. dose anyone know of a quick fix? or should i calibrate the hotend?

[Jimustanguitar]

You should definitely do the PID autotune procedure outlined in the manual. It's also a good idea to calibrate the thermistor using a meter with a thermocouple or something like that. You can also use the boil/ice trick with water.

In my opinion, you're going to tweak the set temps to your liking anyway, so it's a little less critical to calibrate with a thermocouple (it's probably correct withing 5-10 degrees if left untouched), but the PID autotune is important to your print quality. Getting that setting right keeps your temps stable while the machine is running.

[626Pilot]

It sounds like you need to calibrate your extruder steps per millimeter. There is a procedure for this in the stickied calibration thread. The way I do it is to remove the Bowden tube from the hot end, use side cutters to cut the filament so that it's exactly even with the end of the tube, then extrude 10 millimeters. I cut that with the same side cutters right at the end of the tube. Then, I hold the filament down on a table and use my calipers to measure it. If it comes out as 9.5 mm (for example) I would multiply the existing extruder steps per millimeter by (10/9.5).

The existing EEPROM setting for steps/mm is really just a starting point... you have to perform this step or it'll never be right. You can get away without doing it for prints where the tolerances don't matter, but if you want to print pieces that are supposed to fit together it's vital.

I'd also recommend trying for a layer height of 0.2mm until you have it properly calibrated. Then you can try 0.1. A layer height of 0.05 is quite aggressive. I wouldn't try that until you have more success, and I'm not sure if it's even wise given that at some point you will run into the resolution limits of the steppers.

[edward]

I'd also recommend trying for a layer height of 0.2mm until you have it properly calibrated. Then you can try 0.1. A layer height of 0.05 is quite aggressive. I wouldn't try that until you have more success, and I'm not sure if it's even wise given that at some point you will run into the resolution limits of the steppers.

You should be ok down to pretty insane layer heights. The (Cartesian) Z-resolution of a standard MAX is 0.125 mm (1/80 steps/mm = 0.0125 mm/step). Yeah, yeah, the delta kinematics are non-linear so this isn't a 1:1 correct comparison, but at 0.05 mm the mechanism shouldn't get in your way. You're going to have a hell of a time getting that first layer uniform, though.

That said, you're correct about the layer height issues. For a new user (OP admitted it!) a layer height that small is only going to be a source of frustrations. The detail level you can obtain at 0.2 is pretty fantastic, and if you're on the stock 0.5 mm nozzle, even that is starting to push it.