Rambo controlled heated chamber

[Xenocrates]

I looked at how heated chambers have been managed in the past, and didn't exactly like the way that they used external controllers. I would prefer to use something which I can just select a file and let it run. As I know I can redefine pins, such as adding a heater for a hotend without a stepper, and all rambos have 4 thermistor inputs (of which I am using one, since I have a PT100 for my hotend), and yet lack a 3rd extruder stepper port, it would only be logical to try putting the chamber heater control on the Rambo. As I had a relay designed to switch wall voltage, and it would accept the signal voltage from the Rambo, I figured there's nothing to lose trying it. I'm rather busy recently, so I'll be testing it over an extended period. But I figured I'd get some of the info out there, and let people know if there are problems.

So without further ado, a picture of the abomination thus far:

Spoiler:

[img]http://i.imgur.com/6yPpksi.jpg[/img]

I'll keep this thread updated with progress and problems. And before anyone asks, yes, that is a 400W infrared bulb. I am aware it's huge and may cause issues. I will be testing it pointed at a spare piece of polycarbonate before I install it. If it's too large or powerful, I am debating between other smaller heat lamps, and one of the ceramic IR emitters. If it works, then I have successfully managed to make the chamber heater more powerful than anything short of a 24V bed. Should solve my bed temperature issues, and low ambient temps.

[teoman]

400w is indeed a lot of power.

From what I read in this forum, the max temp inside should not exceed 50degs C. Or the other components go soft.

I cannot remember what the arms were made out of but the old carriages have acetal wheels which go soft with temperature and if you have long pauses with chamber heated then you can end up with flat spots on the wheels.

Pc is relatively higher temp material compared to what you have on the printer.

With a lamp at full blast you could be generating too much localized heat.

Also something to consider is temp differences will create warping.

If you could focus it just on the printed item that would be awesome ( I could not see uour pic on my mobile phone, so not quite sure what you have done).

Good luck.

The rambo controlled heated chamber idea is excellent btw. That way the whole process can be automated.

With additional i/o s you can cool the setup by adding fans to vent the cabin.

I have had success talking to the Rambo over i2c (that way you can connect lots of arduinos to the rambo)and modifying the g-code set of repetier to accept my own M-codes. But did not find time to complete it. I have a very strong fan that could push the parts off the bed so i could remotely print multiple parts. Never did get repetier server to function correctly so i ran out of enthusiasm for the project.

[Xenocrates]

I have not yet gotten a chance to install it in the printer, nor do I plan to before I test it with some printer representative parts, such as poly panels, and the older arms I have. And the nice thing is that due to the way the relay I'm using is designed, I can plug things into the "normally on" side of it, which will switch off when the lamp is going. Or have a small fan running while the lamp is on, to circulate the heated air. My big concern is that as it's an IR primarily source, that the polycarbonate will absorb more heat than the glass filled nylon (which IIRC, is what they use for the arms). And with it being regulated by the rambo, it would have the same time out as extruders before being shut off when idle, and would turn off when not printing. So I shouldn't experience too many flat spots. As an aside, the new carriages also use acetal wheels, but with the mostly closed air gap, I'm less worried about it.

I think my largest concern at the moment though, is if the damned thing will fit in the printer at all.

[Xenocrates]

Tested the 400W light with a scrap bit of lexan, and some old arms. lexan survived 15 minutes continuous exposure at ~4 inchs with only a minor dent where I pushed down to check if it was softening. Arm began to smoke gently after 3 minutes. 1 minute later the surface color began to lighten as bubbles appeared. By two minutes after that, the bubbling had spread across the width of the arm from the focal point, and was about 1.5 inches in length. Structural integrity was compromised and a minimal amount of force on the arm caused irreversible warping. So I bought a 150W ceramic emitter, which should arrive Tuesday. During the limited time I have between now and then, I will work on mounting the relay on the side panel, and de-bugging getting the firmware to talk to it, as well as work on finding a good mounting solution for the chamber thermistor. (I'm thinking of putting it in the hollows on the inside of the Raymond brackets, as it shields it from direct IR heating, and keeps it near the lexan so it can read the re-emitted heat from it)

[Xenocrates]

So, first ceramic bulb failed after about 7 minutes. Started pinging occasionally, and then I noticed a crack in the side of the bulb. So that's going to hold up progress for a bit while I get a refund and pick a new supplier.

[Windshadow]

what about the 50 watt can heaters we use in the e3dv6 hot end block could we take an old cpu heat sink and drill holes in it for a few of them and turn them into little radiators? or is my late evening beer consumption showing

[Xenocrates]

It would probably work, But while I happen to have a pile of CPU heatsinks around, I don't have heater cartridges, or a 12V (or 24V) DC relay laying around. And designing a way to connect the heater cans to the heat pipes (I happen to not have many of the finned block sinks, but more of the aftermarket heat pipe coolers for whatever reason) It would also be somewhat painful to spread the heat from those around without creating a breeze that might warp ABS.

Don't get me wrong, it could be made to work. But being a frugal college student, I'd rather not spend as much for each canned heater as I do for a bulb, while also having to buy new relays and work out some of the kinks. Working out the other kinks in the plan is already nearly too much for my schedule.