Shenanigans, and Modifications

[Mac The Knife]

And so it's begun.

I've drilled and tapped the heater block for a 3mm setscrew to hold a 6 x 15mm heater cartridge in place. I turned down a 1/4" aluminum round bar to slide into the heater block, so I could drill and tap without worrying about the drill walking, or the tap breaking.
While I'm waiting on a 6 x 15 mm heater to get here, I've cut down a 20mm heater to mock things up.

Also in the works, is to form a heatshield to place between the heat break, and circuit board. A friend did suggest using gold foil heat reflector tape,,, http://www.thermalcontrolproducts.com/o ... gold-foil/

I was debating putting a plug on the heater cartridge, but with a setscrew holding the cartridge in place, there shouldn't be a need for it.
And yes, I plan on positioning the heater block as shown, 180 degrees from the stock position. In the stock position, the heater is pretty close to being under the accelerometer,

[U.S. Water Rockets]

This is for an Eris?

Looks like the new hot end in the photos, but an RMAX in the background.

[Mac The Knife]

This is for an Eris?

Looks like the new hot end in the photos, but an RMAX in the background.

Yes, for my Eris.

[Mac The Knife]

The bottom of a Coke can should do the trick, It's already concave, and thicker then the foil they use for disposable pie pans. Drill a 4mm hole, and then cut out a 1" diameter disc, off center of the hole about an 1/8th of an inch. you will have to notch it to clear the power leads for the heater.

[geneb]

Why on earth replace the heating resistor?

g.

[Qdeathstar]

gene, as much as I understand the safety aspect of the resistor, a common theme on the forums is that they fail. Just because you can expertly put them in so they do not fail doesn't mean that for the ROW, a heating element is more reliable, until it catches fire and metals a hole into the center of the earth.

[Mac The Knife]

Why on earth replace the heating resistor?

g.

It cooked my board. When they solder the resistor, it is applied to the topside of the board. The traces that provide the power to the resistor is on the bottom of the board. By the time auto cal developed Alzheimers, there was no evidence of solder on the bottom, and the resistor was loose in the heater block. If I had the temp set at 240, the thermistor registered 230. Of course, all of this is discovered after the problems developed.

Today I fired up the new board, with a 40 watt cartridge, wired to the board with silicone jacketed,16 GA multi strand wire, and added a heat shield between the heatbreak, and the pc board. It auto calibrated like a champ, and after doing a PID tune, held 250C rock steady.

Overkill? Maybe, but I've also done alot of electric radio controlled car racing. cars and a little boat racing. You can't win a race if you don't finish.

[Mac The Knife]

Oh, and the resistor was designed to limit current, not to melt plastic. It was a hack that got the job done, and would fail if it got to hot. A heating cartidge was designed to transfer heat, and does so rather well,,,,,, in fact with the Eris heat block, you don't have to wrap aluminum foil around the cartridge, as you show us in your YouTube video. They drilled a 6mm hole.

[Mac The Knife]

Bartender!! Another drink!!!

[Xenocrates]

So tempted to create a sock-puppet account named bartender (Or barkeep) just to post "no, get your own damned drink"

But I'm mostly with Mac here, although I understand why Seeme did what they did (What with part-daddy wanting to make sure the resistor fails before the hotend does, while a cartridge won't fail before then if it gets stuck)

[Jetguy]

I hate to say it but I also already saw failure and overheating the PCB at the solder joints which oxidized quickly from the heat. I literally saw drops of solder drip to the bed surface and knew where it came from.

I don't want to go off the deep end on the resistor debate but certainly, we can have a sensible discussion about the termination method.

For example, the same basic resistors use crimped connections, not solder on the Rostock and I assume the same for Orion, where this direct solder the resistor lead to the PCB, even with silver solder is just not a great idea. I get it, for manufacturing, and keeping cost down, yes, on paper this seems fine. Reality in the field is a different story altogether and if it starts costing you entire replacement effector/hotend systems, the savings went out the window.

My fix (and I'm not saying it's a good idea or anyone should copy), was to cut some 5.08 spacing screw terminal blocks to remove the plastic housing, then desoldered the stock resistor, silver soldered (high temp) the bare metal screw terminals, then inserted the resistor through them to make the connection. Not all screw terminals are suited. I found these at Radioshack that have a solid pin and block that makes up the terminal.

[geneb]

The solder evaporation is a pretty serious issue that needs to be looked into. Had all my brain cells been firing in sequence, I would've twigged to that right away.

I'm not going to wade into the resistor vs cartridge debate any more. You guys are adults and know why the choice was made.

g.

[Mac The Knife]

The solder evaporation is a pretty serious issue that needs to be looked into. Had all my brain cells been firing in sequence, I would've twigged to that right away.

I'm not going to wade into the resistor vs cartridge debate any more. You guys are adults and know why the choice was made.

g.

We have video evidence of you replacing a resistor with a heating cartridge,,,,,,

Any hoo, the 40 watt, cut down from 20mm to 15mm cartridge is still chugging along, and with a smart contoller installed, I can monitor the extruder temperature, and it's rock steady. I have way more wire then I need,,,, but they are warm when printing at 240C.

Also, with the smart controller hooked up, In the advanced menu it shows an option for "Full Calibration"? I tried it, and it didn't go well. apparently it fires up the heater, and that ain't good to do with the Eris.
Attached are some pics,,,

[Mac The Knife]

A previous Shenanigan, with the stock hotend, on a my Max V2,,, well stock except for two, 40 watt heaters, and a ceramic heat break. That blue stuff is weed eater line,,,, nylon.

[Qdeathstar]

yikes.


are you going to be able to salvage that?

[Mac The Knife]

It's all clean,,, took 6 hours. Here's a link http://forum.seemecnc.com/viewtopic.php ... lon#p48077

[JATMN]

Please share your changes in more detail. I see quite the modifications on that head and some reason I get the idea your not done.

Also where did you get shorter heater cart?

[Mac The Knife]

Please share your changes in more detail. I see quite the modifications on that head and some reason I get the idea your not done.

Also where did you get shorter heater cart?

Well first with the heater cartridge. I had ordered a 12 volt, 30 watt, 6 x 15mm heater from Amazon. What arrived was 6 x 20mm heater. When I contacted the seller, they replied back that I could either return it, or cut 5mm off the end. Well, I ordered another one off of Ebay,,,,, from a seller in China. And I got impatient and figured I'd at least cut it to use as a mock up. I have a mini chop saw from Harbor Freight. That is not the tool to use. Destroyed the heater. Since I had a few extra 40 watt heaters, I tried again, only with a Dremel and a cut off wheel. Carefully cutting just the case. That one is still presently working.

The Heater block. The only mod, as I wrote earlier, was to drill and tap a hole for a setscrew to hold the heater in. It also wedges the heater towards the nozzle. I also added a little heatsink compound. I turned the heater block 180 degrees because in the stock position, it is just under the accelerometer chip. The heatshield I placed in between the heatbreak and the board I made from the bottom of a soda can. Basically I cut a 1 inch diameter disc out the bottom, and drilled a 4mm hole about an 1/8th of an inch off center. A little tweaking, and nibbling was required to miss any thing it might short to, because the hotend is not elctricaly isolated from the other circuits.

The wire I used was some 16ga silicon jacketed wire to hook up brushless motors in 12th scale RC cars. I had to open the hole up a little with a 1/16th inch drill bit. To get the wire through the holes without fraying out, you apply solder to the end of the wire before you trim back the jacket. The solder wicks in, and keeps the wire together. Having a good, hot iron, with a small tip helps. I removed the brass butt connectors, and connected the 16ga wire to them with a blue butt connector I had cut in half,,, overlapping the wires before I crimped them. Then wrapped the connection with the high temp silicone tape. I did end up with more wire than I needed.

I used a screw in thermistor, but instead of wiring it directly into the board like the original, I soldered the plug end on the topside, feeding the wires through a notch I cut in the blower shroud. I had issues with the fan wires also,,, they kept getting pinched, so I rerouted them also. Ugly, but I pinched them good once,,,, not again.

If you look closely at the picture with it installed and operating, You may be able to see where I cut some slots between every other fin on the heatsink. The heatsink was bored out to 8mm for the liner kwik connect, and it leaves a dead airspace inside between the heatsink and the liner. When I started printing with PetG, It would eventually stop extruding, and when I tore it apart, there was an 1/8th inch gap between the liner, and the heatbreak. The first time I thought it was from not installing it correctly, and I didn't pay attention to how the liner looked a little zig-zaggy at the end. When it happened again, I then assumed that since I'm printing at a higher temperature, the dead airspace wasgetting warm enough to soften the liner, allowing the retracts to pull it out of the heatbreak. Once I ventilated it, I haven't had that problem again.


Once I reset the PID for the heater, It heats up way faster, and maintains a steady temperature where it is set. Monitoring the temps with the LCD display, There was a 10 degree difference in what was called for, and what was being shown by the thermistor.

84 meters of filament through it, and it's still going.

[themitch22]

I turned the heater block 180 degrees because in the stock position, it is just under the accelerometer chip.

Do you think the heat from the hot-end could have caused the calibration issues JATMN and myself had. I'm getting a replacement effector assembly sent to me from support, I might try this mod with my original hotend and board and try to see if there's any solder issues like mentioned. I don't know why there's not a heatsheild between the hotend and the board, that sounds like a failure point.

[Mac The Knife]

I was hoping someone else would have chimed in,, But yes, I think it needs to have some sort of heatshielding. The heatsink is going to do its best to suck the heat away from the board where the heatbreak goes through, but that doesn't do anything for the heat radiating from the hotend itself.

For the past week, I have not had any problems, other then a wire leading to the heater cartridge breaking cuz I made it to long, and it was hitting a bed retainer clip.

[Mac The Knife]

I received my assembled hotend from SeeMeCNC yesterday, and I noticed two changes that they have made since the first batch of printers went out. First, they extended the length of the leads for the resistor, and Second, they are now installing the fan wires on the top of the board, instead of the bottom.

I bought this one to see if my problems with the autolevel not working correctly was a faulty accelerometer, or something else going on inside the printer. Other then wrapping the heater block with high temp silicone tape, and sealing the blower duct with 1/4" wide pinstriping tape, I'll be leaving this one alone, and wait for more spare parts to show up on their website to rebuild the modified one. For now I'll just print with PLA instead of the PetG.

[Mac The Knife]

Oh, and I did add a little more solder to the resistor leads.